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Document name Project Coordination,Path Rating and
Progress Report Processes
Category ()Regional Reliability Standard
()Regional Criteria
()Policy
(X)Guideline
()Report or other
()Charter
Document date October 15,2015
Adoptedlapproved by Planning Coordination Committee
Date adoptedlapproved October 15,2015
Custodian (entity Planning Coordination Committee
responsible for
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upkeep)
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Categorization%20Files/Guidelines/Pro¡ect Coo
rdination Path Ratinq and Proqress Report
Processes.pdf
Previous namelnumber Project Coordination and Path Rating
Processes
Status (X)in effect
()usable,minor formattinglediting required
()modification needed
()superseded by
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()obsoletelarchived)
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WE CC
Project Coordination,Path Rating
and Progress Report Processes
Western Electricity Coordinating Council
Revised October 15,2015
Project Coordination and Path Rating Processes Page 3 of 121
Table of Contents by Section
Project Coordination and Path Rating Processes...................................................4
Project Coord ination Process .................................................................................16
Path Ra tin gP rocess.................................................................................................24
WECC Progress Report Policies and Procedures...............................................112
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Project Coordination and Path Rating Processes
Table of Contents
1.Introduction...........................................................................................................5
2.Process Outline ....................................................................................................6
3.The Project Coord inat ion Process ......................................................................7
4.Path Rating Process.............................................................................................7
5.P rogress Re port....................................................................................................8
Attach ment A -Definitions ....................................................................................12
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Project Coordination and Path Rating Processes
1.Introduction
This Project Coordination and Path Rating Processes document addresses the
followingpurposes:
1.Provide procedures for WECC members and others to report on planned projects
and to work togetherto expand the Western Interconnection's capacity according to
member and stakeholder needs.
2.Provide an opportunity to recognize regional transmission planning conducted by the
Transmission Expansion Planning Policy Committee (TEPPC)and others.
3.Provide project sponsors with an industry-agreed upon procedure that,when
completed,could potentiallybe used to help demonstrate that coordinated planning
has been performed for proposed projects,as may be required to obtain required
regulatory approvals.
4.Provide the policies and procedures for notification and reliability assessment
requirements related to projects planned within the Western Interconnection.
5.Provide agreed upon methods applicableto the rating of transmission facilities.
6.Promote the reliable and coordinated integration of existingand new projects so that
the use of the system is maximized for all participants.
The Planning Coordination Committee (PCC)has the responsibility for oversightand
review of the Project Coordination and Path Rating Processes.1 All steps outlined in this
document are considered voluntaryunless explicitlyidentified as a requirement.During
all processes described in this document,the Project sponsors retain sole responsibility
for ensuring its compliance with NERC ReliabilityStandards and WECC Criteria.
1 TEPPC has oversight and review of the Regional Planning Process.Regional Planning is defined in the
TEPPC Protocol document.
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These Policies and Procedures are comprised of three WECC processes:
1.Project Coordination Process
Facilitates informing others of the opportunity to participate in or review a project and
solicits participation.It is intended to avoid duplication of projects and to allow a new
project to integrate the needs of other WECC member(s)by mutual agreement.
2.Path Rating Process
Provides new projects being integrated into the system with a Path rating,while
recognizing protected ratings of other Paths.
3.Progress Reports Policies and Procedures
Requires reports from project sponsors regarding potentialsignificant additions and
changes to the Western Interconnection.WECC members are provided the
opportunity to review and comment on these additions or changes.
While these processes function separately,for significant projects these processes are
interrelated and support each other.For example,the Progress Reports process is used
for reporting on all projects and also supportscompletion of reporting on project
coordination and Path rating for significant projects.
2.Process Outline
The policies,guidelines,Project Coordination Process,scenario examples,and study
methodologypresented in this document are intended to provide guidance to members
on the process of coordinating and placing a project in service as well as to outline
member responsibilities with regard to this process.Specifically,this document has
been developedto establish the following:
1.Procedures for reviewing project conformity with WECC's role for project
coordination;
2.Guidelines to demonstrate that regional needs and efficiencies are considered;
3.A process for project coordination (who does what,when,etc.)that is well
understood,consistent,and predictable and is accepted as standard practice in the
Western Interconnection;
4.Consistent methods for determining and demonstratingPath ratings based on
performance requirements in the NERC Reliability Standards and WECC Criteria;
5.Accepted Ratings that have been reviewed by the WECC membership;
6.A process for negotiationsto resolve capacity allocation issues between parties;
and;
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7.Means for resolving disputesover capacity allocation issues that is consistent and
effective,should negotiationsfail.
The sequence of Project Coordination and Path Rating Processes that the project
sponsor normally should follow are shown in Figure 1
3.The Project Coordination Process
The Project Coordination Process encompasses the initial developmentphase of a
significant transmission project.2 The process addresses how transmission project
sponsors should work and interact with other parties when developinga project that has
or may have a significant regional benefit or impact.Through this process,WECC
members cooperate to identify transmission expansionprojects that may be beneficial
to the region.By followingthis process,project sponsors might also address certain
issues related to regulatory approvalof their projects.
The Project Coordination Process should begin as soon as possible and involve all
interested project participants.Althoughit will vary,this phase of the process should
start when interested project participants are developingtheir individual and collective
transmission needs.This phase is completedwhen the PCC has made a final
determination regarding the project's conformity with the Project Coordination Review
Objectives.
4.Path Rating Process
The purpose of the Path Rating Process is to provide a formal process for project
sponsors to attain an -Accepted Rating and demonstrate how their Project will meet
NERC ReliabilityStandards and WECC Criteria.This three-phaseprocess addresses
planned new facility additions and upgrades,or the re-rating of existing facilities.It
requires coordination through a review group comprised of the project sponsors and
representativesof other systems that may be affected by the project.Section 1.2 of the
Path Rating Process explainswhich projects must undergo the three-phaserating
process.
2 A significant transmission project is defined as 200 kV and above (for transformer banks the operating
voltage refers to the low side of the transformer bank)unless granted a waiver by the PCC chair based
on the two criteria below and in accordance with the process outlined in Subsection 4 of the Project
Coordination Process:
1.The purpose of the transmission project is to serve local load.
2.The transmission project does not have a significant impact on the operation of the Western
Interconnection.
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At the completion of this process,an Accepted Rating may be granted by WECC that
affords the project sponsor some protection against erosion of established capacity of
this facility when further expansionof the Interconnection is proposed or new limitations
are discovered.
The Path Rating Process is divided into three separate phases.
Phase 1 is conducted by the project sponsor and is initiated when the project sponsor
submits a report through the WECC Progress Report Process or when a formal letter of
notification is provided to the PCC and Technical Studies Subcommittee (TSS).During
Phase 1,the project sponsor conducts sufficient studies to demonstrate the proposed
non-simultaneous rating of the Path associated with the Project and prepares a
ComprehensiveProgress Report documentingstudy results and describing Project
details including a preliminary Plan of Service.Known simultaneous relationships
should also be addressed in the ComprehensiveProgress Report.In general,the
acceptance of the ComprehensiveProgress Reportsignals the completion of Phase 1,
at which time the Path associated with the Project is granted a Planned Rating.
Phase 23 enCOmpasses a review of the Project's Plan of Service by a Project Review
Group (PRG)that is comprised of interested WECC members.During this phase,the
Project's Planned Rating is validated.In addition,the simultaneous Transfer Capability
effects and the impact of the Project on neighboring transmission systemsare further
assessed.The project sponsor and the PRG must document all the studies and findings
in the ProjectReview Group Phase 2 RatingReport.Phase 2 is completedwhen the
Phase 2 Rating Report is accepted and the Path associated with the Project is granted
an "Accepted Rating."
Phase 3 is the last part of the Path Rating Process.Phase 3 is a monitoring phase
where majorchanges in assumptionsand conditions are evaluated to assure the
"Accepted Rating"is maintained.Phase 3 is completed when the Project is placed into
service.
5.Progress Report
The WECC Progress ReportPolicies and Procedures provide comprehensivedirection
regarding requirements for notification and reliability assessment related to projects
planned within the Western Interconnection.The intent of this document is to provide
direction for all generation and transmission projects that may have a significant impact
3 Phase 2 consists of Phase 2A and Phase 2B.Completion of Phase 2 requires completion of both
Phases 2A and 2B.Please refer to Section 5 of the Path Rating Process for more detailed description
of Phases 2A and 2B.
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on the reliability of the Western Interconnection.All projects subjectto the procedures
are required to adhere to the WECC Progress Report Policies and Procedures.
Projects subjectto these WECC Progress Report Policies and Procedures include:(1)
generation projects 200 MW or greater connected to the transmission system through
step-up transformers,(2)all new and upgraded transmission facilities with voltagelevels
over 200 kV,and (3)any facilities that may have a significant impact on the reliability of
the Western Interconnection.The term "generation projects"includes,but is not limited
to:new generation plants,generation repower,or upgrades that may significantly alter
the operation of the generation facilities.The term "transmission projects"includes,but
is not limited to:new transmission facilities,transmission re-designs or upgrades,
permanentremoval of existing transmission facilities,or other changes that may
significantly alter the operation of the transmission facilities (e.g.,operating procedures).
In general,these WECC Progress Report Policies and Procedures require the following
to be submitted and/or completedduring the planning of a project.
Initial Progress Report
ComprehensiveProgress Report
SupplementalProgress Report
Review of Progress Reports By All TSS members
Informal Reports Presented At TSS meetings
A Path Rating Report is optional because it is required only if a project sponsor desires
an Accepted Rating.
A ComprehensiveProgress Report can be used to fulfill the requirement of a Path
Rating Reportonly if no comments were received on the ComprehensiveProgress
Report from the WECC membershipand no WECC member desires to form a PRG
(see Section on Expediting the Process).
Approvedby Planning Coordination Committee July 15,2014
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Figure 1
Sequenceof Project Coordination and Path Rating Processes
Project Phases Formation Studies Licensing Construction
Project Coordination Assessment,Project ReviewProcess
Phase 1 Phase 2A Phase 2B Phase 3PathRatingProcessProposedRatingPlannedRatingAcceptedRating
Progress Reports Progress Reports Are Required Throughoutthe Entire Planning Process
Notes:
1."Proposed Rating"-used at the initiation and throughoutPhase 1 of the Path Rating Process.
2."Planned Rating"-final rating at the conclusion of Phase 1 of the Path Rating Process and used throughout
Phase 2 of the Path Rating Process.Phase 2 consists of Phase 2A and Phase 2B.Completionof Phase 2 requires
completionof both Phases 2A and 2B.Please refer to Section 5 of the Path Rating Process for more detailed
description of Phases 2A and 2B.
3."Accepted Rating"-final rating granted at the conclusion of Phase 2 of the Path Rating Process and is also the
rating that is used when the Project is placed in-service.
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Attachment A
Definitions
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Attachment A -Definitions
Accepted Rating -a Path rating that has been reviewed and accepted by WECC
members.This rating is granted by WECC at the conclusion of reviewed planning
studies and will be the rating of the Path associated with the Project when it is put in
service if it is built in accordance with Plan of Service specified in the Phase 2 Rating
Report.This is a comprehensiverating including both Simultaneous and Non-
simultaneous Transfer Capabilities.
Adversely-Impacted Transfer Capability -the reduction of either the Simultaneous or
Non-simultaneous Transfer Capability.A new project causes a significant and verifiable
adverse impact that needs to be mitigated if it reduces the Transfer Capability of a rated
Path in a Benchmark Case comparison.
Benchmark Case -a case that models the existing system (including appropriate
recognition of other projects in the Rating Process)in the timeframe of the new project
and shows the maximum Transfer Capabilities (e.g.,the Existing or Accepted Rating)of
existing Paths that may interact with the new project.
Capability -the maximum load that a generator,turbine,transmission circuit,
apparatus,station,or system can supply under specified conditions for a given time
interval,without exceeding approvedlimits of temperatureand stress.
Capacity -synonymous with capability.
Comparison Cases -cases with the new Project showing range of desired operation
of new project and illustrating whether there are impacts or interaction with existing
projects.
Existing Rating -transmission Path ratings that were known and used in operation as
of January 1,1994.4 An Existing Rating is for a Path that is defined and included in the
WECC Path Rating Catalog.
Foundational Base Case -the first base case developedby a project sponsor(s)that
would be ready for the first simultaneous assessment as agreed to by the Project
Review Group.This Foundational Base Case must be defined in the Project Review
Group-approvedstudy plan and must include data suitable for conducting dynamic
stability studies.
Latent Capacity -Transfer Capability is considered "latent"when it can be acquired
due to changes in the system conditions or by making transmission equipmentadditions
4 WECC's three-phase Accepted Rating Process was implemented after January 1,1994.
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(e.g.,series or shunt reactive devices,reconductoring or re-tensioning portions of an
existing line or phase shifters,Looping transmission line(s)within a Path into a new or
existing switching station,remedial action schemes (RAS),etc.)on an existing path
without adding new transmission lines to the path.Latent Capacity is not protected
unless the project sponsor(s)completesthe process in this Path Rating Process.
Mitigation Plan -A comprehensivelist of the measures that the Project Sponsor and
Project Review Group believe will be required to address issues found during the Path
Rating studies in order to ensure compliance with NERC ReliabilityStandards and
WECC Criteria,the entity(ies)responsible for managing the issue in Phase 3 and the
expectedtimeframe for completion.
Non-Simultaneous Transfer Capability (or Limit)-The Capability,in megawatts,of a
transmission circuit or path to transfer power reliably and in accordance with prescribed
Reliability Criteria independentof concurrent flows on other circuits or paths.It is
normally determined with all potentiallyinteracting circuits or paths loaded below the
levels at which limitations are observed.
Other Rating -A transmission Path rating,either proposed or planned,that is not an
Accepted or Existing Rating.
Path -In the context of the Path Rating Process,a path is defined as a facility(ies)
between systemsor internal to a system,for which schedules and/or actual flows can
be monitored for reliability purposes.Facilities in a path may originate and terminate at
the same point (substation or generating station)or at different points.Two or more
individual paths can be combined into a single path for rating purposes,althoughthey
may be separate scheduling paths.Paths are often called cutplanes.
Planned Rating -The tentative rating assigned to a Project that is in Phase 2 of the
rating process.
Plan of Service -The completeset of facilities,remedial actions,and operating
procedures proposed by a sponsor for a particular project,togetherwith their in-service
dates.
Project -A Project is defined as a new generatoror transmission facility or a change in
rating of an existing generatoror transmission facility through facility additions,facility
upgrades,facility retirements or the re-rating of existing facilities that would result in a
new Path or changes in existingPath ratings.
Proposed Rating -This is a preliminary rating proposed by a project sponsor.
Rating Process -The three-phaseprocess described in the Path Rating Process.
Reliability Criteria -Western Electricity Coordinating Council Reliability Criteria.
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Similarly-Situated Projects -At any point in time,if any two Projects are togetherin
Phase 2B of the Path Rating Process,they are Similarly Situated and have a
responsibility to mitigate interaction they have with each other until both become
operational.
Simultaneous Transfer Capability (or Limit)-The Capability,in megawatts,of a
transmission circuit or path to transfer power reliably and in accordance with prescribed
Reliability Criteria in concert with other interacting paths,circuits,or generators.It is
normally defined by its interactive relationship in the form of nomograms (parametric
functions)with the flows on other transfer paths or circuits or the outputsof generators.
Subregional Planning Group -a TEPPC-recognized entity that performs planning
within a defined geographical area within the Western Interconnection.
Transmission Expansion Planning Policy Committee (TEPPC)-a Western
Electricity Coordinating Council Board-level committee.
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WE CC
Project Coordination Process
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Project Coordination Process
Table of Contents
1.Introduction and Purpose..................................................................................17
2.Project Coordination Review Objectives..........................................................17
3.WECC Project Coordination Process ...............................................................19
1.Initiating the Process....................................................................................19
2.During the Process ......................................................................................19
3.Completingthe Process...............................................................................20
4.Waiver of "Significant Impact"Status ..............................................................20
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1.Introduction and Purpose
This process identifies how transmission project sponsors should work and interact with
other interested parties when developinga significant transmission project.A significant
transmission project is defined as 200 kV and above6 unless granted a waiver by the
PCC chair based on the two criteria below in accordance with the process outlined in
Subsection 4:
1.The purpose of the transmission project is to serve local load.
2.The transmission project does not have a significant impact on the operation of
the Western Interconnection.
The purpose of the Project Coordination Process is to:
1.Foster the developmentof a broad perspective among all stakeholders in the
project planning process.
2.Promote and encourage a more efficient use and developmentof the region or
subregion'sexisting and future facilities to enhance interconnected-system
operation.
3.Facilitate consideration of all relevant regional or subregional planning issues
during the planning of specific transmission projects.
4.Provide procedures and guidelinesfor coordinated project review.
5.Involve WECC member representatives,member executives,regulators,
existing planning bodies,environmental groups,land-use groups,and other
non-utility interest groups in the process.
6.Allow stakeholders to identify opportunitiesfor improved regional transmission
efficiencies and make recommendations to achieve them.
7.Provide a voluntarydispute resolution procedure.
The PCC has the responsibility for oversightand review of the Project Coordination
Process.
2.Project Coordination Review Objectives
Sponsors of all significant transmission projects are required to prepare a Project
Coordination Report.This report documents how the project sponsor meets four
objectives:
6 For transformer banks,the operating voltage refers to the low side of the transformer bank.
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1.Undertake Integrated Project Evaluation
Take multipleproject needs and plans into account,including identified utilities
and non-utilities'future needs,as well as environmental and other stakeholder
interests.The findings of TEPPC,the Subregional Planning Groups (SPG),or
other analyses may be used to satisfy these requirements.
Identify transmission physical and operationalconstraints resulting from the
project or that are removed by the project.
Look beyond specific end points of the sponsors'project to identify broader
regional and subregional needs or opportunities.
2.Conduct Coordination and Outreach
Cooperate with Project Coordination Review Group members in determining the
benefits and impacts from the project.
Coordinate project plans with and seek input from all interested members,
TEPPC,SPGs,power pools,region-wide planning group(s),and other
stakeholders including utilities,independentpower producers,environmental and
land-use groups,and regulators.
3.Describe Generation Resources and Related Policy Initiatives
Review how the project improvesor impacts efficient use of existing and planned
resources of the region.
Address impacts of project for transmission congestion mitigation.
Describe how the project addresses specific energy policy initiatives.
4.Consider Reasonable Alternatives to the Project
Review the possibility of using the existing system,upgrades,or reasonable
alternatives to the project to meet the need (including non-transmission
alternatives where appropriate).
Address the efficient use of transmission corridors and take rights-of-way,new
projects,optimal line voltage,upgrades,etc.,into account.
Specify how the evaluation of the project has taken into account costs and
benefits of the project compared with reasonable alternatives.
Describe potentiallyaffected or competing projects and consolidate projects
where practicable.
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3.WECC Project Coordination Process
1.Initiating the Process
The sponsor(s)of a project should start the Project Coordination Process when a
project is in the conceptual level of project development.At the earliest possible
time,the project sponsor should notify the PCC,TSS,and TEPPC of the intention to
initiate the Project Coordination Process and the purpose of the project.Notifications
should be made prior to submittal of project data for the WECC Data Collection
Process.If the project sponsor intends to have the project considered in a broader
planning context in TEPPC,the project sponsor should also submit project
information,if available,to WECC staff for inclusion in the WECC Transmission
Projects Portal.
The process may also be initiated by the PCC upon determining that regional
interest has been expressedor at the request of a member.The PCC will maintain a
list of projects under consideration by members that are not yet reported through the
WECC Data Collection Process so that the PCC may determine whether regional
interest has been expressed.
Upon initiation of the review process,the project sponsor shall form a Project
Coordination Review Group (PCRG).The project sponsor shall provide notice of the
formation of the PCRG to all PCC,TSS,and TEPPC members.The project sponsor
shall accept all persons who express a desire to participate in the PCRG as
members.The purpose of the PCRG is to identify opportunitiesto incorporate
multipleinterests and multipleneeds into a single project.To reduce meetingsand
the time frame to completethe Project Coordination Process,a project sponsor may
use TEPPC or a Subregional Planning Group to meet the requirements of Project
Coordination Process in lieu of forming an independentPCRG for the project.A
project sponsor must notify the TSS,PCC,and TEPPC in writing of the forum the
project sponsor plans to use for the Project Coordination Process if an independent
PCRG is not used.TEPPC or the host Subregional Planning Group must agree with
the project sponsor to be a host forum for the Project Coordination Review.
However,the project sponsor is still responsible for all items associated with the
Project Coordination Process,such as sending updates to the TSS and PCC,and
sending reports to the PCC.
2.During the Process
The project sponsor,in coordination with the PCRG or host forum,will prepare a
Project Coordination Report indicating how the project conforms or plans to conform
to each of the Project Coordination Review Objectives.Upon approvalof this report
by the PCRG,the sponsor shall submit this report to the PCC,TSS,and TEPPC.
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The PCC shall review the proposed project relative to the Project Coordination
Review Objectives.The PCC -through the PCRG or host forum -may:
Require that the project sponsor performs additional studies or provides the
sponsor'sown studies to the PCC.
Require the evaluation of alternatives or options that may provide greater
regional benefits.
Upon completion of the PCC's review,the PCC chair will approve the report.During
the review process,the project sponsor remains solelyresponsible for performing
analyses and responding to PCC requests.
3.Completing the Process
Upon approvalof the Project Coordination Report by the PCC,the project sponsor
shall document that it has completedthe WECC Project Coordination Project
Process and has met the four Project Coordination Review Objectivesspecified in
Subsection 2 above.
The project sponsor will submit the Project Coordination Report to the PCC to be
posted for 30-day review and comment on the project's conformity with the Project
Coordination Review Objectives.WECC staff shall notify all WECC members of the
posting.When comments from this review are addressed by the project sponsor,the
project sponsor will notify the PCC chair.The PCC chair will notify the Project
Sponsor as well as the PCC,TSS,and TEPPC of the completion of the Project
Coordination Process.
If a project sponsor does not demonstrate any evidence of activity for a period of 18
months,the project will no longer be considered to be within the Project
Coordination Process.Evidence of activity is demonstrated in the WECC Project
Coordination logs.If no evidence of activity is demonstrated,the project will be
removed from Project Coordination logs and the PCC chair will notify the project
sponsor (if possible)that the project has been removed.The project sponsor can re-
initiate the process as outlined in Subsection 1 above,if desired.
4.Waiver of "Significant Impact"Status
The sponsor(s)of transmission projects with operating voltages6 200 kV and above,and
are not seeking a path rating,may request waivers of the WECC Project Coordination
Process.The request must either provide documentation of how the project is being
coordinated in another forum,or provide an explanationof why the project is not
expectedto have any significant impact to the operation of the WECC interconnected
6 For transformer banks the operating voltage refers to the low side of the transformer bank.
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electric system.Project sponsors can request the waiver according to the following
process:
1.The project sponsor includes a list of projects for which waiver is requested in a
separate section in its Annual Progress Report to the TSS with a copy to WECC
staff.If the request for waiver is needed before the next Annual Progress Report
is to be submitted,the project sponsor submits a request to WECC staff with a
copy to the TSS.
2.The followingproject information shall be included,as a minimum:
a.Project name
b.Project purpose
c.Brief Project description,including expectedtermination points
d.Expected date of release to operations
e.Expected operating voltage
f.Either:
i.Description of how the Project has been coordinated through a
transmission planning forum,such as a Subregional Planning Group
(SPG),the Transmission Expansion Planning Policy Committee (TEPPC),
or another appropriate forum.7 The description should include references
to any transmission studies performed.
OR
ii.Explanationof why the Project is not expected to have a significant impact
on the operation of the WECC interconnected electric system.
The followingquestionsmay be considered in determining whether a
project has significant impact to the WECC interconnected system:
Have studies demonstrated that there are impacts to other systems?
·Is there any impact on flow of energy on other systems?
·Are any WECC transfer paths impacted?
·Is some kind of flow control device needed or required as a part of the
project?
·Is the project connected to other utilities'systems?
·Do disturbances impact other entities?
7 If the project is being coordinated through a transmission planning forum,the sponsor shall provide an
open invitation for participation to all WECC members and other interested stakeholders.
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3.WECC staff posts the list of projects and notifies the PCC,TEPPC,and TSS.
The waiver is granted unless a letter from a WECC member opposing the waiver
is received within 30 days.
4.Any WECC member(s)that believes the project should not be granted a waiver
must submit a letter to the PCC chair with a copy to the project sponsor and
WECC staff within 30 calendar days of the posting of the list.The letter must
outline the reason(s)for not granting the waiver and include a request that the
project proceeds with the Project Coordination Process.
5.WECC staff posts the letter opposing the waiver and notifies the PCC,TEPPC,
and TSS.
6.The PCC chair determines if the waiver will be granted within 20 calendar days of
posting the letter opposing the waiver.If the project sponsor is also the PCC
chair,such determination will be made by the PCC vice chair.
Approvedby Planning Coordination Committee July 15,2014
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WE CC
Path Rating Process
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Path Rating Process
Table of Contents
1.Introduction.........................................................................................................27
2.Policies and Guidelines for Path Rating Review..............................................28
2.1.Objectives....................................................................................................28
2.2.Policies ........................................................................................................28
2.3.Paths Subject To This Procedure ................................................................29
2.4.Protection of Ratings....................................................................................29
2.5.Guidelines....................................................................................................31
3.Path Rating Process ...........................................................................................32
3.1.Objectives....................................................................................................32
3.2.The Rating Process .....................................................................................33
3.3.Expediting the Process ................................................................................42
3.4.Monitoring Project Progress.........................................................................43
3.5.Formation of a WECC Project Review Group ..............................................46
4.Philosophy and Principles For Transmission Path Rating Methods .............51
4.1.Introduction..................................................................................................51
4.2.Philosophy ...................................................................................................51
4.3.Principles .....................................................................................................53
5.Phase 2 Accepted Rating Comprehensive Study Plan....................................57
5.1.Introduction ..................................................................................................57
5.2.Study Objectives..........................................................................................57
5.3.Major Study Assumptionsand System Representation...............................58
5.4.Study Methodology......................................................................................60
5.5.Study Guidelines..........................................................................................63
5.6.Documentation of Study Conclusions ..........................................................66
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6.Process Examples..............................................................................................67
6.1.Expediting the Process --Project with no Comments Received...................67
6.2.Project with Minor Comments ......................................................................68
6.3.ComplexHigh-Impact Project ......................................................................69
6.4.Project With Protest .....................................................................................70
6.5.Rating Determined By Alternative Method ...................................................72
6.6.Similarly Situated Projects ...........................................................................73
7.P rin ci p le Sce narios ............................................................................................74
7.1.Neutralityof Path Definition .........................................................................74
7.2.Reverse Flow...............................................................................................76
7.3.Flow-Limited Ratings -Flow-Limited By Available Resources (Using MFT
Method)........................................................................................................77
7.4.Flow-Limited Ratings -Flow-Limited By Low Impedance Parallel Path ......78
7.5.Accepted Rating Protection -ReliabilityCriteria Violation............................79
7.6.Accepted Rating Protection -ReliabilityCriteria Violation.Acceptable
Reduction in Accepted Rating Caused By Another Party ............................79
7.7.Accepted Rating Protection -ReliabilityCriteria Violation.Retention of
Accepted Rating for Facility Removal by Another Party ..............................81
7.8.Accepted Rating Protection -Failure to Meet Maximum Flow Test (MFT)-
Retention of Accepted Rating as a Result of Changes Made By Another
Party ............................................................................................................82
7.9.Accepted Rating Protection -Failure to Meet Maximum Flow Test (MFT)-
Reduction of Accepted Rating as a Result of Changes Made By Path
Owner/Operator...........................................................................................83
7.10.Accepted Rating Protection -Failure to Meet Maximum Flow Test (MFT)-
Reduction of Accepted Rating as a Result of Changes Made By Both the
Path Owner/Operatorand Other Parties......................................................84
7.11.Accepted Rating Protection -Increase in Accepted Rating Caused By Path
Owner/Operator...........................................................................................86
7.12.Accepted Rating Protection -Increase in Accepted Rating Caused By
Another Party...............................................................................................87
Appendix A:Rating Methods Discussion and Background .................................89
AffectedPathStressLevels.................................................................................89
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Latent Capacity....................................................................................................90
Maximum Flow Test (MFT)..................................................................................91
Flow Test Exemption...........................................................................................93
Fictitious Elements...............................................................................................95
Resource Modeling Assumptions........................................................................96
System Representation........................................................................................97
Delay,Cancellation,or Changes to Resources PotentiallyAffecting Ratings ......98
Appendix B:Simultaneous Studies,Similarly Situated Projects,and Combined
Project Studies .......................................................................................................100
Simultaneous Studies ........................................................................................100
Similarly Situated Projects .................................................................................101
Combined Project Studies .................................................................................101
Appendix C:Phases 1-3 Templates.....................................................................103
Appendix D:Testing Path Independence.............................................................106
Appendix E:Treatment of Projects Sent Back To Earlier Study Phases...........109
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1.Introduction
This document has been developedto establish consistent methods for obtaining
Accepted Rating(s)for transmission facilities through:
·A predictable path rating process (who does what,when,etc.)that is well
understood and is accepted as standard practice in WECC;
Methods for determining and demonstratingratings;
A review by the WECC membership;and
A level field for negotiationsto resolve capacity allocation issues between
parties.
This procedure describes the path rating process project sponsors and participants shall
follow to obtain an Accepted Rating.It is divided into three separate phases and is
meant to mirror the developmentprocess for projects.
Phase 1 is conducted by the project sponsor and is initiated when the project sponsor
submits a report through the WECC Progress Report Policies and Procedures process
or when a formal letter of notification is provided to the PCC and TSS.During Phase 1,
the project sponsor is to conduct sufficient studies to demonstrate the proposed non-
simultaneous rating of the Path associated with the Project.The project sponsor
prepares a ComprehensiveProgress Report documentingstudy results and describing
project details,including a preliminary Plan of Service.
Phase 26 encompasses a review of the Project's Plan of Service by a Project Review
Group (PRG)comprised of WECC members with an interest in the Project.During this
phase,the Planned Rating associated with the Project is validated and the
simultaneous Transfer Capability effects and the impact of the Project on neighboring
transmission systemsare further assessed.The project sponsor and the PRG must
document all the studies and findings in a report called the Project Review Group Phase
2 RatingReport.Phase 2 is completedwhen the Phase 2 Rating Report is accepted
and the Project is granted an "Accepted Rating."
Phase 3 is the last part of the Path Rating Process.Phase 3 is a monitoring phase
where majorchanges in assumptionsand conditions are evaluated to assure the
"Accepted Rating"is maintained.Phase 3 is completedwhen the Project is placed into
service.
6 Phase 2 consists of Phase 2A and Phase 2B.Completion of Phase 2 requires completion of both
Phases 2A and 2B.Please refer to Section 5 of the Path Rating Process for more detailed description
of Phases 2A and 2B.
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The three-phaseprocess is intended to address Path rating due to planned new facility
additions and upgrades or re-rates of existingfacilities that require coordination through
a review group comprised of the project sponsors and other members that may be
affected by the Project.It is recognized that some re-rates of existing transmission
paths or the addition of new facilities will not be of significance to others or may not
require the formation of a review group.If an Accepted Rating is desired,these Projects
can be expeditedthrough the three-phasePath Rating Process described in Section
3.0.
2.Policies and Guidelines for Path Rating Review
Principles for establishinga transfer path "Accepted Rating"are encompassedin the
followingpolicies and guidelines.
2.1.Objectives
The objectivesof the policies and guidelinesare to:
1.Promote the developmentof an efficient,reliable electric transmission
system;
2.Balance the competing interests of protecting the Accepted and Existing
Ratings of existing Paths;and
3.Encourage the economic,reliable,and environmentallysound expansionof
the electric transmission system.
Ratings of existing Paths deserve a degree of protection;however,this should
not discourage needed system expansion.Conversely,system expansionshould
not unfairly penalize existingsystem facilities.
2.2.Policies
To supportthese objectives,WECC has adopted the followingpolicies for rating
transmission Paths.
1.Parties will plan,design,and operate their systemsconsistent with the
following:
·NERC ReliabilityStandards
WECC Criteria
·Project Coordination Process,Path Rating Process,and Progress Reports
Policies and Procedures
2.New facilities and facility modifications should not adverselyimpact Accepted
or Existing Ratings,regardless of whether an Accepted Rating for the path
associated with the new facility or modification is being sought.New or
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modified facilities can include transmission lines,generating plants,
substations,series capacitor stations,remedial action schemes,or any other
facilities affecting the capacity or use of the Western Interconnection.
2.3.Paths Subject To This Procedure
Transmission paths shall completethe Path Rating Process specified in this
document and obtain an Accepted Rating if any of the followingcriteria apply:
1.The limiting condition (e.g.,thermal limit,stability,or voltage)in determining
the Total Transfer Capability of the path or the System Operating Limit for
transmission facilities that impact the path is on another system and the
affected member system requests the path be rated.
2.The path must be operated within the constraints of a nomogram to meet
NERC ReliabilityStandards and WECC Criteria,the elements of the
nomogram (e.g.,path flows or generation levels)are in different systems,and
one of those systemsor a neighboring member system requests the path be
rated.
3.The path owners or operators have requested a seasonal or operational Total
Transfer Capability for a new path or the path owners or operators have
requested a seasonal or operationalTotal Transfer Capability that is in
excess of an existing path'srating (Accepted,Existing,or Other).
4.A facility (generator,series,or shunt reactive equipment;Remedial Action
Scheme;etc.)that an Existing or Accepted Rating dependson is modified or
retired from service,without regard to whether the facility is owned by the
same system as the rated path.
For the purposes of these criteria,transmission dependentutilities,loads,or
generators interconnected exclusivelyto the path operator'ssystem are not
considered other systems.In addition,any Project may seek a Path rating under
the WECC Path Rating Process on a voluntarybasis.
2.4.Protection of Ratings
The protection of ratings encompasses the following:
1.The amount of power that a rated Path can transfer is protected from being
diminished due to subsequentprojects;
9 If the modified RAS is functionally equivalent to the existing RAS and is approved by the RASRS,then
the Path does not need to be rerated.
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2.Protection for a rating is conferred by obtaining an Accepted Rating or by
virtue of having an Existing Rating and is subjectto a benchmarking case
comparison;
3.If the capability of a path was diminished due to new or modified
Transmission or Generation projects (as demonstrated in benchmark
comparison of studies with and without the change)it would constitute an
"impact"to a protected rating that will require mitigation;
4.All WECC members shall activelyparticipate in defining,in advance of
operation,any potential simultaneous transfer limits.The burden of reporting,
modeling,and studying the Project,and of assessing its impact on the
Western Interconnection,will be shared with the sponsors taking the lead and
primary responsibility.Other affected members have the responsibility to
actively participate in the review process;
5.All parties benefit from interconnected-systemoperation.There may be
benefits to interconnected-system operation other than increased Transfer
Capability and these benefits should be appropriately recognized;
6.The WECC process for determining the Accepted Rating of a Path associated
with the Project will:
allow for the review of studies by all potentiallyaffected parties;and
comprehensivelyaddress both simultaneous and non-simultaneous
conditions.
7.Facility ownersloperatorsare responsible for establishingoperating
procedures and notifying the WECC Reliability Coordinator that these
procedures are in place.The involved parties will expeditiouslynegotiate
operating strategiesand/or curtailment allocations prior to initial operation to
assure operation within safe limits.Negotiationsshould not unduly delay new
Projects and disputes should be resolved expeditiouslythrough WECC's
Alternate Dispute Resolution (ADR)process or some other process as
mutuallyagreed to by the parties;
8.If all planned facilities,including facilities of other projects on which the rating
studies relied,are not installed for a Project or are modified or retired from
service,project sponsor(s)are responsible for the corresponding reduced
Path rating and associated curtailments;
9.New simultaneous limits may be discovered between existingtransmission
paths even when no facilities or ratings are being changed.The limits may be
caused by the retirement of existingfacilities or changes in system load
and/or resources that occur over time in several systems.The involved
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parties should negotiate operation strategies and/or curtailment allocations to
promote continued operation within safe limits.Negotiationsshall not
adverselyaffect ongoing reliable system operationsand disputesshould be
resolved expeditiouslythrough WECC's ADR process or some other process
as mutuallyagreed to by the parties.
2.5.Guidelines
The followingguidelines apply with respect to adverse impacts on Transfer
Capability:
1.Sections 6.0 and 7.0 address Principais and Scenario examplesfor rating
transmission facilities.Project sponsors should refer to these for guidance in
determining new ratings.It should be recognized that it is not possible to
address all situations and issues that may arise in facility ratings.Project
sponsors should be prepared to apply judgmentin addressing facility rating
issues not addressed in Sections 6.0 and 7.0.
2.A new Path rating should not adverselyimpact the Transfer Capability of the
existing system and individual Paths in the system.A new project shall not
result in a reduction of another Path's Existing or Accepted Rating.If it does,
the sponsors of the project should work with all adverselyaffected parties to
mitigate Transfer Capability limitations or to negotiate appropriate and
reasonable compensation.The intent is that new projects will be developedin
consideration of the existing system and not cause reductions in existing
Transfer Capabilities where mitigation options can be developed.The key
consideration is achieving balance.Existing Paths deserve a degree of
protection;however,existing Paths should not discourage needed system
expansion.For example,a new project could create a new simultaneous
relationship with an existing Path or alter an existing simultaneous
relationship between existing Paths and still meet the intent of the rating
process.Conversely,system expansionshould not unfairly penalize existing
system facilities.
3.When a simultaneous transfer conflict occurs between systemsthat have
established Accepted Ratings,the vintageof the rating should not,in itself,
grant preference in determining curtailment allocations.
4.Negotiatedagreementbetween the affected parties is the preferred method
for resolving simultaneous transfer conflicts.If negotiationsfail,alternative
dispute resolution should be considered.
5.Generally,the burden of resolving limitations between Projects in Phase 2B of
the Path Rating Process should be shared between the Projects.In addition,
the mutual impacts of Similarly Situated Projects need to be investigatedin
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Phase 2B.(Please see AppendixB for a discussion on Similarly Situated
Projects).
In allocating curtailments or costs of mitigation,consideration should be given
to factors including:
State of completionof planning
Level of commitment to Project
Speed of progress
Projected completiondates
3.Path Rating Process
3.1.Objectives
To fulfill the purpose of these Processes,Policies and Procedures,project
sponsors should consider potentialinteractions and problems of simultaneous
transfers when performing the planning studies for a Project.To facilitate this
purpose,WECC has adopted the followingPath Rating Process to guide the
project sponsors through their planning effort.
The objectivesof the Path Rating Process are to:
1.Facilitate communication of Project plans,performance,and limitations to all
affected parties during the period from Project inception to commercial
operation.
2.Encourage a reasonable and diligenteffort to discover simultaneous
limitations and assure their resolution prior to operation.
3.Provide the opportunity for owners of existingor future facilities that may be
affected by the Project to participate in review of the Project studies.
4.Facilitate the conclusion of all necessary studies in a timelymanner.
5.Identify operating limitations and facilitate the project sponsor's development
of mitigation measures with sufficient lead-time to allow developmentof
operating procedures.
6.Integrate Projects into the existingsystem in a manner that will preserve
interconnected-system reliability and operating efficiency.
7.Provide clarity,consistency,and transparency in classifying Projects that are
Similarly Situated (see AppendixB).
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3.2.The Rating Process
The project sponsor is responsible for initiating and followingthrough with the
rating process.The rating process covers the period of activity from the first
announcement of a Project (through either the WECC Data Collection Process or
through a letter of notification to PCC and TSS members)to when it is placed in
operation.While the sponsor is responsible for initiating and completing the
Rating Process,there is a shared responsibility between the project sponsor and
the rest of the WECC membershipto completesome parts of the process.
The Rating Process consists of three phases:
Phase 1 -Non-simultaneous Study and Path Definition
This phase includes defining the proposed Path and including a proposed
Path rating and the Project Plan of Service that supports the proposed
Path rating.This phase builds on the work done in the Project
Coordination Process.
Phase 2 -Simultaneous Study,Review,and Planned Ratinq
This phase is to address issues related to the Path rating,mainly
Simultaneous Transfer Capability,but also Non-simultaneous Transfer
Capability if issues were not resolved in Phase 1.
Phase 3 -Accepted Rating and Project Implementation
This phase covers the construction period for the Project.Phase 3 is
deemed completewhen the Project is placed in service.
The Rating Process also provides for project sponsors to compress activities
when the Path rating is not expectedto raise significant concerns.This is
described in Section 3.3 -Expediting the Process.
Throughoutthe planning process the project sponsor is responsible for
adequatelycommunicating and coordinating the developmentof the Project with
existing facilities and other projects.WECC provides many opportunitiesfor the
project sponsor to communicate information to members and interested parties
about the Project through informal reports at various committee meetings,as well
as the preparation of progress reports.(See AppendixC for a list of templatesto
provide some exampleson the contents of such communications.)
This Path Rating Process has been established to promote that the planning
process is completedin a timelyand orderly manner.The process is pictorially
illustrated in Figure 2.
3.2.1.Phase 1 -Path Definition
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The purpose of Phase 1 is to define the proposed Path and proposed rating.
Phase 1 is often carried out concurrently with the Project Coordination Process
and is completeupon acceptance of a ComprehensiveProgress Report by the
TSS.Phase 1 is also the most appropriate phase for the project sponsor to
decide if the proposed Project would constitute a subset of an existing Path.
Otherwise,this determination should be made as early as possible in Phase 2.
Please refer to AppendixD for the two tests the project sponsor is required to
perform in order to provide information to the PRG to aid in determining whether
a proposed Project is a subset of an existing Path.
However,if a project sponsor's study plan includes treating the proposed Project
as a subset of an existingPath,or the sponsor makes that decision in Phase 1,
performing the two tests referred to in AppendixD will not be needed.If the
proposed Project is determined to be a subset of an existing Path,the project
sponsor will also be required to re-rate the combined Path within the Path Rating
Process.The determination that a Project is a subset of an existing Path does
not preclude a Project from defining a separate Path or from seeking a separate
Path rating for itself.
The project sponsor'sinitial announcement of a project starts Phase 1 of the
planning process.This announcement takes place when the project sponsor
submits data on the Project in accordance with the WECC Progress Report
Policies and Procedures or provides a letter of notification.If a letter of
notification is used,the letter should include a completedescription of the Project
including the proposed Path and proposed Path rating and shall be distributed to
all PCC and TSS members (WECC staff will distribute material upon request of
the project sponsor).For the purposes of these criteria,transmission dependent
utilities,loads,or generators interconnected exclusivelyto the Path operator's
system are not considered other systems.
3.2.2.Phase 1 Requirements
During Phase 1 the Project is in the preliminary phase of developmentand a
definitive Plan of Service may not be available.The sponsor should be
performing the necessary studies to developa preliminary Plan of Service and a
Planned Rating.Studies should focus on the non-simultaneous rating;however,
known simultaneous effects should also be addressed.In addition,the project
sponsor is required to determine whether the proposed Project is part of an
existing Path either in Phase 1 or in Phase 2 as part of project review.(Refer to
AppendixD for the two tests required to provide information to the PRG to aid in
determining if a proposed Project is a subset of an existing Path.)During Phase
1,the Path associated with the Project has only a Proposed Rating and other
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projects in later phases of the planning process are not obligated to recognize
the Project in their studies.
3.2.3.Completion of Phase 1
The transition from Phase 1 to Phase 2 is accomplished by notification from the
TSS chair to PCC,OC,TSS and the project sponsor of the completion of all the
following:
1.PCC has completedits assessment of the Project's conformity with the Project
Coordination Review Objectives.
2.The project sponsor has submitted a full Project representation to WECC for
inclusion in WECC base cases.The project sponsor should work with applicable
Area Coordinators so that it is clearly understood when transmission facilities
associated with the Project should be modeled in specific WECC base cases.
3.The project sponsor has distributed a ComprehensiveProgress Report
accompanied by a letter to TSS and PCC requesting Phase 2 Status for the
Project.TSS and PCC members have 60 days to comment on the
ComprehensiveProgress Report by submittinga letter to the project sponsor
with copy to WECC staff.
If the above criteria have been satisfied and no objectionswere received within
60 days,the project sponsor(s)will so notify the TSS chair and provide evidence
that the project has satisfied all requirements.The TSS chair will notify PCC and
TSS members that the ComprehensiveProgress Report has been accepted and
the Project has entered Phase 2 of the planning process.If any objection is
received,the TSS chair will consult with WECC staff and TSS members to
determine whether the Project has met the above requirements to transition to
Phase 2.This transition from Phase 1 to Phase 2 signals that the project
sponsor's preliminary planning studies have been completedand a Planned
Rating for the Path associated with the Project has been established using
accepted methodology.
It is recognized that the Rating Process can be very complex.Notwithstanding
the minimum reporting requirements necessary to qualify for transition to Phase
2,it may not be practical to address all technical questionswithin the defined
Phase 1 scope.Unresolved issues may include:
1.Planning and technical issues that the project sponsor is responsible for
demonstratingunder NERC ReliabilityStandards and WECC Criteria.This
includes:
determining whether a proposed Project is a subset of an existing Path;
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addressing simultaneous technical interactions between projects,
including:
known interactions;and
new interactions that are intended to be identified and that have a bearing
on the reliability of the interconnected electric system and developmentof
associated nomograms.
2.Adequacy of supply is not a factor in the rating process as a stand-alone
requirement.It may be an indirect factor if generation patterns have bearing
on the technical rating issues described above.Adequacy of supply issues
are to be addressed in other forums.
3.Commercial issues are to be addressed outside of the rating process by the
affected parties.It is the intent of these policies and procedures that
commercial issues be resolved before operation at the new Accepted Rating
commences.It is intended that at the end of the Path Rating Process
operation at the new Accepted Rating of the Path associated with new
Projects that meet all reliability requirements not be unreasonablydelayed by
commercial discussions.
The PCC expectsthat,early in the 60-day comment period,personnel with
authority to resolve these areas of disagreementfrom each of the involved
parties will make a good faith effort to identify issues and resolve any issues
of disagreement.If at the end of the 60-day period,there remains objections
to the ComprehensiveProgress Reportthat have not been resolved,the
project sponsor may agree to resolve the objectionsin Phase 2,in which case
the ComprehensiveProgress Report can be accepted and the Project can
move into Phase 2,provided that all other Phase 2 entry requirements have
been satisfied.Otherwise,the Project will remain in Phase 1.
Notification by the TSS chair of the acceptance of the Comprehensive
Progress Report and the Planned Rating indicates completion of Phase 1 and
transition to Phase 2.
3.2.4.Phase 2 -Path Rating
The purpose of Phase 2 of the Rating Process is to:
Confirm the Non-Simultaneous Transfer Capability of the Path associated
with the proposed Project for a specific Plan of Service determined in
Phase 1;
Identify Simultaneous Transfer Capability of the Path for specific Project plans
of service on a combined basis for all affected paths and all Projects
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classified as Similarly Situated;(please see AppendixB for discussion on
Similarly Situated and Combined Project studies.)
·Address the mitigation of adverse impacts on simultaneous and non-
simultaneous Transfer Capability relative to the existing system;
Determine impacts on the Western Interconnection of outagesof all facilities
in the same corridor as the proposed Project.10
·Address all comments to the ComprehensiveProgress Report.
3.2.5.Phase 2 Requirements
During Phase 2,the project sponsor will lead a PRG comprised of interested
WECC member representatives.Prior to or during Phase 2,the project sponsor
will send a letter to all TSS,PCC,and OC members soliciting interest in
participating in a PRG.A 30-day period (starting from WECC's distribution of the
request letter)will be allowed for recipients of the letter to respond with their
interest in participating in the PRG.This letter may be distributed at the same
time as the ComprehensiveProgress Report is distributed,althoughthe deadline
for expressinginterest in participating in the PRG cannot be before the deadline
for comments on the ComprehensiveProgress Report.
Details concerning the formation of the PRG are discussed in Section 3.5,
Formation of a WECC PRG.All members interested in participating in a PRG
shall be allowed to participate.Members with interest in the Path rating should
participate in the PRG,as it is the PRG comments that will determine the
outcome of Phase 2 and transition to Phase 3.In addition,the PRG is also
responsible for approving the study plan and the base cases to be used for
simultaneous transfer studies in Phase 2.
All Projects associated with Paths that have Planned Ratings must consider each
other as relevant to their planning studies.Once a Project has entered Phase 2
its associated Path has attained a Planned Rating and,it is considered on an
equal basis with other Projects Similarly Situated in Phase 2.Similarly Situated
Projects must consider each other on an equal basis.
To aid in the determination of Projects that are Similarly Situated,Phase 2 is
further separated into Phases 2A and 2B with a bright line.This bright line"is
used to identify those Phase 2 proposed Projects that have completedand
obtained approvalby the PRG of a study plan and the first base case (or
10 Loss of all facilities in the same corridor is an Extreme Event.Mitigation of the impacts due to Extreme
Events is not required to achieve an Accepted Rating.
11 The bright line is further defined in Section 3.2.6
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Foundational Base Case)needed to perform simultaneous studies.Phase 2A
Projects that cross this bright line will be moved to Phase 2B.(See AppendixB
for further discussion of Similarly Situated Projects,Simultaneous Studies and
Combined Project Studies and the relationship between proposed Projects in
Phase 2A and Phase 2B.)
Phase 2 is the phase in which adverse impacts must be identified and Mitigation
Plans must be established.If a new transmission Project potentiallyimpacts an
Existing Rating or an Accepted Rating then it is required that preliminary
Mitigation Plans be developedin Phase 2B by the project sponsor to alleviate the
adverse impact.For example,a change that affects the effectiveness of a RAS is
expectedto be addressed in Phase 2B if the RAS effectiveness has a direct
adverse affect on an Existing or Accepted Rating.
The essential burden of mitigating or compensatingfor new problemsrelative to
the existing system lies with the project sponsor.Project sponsors of proposed
Projects are encouraged to work togetheron mitigation needed.The burden of
mitigation of new impacts associated with a new Project only applies for
interactions with Paths having Existing or Accepted Path Ratings as of the date
the new Project enters Phase 2B.The burden of mitigating new impacts does not
apply for interactions with Paths with Other Ratings.Allocations of ratings are
considered to be commercial issues and are not addressed by this process.
Phase 2B is also the phase in which project sponsors must determine impacts on
the Western Interconnection of outagesof all facilities in the same corridor as the
proposed Project.12
3.2.6.Process to establish the Bright Line between Phase 2A and 2B
Phase 2 is divided into two parts with a bright line;Phases 2A and 2B.All
Projects entering Phase 2 will need to comply with the followingprocess to
establish the basis by which these Projects will be classified as Similarly
Situated.
The bright line between Phases 2A and 2B is drawn when the project sponsor(s)
has developed,and the PRG has approved,the study plan and the first
simultaneous base case,and the project sponsor(s)is ready to perform
simultaneous analyses.Based on PRG requests,multiplesimultaneous analyses
may need to be performed requiring multiplesimultaneous base cases.However,
the Foundational Base Case that will establish this bright line is the first base
case that would be ready for the first simultaneous assessment as agreed to by
12 Loss of all facilities in the same corridor is an Extreme Event.Mitigation of the impacts due to Extreme
Events is not required to achieve an Accepted Rating.
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the PRG.Additionally,this Foundational Base Case must be defined in the PRG-
approved study plan.
1.In general,the PRG,once formed,will developand agree to the study plan
within 60 calendar days unless otherwise agreed to by the PRG.This study
plan,at a minimum,must include study assumptions,methodology,
milestones,and time lines.(See Section 5.0 for a ComprehensiveStudy Plan
outline.)Once the study plan is approved by the PRG the project sponsor will
notify WECC staff.WECC staff will document the completion of this step in
the WECC Three-Phase Rating Process Log.
2.The PRG,togetherwith the project sponsor,must reach consensus that the
Foundational Base Case is completeand then establish a time stamp to
indicate that the Project has entered Phase 2B.This transition and time
stamp will be documented in the Path Rating Log.(Typically,such
Foundational Base Cases would take about three months to complete.)
3.Completionof the study plan and the Foundational Base Case will establish a
time stamp that creates a clear bright line on a consistent and transparent
basis by which to identify those individual Projects among multipleProjects
that qualify to be considered Similarly Situated.Moreover,this process should
give the project sponsor(s)a time line to perform the rating study.The intent
is to tie study progress with the study plan and to establish a time line for the
study that has been agreed to by the project sponsor(s)and the PRG.Once
the time stamp has been established,the project sponsor(s)will communicate
this fact to the TSS chair and WECC staff.WECC staff will keep track of the
time stamp and notification process in the WECC Three-Phase Rating
Process Log.
4.If Similarly Situated Projects impact (or may be part of)an existing Path or a
new Path,then these Projects must conduct a Combined Project Study which
will examine the non-simultaneous rating13 Of this Path with the addition of
these Projects.Project sponsors togetherwith PRG members will determine
the need for,and the nature of,a Combined Project Study.Refer to Appendix
D for the two tests required to provide information to the PRG to aid in
determining if a proposed Project is on the same Path.
3.2.7.Notification of establishment of the Bright Line between Phase 2A and 2B
13 The Combined Project Study will determine the simultaneous impact of the projects on the path,but the
Path Rating thus determined will constitute the non-simultaneous rating in relation to other WECC Paths.
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The Similarly Situated Bright Line Notification does not need to have the same
formality as going from Phase 1 to Phase 2,or from Phase 2 to Phase 3.
However,at a minimum it must consist of the following:
The notification must contain the final date establishingthe bright line as the
basis for determining the Similarly Situated classification.This final date shall
be based on the latest date when both the study plan had been approved and
the Foundational Base Cases were approved by the PRG (i.e.,assumingthey
were approved on different dates,the final date would represent the latest
approvaldate).
Project sponsor(s)shall send written notification to the TSS chair and WECC
staff within five working days after the bright line date was identified by the
PRG.If the notification is received after five working days,the bright line date
will be the date that the TSS chair and WECC staff receive notification.
WECC staff will distribute the notification to WECC members and enter the
status in the WECC log for Phase 2 Projects.
Please refer to Section 7.0 for examplesof specific situations to aid in applying
the policy on Similarly Situated Projects.
3.2.8.Completion of Phase 2
After completing the technical studies defined in the study plan and drafting a
detailed technical report that reflects the technical study findings,the project
sponsor shall send a Phase 2 Rating Report to the PRG and a copy of the report
to WECC staff.The Phase 2 Rating Report shall document and its executive
summary shall include highlights of key aspects of at least the followingitems:
1.Plan of Service (including milestones)and a statement that the Plan of
Service meets NERC Reliability Standards and WECC Criteria;
2.Corrective actions and/or Mitigation Plan,if needed,to supportthe Accepted
Rating
3.Assumptionsused in the Rating Study,including load levels,existing and
future resources,and other projects upon which the Accepted Rating relies.
A 30-day period for comments from the PRG on the Phase 2 Rating Report
(starting from the distribution date of the report)shall be provided during which
the PRG may raise concerns or provide comments.This may be shortened by
agreementof the PRG if all its members are satisfied with the Phase 2 Rating
Report.
The project sponsor shall work with the PRG to resolve all concerns and
comments received during the comment period.Once the PRG group agrees
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that all concerns and comments have been addressed or if the project sponsor
has made a good faith effort to address the comments received,the project
sponsor will distribute the Phase 2 Rating Report to the PCC,TSS,and OC and
request Phase 3 status.
PCC members will have 30 days to comment on conformance with the
procedures in this document.The PCC comments will not encompass adverse
impacts or Mitigation Plans,as these are the responsibility of the PRG.The
project sponsor shall work with the PCC to resolve all concerns and comments
received during the PCC comment period.Completionof Phase 2 can be
addressed in a number of ways:
1.If all comments received have been resolved,the project sponsor will so
notify the PCC chair and formallyrequest Phase 3 status.The PCC chair will
-upon determination that the requirements have been met -notify the
PCC,TSS,and OC members that the Phase 2 Rating Report has been
accepted and the Project has entered Phase 3 of the planning process.
2.If comments from the PRG or PCC concerning the Project's compliance with
NERC Standards and WECC Criteria,policies,and procedures are received
that cannot be resolved,the disagreementswill be handled in accordance
with the resolution process provided in the WECC Progress ReportPolicy and
Procedure,Section 4.4.
3.In the event that outstandingissues have not been resolved using the above
process,upon request by the project sponsor or any member of the PRG or
PCC,the PCC chair will provide a forum for discussion and the PCC will
determine through a vote whether PCC members are satisfied that the Project
has met all requirements of Phase 2 of this Path Rating Process.The PCC
chair will consider the need to consult with the WECC Board chair and WECC
CEO regarding Phase 2 completiondetermined in this manner.
4.PRG members (including the project sponsor)that have outstandingissues
may use the WECC Alternative Dispute Resolution (ADR)process to seek
resolution.
Upon determination that Phase 2 has been completed,the PCC chair,in
consultation with the TSS chair and WECC staff,will notify the PCC,TSS,and
OC members that the Phase 2 Rating Report has been accepted and the Project
has entered Phase 3 of the Path Rating Process.The final accepted Phase 2
Rating Reportwill be attached to the notification.The acceptance of the Phase 2
Rating Reportwill completePhase 2 and establish an Accepted Rating that must
be considered by other projects in all phases of the planning process.
3.2.9.Phase 3
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Phase 3 is entered upon successful completion of Phase 2.This phase includes
construction and assumes the sponsor is committed to the Project.The essential
planning activity during this phase is maintenance and monitoring of the
Accepted Rating and assuring that the Project will be completedin a timely
manner in accordance with the Plan of Service presented in the Phase 2 Rating
Report.For a Project consisting only of a rerating of the existing system,Phase 3
would simply entail instituting the rating.
A Project in Phase 3 will be considered to be part of the "existing system"for the
purposes of a project being planned.All other Projects that are not Similarly
Situated with this Project or in earlier phases of the planning process must treat
Phase 3 Projects as part of the existingsystem.Because a Phase 3 Project is
considered a peer with the existing system,if new simultaneous transfer
limitations are discovered,their resolution will be shared among the parties as if
the Project were complete.
The Project's Accepted Rating is only "at risk"if the project sponsor fails to
completethe Plan of Service or meet milestones within the required time as
presented in the Phase 2 Rating Report or there is a failure or delay of other
projects that were relied on in establishingthe rating.The PRG and the TSS
have the responsibility of monitoring the progress of the Project.If the schedule
for Project completion is delayed or interrupted,the project sponsor may be
required to repeat or update Phase 2 of the planning process.The PRG shall
decide the appropriate action.This is further described under Monitoring Project
Progress.
When construction is complete(or in the case of up-rates of existing facilities -
when all operating procedures,etc.,are accepted by the Operating Procedures
Review Group and are in place)and the Project is put into operation,the
planning process is also completeand the Project is a fully-accepted part of the
existing system.
3.3.Expediting the Process
The Path Rating Process is designed to provide for an orderly completionof
steps with adequatetimes for member participation and comments for significant
or complexProjects.However,in some cases (when the project sponsor
anticipates that there will be few comments or that comments can be addressed
and incorporated in the Project without delays)the project sponsor may seek to
expeditethe process of achieving an Accepted Rating.Expediting the process
will result in simultaneous acceptance by the PCC of both the Phase 1 and
Phase 2 requirements.One exampleof a Project seeking expeditioustreatment
is the up-rating of an existing transmission Path accomplished by changing an
operating procedure or installing a new remedial action scheme.
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Expediting the process involves combining several of the rating process steps.
The Letter of Notification,the ComprehensiveProgress Report,and the request
for interest in forming a Review Group may all be combined into a single
distribution.Project sponsor notification to all PCC,OC,and TSS members at the
beginning of the process shall include a clear statement of the desire to expedite
the process.Members concerned that expeditingthe process will not give
adequateopportunityfor rating review should notify the Project sponsor,TSS
chair and PCC chair as soon as possible.The project sponsor and the member
should work togetherto resolve the concerns.If concerns cannot be resolved,
then the TSS will determine if the process can be expedited.
While all requirements herein remain the same and all timelines for the individual
steps would still apply,they may be done concurrently and the PRG may be
formed before comments are due on the ComprehensiveProgress Report.For
example,the WECC Progress Report Policies and Procedures requires a 60-day
comment period for the ComprehensiveProgress Report that can be concurrent
with the 30-day period required for forming the PRG and the 30-day period
allowed for the PCC to comment on the conformance with this procedure.
However,while these two processes are allowed to overlap,the deadline for
expressing interest in participating in a PRG cannot end before the end of the 60-
day comment period for the ComprehensiveProgress Report has expired.
Acceptance of completion of Phase 2 and transition into Phase 3 is as described
above.If the Phase 2 Rating Report is unchanged from the Comprehensive
Progress Report,the project sponsor should send a letter stating such to the
PCC and TSS.
Expediting the process has the advantageof facilitating the process of achieving
an Accepted Rating for a Path associated with a straightforward Project.
However,during the expeditingof a Path Rating Process,the Project remains in
Phase 1.Consequently,the Project does not achieve any status with respect to
Projects in Phase 2.Should significant or unanticipated issues arise,the project
sponsor may find that the process cannot be expeditedand may request Phase 2
status,and then follow the Phase 2 process discussed in Section 3.2.
If the proposed Path rating change is planned to occur within six months after
WECC notification,the Operating Practices Subcommittee (OPS)and the
Technical OperationsSubcommittee (TOS)should be included in the various
Path rating process mailings.
3.4.Monitoring Project Progress
Granting of Phase 2 status or an Accepted Rating to a Path associated with a
Project/project sponsor obligatesother WECC members to various levels of
recognition and accommodation in the planning of other projects.In exchangefor
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this,a project sponsor is responsible for maintaining the Project's Phase 2A or
2B status and rating with a continuous demonstration of steady progress toward
commercial operation through continued compliance with the WECC Progress
Reporting Procedure.
A Phase 2A or 2B status may be lost if a Project in Phase 2 shows no evidence
of any activity14 8 periOd of time after the achievement of Phase 2 status.The
project sponsor can revive the Project's Phase 2 status by providing evidence
that Phase 2 studies and/or PRG meetings are being conducted.Table 1 below
outlines the conditions under which a proposed Path rating study can be reverted
back to previous phases due to inactivity.
14 Refers to study activities visible to PCC,TSS,or PRG and WECC staff.
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Table 1"
The start time is initiated once a Project enters Phase 2A.The following requirements shall be
met or the Project in Phase 2 will either revert back to Phase 1 or Phase 2A (depending on if
the Project is in Phase 2A or 2B)under the follovving conditions:
Elapse time
(calendar Projectdays)without reverts back
Conditions Notifier activities to
If project sponsor does not form a Project TSS
Review Group while in Phase 2A chair/TSS 60 days Phase 1
If project sponsor does not initiate any study on
simultaneous Path Transfer Capability limits PRG 12 months16 Phase 1
If project sponsor misses completing any
Project study milestones by 12 months or more PRG 12 months17 Phase 2A
If project sponsor does not show any evidence TSS
of any activity for 12 months during Phase 2.chair/TSS 12 months Phase 1
If the project sponsor cannot be located by the
TSS chair or WECC staff,or no response is Remove the
received from the project sponsor after a formal project from
WECC announcement on the Project status TSS the WECC
has been made.chair/TSS 18 months Log
A project sponsor may appeal these decisions to eilher the TSS or PCC if the pro ect sponsor
can demonstrate that group meetings or studies coordinated with the PRG were in progress
prior to the notification of being removed from the current status.
Refers to study activities visible to PCC,TSS,or PRG and WECC staff.
Phase 3 Accepted Rating Status may be lost if a delay in meeting any Project
milestones by 12 months or more occurs or a change in the Project's Plan of
Service adverselyimpacts the Accepted Rating.The PRG and the TSS have the
responsibility of monitoring the progress of the Project in this Phase.
If either of these conditions occurs,the project sponsor shall promptly notify TSS,
PCC,and the PRG.The PRG will determine if the Project status will revert back
to the appropriate status within Phase 2 with a Planned Rating or remain in
Phase 3 with an Accepted Rating.In addition,a determination will be made if
more study work is necessary.The project sponsor will promptly notify PCC and
TSS regarding the determination of the PRG.
16 Table 1 will be effective 90 calendar days after the approval of this version of the document by the
WECC Board of Directors.
16 12 months after achieving Phase 2B.
17 12 months counting from the missed milestone.
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See AppendixE for guideline on treatment of proposed Projects for which rating
studies were reverted back to earlier phases.
3.5.Formation of a WECC Project Review Group
A WECC PRG is formed to facilitate review of planning studies for a Project in
Phase 2 of the Path Rating Process.The PRG provides WECC members with
the opportunityto meaningfullycontribute to the Plan of Service for the Project
and identify concerns with potentialimpacts of the Project.
Timing of the PRG formation is at the project sponsor's discretion,but should be
within 60 Calendar Days after the Project enters Phase 2.While the PRG will
normally completeits task at the end of Phase 2,the PRG members should
stand ready to help the project sponsor resolve additional simultaneous transfer-
related issues should they occur and to determine if the Project status should
revert back to earlier phases as described under the Section 3.4,"Monitoring
Project Progress."
While participation in a PRG is voluntaryand open to all WECC members,it is
required that,at a minimum,the PRG membershipinclude all WECC members
who desire to join the PRG.The responsibility for forming the PRG belongs to the
project sponsor,but the responsibility for facilitating an objective,positive,and
effective PRG is shared by all WECC members.
The PRG's main area of interest lies in identifying all non-simultaneous and
simultaneous impacts and methods for mitigating these for both the existing
system (including Phase 3 Projects)and other Projects in Phase 2.The PRG is
also responsible for approving the study plan and the base cases to be used for
simultaneous transfer studies.PRG participants are responsible to provide any
necessary information required to prepare the simultaneous transfer studies,
which should be fully supported by studies and/or mitigation measures.Likewise,
it is the responsibility of the project sponsor to adequatelyaddress all appropriate
issues raised by the PRG members or as they arise during the course of the
study process.
Mitigation methods may include,but should not be limited to,additional facilities,
remedial action measures,and operating nomograms.The project sponsor will
select the available mitigation measure(s)to be implementedor adjustthe Path
rating to mitigate any adverse impacts.The functions of the PRG are technical in
nature and shall not address commercial issues.While the project sponsor is
responsible for addressing curtailment procedures,because they are commercial
issues they shall be addressed through negotiationsoutside of the PRG.
It should be recognized that some Projects will be more difficult to evaluate than
others,which may require a significant effort by the project sponsor and the PRG
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members.The PRG is a shared responsibility between the project sponsor and
the WECC members and as such,the project sponsor is not obligated to "study
the world."Should circumstances arise where studies being requested go
beyond the scope of the Project,the project sponsor may request a PRG
member(s)to run some of the studies as may be needed to be included in the
report.
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Figure 2
Path Rating Process
Phase 2B:started
by acceptance ofPhase1:started by Phase 2B:the study plan andProject completed whenPhase2A:started Foundationalannouncement the WECC Path RatingbyacceptanceofaBaseCase(s)bythroughWECC Phase 2 Rating Process:Comprehensive the ProjectDataCollection Report is completed whenProgressreportbyReviewGroup.Process or by letter accepted by Project entersTSS.This This establishestoPCCandTSS..PCC.This Commercialestablishesthethe"Similarlymembers.This establishes the Operation."Planned Rating."Situated"establishes the AcceptedProjectsthatmust"Proposed Rating."Rating."be studied by the
Project.
Planning Phase Phase 1 Phase 2A Phase 2B Phase 3
..Permitting &Project Activities Planning Planning &Permitting Construction
At any point in time,if any two projects are together in Phase 2B,they are Similarly Situated and have a responsibility to mitigate interaction
they have with each other until both become operational.
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Figure 2
Path Rating Process
WECC Review Group
Sponsor forms WECC Rating Studies
Sponsor's Independent Project Review Group,demonstrate both Non-Monitoring Progress
.Studies and draft develops Rating Study Simultaneous Rating and final determinationStudyEmphasis.Comprehensive Project Plan and appropriate and any Simultaneous of all identified
Report.WECC system base Ratings with other mitigation measures.
cases.Similarly Situated
Projects.
All Projects shall
All Projects in Phase 2A identify any interactions Other projects MUSTOtherprojectnot
.shall include all Projects with other concurrent treat Project as part of
Study Considerations obligated to recognize in Phase 2B and Phase 3 Phase 2B Projects the existing systemnewProjectintheir.
studies in their studies as agreed The burden of study provided it continues to
to by the PRG.shall rest with Projects meet milestones.
entering Phase 2B.
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Figure 2
Path Rating Process
Other Projects that areAllProjectsnotsimilarlysituatedorconcurrentlyinPhasenotinPhase3are2Bareequallyresponsibletomitigateresponsibletomitigate.
.impacts,if any,on thisforimpacts,if any,on Project provided thisanyothersProjectsinProjectcontinuestoPhase2B.meet milestones.Mitigation None NoneRequirements Projects in Phase 28 Mitigationareresponsibleto .
.requirements,if any,mitigate for impacts,if must have beenany,on Paths .determined andassociatedwithProject
..resolved prior towithan"Existing"or an ,,,commercial operationAccepted"Rating.of the new Project.
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4.Philosophy and Principles For Transmission Path Rating Methods
4.1.Introduction
A Project is defined as a new generatoror transmission facility or a change in
rating of an existing generatoror transmission facility through facility additions,
facility upgrades,facility retirements or the re-rating of existing facilities that
would result in a new Path or changes in existingPath ratings.The primary focus
of the Path Rating Process is to establish a set of well-defined principles for
determining Accepted Ratings for Transmission Paths.These principles are
intended to foster a consistent transmission rating method that will provide a level
playing field for the traditional utility as well as the non-utility organizationsthat
are participating in the planning and operation of the WECC interconnected
system.All participants are expectedto follow these principles.Consequently,
these principles must be practical,technically sound,unambiguous,and
consistent with the NERC ReliabilityStandards and WECC Criteria,and must
promote efficient use of the system.The determination of an Accepted Rating for
a Path is importantfor several reasons that include,but are not limited to;
assuring reliable operation,determining access or contract rights,and
establishingscheduling limits.
4.2.Philosophy
To determine the Accepted Rating for a path,use the method described above in
the Path Rating Process.This applies to all paths whether they are considered
"internal"or "external."Ratings are pre-outage,with all facilities in service,and
may be achieved through the use of appropriate Remedial Action Schemes.The
adoption of a consistent study method should ensure that the Accepted Rating of
a Transmission Path:
Is technically sound;
Can be used in actual operation,and;
Is consistent with the flow achievable on the Transmission Path.
This method does not constrain how parties may commercially allocate the rating
of a path among its owners.In addition,this method does not constrain how
owners of interacting paths may allocate curtailments among their paths.
However,project sponsors are required to determine if the proposed Project
would constitute a subset of an existing Path.Refer to AppendixD for the two
tests required to provide information to the PRG to aid in determining if a
proposed Project is a subset of an existing Path.
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If a project sponsor includes that it will treat the proposed Project as a subset of
an existing Path in its study plan,performing the tests is be needed.In addition,
being a subset of an existing Path does not preclude a Project from defining a
separate Path or from seeking a separate Path rating for itself.However,if the
proposed Project is determined to be a subset of an existingPath,the project
sponsor(s)is required to re-rate the Path within the Path Rating Process.
The WECC PRG described in these procedures is responsible for ensuring that
these guidelinesare followed in developingan Accepted Rating.The PRG is also
responsible for ensuring that the study plan and base cases represent realistic
conditions.
The planning process should address potential unscheduled flow impacts.One
possible way to address unscheduled flow is to establish Transmission Path
ratings at a level where no system reliability problems exist and schedules will be
limited by the maximum flow that can occur on the Path under realistic (although
perhaps optimistic)conditions.This rating philosophy embodies a Maximum Flow
Test (MFT)and precludes having operating schedules on the transfer path that
exceed the resulting Accepted Rating (see AppendixA).Consequently,this
aspect of the planning process is a positive step in limiting unscheduled flow that
would otherwise be higher if the Accepted Rating is not constrained by the MFT.
With the concurrence of all affected parties,the sponsor may use some method
other than the MFT.
All sponsors must provide notification to the PCC of what method they will use;
including an explanationof what the proposed method is intended to accomplish.
With the concurrence of all affected parties,the sponsor may use some method
other than the MFT.
It is the intent of these procedures to afford the appropriate measure of protection
for Path ratings.Protection is a fundamental element of what an Accepted Rating
provides.An Accepted Rating is fully peer reviewed,recognized in future
planning studies,and directly usable in operations for both scheduled and actual
flows.An Accepted Rating addresses both simultaneous and non-simultaneous
Transfer Capabilities and may involve the use of nomograms or remedial action
schemes.It is not acceptable for a new project to cause a reduction in an
Accepted Rating of another Path unless mitigated or compensatedby the new
project.Notwithstandingthis protection philosophy,compliance with the NERC
ReliabilityStandards and WECC Criteria is always the overriding consideration
for the project sponsor.
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4.3.Principles
The followingprinciples are the basis for the methodologyto be used in
determining the Accepted Rating of a Transmission Path.
4.3.1.Reliability Limited Ratings
An Accepted Rating is determined such that the scheduled and actual use of a
transmission Path is limited to levels that meet the NERC ReliabilityStandards
and WECC Criteria.
4.3.2.Realistic Simulation
Studies and analyses performed to determine the Accepted Rating of a transfer
path must use realistic simulations;i.e.,the use of fictitious devices is not allowed
and the system conditions represented must be realistic,as determined by the
PRG.Considerable latitude is intended to be allowed in determining realistic
conditions.When remedial action schemes are used,they are modeled as they
are anticipated to be applied in operation.If a change in RAS actions occurs,
additional studies may be required to verify the Rating.See AppendixA for
guidelineson Resources Acceptable for Path Rating Studies.
4.3.3.Flow-Limited Ratings
Certain Transmission Paths may not be limited by reliability considerations.For
example,a Path may be limited by the amount of available resources,or parallel
a lower impedance path.Where this occurs,these Paths will be described as
flow-limited (as opposed to reliability-limited).When testing for this condition,
considerable latitude in the base case assumptionsis allowed in maximizing the
flow on the Path being rated.After the flow on the Path has been maximized with
the above consideration and a reliability limit has not been reached,an MFT is
defined as having been passed for the Path being rated.This maximum flow
achieved is called a Flow-Limited Rating and is protected.
An advantageto defining this maximum flow as a Flow-Limited Rating is that this
produces a reasonable way to address potential unscheduled flow in the
planning process.By defining this as a "rating,"schedules will be limited by the
maximum flow that can occur on the Path under realistic conditions.
However,if the MFT is not applied,the project sponsors must provide notification
to the PCC of what method they will use during Phase 2 of the rating process;
including an explanationof what the proposed method is intended to accomplish.
The intent of this notice is to allow potentiallyaffected parties not already on the
PRG to come forward.With the concurrence of all affected parties,the project
sponsor may use some other method to determine a Path rating.
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4.3.4.Accepted Rating Protection
A new project shall not cause a reduction in an Accepted Rating of another Path
(e.g.,because of a reliability criteria consideration)unless mitigating or
compensatingmeasures are provided.However,if a facility is retired from
service (e.g.,generator,shunt reactive equipment,RAS),all Path ratings that rely
on the facility must be reviewed and reduced to the extent that system impacts of
such retirements are not mitigated.Just as with the addition of facilities,planning
for the retirement of facilities must be closely coordinated with affected systems
(e.g.,through the Progress Reporting Procedure or Path Rating Process)to allow
adequatetime to mitigate any adverse impacts and negotiate any commercial
issues (e.g.,which system should be responsible for the costs of mitigation).If a
Path's Accepted Rating relied on facilities that are not part of the Path's Plan of
Service,and if those facilities are retired,modified,or never built,the Accepted
Rating is subjectto review in the same manner as if changes had occurred in the
Path's Plan of Service.
A transmission Path's Accepted Rating will not be lowered because its maximum
achievable flow is reduced (i.e.the Path can no longer meet the MFT)due to
system changes made by others with the exception of the changes described in
the previous paragraph.System owners that make such changes shall be
responsible for mitigating any adverse impacts on the other system(s).
Transmission Path owners that make changes to their system that increase the
flow on a Path with a Flow-Limited Rating can receive a higher Accepted Rating
consistent with the MFT.This same principle applies if the flow on the Path is
increased by a project initiated by another party;althoughin that case,it should
be recognized that the higher Accepted Rating relies on and is subjectto the
operation of the other party's facilities.
4.3.5.Application To Existing Systems
Althoughthe primary focus of the Path Rating Process is to establish ratings for
new Paths,existing transmission paths cannot be ignored.Existing transmission
paths have been rated using various methodologiesand guidelines,some of
which are inconsistent with the methods proposed in this document.These
inconsistencies are primarily in the areas of flow-limited paths,use of fictitious
elements,and Latent Capacity.
This document is intended to assure the developmentof an efficient,reliable
electric system and to balance the competing interests of protecting the
legitimateratings of existing facilities while encouraging the economic and
environmentallysound expansionof transmission capacity.The following
principles guide how existingtransmission paths are treated within the WECC
rating process.
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1.Transmission path ratings that were known and used in operation as of
January 1,1994,will be classified as Existing Ratings.
2.A sponsor of a new Project who is impacted by an Existing Rating and is in
Phase 2 of the Path Rating Process may ask that the Existing Rating be
reviewed by the PRG.The PRG is responsible for deciding if,and how,the
Existing Rating will be demonstrated.
3.If an owner desires to establish an Accepted Rating for an existing
Transmission Path,the current WECC approved guidelineswill be followed.
4.A Transmission Path's Existing Rating will not be lowered because of reduced
maximum achievable flow on the path due to system changes made by
others.
5.Transmission path owners that make changes to their system that reduce the
maximum achievable path flow,will have their Existing Rating reduced by the
amount the path's flow was reduced.
4.3.6.Latent Capacity
Latent Capacity is the Transfer Capability that may be acquired by improving an
existing path without adding new lines to the path.Latent Capacity is not
protected,it cannot be used in operation,and it is not recognized nor
incorporated by others in their rating studies.The only means of protecting Latent
Capacity is to take the path through the Path Rating Process.
Project sponsors,as appropriate,need to identify and document Latent Capacity.
Documenting information on Latent Capacity may be useful for:
·Promoting appropriate decisions in generatorsiting;
Facilitating Project Coordination;
Fulfilling transmission access request requirements;
Establishing one's intent to expand the transmission system;
Gaining expeditedreview by a PRG provided that the Latent Capacity has
been adequatelyreviewed and documented and the PRG determines that the
original documentation is still applicable;and
Providing some assistance in contract negotiations.
4.3.7.Margin
If planning margin beyond that afforded by the NERC Reliability Standards and
WECC Criteria is considered necessary,the PRG may agree to establish the
additional planning margin requirementwhen determining a Path rating.To allow
potentiallyaffected parties not on the PRG to come forward,the project sponsors
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must provide notification to the PCC of their intent regarding the requirement for
additional planning margin during Phase 2 of the rating process,including a
justificationof why the additional planning margin is needed.
The justificationfor additional planning margin needs to specifically address the
followingpoints:
1.Explain how the amount of planning margin is related to risk.
2.Describe how the amount of planning margin applied to a path rating is
related to the level of uncertainty in determining the rating.
3.Define the rationale for the amount of additional planning margin
recommended.
4.Explain how the amount of planning margin would be consistentlyapplied.
4.3.8.Neutrality of Path Definitions
When a new facility interacts with an existing Path,two options are available to
address this interaction.One option is to include the new facility in the existing
Path and manage the expandedPath as a single unit.The second option is to
define the new facility as a new Path and define the relationship with the existing
Path in a nomogram.
In either case projects sponsors are required to determine if the proposed Project
would constitute a subset of an existing Path.Ideally,this is done as early in the
Path Rating Process as possible.If the proposed Project is determined to be a
subset of an existing Path,the project sponsor must re-rate the Path within the
Path Rating Process.Please refer to AppendixD for the two tests required to
provide information to the PRG to aid in determining whether a proposed Project
is a subset of an existingPath.However,if a project sponsor includes in its study
plan or decides in Phase 1 that it will treat the proposed Project as a subset of an
existing Path,performing the tests will not be necessary.
4.3.9.Reverse Flow
It may be impossible to achieve a desired MFT if a project sponsor is trying to
rate a line in a direction counter to prevailing flows.Parties faced with such a
circumstance could still schedule transactions over the path in the opposite
direction using a net scheduling approach.Once the rating of a Transmission
Path has been established,scheduled transactions over the Path are permitted
in either direction providing the net schedule at any time does not exceed the
Path rating in either direction.For example,if the Path rating has only been
established in one direction,schedules are still permitted in both directions as
long as the net schedule is in the same direction as the Path rating direction and
does not exceed the Path rating.
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5.Phase 2 Accepted Rating Comprehensive Study Plan
5.1.Introduction
The purpose of this study plan is to provide a consistent,comprehensivestudy
methodologyfor the path or project sponsor to follow in establishingan Accepted
Rating for either an existing Transmission Path or a Transmission Path which
includes a new Project.
The followinggeneric study plan is an exampledescribing activities appropriate
to rating a major transmission Path associated with a Project.Not all of these
proposed activities are necessary for all Projects.Project sponsors,with
agreementfrom the PRG,shall determine the study activities required.
5.2.Study Objectives
5.2.1.Satisfy Reliability Criteria
In establishingan Accepted Rating for an existing Path or for a Path with a new
Project,the project sponsor is responsible for assuring that the Accepted Rating
complies with NERC ReliabilityStandards,WECC Criteria,and requirements in
this document.
5.2.2.Affirm Plan of Service For a New Project
1.If a new Project is planned,the PRG shall review and comment on the Plan of
Service.
2.The PRG shall establish a consensus that the Plan of Service supportsthe
Accepted Rating.
5.2.3.Acquire An Accepted Rating
1.In establishingthe Accepted Rating for a Transmission Path,the non-
simultaneous and simultaneous Transfer Capabilities must be determined.
2.All new Projects that are Similarly Situated on the same Path are required to
establish a combined non-simultaneous rating19 increase on that Path.
3.The impact of the new Project on other Projects or Paths with Existing
Ratings,Planned Ratings Similarly Situated in Phase 2B,or Accepted
Ratings,must be determined.
4.The project sponsor should obtain agreementfrom the PRG regarding the
study results.
5.A Phase 2 Rating report must be prepared for submittal to the WECC PCC
based on the findings of the PRG.
*The Combined Project Study will determine the simultaneous impact of the projects on the path,but the
Path Rating thus determined will constitute the non-simultaneous rating in relation to other WECC Paths.
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5.3.Major Study Assumptions and System Representation
5.3.1.Project Description
Detailed information regarding the Plan of Service must be provided to the PRG
and WECC staff and must include the technical and physical characteristics of
the Project such as:
Associated generation (if any);
Line voltage,line length,and other line characteristics;
Use of series capacitors,series compensationlevel,location of capacitor
banks within the line,capacitor over voltageprotection type (varistor or
conventional gap);
Phase Shifters;
Shunt reactive compensation;
SVCs (with ratings);
Remedial Action Schemes;
Indication of whether the proposed Project is part of a new Path or existing
Path;and
Any other relevant characteristics.
5.3.2.Other Phase 2B and Phase 3 Projects Included
The project sponsor must provide a list of planned Projects in Phase 2B and
Phase 3 of the Path Rating Process that could affect or be affected by the Project
under consideration.
5.3.3.RegionallArea Loads and Resources
System studies must be performed using the latest available load and resource
data for the Western Interconnection for the time frame being studied.In general,
the load level modeled for the base cases should be typical for the time of year
being evaluated.Sufficient generation shall be represented to accommodate the
interchange patterns described and in accordance with the individual system's
plans or operating policies.Interchange transfers shall reflect the objectivesof
the case.
5.3.4.System Representation
The Path or project sponsors must explainhow the system,both transmission
and generation,will be modeled.The PRG must approve the representation.For
further guidance,see AppendixA and the System Review Work Group (SRWG)
Data Preparation Manual.
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The followingare general guidelinesfor system representation:
1.Full loop representation is to be used with the entire WECC system modeled.
2.All system elements will be in service for the assumed initial conditions.
3.System transfer levels for major WECC Paths should be agreed upon and
listed.Additional transfer paths should be included as appropriate.
4.Voltagecriteria should be applied in accordance with existing practice by the
respective utilities or the operating agents.
5.The phase shifter methodologyto be followed for all applicablephase shifters
should be identified.
6.A list of the series compensationassumptionsfor the majorextra-high voltage
(EHV)lines should be provided.
7.A detailed system representation of the study area should be modeled when
appropriate.
5.3.5.System Stressing/Loading
1.Loading on the subjectPath shall be accomplished in such a way as to
achieve the expected Accepted Rating of the Path.In achieving the
Simultaneous Transfer Capability on the subject Path,affected Transmission
Paths must not be loaded above their applicable Transfer Capabilities.The
intent here is to set guidelinesin developingreasonable base cases.
2.The Transfer Capability of a path is based on the amount of power that flows
on a path and not how much schedule change was required to load the path
to its rating.
3.Possible methods in which power will be made available for stressing the
subjectPath include:
a.Sending Region
i.Available generating units should be added in a reasonable manner
within the appropriate areas as agreed to by the PRG.
ii.Loads should be decreased in a reasonable manner as agreed to by
the PRG within the appropriate areas.The amount of load reduction
should be documented.
b.Receiving Region
i.Those generators to be decreased in a reasonable manner should be
specified within the appropriate areas as agreed to by the PRG.
ii.Load should be increased in a reasonable manner as agreed to by the
PRG within the appropriate areas.The amount of load increase should
be documented.
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5.4.Study Methodology
Power flow,stability,and post-transientstudies shall be performed in accordance
with the NERC Reliability Standards,WECC Criteria,the WECC Post-Transient
Study Methodology,local utility criteria and guidelines,and the process
described herein.General study guidelinesfollow in Section 5.5.
5.4.1.Developmentof Base Cases
1.Select base cases from the most recent WECC cases available for the study
time frame and conditions.
2.The PRG shall update the base cases to reflect the most accurate system line
configuration,generation,and load representation for each appropriate
individual control area for the study time period.
3.Incorporate all appropriate study assumptionsagreed to by the PRG into the
base cases.
4.Representsignificant non-utility generators.
5.Considerable latitude in the base case assumptionsis allowed in maximizing
the flow on the Path being rated.The PRG is responsible for ensuring that the
representation is realistic.
5.4.2.Developing an Accepted Rating for an Existing Path
1.Determine the non-simultaneous Transfer Capability.
a.The objectiveof this phase of the study is to have the Project sponsor
ensure and demonstrate that the Path being rated meets the NERC
ReliabilityStandards,WECC Criteria,and other specific regional criteria
where appropriate.
b.Stress the subjectPath to its proposed or expectedNon-Simultaneous
Transfer Capability and take outages.All affected Path flows should be at
flow levels that result in non-interaction with the Path being rated.If a limit
due to a Reliability Criteria violation has not been reached or has been
exceeded,increaseldecrease,as appropriate,the stress level for the
subjectTransmission Path until a limit is reached.
c.If the ability to increase flow on the Path is exhausted (due to lack of
generation,affected Path overloading,etc.)prior to reaching a reliability
limit,then the maximum flow achieved on the Path is defined to be the
Non-Simultaneous Transfer Capability and the Path is considered to be
flow-limited.
2.Conduct screening studies to determine which affected Paths are to be
evaluated on a simultaneous basis.
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a.If the interacting paths are already identified,then the screening studies
described below are not required.
b.If the interacting paths are not already identified,then a screening study
should be conducted using the base case that established the Non-
Simultaneous Transfer Capability:
Apply the most critical outageon the path that established the Path's
Non-Simultaneous Transfer Capability.
Phase shifters should be in a non-regulating mode.
As a minimum study requirement,identify all affected paths that pick
up a ten percent increment or more,based on that affected path's
rating,due to the outage.
It should be noted that this screening test is not intended to be the only
consideration in determining the impact on affected paths.
3.Determine the Simultaneous Transfer Capability.
a.The objectiveof this phase of the study is to have the project sponsor
ensure and demonstrate that the Path being rated meets the NERC
ReliabilityStandards and WECC Criteria under simultaneous conditions.
b.Using the base case that established the Non-Simultaneous Transfer
Capability,maintain the Path being rated at its Non-Simultaneous Transfer
Capability,in Steps c and d.
c.Individually stress every affected path,one at a time,to its Non-
Simultaneous Transfer Capability (whetherreliability or flow based).
d.Apply outagesand look for criteria violations.This step is performed on a
path by path basis.If a violation occurs,determine a simultaneous
nomogram describing the safe operating range.If criteria violations are not
observed,then a simultaneous interaction problem does not exist.
4.Conduct sensitivitystudies.
Sensitivitystudies should be conducted as agreed to by the PRG and as they
relate to the study objectives.
5.4.3.Developing an Accepted Rating for a New Path:
1.Conduct pre-Project benchmark studies,if needed.
a.Pre-Project benchmark studies for the Non-Simultaneous and/or
Simultaneous Transfer Capabilities should be performed for the subject
Path (and,if necessary,other paths)if the system performance and/or the
existing Transfer Capability without the Project in service is unknown.
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2.Determine post-Projectnon-simultaneous Transfer Capability.
a.The objectiveof this phase of the study is to demonstrate that the
proposed Plan of Service for the Project is adequateto support the
proposed rating while meeting the NERC ReliabilityStandards and WECC
Criteria and specific regional criteria where appropriate.
b.Stress the Path with the new Project to its proposed or expected Non-
Simultaneous Transfer Capability and take outages.All affected path flows
should be at flow levels that result in non-interaction with the Path being
rated.If a limit due to a reliability criteria violation has not been reached or
has been exceeded,increaseldecrease,as appropriate,the stress level
for the Transmission Path until a limit is reached.
c.If the ability to increase flow on the Path is exhausted (due to lack of
generation,affected path overloading,etc.)prior to reaching a reliability
limit,then the maximum flow achieved on the Path is defined to be the
Non-Simultaneous Transfer Capability and the path is considered to be
flow-limited.
3.Conduct screening studies to determine which affected paths are to be
evaluated on a simultaneous basis.
a.If the interacting paths are already identified,then the screening studies
described below are not required.
b.If the interacting paths are not already identified,then a screening study
should be conducted.Using the base case that established the Non-
Simultaneous Transfer Capability,take the most critical outage on the
Path that established the Non-Simultaneous Transfer Capability.As a
minimum study requirement,identify all paths that pick up an increment of
ten percent or more based on the affected path's rating due to the outage.
Phase shifters should be in a non-regulating mode.It should be noted that
this screening test is not intended to be the only consideration in
determining the impact on affected paths.
4.Determine Simultaneous Transfer Capability.
a.The objectiveof this phase of the study is to have the project sponsor
ensure and demonstrate that the path being rated meets the NERC
ReliabilityStandards and WECC Criteria under simultaneous conditions.
b.Using the base case that established the Non-Simultaneous Transfer
Capability,maintain the path being rated at its Non-Simultaneous Transfer
Capability,in Steps c and d.
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c.Individually stress every affected path,one at a time,to its Non-
Simultaneous Transfer Capability (whetherreliability or flow based).
d.Apply outagesand look for criteria violations.This step is performed on a
path by path basis.If a violation occurs,determine a simultaneous
nomogram describing the safe operating range.If criteria violations are not
observed,then a simultaneous interaction problem does not exist.
5.Conduct sensitivitystudies.
Sensitivitystudies should be conducted as agreed to by the PRG and as they
relate to the study objectives.
5.5.Study Guidelines
5.5.1.General Principles
In general,companies involved will base the criteria applied to the Transmission
Paths on the current criteria in use.These criteria shall be made available to the
PRG and consistentlyapplied.
5.5.2.Power Flow Guidelines
Power flow studies shall be performed using the followingguidelines:
1.Phase Shifter Operation
a.Phase shifters shall be operated according to operating procedures
established by the owners.The PRG must agree to deviations to the
procedures.
b.For line outages,phase shifters shall be operated at pre-outage phase
anglesunless resultant flows exceed established limits.If emergency
loadings are exceeded,the owner of the overloaded phase shifter shall be
consulted about the impact of the disturbance on their system to
determine an appropriate action to reduce the overload.The action could
include reducing transfers.
2.Thermal Capacity Limits
a.No transmission element will be loaded above 100%of its continuous
rating under normal conditions.
b.For a single contingency loss of an element(s),no transmission element
will be loaded above its emergency rating.A list of continuous and
emergency ratings for applicablefacilities shall be developedby the PRG
and included in the study documentation.
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3.System VoltageLimits
a.System stresses shall be limited such that the NERC ReliabilityStandards
and WECC Criteria will govern voltagedeviation for loss of a system
element.All deviations from the WECC Criteria shall be listed.
b.Document importantbase case voltagecriteria in this section.Also include
a list of minimum acceptable bus voltagesfor outages.Provide a list of
bus voltagesto be monitored.The PRG must review and approve this list
to ensure all meaningful buses are monitored.
4.Important path flows must be monitored and listed in this section.The PRG
must review and approve this list to ensure that all meaningful paths are
being monitored.
5.5.3.Stability Guidelines
Stability studies shall be performed as needed to establish the stability transfer
limit and to ensure system stability followinga critical fault on the system.These
studies facilitate the developmentof the dynamic voltagesupportrequirements.
1.Fault Damping
Three phase fault damping shall be applied according to the appropriate
operating guidelines.The rationale and use of it shall be documented in the
assumptionsused.
2.Machine Representation
a.Representationof generators in the WECC transient stability database
must be consistent with available generatordata modeled in current
WECC base cases.Machines greater than 20 MVA must be represented.
b.The power system stabilizers that are normally in service within the WECC
system must be modeled for the appropriate case selected.
3.System Disturbance
System disturbances for stability studies must be initiated by a three-phase-
to-ground fault on the EHV bus adjacentto the majorinterconnection point
and/or power plantof interest.A single line-to-ground fault must be studied as
a sensitivity,if requested by the PRG.The list of outagesto be studied must
be agreed upon by the PRG and listed in the report.
4.Fault Clearing Time
a.Faults on the transmission lines being evaluated will be cleared in
accordance with guidelines provided by the appropriate members of the
PRG.
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b.Backup clearing time for stuck breaker operation will be provided by the
appropriate members of the PRG.
5.Series Capacitors
Particular attention should be paid to modeling the correct performance of
series capacitors.The protective schemes (i.e.,bypass arc gaps,zinc oxide
varistor)on the series capacitors vary widely and consequentlycan affect the
system performance differently.The series capacitors must be modeled as
they will perform in actual use.
6.Evidence of System Stability
The system will be considered stable if the followingconditions are met:
a.Machine Synchronism
All machines in the system remain in synchronism as demonstrated by the
relative rotor angles.
b.System Damping
A stabilitysimulation is deemed to exhibit positive damping if a line
defined by the peak of the machine-relative,rotor-angle swing curve will
intersect a second line connecting the valleyof the curves with an
increase in time.Corresponding lines on bus voltageswing curves will
also intersect with an increase in time.Duration of a stabilitysimulation is
ten seconds unless a longer time is required to ascertain stability.
c.Transient VoltageCriteria
i.Major transmission bus voltagesand machine terminal voltagesshould
meet the appropriate guidelinesfollowingthe disturbance.The PRG
shall review and approve a list of the buses to be monitored.
ii.System transient voltageperformance must meet the WECC Criteria at
a minimum.
d.Stability Plot List
A standardized stability plot list shall be included with the study plan.This
list must be approved by the PRG to ensure all meaningful quantitiesare
monitored.
5.5.4.Post-transient Governor Power Flow Study
Post-transient power flow analysis shall be done when requested by the PRG.
This analysis must be consistent with the "Voltage Stability Assessment
Methodology"and "Voltage Stability Criteria,UndervoltageLoad Shedding and
Reactive Reserve Monitoring Methodology"documents.The analysis must
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demonstrate conformance of the Plan of Service with the NERC Reliability
Standards and WECC Criteria.
5.5.5.Remedial Actions
All RAS required to obtain the Accepted Rating must be described in detail and
modeled as they will be applied in operation.
5.5.6 Loss of Entire Corridor Analysis2°
The detailed study and reporting of impacts due to Extreme Events,particularly
"loss of entire corridor"events,shall be a part of the path rating analysis
performed in the PRG and documented in the Phase 2 Rating Report.The
corridor(s)and facilities in the corridor(s)for this analysis will be specified in the
study plan approved by the PRG.This analysis allows WECC and all
interconnected parties to be made aware of the impacts related to an outageof
multipletransmission lines in the same corridor.This analysis is most important
to high-capacity EHV transmission lines and their potential reliability impact to the
Western Interconnection.
5.6.Documentation of Study Conclusions
The purpose of the Project Review Group Phase 2 Rating Report is to document
the study results and conclusions and to demonstrate how a Project affects the
overall system performance as defined by WECC requirements.The project
sponsor is responsible for ensuring that the report demonstrates conformance
with NERC ReliabilityStandards and WECC Criteria.
1.The report documenting the Accepted Rating must also provide a general
background about the existing system or Project.The background could
include historical information,a general Project description,Project need and
use,and Project participation.The central elements of a Phase 2 Rating
Report are:Plan of Service (including milestones)specified for the Phase 2
studies and a statement that the Plan of Service meets NERC Standard and
WECC Criteria;
2.Corrective actions and/or Mitigation Plan,if needed,to supportthe Accepted
Rating
3.Assumptionsused in the Rating Study,including load levels,existing and
future resources,and other projects upon which the Accepted Rating relies.
The corrective actions and/or Mitigation Plan shall ensure that issues identified
will continue to be addressed in Phase 3 and appropriate steps taken in a timely
manner to mitigate impacts prior to operation of the new project.Mitigation of
impacts can include operating the Path associated with the Project at levels
below the Accepted Rating with PRG approval.
20 Mitigation of the impacts due to Extreme Events is not required to achieve an Accepted Rating.
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6.Process Examples
The followingprocess scenarios are intended to provide guidance on how a project
sponsor could proceed through the Path Rating Process for Projects of various
complexities.
6.1.Expediting the Process -Project with no Comments Received
As explainedabove in Section 3.3 (Expediting the Process),this scenario is
illustrative only.All requirements of the Path Ratings Process described in
Section 3 remain the same and all timelines for the individual steps still apply.
The followingis simply a description of how several steps of the process may be
followed concurrently.
6.1.1.Phase 1
1.Member A has conducted internal studies and determined that installing a
generation shedding scheme will increase the Accepted Rating of its path.
The lead time to order and install the necessary equipmentis three months.
2.One month later,Member A completesadditional studies and submits a
comprehensivereport to all TSS,PCC,and OC members announcing the
proposed increase in the rating of its path.The cover letter advises TSS,
PCC,and OC members of Member A's desire to expeditethe process and
requests expressionsof interest in joininga Project Review Group (PRG).
Since the equipmentwill be installed within three months,Member A should
also copy these notices to members of the Operating Practices Subcommittee
(OPS)and the Technical OperationsSubcommittee (TOS)to facilitate the
review process.
3.The Project has entered and remains in Phase 1.
4.During the 60-day period,there are no comments on the proposed rating or
expeditingthe process and no expressionsof interest in a PRG.
6.1.2.Phase 2
Since all requirements to enter Phase 3 have been met,this Project proceeds
directly from Phase 1 into Phase 3.Member A notifies the PCC chair that all
requirements to enter Phase 3 have been met.
6.1.3.Phase 3
1.The PCC chair,upon determination that the Project has met all requirements
to enter Phase 3,notifies all TSS,PCC,and OC members that the Project
has entered Phase 3,and that the comprehensivereport is considered to be
the Phase 2 Rating Report.The Path associated with the Project has an
Accepted Rating.
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2.If Member A has installed the necessary equipment,the new Accepted Rating
can be used immediately-60 days after submittingits report and notifications
to WECC.
6.2.Project with Minor Comments
6.2.1.Phase 1
1.Member A lists a new transmission line in the WECC Data Collection
Process.The Project is now in Phase 1.
2.Member A then submits a ComprehensiveProgress Report to all TSS,PCC,
and OC members with a letter requesting Phase 2 status.The Report
includes a full Project description suitable for modeling the Project in WECC
base cases.The cover letter also requests expressionsof interest in a PRG
(hoping there will be no interest expressedfor formation of a PRG).
3.The Report shows no criteria violations at the Planned Rating and details how
the Project will curtail to maintain the Accepted Rating of an existingPath with
a known simultaneous rating conflict.
4.Within the 60-day review period,Member B requests that some additional
contingencies in member A's system be studied,and that the voltageand
frequency at several of Member B's load buses be monitored.
5.Member A conducts the requested studies and provides the study results to
Member B,requesting confirmation within an agreed-upon time frame that
they have no objections to the Planned Rating.
6.Member B confirms within the stated time period that they are satisfied and
do not express an interest in joining a PRG.
7.No other members express an interest in forming a PRG.
6.2.2.Phase 2
Since all requirements to enter Phase 3 have been met,this Project proceeds
directly from Phase 1 into Phase 3.Member A notifies PCC,TSS,and OC
members that the project's ComprehensiveProgress Report is considered to be
the Phase 2 Rating Report and that the Project has met all requirements to enter
Phase 3.PCC will have 30 days to comment regarding conformance with these
procedures.
6.2.3.Phase 3
Based on the resolution of all comments,and no interest in formation of a PRG
and no comments from PCC,the PCC chair notifies PCC,TSS,and OC
members that the Project has entered Phase 3 and the Path associated with this
Project is granted an Accepted Rating.
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6.3.Complex High-Impact Project
6.3.1.Phase 1
1.Member A lists a new transmission line in the WECC Data Collection
Process.The Project is now in Phase 1.
2.The Planning Coordination Committee finds that the Project conforms to the
Project Coordination Objectives.
3.Member A then submits a ComprehensiveProgress Report to all TSS and
PCC members with a letter requesting Phase 2 status.The report includes a
full Project description suitable for modeling the Project and it is represented
in WECC base cases.
4.The report shows no criteria violations at the Planned Rating for numerous
contingencies within Member A's system and details how the Project will
curtail to maintain the Accepted Rating of an existing Path with a known
simultaneous rating conflict.
5.Within the 60-day review period,Member B requests that some additional
contingencies in Member A's system be studied and that the voltageand
frequency at several of Member B's load buses be monitored.
6.Member A conducts the requested studies and provides the study results to
Member B.Member A found some problemsand agrees to address those
issues in Phase 2.Member A notifies the TSS chair that the Project has met
all requirements to enter Phase 2.
6.3.2.Phase 2
1.The TSS chair,in consultation with WECC staff,verifies that all requirements
have been met.The TSS chair notifies all PCC and TSS members that the
Project has entered Phase 2A of the Path Rating Process and the Path
associated with the Project is conferred a Planned Rating.
2.Member A writes to all members of PCC,TSS,and OC,requesting
expressionsof interest in participating in a PRG,and allows at least 30 days
response time.To increase participation,Member A also reaches out to
members that may be interested to request participation.Some interest is
expressedand meetings are scheduled.
3.The PRG meets several times.The members also identify a number of
additional studies and potentialsimultaneous limits that they wish to be
addressed.Member A developsthe study plan and the base cases.The PRG
members approve the study plan (which includes at a minimum the study
timeline,milestones,other Projects in Phase 2B and Phase 3)and the
Foundational Base Case.The PRG agrees that the Project study meets the
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requirements to enter Phase 2B.Member A notifies the PCC chair and
WECC staff within five working days after the date the PRG approved the
study plan and the Foundational Base Case.
4.During the studies,simultaneous limits are discovered and studies are
continued over the next year.Member A modifies the Project to partially
mitigate the simultaneous limits and identifies the curtailments necessary to
mitigate remaining simultaneous operating problems.
5.At the last meeting of the PRG,all members are satisfied exceptfor Member
C who feels that additional study work is required.
6.Member A submits a Phase 2 Rating Report to all members of TSS,PCC,
and OC without performing the additional work requested by Member C.
7.No protests from the members of the PRG (including Member C)are received
within 30 days and all PCC members'concerns regarding conformance with
the procedure have been addressed.Since no member raise any objections,
Member A notifies the PCC chair that the Project has met all requirements to
enter Phase 3.
6.3.3.Phase 3
When the PCC chair determines that all requirements for entering Phase 3 have
been met,the PCC chair notifies all TSS,PCC,and OC members that the Phase
2 Rating Report has been accepted and the Project has entered Phase 3.The
Path associated with the Project has an Accepted Rating.
6.4.Project With Protest
6.4.1.Phase 1
1.Member A lists a new transmission line in the WECC Data Collection
Process.The Project is now in Phase 1.
2.Member A then submits a ComprehensiveProgress Report to all TSS and
PCC members with a letter requesting a Phase 2 status.The Report includes
a full Project description suitable for modeling the Project in WECC base
cases.
3.The Report shows no criteria violations at the Planned Rating for numerous
contingencies within Member A's system.
4.Within the 60-day review period,Member B requests that some additional
contingencies in Member A's systemsbe studied,and that the voltageand
frequency at several of Member B's load buses be monitored.
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5.Members A and B agree to form a PRG and address the concerns in Phase
2.Member A notifies the TSS chair that the Project has met all requirements
to enter Phase 2.
6.4.2.Phase 2
1.The TSS chair,in consultation with WECC staff,verifies that all requirements
have been met.The TSS chair notifies all PCC and TSS members that the
Project has entered Phase 2A of the Path Rating Process and the Path
associated with the Project is conferred a Planned Rating.
2.Member A writes to all members of the PCC,TSS,and OC,requesting
expressionsof interest in participating in a PRG,and allows at least 30 days
response time.Some interest is expressedand meetingsare scheduled.
3.A PRG is formed and meets several times.The members also identify a
number of additional studies and potential simultaneous limits that they wish
addressed.Member A developsthe study plan and the base cases.The PRG
members approve the study plan that includes,at a minimum,the study
timeline,milestone,other Projects in Phase 2B and Phase 3 and the
Foundational Base Case(s).The Project study meets the requirements to
enter Phase 2B.Member A notifies the PCC chair and WECC staff within five
working days after the PRG approves the study plan and the Foundational
Base Case.
4.During the studies,a criteria violation in Member B's system is discovered
under high simultaneous transfers.Member A proposes to mitigate the
problem by paying for the installation of a shunt capacitor on Member B's
system.Member B does not like the idea.
5.Member A drafts a review group report proposing the shunt capacitor
mitigation.After review and editing,a majority of the PRG accepts the report
with the shunt capacitor mitigation.Member B votes against the report.
Member B also submits a minority report.
6.The report,including the minority report submitted by Member B,is submitted
to the PCC with a request for Phase 3 status.
7.Member B files a protest within 30 days claiming the proposed mitigation is
unacceptable.
8.The PCC withholds acceptance pending resolution of Member B's protest.
The PCC raises no concerns regarding conformance with the procedure.The
PCC chair informs Members A and B that they must agree to resolve the
protesteither between themselves,with assistance of the TSS or PCC,using
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the WECC Dispute Resolution Procedures in the WECC Bylaws,or with
outside assistance.
9.At the request of either Member A or Member B,the PCC chair holds a
discussion at a PCC meeting.Based on the discussion,the PCC votes to
affirm that Member A's proposed mitigation was acceptable in accordance
with the ReliabilityCriteria.Member B does not agree with the PCC vote.
10.The parties choose arbitration and accept WECC assistance in providing an
arbitrator and associated support.Both parties state their cases per the
process set up by the arbitrator.The arbitrator accepts Member A's proposed
resolution.
11.The results are sent to the PCC chair and,since all PCC members'concerns
regarding conformance with this procedure have been addressed,Member A
notifies the PCC chair that the Project has met all requirements to enter
Phase 3.
6.4.3.Phase 3
1.When the PCC chair determines that all requirements for entering into Phase
3 have been met,the PCC chair notifies all TSS,PCC,and OC members that
the protest has been resolved.The Phase 2 Rating Reportis accepted by the
PCC and the Project enters Phase 3.
The Path associated with the Project now has an Accepted Rating.
2.Members A and B implementthe mitigation as described in the Phase 2
Rating Report.
3.Member A begins commercial operation at the rating set in the Phase 2
Rating Report.
6.5.Rating Determined By Alternative Method
6.5.1.Phase 1
1.Member A has conducted internal studies and determined the Proposed
Rating of its flow-limited path using some method other than the Maximum
Flow Test (MFT).
2.Member A completesadditional studies and submits a comprehensivereport
to all TSS,PCC,and OC members announcing the Proposed Rating of its
path.In the mailing,Member A includes a description of the alternative
method they used and what the proposed method is intended to accomplish.
The cover letter requests Phase 2 status and expressionsof interest in joining
a PRG.
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3.The Project has entered Phase 1.During the 60-day period,the only
comments received are questionsabout the alternative method used.Several
members express interest in a PRG.Since formation of a PRG has been
requested,questionsabout the alternative method will be addressed in the
Phase 2 process.The Project sponsor notifies the TSS chair.
6.5.2.Phase 2
1.After verification with WECC staff that no comments were received about the
deficiency of the comprehensivereport,the TSS chair notifies all PCC and
TSS members that the Project has entered Phase 2A of the Path Rating
Process and the Path associated with the Project is conferred a Planned
Rating.
2.Member A informs the PCC,TSS,and OC that a PRG is being formed and
gives details about the alternative method that will be used in the Rating
Studies.
3.The PRG agrees that the only issue concerns the alternative methodology
and no member of the PRG requested any simultaneous studies.The PRG
agrees that the Project can proceed to Phase 2B.Member A notifies the PPC
chair and WECC staff within five working days.
4.The PRG meets and all the affected parties concur that the project sponsor
may use this method for determining the path'srating.
5.At the last meeting of the PRG,all members are satisfied.
6.Member A submits a Phase 2 Rating Report to all members of the TSS,PCC,
and OC.
7.No protests from the members of the PRG are received within 30 days and all
PCC members'concerns regarding conformance with this Path Rating
Process have been addressed,Member A notifies the PCC chair that the
Project has met all requirements to enter Phase 3.
6.5.3.Phase 3
When the PCC chair determines that all requirements for entering Phase 3 have
been met,the PCC chair notifies all TSS,PCC,and OC members that the Phase
2 Rating Report has been accepted and the Project has entered Phase 3.The
Path associated with the Project has an Accepted Rating.
6.6.Similarly Situated Projects
6.6.1.Relationship between Projects in Phase 2A,2B,and Phase 3
The followingdiagram shows four Projects in various stages of studies in Phases
2A,2B,and 3 based on the definition of "Similarly Situated Projects."
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Similarly-Situated Projects -At any point in time,if any two Projects are
togetherin Phase 2B of the Path Rating Process,they are Similarly Situated and
have a responsibility to mitigate interaction they have with each other until both
become operational.
Phase 1 Phase 2A Phase 2B Phase 3 Operation
1.Project X and Project Y are Similarly Situated.
2.Project Y enters Phase 2B after Project X and has the burden of performing
the simultaneous study that includes Project X.
3.Project X does not have the burden of (but is not precluded from)performing
the simultaneous study that includes Project Y.
4.Project X and Project Y have to consider the impacts on each other and share
in the responsibility of mitigating the impacts (Planned Ratings are not
protected).
5.Projects X,Y,and Z have the burden of mitigating the impacts on Project W
in Phase 3 (Accepted Ratings are protected).
6.Project Z is in Phase 2A,and must take Projects W,X,and Y into account in
its studies.
7.Principle Scenarios
7.1.Neutrality of Path Definition
7.1.1.Principle to Illustrate:
Section 4.3.8:"When a new facility interacts with an existing Path,two options
are available to address this interaction.One option is to include the new facility
in the existing Path and manage the expandedPath as a single unit.The second
option is to define the new facility as a new Path and define the relationshipwith
the existing Path in a nomogram."and
"In either case,projects sponsors are required to determine if the proposed
Project would constitute a subset of an existing Path.Ideally,this is done as early
in the Path Rating Process as possible.If the proposed Project is determined to
be a subset of an existingPath,the project sponsor must re-rate the Path within
the Path Rating Process."
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7.1.2.Existing Situation:
A and B have a rating in the A to B direction (Path Y)and have established a
rating of 1000 MW on Path Y and 1200 MW on Path X.
A B '°°°
Y
Flow
x
C X FIOW 1200
7.1.3.Changeto the Existing Situation:
1.Owner D builds Line Z between B and A.
2.Line Z has a non-simultaneous rating of 550 MW.
3.Owner D has not decided in Phase 1 to include Line Z as part of Path Y for
rating purposes.
4.Owner D conducts the two tests in AppendixD and determines the
percentage change in power flow with addition of Line Z.The information was
provided to the PRG.The PRG determines that Line Z is a subset of Path Y.
5.Owner D re-rates the existing Path Y.
6.From the MFT analysis it is found that the maximum possible flow across Z +
Y is 1500 MW.
7.1.4.Alternative 1:
Line Z is combined with Path Y for rating purposes and the rating of the
combined path under the MFT is 1500 MW.
7.1.5.Alternative 2:
1.Owner D does not want to include the new line with Path Y for rating
purposes,but rather chooses to be a separate path,and the PRG determines
that the Path Y does not have to be rerated to include Line Z.
2.Line Z remains a separate path and establishes a nomogram with a non-
simultaneous limit of 550 MW.Line Z (OwnerD)must make arrangements
with Path Y to keep the combined Z +Y schedule at or below 1500 MW.
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z
550
500 -------A Y B
\Z
\Flow
I
I
C I
950 1000YFlow
7.2.Reverse Flow
7.2.1.Concept to IIIustrate:
Section 4.3.9:"It may be impossible to achieve a desired MFT if one is trying to
rate a line in a direction counter to prevailing flow.Parties faced with such a
circumstance could still schedule transactions over the path in the opposite
direction using a net scheduling approach.Once the rating of a Transmission
Path has been established,scheduled transactions over the path are permitted in
either direction providing the net schedule at any time does not exceed the path
rating in either direction.For example,if the path rating has only been
established in one direction,schedules are still permitted in both directions as
long as the net schedule is in the same direction as the path rating direction and
does not exceed the path rating."
7.2.2.Existing Situation:
1.System A is resource deficient by 900 MW.
2.System B has surplus generation of 1000 MW.
3.System C is energy deficient at various times (primarily hydro).
4.System A has a high-load-factor system and always imports at least 500 MW
from System B.
5 Maximum achievable flow from B to A on Y is 1000 MW,which meets
ReliabilityCriteria.Using the MFT,the maximum rating is 1000 MW.
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C
1000 MW RATING B TO A
A B
LOAD =2000 MW LOAD =1000 MW
GEN =1100 MW GEN =2000 MW
7.2.3.Changeto Situation:
System D builds a 500 MW plantadjacentto system A.
7.2.4.Application of Principle:
System D arranges to schedule up to 500 MW in the A to B direction as long as
the net schedule is in the rated direction (B to A)and does not exceed that rating.
Since A is always importing,D will always have a schedule to net against.If the
situation changes such that A does not import,then it will be possible to establish
an A to B rating using the MFT.
7.3.Flow-Limited Ratings -Flow-Limited By Available Resources (Using MFT
Method)
7.3.1.Principle To Illustrate:
Section 4.3.3AcceptedRating is limited by a shortage of available resources;
reliability limit not reached.
1000 MW
System A System B
Area Gen 2000 MW
Interchange Load 900 MW
-1000 MW Losses 100 MW
7.3.2.Existing Situation:
1.System B,being resource limited,has a maximum of only 1000 MW of
generation surplus to its system.
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2.The path A-B is a two-line intertie system with nominal capability of 1200 MW
per line.
3.The outage of either line in path A-B or any other outage in system A or B
does not result in a criteria violation.
7.3.3.Application of Principle:
Path A-B is given a 1000 MW Accepted Rating althoughit possibly could be
rated higher if more resources were available in System B.The path A-B has
passed the MFT and the rating achieved is called a Flow-Limited Rating and is
protected.
7.4.Flow-Limited Ratings -Flow-Limited By Low ImpedanceParallel Path
7.4.1.Principle to Illustrate:
Section 4.3.3Acceptedrating on the New Project is limited by the existingsystem
reaching a limit before the New Project reaches its limit.
Area A
New Project Area B300MW
System A1
System B
System A2 2000 MW
Accepted
Rating
7.4.2.Existing Situation:
The Accepted Rating of path A2-B (low impedance path)is thermallylimited at
2000 MW.
7.4.3.Changeto Existing Situation:
1.The New Project is being planned as a higher impedance path with a nominal
rating of 500 MW.
2.With the addition of the New Project,due to the network and location of
resources,path A2-B will overload when the New Project is increased above
300 MW.
7.4.4.Application of Principle:
Path A1-B is given a flow-limited Accepted Rating of 300 MW and is protected.It
may be possible to uprate path A1-B in the future if a higher flow can be
demonstrated after completion of appropriate studies and review.
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7.5.Accepted Rating Protection -Reliability Criteria Violation
7.5.1.Principle to Illustrate:
Section 4.3.4."A new project shall not cause a reduction in an Accepted Rating
of another Path (e.g.,because of a reliability criteria consideration)unless
mitigating or compensatingmeasures are provided."
New Project
1000 MWSystemA System B
/2000 MW
Accepted Rating
System C
7.5.2.Existing Situation:
Path B-C has an Accepted Rating of 2000 MW limited by a criteria violation for
contingencies on that path.
7.5.3.Changeto Existing Situation:
1.The New Project on path A-B has completedstudies and proposed a Planned
Rating of 1000 MW.
2.System C determines that the capability of path B-C has been reduced due to
a contingency on path B-C that no longer meets the ReliabilityCriteria (for
example,low swing voltagein system A).It also shows that path B-C meets
the Reliability Criteria at the Accepted Rating prior to addition of the new
Project.
3.System C claims its protected rating on path B-C has been impacted and
should be mitigated.
7.5.4.Application of Principle:
Path A-B must mitigate the adverse impact on path B-C by reducing the rating of
path A-B or by other means (addition of shunt reactive,addition of series
capacitors,etc.)
7.6.Accepted Rating Protection -Reliability Criteria Violation.Acceptable
Reduction in Accepted Rating Caused By Another Party
7.6.1.Principle to Illustrate:
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Section 4.3.4."...if a facility is retired from service (generator,shunt reactive
equipment,RAS,etc.)all path ratings that rely on the facility must be reviewed
and reduced to the extent the System Impacts of such retirement are not
mitigated."Further,"if a path's Accepted Rating relied upon the facilities that are
not part of the path's Plan of Service,and if those facilities are retired,modified,
or never built,the Accepted Rating is subjectto review in the same manner as if
changes had occurred in the path's Plan of Service."
System B
I o
System A
1000 MW
Accepted Rating r Shunt
Capacitor
System D System C2000MW
Accepted Rating
7.6.2.Existing Situation:
The Accepted rating for path B-A is 1000 MW and the Accepted Rating for path
C-D is 2000 MW.
7.6.3.Changeto Existing Situation:
1.System B announces that it is planning to remove a shunt capacitor in its
system and shows that path A-B meets the Reliability Criteria and the
Accepted Rating has not changed,nor are there any ReliabilityCriteria
violations for contingencies in System B.
2.However,System C determines that the removal of the shunt capacitor in
System B causes path C-D to violate the Reliability Criteria and claims that
the rating should be protected.
3.System B establishes that the shunt capacitor was installed before path C-D
received its Accepted Rating and that the rating study relied upon that
capacitor.
7.6.4.Application of Principle:
System C is not entitled to retain its Accepted Rating because of the change
made by System B.In essence,System C was making use of the shunt capacitor
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to supportits Accepted Rating on path C-D.System B is not responsible for
mitigating the reduction of the Accepted Rating of path C-D.
7.7.Accepted Rating Protection -Reliability Criteria Violation.Retention of
Accepted Rating for Facility Removal by Another Party
7.7.1.Principles to Illustrate
Section 2.3:"Transmission paths shall completethe path rating process specified
in this procedure and obtain an Accepted Rating if any of the followingcriteria
apply:...
4.A facility (generator,series,or shunt reactive equipment;Remedial Action
Scheme;etc.)that an Existing or Accepted Rating dependson is modified21
or retired from service,without regard to whether the facility is owned by the
same system as the rated path."
Section 4.3.4."...if a facility is retired from service (e.g.,generator,shunt
reactive equipment,Remedial Action Scheme,etc.)all path ratings that rely on
the facility must be reviewed and reduced to the extent the System Impacts of
such retirement are not mitigated..."
System B
I o
System A
1000 MW
Accepted Rating -r Shunt
Capacitor
System D System C2000MW
Accepted Rating
7.7.2.Existing Situation
The Accepted Rating for path B-A is 1000 MW and the Accepted Rating for path
C-D is 2000 MW.
21 If the modified RAS is functionally equivalent to the existing RAS and is approved by the RASRS,then
the Path does not need to be rerated.
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7.7.3.Changes to Existing System
1.System B announces that it is planning to remove a shunt capacitor in its
system and shows that path A-B meets the Reliability Criteria and the
Accepted Rating has not changed,nor are there any ReliabilityCriteria
violations for contingencies in System B.
2.However,System C determines that the removal of the shunt capacitor in
System B causes path C-D to violate the Reliability Criteria and claims that
the rating should be protected.
3.System C establishes that System B installed the shunt capacitor as part of
the Plan of Service for path A-B,as documented in the Phase 2 Rating
Report.
7.7.4.Application of Principle
System B must mitigate the Adverse Impact on path C-D by reducing the rating
of Path A-B or by other means (retention or replacementof the shunt capacitor,
etc.).
7.8.Accepted Rating Protection -Failure to Meet Maximum Flow Test (MFT)-
Retention of Accepted Rating as a Result of Changes Made By Another
Party
7.8.1.Principle to Illustrate:
Section 4.3.4."A transmission path's Accepted Rating will not be lowered
because its maximum achievable flow is reduced due to system changes made
by others..."
New Project
1000 MWSystemA System B
System D System C2000MW
Accepted Rating
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7.8.2.Existing Situation:
Path C-D has an Accepted Rating of 2000 MW and is limited by the MFT (no
ReliabilityCriteria violation).
7.8.3.Changeto Existing Situation:
1.The New Project on path B-A proposes a Planned Rating of 1000 MW.Phase
2 studies show acceptable performance.
2.System C determines that the maximum achievable flow on path C-D has
been reduced to a maximum of 1500 MW due to the New Project.System C
also shows that prior to the New Project it could load path C-D to its Accepted
Rating of 2000 MW.
7.8.4.Application of Principle:
Path C-D retains the protection for its Accepted Rating of 2000 MW.The New
Project on path B-A gains an Accepted Rating of 1000 MW.The Simultaneous
limit is 2500 MW.By the time the New Project commences operation,the owners
of path B-A and path C-D must make operating agreementsto ensure path C-D
is kept whole in scheduling rights (2000 MW)while not violatingsimultaneous
transfer limits between paths B-A and C-D.Alternatively,the New Project may
change its Plan of Service to mitigate the impacts on path C-D.
7.9.Accepted Rating Protection -Failure to Meet Maximum Flow Test (MFT)-
Reduction of Accepted Rating as a Result of Changes Made By Path
Owner/Operator
7.9.1.Principle to Illustrate:
Section 2.3:"Transmission paths shall completethe path rating process specified
in this procedure and obtain an Accepted Rating if any of the followingcriteria
apply:...
4.A facility (generator,series,or shunt reactive equipment;Remedial Action
Scheme;etc.)that an Existing or Accepted Rating dependson is modified22
or retired from service,without regard to whether the facility is owned by the
same system as the rated path."
Section 4.3.4."...If a facility is retired from service (e.g.,generator,shunt
reactive equipment,Remedial Action Scheme,etc.)all path ratings that rely on
the facility must be reviewed and reduced to the extent the System Impacts of
such retirement are not mitigated..."
22 If the modified RAS is functionally equivalent to the existing RAS and is approved by the RASRS,then
the Path does not need to be rerated.
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System A System B
2000 MW
Accepted Rating
Series
Capacitor
System C
7.9.2.Existing Situation:
Path B-C has an Accepted Rating of 2000 MW.
7.9.3.Changeto Existing Situation:
1.Owners of path B-C remove the series capacitor that is part of path B-C.
2.System B completesstudies that show that path B-C will no longer load to its
Accepted Rating.
7.9.4.Application of Principle:
The owners of path B-C re-rate their path to establish a new lower Accepted
Rating.
7.10.Accepted Rating Protection -Failure to Meet Maximum Flow Test (MFT)-
Reduction of Accepted Rating as a Result of Changes Made By Both the
Path Owner/Operatorand Other Parties
7.10.1.Principle to Illustrate:
Section 2.3:"Transmission paths shall completethe Path Rating Process
specified in this procedure and obtain an Accepted Rating if any of the following
criteria apply:...
4.A facility (generator,series,or shunt reactive equipment;Remedial Action
Scheme;etc.)that an Existing or Accepted Rating dependson is modified23
or retired from service,without regard to whether the facility is owned by the
same system as the rated path.."
23 If the modified RAS is functionally equivalent to the existing RAS and is approved by the RASRS,then
the Path does not need to be rerated.
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Section 4.3.4."...if a facility is retired from service (e.g.,generator,shunt
reactive equipment,Remedial Action Scheme,etc.)all path ratings that rely on
the facility must be reviewed and reduced to the extent the System Impacts of
such retirement are not mitigated..."Further,"...However,if a path'sAccepted
Rating relied upon the facilities that are not part of the path'sPlan of Service,and
if those facilities are retired,modified,or never built,the Accepted Rating is
subjectto review in the same manner as if changes had occurred in the path's
Plan of Service..."
System A System B
2000 MW
Accepted Rating
Series
Capacitor
System C
7.10.2.Existing Situation:
1.Path B-C has a previously-establishedAccepted Rating of 2000 MW.
2.Owners of path B-C perform new studies that show path B-C will now load to
only 1900 MW due to the developmentof parallel systems.There are no
reliability problemsat this flow.
7.10.3.Changeto Existing Situation:
1.Owners of path B-C remove the series capacitor that is part of path B-C.
2.System B completesstudies that show that path B-C will load to only 1400
MW with the series capacitors removed.There are no reliability problemsat
this flow.
3.The decrement in rating due to the removal of the series capacitors is 500
MW.
7.10.4.Application of Principle:
The owners of path B-C rerate their path to establish a new lower Accepted
Rating.The owners of path B-C cannot assume the original rating of 2000 MW is
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still valid simply because the flow reduction to 1900 MW was not in their control
(due to parallel system changes).The new Accepted Rating is 1400 MW unless:
1)they can establish that the reduction was due to Adverse Impacts caused
by specific actions of other systemsthat should be mitigated in
accordance with these procedures,and
2)mitigation for the 100 MW flow reduction is implemented(see Section
7.7.).
7.11.Accepted Rating Protection -Increase in Accepted Rating Caused By Path
Owner/Operator
7.11.1.Principle to Illustrate:
Section 4.3.4."Transmission path owners that make changes to their system that
increase the flow on a path with a Flow-Limited Rating can receive a higher
Accepted Rating consistent with the MFT."
New Series
Capacitor2000MWSystemAI System B
Accepted
Rating
System C
7.11.2.Existing Situation:
Path A-B has an Accepted Rating of 2000 MW and is limited by the MFT (no
Reliability Criteria violations).
7.11.3.Changeto Existing Situation:
The owners of path A-B completestudies showing that the series capacitor they
have planned to add to path A-B will increase the Accepted Rating of that path to
2500 MW.
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7.11.4.Application of Principle:
Path A-B owners may obtain a higher Accepted Rating for path A-B if they can
demonstrate increased flow due to a project they have planned and satisfy the
other requirements of this Path Rating Process.
7.12.Accepted Rating Protection -Increase in Accepted Rating Caused By
Another Party
7.12.1.Principle to Illustrate:
Section 4.3.4."Transmission Path owners that make changes to their system that
increase the flow on a Path with a Flow-Limited Rating can receive a higher
Accepted Rating consistent with the MFT.This same principle applies if the flow
on the Path is increased by a project initiated by another party;althoughin that
case,it should be recognized that the higher Accepted Rating relies upon and is
subjectto the operation of the other party's facilities."Further,"if a path's
Accepted Rating relied on facilities that are not part of the Path's Plan of Service,
and if those facilities are retired,modified,or never built,the Accepted Rating is
subjectto review in the same manner as if changes had occurred in the Path's
Plan of Service."
Series
Capacitor2000MWSystemAI System B
Accepted
Rating
System C
O New
Generator
7.12.2.Existing Situation:
Path A-B has an Accepted Rating of 2000 MW and is limited by the MFT (no
ReliabilityCriteria violations).
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7.12.3.Changeto Existing Situation:
The owners of Path A-B completestudies showing that the addition of the new
generatorin system C would allow an increase in the Accepted Rating of Path A-
B to 2500 MW.
7.12.4.Application of Principle:
Path A-B owners may obtain a higher Accepted Rating for Path A-B if they
demonstrate increased flow due to a project planned by another party (i.e.,the
new generatorin system C)and satisfy the other requirements of these
procedures.The OTC under this new Accepted Rating will be dependenton the
operation of the new generator.
Approvedby Planning Coordination Committee July 15,2014
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Appendix A:Rating Methods Discussion and Background
The followingexplanatorysections address several majorissues in the transmission
rating process.The intent is to guide transmission studies toward a uniform basis for
ratings.
Affected Path Stress Levels
The nature of AC electrical networks is such that the loss of a loaded transmission line
in one path impacts all affected paths.Each affected path will pick up a portion of the
power that was flowing in inverse proportion to its impedance relative to the other
affected paths.This ability of paths to affect each other has led to the developmentof
nomograms that describe the simultaneous capacity relationships between affected
paths.
The sponsor of a new rating has an obligation to address,and potentiallymitigate,all
criteria violations on affected paths that are identified by affected parties.This could
imply multiplestudies being run with every potentiallyaffected path fully loaded.
However,that would be an unrealistic and unreasonable study burden,both on the
sponsor and on the Project Review Group (PRG)participants that are responsiblefor
identifying problems.Therefore,WECC requires using a screening test procedure as a
minimum study requirement.Screening studies must be performed that identify all
affected paths that pick up an increment of 10 percent or more (based on that affected
path's rating)for an outage on the path being rated with all phase shifters in a non-
regulating mode.
This screening test is not intended to be used as a margin criterion nor does it imply that
a change of 10 percent is required before mitigation is appropriate.The determination
as to whether mitigation is required is made independentlyas described elsewhere
herein.Once these affected paths are identified,both parties (the sponsor of the new
rating and the owner of the affected facility)need to jointlydecide how to determine the
simultaneous capability of both paths.There are several possible outcomes of this
determination:no simultaneous studies are required,joint studies will be performed,the
sponsor will perform the studies with input from the affected party,or the affected party
will perform the studies.
The obligation of the project sponsor to perform screening studies does not remove the
responsibility that the owners of affected paths have to identify for themselves the
impact that a new facility or rating will have on their systems.All members need to make
a determination for themselves as to whether they are impacted and need to ensure
that proper levels of stress are represented on their Transmission Paths in all applicable
studies.
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Latent Capacity
Transfer capability is considered "latent"when it can be acquired by improving an
existing path without adding new lines to the path.Some examplesof possible
improvementsinclude:
·Installing shunt devices that improve the voltageprofile and/or system damping;
Placing existing unused equipmentinto service;
Implementinga remedial action scheme;or
Adding new generation.
Questions have been raised whether Latent Capacity should be protected similar to the
Accepted Rating.For the reasons listed below the protection of Latent Capacity is not
allowed.They are:
·The planning process for new facilities would become extremelycomplicated.
New projects would have to deal,not only with existing owners'rights,but also
with claimed Latent Capacity rights.Planning studies would have to be done with
base cases that use fictitious devices to represent the system in an ideal state
with no Latent Capacity left.
There are no published Latent Capacity numbers.Claims to Latent Capacity
would have to be demonstrated by some other procedure.This would produce an
unacceptable burden of new work with little benefit.
There are no published plans for placing future equipmentin service.Planners
would not know how to study future systemsto ensure that no utility is negatively
affected.
One of the major objectivespromulgatedin the rating process is that an Accepted
Rating could be used in operation.Thus the principles of realism,demonstration of flow,
and no use of fictitious devices,have been developed.In this context,the determination
of Latent Capacity violates some or all of these principles.Latent Capacity does not
exist until improvementsare made and therefore cannot be used in operation.
For planning,regulatory and other reasons,members may find that identifying and
documenting Latent Capacity would be useful.Some possible uses are:
·Knowledgeof Latent Capacity may promote appropriate decisions in generator
siting;facilitate Project Coordination;or assist in fulfilling transmission access
requests.
Latent Capacity that has been adequatelyreviewed and documented may gain
expeditedreview if the TSS determines that the original documentation is still
applicable.
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At their discretion,project sponsors may identify and document the Latent Capacity in
the Phase 2 Rating Report.
Latent Capacity is not protected;it cannot be used in operation;and it is not recognized
nor incorporated by others in their rating studies.The only means of protecting Latent
Capacity is to have a committed Project and pursue that Project through the Path
Rating Process.
Maximum Flow Test (MFT)
The ability of a path to acquire flow within an electric system is an intrinsic property of
the electric system.The actual flow on a path is a result of the impedance ratios of the
transmission lines in the electric system and the circumstances of geographic load and
generation patterns,phase shifter operation,etc.Adverse unscheduled flow
performance reflects a mismatch between scheduling practice (which is a commercial
decision and from an electric point of view,arbitrary)and this intrinsic property.
The Planning Coordination Committee (PCC)requires that the rating process must
include an examination of flow distributions to recognize physical properties of the
system and,at least to some extent,should address potential unscheduled flow
impacts.A reasonable way to address unscheduled flow is to establish Transmission
Path Ratings at a level where no system reliability problemsexist and schedules will be
limited by the maximum flow that can occur on the path under realistic conditions.
The Rating Methods Task Force (RMTF),now dissolved,gave careful consideration to
how a rating should be related to scheduled and/or actual flows.For several reasons,
the RMTF decided that ratings should be developedon the basis of actual flows rather
than schedules.First,the RMTF's position is that a rating should reflect a path's ability
to carry flow.(The relationship between actual flow and scheduled flow is an
unscheduled flow issue.Additionally,assigning path capabilities to schedules rather
than actual flow actually rewards those paths that maximize unscheduled flows,thus
penalizing parallel paths.24)Second,associating a rating with a schedule implies that
the path should have that rating only when that particular schedule is in place.This
would severelylimit the usability of the rating.And third,there are too many scheduling
entities and combinations of schedules that produce the same flow on a given path for it
to be practical to state a rating in terms of schedules.
The RMTF developedprocedures and guidelinesbased on a path's ability to carry
power and the project sponsor'sability to demonstrate adherence to NERC Reliability
Standards and WECC Criteria.To prove adherence to the Criteria,the project sponsor
must demonstrate through simulation that power will flow equal to the desired rating and
meet all applicable Reliability Criteria.
24 IOCluding affected paths.
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1.Flow-Limited Ratings
The rating of a non-flow controlled Transmission Path should be capped by the flow
that can be achieved with realistic generation and load patterns (no use of fictitious
devices or operating practices).
The preferred method to calculate a flow-based rating limitation is the MFT.This test
consists of developinga power flow test case that depicts a reasonable condition
which produces a flow on the path at least equal to or greater than the proposed
rating.
MFT attributes:
a.The MFT must not use fictitious devices or have overloaded transmission
facilities.
b.Considerable latitude is allowed in the developmentof the test case.A
reasonable load and generation dispatch pattern,which is able to support the
rating,is appropriate.
c.Since the Accepted Rating is limited by the MFT,any capacity above the MFT is
Latent Capacity.
2.Realistic Simulation
The RMTF believed considerable latitude is appropriate in the assumptionsused to
build the power flow case that sets the upper limit on the flow and the rating.The
only requirement is that the case must represent a realizable geographic load and
generation pattern within recognized operating procedures and be accepted by the
PRG for that path.It is acknowledgedthat the likelihood of the particular
load/resource pattern occurring in actual system operation may be low.
In allowingthis latitude,the RMTF recognized that there may be many hours in the
year when the actual load and generation distribution may not result in the actual
flow approaching the rating,even if the path is scheduled to its limit.This mismatch
between schedule and flow does create unscheduled flow.However,the elimination
of fictitious devices and capping the rating at the maximum optimistic flow that can
be obtained represents an effort to address unscheduled flow issues in the planning
and rating process.
3.Alternative Methods
With the concurrence of all affected parties to a rating,the project sponsor may
apply some test other than the MFT to demonstrate that unscheduled flow impact is
within an acceptable level.If the project sponsor proposes to use some test other
than the MFT,the sponsor should notify the PCC and explainthe alternative test in
sufficient detail prior to completingPhase 2.
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4.Phase Shifter Operation
If a path has flow control elements,such as phase shifters,then its rating must be
within the range of loading that can be achieved with realistic generation and load
patterns without violatingthe capabilities of the devices.Also,the project sponsor
must have procedures to assure the devices will be operated consistent with the
principles on which the path was rated.
5.Reverse Flow
It may be impossible to meet an actual flow test when trying to rate a line in a
direction counter to prevailing flows.Parties faced with such a circumstance should
developa net schedulinglallocationapproach.It should be remembered that,once
the rating of a transmission path has been established,scheduled transactions over
the path are permitted in either direction providing the net schedule at any time does
not exceed the path rating.For example,if the path rating has only been established
in one direction,schedules are still permitted in both directions as long as the net
schedule is in the same direction as the path rating direction and does not exceed
the path rating.
6.Allocation
Allocation of rights on a path is a commercial issue that the owners of the path may
need to resolve;however,it does not affect the rating of the path.The allocation
method need not bear any resemblance to the rating method.
Flow Test Exemption
A transmission path's Accepted Rating is established in accordance with the processes
set forth previously in this document.The majority of transmission facilities in WECC
have ratings that are limited by reliability constraints that will be referred to as system-
limited.A few EHV transmission facilities in WECC will have ratings that are limited by
the highest flow on the path under realistic conditions and are not system-limited.These
paths and their ratings will be referred to as flow-limited.A flow-limited path is restricted,
not by a reliability problem,but by the impedance of the path,lack of generation,load,
etc.
A path's Maximum Achievable Flow (MAF)is the highest flow that can be obtained
under realistic conditions where a reliability limit is not reached.Because of system
changes,the MAF may change over time;it may become less than the Accepted
Rating.The followingprinciples guide how Flow-Limited Ratings are protected:
1.Meet WECC Criteria
Having an Accepted Rating does not exempta company from having to operate the
system in a manner that meets NERC Reliability Standards and WECC Criteria.If it
is demonstrated that a violation of these requirements occurs when a Transmission
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Path flow is less than its Accepted Rating,changes must be made to ensure the
system will not be operated under those conditions.An MFT exemptionapplies
strictly to Flow-Limited Ratings.
2.System Changes Made by Others
A Transmission Path's Accepted Rating will not be lowered because the MAF on the
path is reduced due to system changes made by others (i.e.,the path can no longer
meet the MFT).The rating should not be reduced for the followingreasons:
a.Existing path owners should not incur a reduced rating due to changes made by
other systemsthat provided no benefit to the path owner.
b.Existing path owners did not have control of the decision to make the system
changes.
c.The system is still being operated reliably.
d.Existing path owners and those who have rights on that path need some
assurance the rating of the path will not be reduced due to changes made by
others.
The potential drawback to this principle is scheduling the Path to the same level as
before the system changes could presumably cause increased unscheduled flow.
3.System Changes Made by Path Owners
A Transmission Path's Accepted Rating will be lowered if its owner makes changes
to the system that reduce the path's flow.The Accepted Rating will be reduced by
the amount the flow was decreased.The path owners should recognize that they
may be required to go through the Path Rating Process when making their decision
to change their system.
The potential drawback to this principle is there may be cases where an owner
decides not to make an improvementto its system that would benefit the
interconnected system because the owner does not want to take a reduction in the
Accepted Rating of a path.
4.Remote Systems Indifferent to Path Definition
When an existing Path's flow is reduced by a new parallel line,remote systems
should be operationallyindifferent to whether the new line is defined in or out of the
existing Path.
If a new project is built parallel to an existingTransmission Path,the new project's
sponsor may decide not to be included in the existing Path.Regardlessof the
sponsor's decision,the existingPath will not have its Accepted or Existing Rating
reduced and the Path rating(s)will be established in such a way that an entity
outside of both Paths will be indifferent to whether the new project is included in the
existing Path or not.
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Fictitious Elements
WECC has established the principle that fictitious elements are not to be used in either
simultaneous or non-simultaneous rating studies.
The concept of prohibiting fictitious elements does not pertain to planned facilities;i.e.,
those facilities that are expectedto be in-service at the time represented in the rating
study.Planned facilities may be used to obtain an Accepted Rating;however,that rating
may only be used when those facilities are in-service.
If there are changes to the planned facility's project plan or schedule,then the section
on Monitoring Project Progress in the Path Rating Process will apply as if the change
was made to the Project associated with the Path being rated.In these cases,it may be
required to repeat or update the requirements for Phase 2 of the Path Rating Process.
For example,an entity that is building a new transmission line may use rating studies
that include a future generator.If the generator is delayed,it may be necessary to
repeat the rating studies to obtain a new Accepted Rating without the generatorand/or
to establish the Accepted Rating at the new in-service date of the generator.
Fictitious elements are facilities or operation procedures used in rating studies that are
modeled unrealistically or that do not exist.Examplesof fictitious elements are:
Generators -a generator that does not exist at the time of rating,will not be on-
line during the timeframe for which the path rating is being sought,or the
dispatch is unrealistic,as determined by the PRG
·Load -unrealistic load conditions,such as load projections unsupported by
those used in planning resources in the same time frame or modeling off-peak
load in one area and on-peakload in another area under similar system
conditions in the same study case
·Lines -change to the impedance of a line unless such changes are part of Plan
of Service for the new Project undergoing the Path Rating Process
Phase shifters -unplanned phase shifter or operation beyond its physical
capability
·Shunt elements -add a non-existent or unplanned SVC
Series elements -add unplanned series capacitors to a line
Opening/switchinglines -open a line that is normally closed unless it is part of
the Plan of Service for the new Project
Remedial action schemes -institute a scheme with no agreementfrom the
provider or other affected parties
Fictitious elements may change and distort study results.At one extreme,fictitious
elements may have little or no effect on the resultant ratings,and thus need not be
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Project Coordination and Path Rating Processes Page 96 of 121
represented.At the other extreme,they may grossly exaggeratethe capability of the
path being rated,either in terms of ability to meet the performance criteria or to increase
the flow limit of the path.
Because the intent of the rating process is to developan Accepted Rating that can be
used in operation,it is necessary to reject the use of fictitious elements in rating studies.
The Accepted Rating that is granted by the rating process can only be used when all
facilities that were represented in the rating studies are in service.
The prohibition against the use of fictitious elements does not apply to reporting of
Latent Capacity.Because the determination and reporting of Latent Capacity is strictly
for information purposes,the owners may model the system in whatever manner they
choose.
Resource Modeling Assumptions
The modeling assumptionlevels of each resource modeled in a ratings study base case
would be presented to the technical study group (Project Review Group)for their
acceptance:
Level 1:Existing Generation
Only generation that exists,is under construction,or is committed with a
planned in-service date within the time frame of the study.
Level 2:Signed Agreement
Generation with a signed Interconnection Agreement,executed Transmission
Service Agreement,and the in-service date is before the time of study.
Level 3:Study Process
Resources that currently are undergoing the interconnection Open Access
Transmission Tariffs Process such as the Generator Interconnection System
Impact Study Process,a Transmission Service Requestanalysis is underway,
or other appropriate state application process.
Level 4:Additional Generation Resources
Additional generation that is required to achieve acceptable flows in the initial
power flow case.Project sponsors are permitted to include resources that are
identified in public reports including:an acknowledgedIntegrated Resource
Plan or a discussion of the resource potential,developmenttimeframe,and
evidence of feasibility.
The project sponsor should describe each resource by location,size,and fuel type and
in sufficient detail to track whether the Plan of Service has been met.It may be the most
appropriate to use only a percentage of the identified resources as can be judgedby the
PRG to be acceptable.
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Use of Resource Modeling Levels
Each of the resource levels would be applicable to base cases as noted on the
followingtable:
Resources
Project Phase 2 Study Cases Level 1 Level 2 Level 3 Level 4
In service in 1 to 2-Years e
In service in 3-5-Years e e
In service in 6-10-Years and
O O O Obeyond
The above modeling assumptionsprovide a guide for developingthe initial power flow
cases.In addition,the initial power flow case should only be considered as a starting
point and not as the definitive case for determining the required transmission upgrades.
The individual PRGs should retain the flexibilityto vary from the above Table.Levels 1
through 4 resources can be modeled,as agreed to by the PRG in the study case,as
long as it is feasible for these resources to be on-line during the timeframe for which the
path rating is being sought.For example,for a new or increased path rating to be
effective in year four,Level 1 through 4 resources that can be in service in the fourth
year (or earlier)can be used if approved by the Project Review Group.The resource
assumptionswill be clearly listed in the study report.If the resource assumptions,on
which the Planned (or Accepted)Rating had relied,did not materialize,the path
owner(s)must demonstrate that the Path Rating can still be supported.
System Representation
One of the objectivesof the rating methods is to allow WECC members to establish
accurate,fair,and equitableratings.System representation (the way transmission
facilities,generators,etc.are modeled)plays a key role in fulfilling this objective.
For rating studies,members should use the full loop and the most recent WECC
standard power flow and stabilitybase cases in their studies.The advantagesof using
the standard base cases are that members are familiar with them and every system
representation should have similar amounts of detail,accuracy,and modeling (if the
member follows the published system representation guidelines).
If a member replaces the representation of its system with a different representation
(presumably with more details and more accurate data)and if the rating dependson this
new representation,the member must demonstrate that the new representation is
appropriate and be willingto submit the new representation to all future WECC base
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cases.In the unlikely event that the new representation affects the established Transfer
Capabilities of other paths adversely,the member must resolve the adverse impacts
with those whose path capabilities are affected during the Phase 2 review process.
Delay,Cancellation,or Changes to Resources Potentially Affecting Ratings
1.Some Projects may be impacted by changes in resource developmentsas Projects
proceed through Phase 2 and during Phase 3.Resources that Accepted Ratings are
based on may be delayed,cancelled,or replaced with other resources.Also,
modeling assumptionsmay ultimatelyprove to be incorrect (such as different
machine models or customer interconnection facilities).Many generation resources
assumed for the six-to-10 year planning horizon have a shorter developmentlead
time than the majortransmission lines required to deliver the outputpower to the
load centers.In fact,developmentof some generation resources may not even
commence until after transmission Projects have completedPhase 2 and provided
evidence that these transmission Projects are feasible.Althoughthese resources
are not part of the project sponsor'sPlan of Service,the Path Accepted Rating
depends on them,so they should logically be treated as if they were part of the Plan
of Service.
2.The anticipation is that actual resources that support the Planned and/or Accepted
rating may change from those assumed at the beginning of Phase 2.Projects may
vary by location,size,simulation models (e.g.,wind).Project sponsors should be
able to continue through Phase 2 with their initial resource assumptionsas long as
replacementresources would have similar impacts on the system as those that were
modeled in the Phase 2 studies.Further,project sponsors will be able to maintain
Phase 3 status (Accepted Ratings)while making substitutions of resources and
models as long as the replacementresources and models would have similar
impacts on the system as those that were modeled in the Phase 2 studies.
3.The anticipation is that all resources assumed in Phase 2 for service may not be on
line at the time that the transmission Projects are energized.During Phase 3,project
sponsors will be given latitude to submit schedules for bringing Projects on and
these schedules may span several years.Project sponsors will be able to maintain
Phase 3 status (Accepted Ratings)by providing evidence that progress is being
made as provided for in Phase 2 of this Path Rating Process.
4.The WECC SOL Methodologystudy process shall be used to "phase in"ratings or
review the rating as substitutions of resources and different modeling assumptions
are developed,as necessary,to maintain Phase 3 status at an Accepted Rating.
This phase in or review would be treated as seasonal operating studies.
5.Sponsors of future transmission projects are provided the opportunity within this
Path rating Process to request benchmarking of Accepted Ratings.Therefore,PRGs
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of Projects in Phase 3 need not challengewhether an Accepted Rating is still valid
as there is already an avenue in this Path Rating Process to allow potentially
affected members to undertake this challenge.
6.Sponsors of future transmission projects are provided the opportunity within this
Path Rating Process to request benchmarking of Existing Ratings.In order to verify
that the rating that has been established for the path and can still be supported.
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Appendix B:Simultaneous Studies,Similarly Situated Projects,and
Combined Project Studies
Simultaneous Studies
All Paths associated with Projects with Planned Ratings must consider each other as
appropriate in their planning studies.Once a Project has entered Phase 2 its associated
Path has attained a Planned Rating.
To aid in the understanding of certain obligationsthat some Projects have to each other,
Phase 2 is separated into Phases 2A and 2B with a bright line.Projects in Phase 2A
must consider Projects in Phase 2B for inclusion in their study plans.Phase 2B is used
to identify those Phase 2 proposed projects that have completedand obtained approval
by the PRG of a study plan and the first base case needed to perform simultaneous
studies.Phase 2A Projects that cross this bright line will be moved to Phase 2B.
The followingdescribes generallythe differences between Projects in Phase 1,Phase
2A and Phase 2B;and the transition from Phase 2A to Phase 2B:
1.Non-simultaneous Studies for Projects in Phase 1 are run on base cases that have
not been reviewed by any group in WECC.
2.To transition from Phase 1 to Phase 2A,a proposed Project will have already
provided data to WECC in accordance with the process for completion of Phase 1.
The data are not necessarily included in WECC base cases for the Annual Study
Program.Such data are used as information for other projects.
3.Projects in Phase 2B will need their study plans and base cases reviewed and
accepted by the PRG;and therefore,will need to cover all elements required to be
included for the Simultaneous Study.
4.Based on PRG requests,multiplesimultaneous analyses may need to be performed,
requiring multiplesimultaneous base cases.However,the Foundational Base
Case(s)that will establish this bright line is the first base case that would be ready
for the first simultaneous assessment,as agreed to by the PRG.
5.Once the PRG is formed and the study plan and Foundational Base Cases approved
by the PRG,the Project would move from Phase 2A to Phase 2B.Therefore,Phase
2A is the formation phase,while Phase 2B is the study phase.
6.As determined by PRG,a Project that transitions from Phase 2A to Phase 2B will
consider all Projects already in Phase 2B and Phase 3 in its base case
development.The PRG has the discretion to decide which Projects in Phase 2B and
Phase 3 to include in the base cases because the proposed Project may not have
interaction with all such Projects.While this approach gives the project sponsor
flexibilityto determine the projects to be included in the simultaneous study,it may
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carry some risk of re-studying if the Projects in Phase 2B or Phase 3 that were not
included in the study should interact with the proposed Project.
7.Projects already in Phase 2B will not have to go back and re-study the effect of
including Projects that later enter Phase 2B,but they may choose to do so for the
purpose of evaluatinginteractions and mitigation solutions.
A Project entering Phase 2B will need to consider Projects already in Phase 2B.
However,the process is not intended to be a queue.If interaction is identified by either
of the Project studies,mitigation measures will be mutuallyagreed upon.For example,
for two proposed Projects (X and Y),Project X is in Phase 2B when Project Y enters
Phase 2B.Project X's study plan will not include Project Y.Upon meeting the
requirementsfor Phase 3,Project X enters Phase 3 without studying Project Y.If
Project Y finds an interaction with Project X (or Project X finds an interaction with
Project Y),mitigation measures will be mutuallyagreed upon before either Project can
be placed in service.
Similarly Situated Projects
At any point in time,if any two Projects are togetherin Phase 2B,they are Similarly
Situated and have a responsibility to mitigate interaction they have with each other until
both become operational.Once a Project enters Phase 3,it will not be Similarly Situated
with new Projects entering Phase 2B.Similarly Situated Projects must consider each
other on an equal basis.
Any interaction identified within the group of Similarly Situated Projects must be
resolved in a mutuallyagreed upon manner by the affected Projects and the
PRG(s).
Similarly Situated Projects will need to coordinate the logistics of performing the
requisite studies.For example,if a Project associated with Path A and a Project
associated with Path B both interact with Path C,then the project sponsors will
need to perform the followingsimultaneous studies:Path A vs.Path C,Path B
vs.Path C,and Paths A and B vs.Path C.
Combined Project Studies
Some Projects that are Similarly Situated may impact the non-simultaneous rating of
each other's Path and in some instances more than one Project may be seeking a non-
simultaneous rating on the same path.In either case,each Project will need to perform
their respective simultaneous studies individuallyand also perform a Combined Project
Study with all affected Similarly Situated Projects modeled in the joint study.The need
for conducting individual and combined studies is to cover cases in which all Projects
move forward or not,and to address the inherent time gaps in Project operating dates.
Each Project has to be examined individuallyin the event that one of the Similarly
Situated Projects goes in service prior to other Similarly Situated Projects or is
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cancelled.As an example,this could happen if one of the Projects is a new line and the
other is an upgrade of an existing line where the upgrade is completedlong before the
new line is in service.The individual studies ensure that individual Projects can be
placed in service and operated reliably.The Combined Project Study shall demonstrate
reliable operation in the event all Projects are placed in service.
Project sponsors,togetherwith PRG members,will decide whether there is a need for a
Combined Project Study,especially if the project sponsors are performing path rating
studies on different paths.For example,a Combined Project Study may not be required
if no meaningful interaction exists when each path is at its non-simultaneous rating.
Project sponsors are responsible for vettingthe need of a Combined Project Study with
their respective PRGs after they have been classified as Similarly Situated.
A Combined Project Study is required to assess the ability of two or more Similarly
Situated Projects to achieve their respective non-simultaneous path ratings on a
combined basis.This study requires project sponsors to perform a joint study,modeling
their respective plans of service with actual power flows at their non-simultaneous
ratings on the Paths to be rated.Some of the Projects that are Similarly Situated may
impact the same Path.In that case,each Project must do simultaneous studies
separatelyand also do simultaneous analyses under a Combined Project Study with
both Projects in the study.
In cases where Projects propose non-simultaneous rating increases on the same Path,
the power flow on the Path should be demonstrated at the combined non-simultaneous
rating increase (e.g.,two Projects seeking Path rating increases of 500 MW and 1,000
MW should be modeled with 1,500 MW of flow).If the resulting power flow is less than
the full combined non-simultaneous ratings,the parties will mutuallyagree on how to
address the interaction.Additionally,the Combined Project Study must include all of the
simultaneous analyses that were identified in their respective individual study plans.
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Appendix C:Phases 1-3 Templates
The followingtemplatesare intended for use by the TSS Chair and for the project
sponsor to provide the needed information to navigatethe process.
Expediting the Process
Dear [Project Sponsor]:
After consulting the Path Rating Process,Section 3.3,the Expedited Rating Process
combines Phase 1 and Phase 2 activities.Listed below are a few items in "Red"that
[Project Sponsor]needs to address.Please let me know if you have any questionsor
comments.
Sincerely,
[TSS chair]
Expedited Rating Process -(Note:Project remains in Phase 1 until completed;the
Project does not achieve Phase 2 status)
Step 1.The final ComprehensiveProgress Report(CPR)should include non-
simultaneous and simultaneous analysis.The final CPR will be submitted to the
Technical Studies Subcommittee (TSS)and the Planning Coordination
Committee (PCC),having TSS and PCC review performed concurrently:the
TSS 60-day review of the CPR and the PCC 30-day review on the conformance
of the process.
Step 2.After the TSS and PCC review of the final CPR,the Project will achieve Phase
3 (if no issues are identified).
-If the CPR included non-simultaneous and simultaneous analysis and no one
requested interest to participate in a PRG,[Project Sponsor]needs to send a
letter to the TSS and PCC stating that all concerns/comments have been
addressed and requesting the PCC to grant Phase 3 status.
Step 3.If issues arise that can't be resolved,the Project will need to go through Phase
2 and form a PRG.
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Phase 1 to Phase 2 Transition Template
Dear Project Sponsor:
To facilitate the transition from Phase One to Phase Two,I would appreciate if you
could provide a response to the Action Items that I have listed below that are shown in
Section 3.2.3 in the Path Rating Process.Also,I would appreciate it if you could draft a
Phase 2 ApprovalLetter for the Project Name.I have attached an examplefor your
reference.If you have any questions,please let me know.
Sincerely,
[TSS chair]
WECC Pro|ect Coordination and Path Ratinq Processes -Section 3.2.3 -
Completion of Phase 1
1.The Planning Coordination Committee (PCC)has completedits assessment of the
Project's conformity with the Project Coordination Review Objectives(applies only to
those projects identified by PCC in which project coordination interest has been
expressed).
Action Item:Insert date the PCC issued an acceptance letter of the Project
Coordination Report or a response why a Project Coordination Report was not
required or issued.
Project Sponsor Response:
2.The project sponsor has submitted a full Project representation to WECC for
inclusion in WECC base cases.
Action Item:Provide confirmation that a full Project representation has been
provided to WECC.
Project Sponsor Response:
3.The project sponsor has distributed a ComprehensiveProgress Report
accompanied by a letter to the Technical Studies Subcommittee (TSS)and PCC
requesting Phase 2 Status for the Project.
Action Items:1).Insert date when CPR was distributed by WECC for 60-day review.
2).Insert date when comments on Phase One CPR were due.
Project Sponsor Response:1).and 2).
4.If the above criteria have been satisfied and no objectionshave been received within
60 days of WECC's receipt of the request to enter Phase 2,the project sponsor(s)
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will so notify the TSS chair and provide evidence that the Project has satisfied all
requirements.
Action Item:Please provide a list of any comments or objectionsreceived during the
60-day review and how [Project Sponsor]addressed these comments or objections.
Were [Project Sponsor's]responses to the satisfaction of the entity that submitted
the comments?
Project Sponsor Response:
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Appendix D:Testing Path Independence
This appendixdescribes the two screening tests to be used to determine whether a path
is independentof another path.These tests apply if the project sponsor has not decided
in Phase 1 or in Phase 2A to include the proposed Project as a subset of an existing
Path (or provided technical explanationto the contrary).The results of the tests are to
be provided to the PRG to aid in determining if a proposed Project is part of the same
path.The most efficient time for the project sponsor to conduct these tests would be in
Phase 1 so the results can be included as part of the ComprehensiveProgress Report,
and available to the TSS before the formation of the PRG.
If the proposed Project is determined to be a subset of an existing Path,the project
sponsor is required to re-rate the Path within the Path Rating Process.A Project that is
a subset of an existing Path is not precluded from defining a separate path or from
seeking a separate Path Rating.A project sponsor can also use a different methodology
to determine whether the proposed Project is part of an existing Path,provided that the
methodologyhas been accepted by TSS and PCC:
To determine whether a proposed path is independentof an existing path,the project
sponsor must perform two flow tests as outlined below.
The justificationfor using two tests is as follows.If a new Project is small relative to the
path being tested,then Test 1 should clearly indicate a dependency between the two as
the existingsystem should pick up a large percentage of the power scheduled on the
new Project.Test 2 would not provide a good indicator since a small Project would not
pick up much "loop flow"from the existing system.If a new Project is large relative to
the path being tested,then Test 1 would not show much effect since most of the
Project's flow would tend to stay on the Project,but Test 2 should show a dependency if
a large percentage of the existing path's schedule now flows on the new Project.
Test 1:
1.Start with a pre-Project WECC base case.
2.Add the proposed Project to the case to create a post-Projectbase case.When
adding the Project,do not initially schedule any flow on the new Project.
3.Schedule a fixed amount of power on the proposed Project (e.g.,100 MW or in
the case of a Project with flow control devices,the Projects rated flow).If there
are flow control devices included as part of a new Project,they may be used to
control flow on the new Path to the schedule on that Path,or they may be
bypassed,at the project sponsor's discretion.However,the flow control devices
cannot be used,for purposes of this test,to artificially create "loop flow"on other
Paths.If the flow control devices have enough control range,the new Path will be
independentof all other paths.
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4.If more than 25-to-40 percent of the scheduled power flows on the existing path
being tested,then the proposed Project is deemed to be a subset of the existing
path.If the proposed Project is deemed to be a part of an existing Path,then the
proposed Project must re-rate the existingPath as part of its Path rating studies.
This independentPath test is NOT optional.Depending on the outcome of the
independentPath test,the developmentof an independentrating could be an
optional second analysis.
If the independentPath test is performed and the new Project is determined to be
part of another Path,then the Path that the Project is a part of MUST be rerated
as part of the Path Rating Process.In this case,the developmentof an
independentrating is optional.If a Project that is part of another Path develops
an independentrating,then there will be two ratings developedas part of the
Path Rating Process,as follows:
the independentrating,and
the rerate of the existing Path that the new Project is a part of.
If the independentPath test is performed and the new Project is determined to
not be part of another Path,then an independentPath rating for the Project is
required as part of the Path Rating Process
5.The project sponsor also has the option of developingan independentrating for
the proposed Project.If an independentrating is developed,the project sponsor
must also determine if any interactions (e.g.,nomograms)exist between the
proposed Project and the existing Path.
Test 2:
1.Start with a pre-Project WECC base case.
2.Add the proposed Project to the case to create a post-Projectbase case.When
adding the Project,do not schedule any flow on the new Project.If there are flow
control devices included as part of a new Project,they may be used to control
flow on the new Path to the schedule on that Path (e.g.,zero MW)or they may
be bypassed at the Project sponsor's discretion.However,the flow control
devices cannot be used,for purposes of this test,to artificially create "loop flow"
on other paths.If the flow control devices have enough control range,the new
Path will be independentof all other Paths.
3.If the new Project picks up more than 55-to-65 percent of the power that was
flowing on the existing Path being tested,then the proposed Project is deemed to
be a subset of the existingPath.
4.If the proposed Project is deemed to be a part of an existing path,then the
proposed Project must re-rate the existingPath as part of its Path rating studies.
This independentPath test is NOT optional.Depending on the outcome of the
independentPath test,the developmentof an independentrating could be an
optional second analysis.
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If the independentpath test is performed and the new Project is determined to be
part of another Path,then the Path the Project is a part of MUST be rerated as
part of the Path Rating Process.In this case the developmentof an independent
rating is optional.If a Project that is part of another Path developsan
independentrating,then there will be two ratings developedas part of the Path
Rating Process,as follows:
the independentrating,and
the rerate of the existing Path that the new Project is a part of.
If the independentPath test is performed and the new Project is determined to
not be part of another path,then an independentpath rating for the Project is
required as part of the Path Rating Process
5.The project sponsor also has the option of developingan independentrating for
the proposed Project.If an independentrating is developed,the project sponsor
must also determine if any interactions (e.g.,nomograms)exist between the
proposed Project and the existing Path.
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Appendix E:Treatment of Projects Sent Back To Earlier Study Phases
The Path Rating Process state that:
A Phase 2A or 2B status may be lost if a Project in Phase 2 shows no evidence
of any activity for a period of time after the achievement of Phase 2 status.
An Accepted Rating status may be lost if a delay in meeting any Project
milestones by 12 months or more occurs or if a change in the Project's Plan of
Service adverselyimpacts the Accepted Rating.
This Process provides for the PRG to determine if the Project status will revert back to
Phase 2 with a Planned Rating or remain in Phase 3 with an Accepted Rating.
Proposed Projects in Phase 2B that are sent back due to inactivity as listed in
Section 3.4,Table 1 will no longer be in the same "Similarly Situated"group.A
Simultaneous study to consider them with this group of the Phase 2B Projects is
then not a requirement for the remaining Projects in the group.
A proposed Project in Phase 2B or Phase 3 that undergoes significant scope
changes (e.g.,changes in termination points or changes in configuration that
affect the interaction with the system)will be moved back to Phase 2A and will no
longer be in the same "Similarly Situated"group.
Projects in Phase 2B are not required to (but can)re-study the interaction with
another Project that is sent back from Phase 3 to Phase 2B with agreementby
the PRG that the Phase 3 Project scope remains essentiallythe same.This is
because Projects in Phase 3 would have 1)already been included in the base
cases for the later Projects;and 2)the later Projects would have mitigated the
impacts on Phase 3 Projects.So moving a Project from Phase 3 back to Phase
2B would not impact the studies required for the other Projects in Phase 2B (or
the base cases to be developedin Phase 2A).
If a Phase 3 Project is moved back as the result of a major change in Project
scope,then the project sponsor and the PRG should discuss which phase the
proposed Project will revert back to.As determined by the PRG,the Project may
revert back to any earlier Phase.Reverting back to Phase 2A may require re-
forming the PRG,redevelopingthe study plan,and developingnew base cases.
If no consensus is reached in the PRG,then the minority report will be included
as an appendixin the PRG report.Major changes in a Project's scope can result
in changes in the proposed Project's own Path Accepted Rating,Simultaneous
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interaction of other Existing Paths or Accepted Paths,or Impact Accepted
Rating(s)of other Path(s).See Section 7 for more examples.
For a Phase 3 Project with minor changes in scope and no increase in Accepted
Rating (e.g.,changes involvingseries compensationlevels or RAS,which
resulted in no criteria violation at the previous studied system conditions),the
Project can be sent back to Phase 2B as determined by the PRG.This change
will place the Project's Accepted Rating at risk.The project sponsor must test its
Accepted Rating based on its new Project scope against its original Accepted
Rating.If the study shows there is no adverse impact to the Accepted Rating
then the Project can retain its Phase 3 status.
If there is an adverse impact on the Accepted Rating,the Project must stay in
Phase 2B and is required to mitigate impacts on Phase 3 Projects and will be
similarly situated with other Projects in Phase 2B.If the mitigation undertaken is
a lowering of the Project's Accepted Rating,then the Project can retain its Phase
3 status at the lowered Accepted Rating.All Similarly Situated Projects will need
to perform studies to test their ratings against the new Accepted Rating of this
Phase 3 Project.
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WE CC
WECC Progress Report Policies
and
Procedures
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WECC Progress Report Policies and Procedures
Table of Contents
1.Introduction.......................................................................................................113
2.Policies..............................................................................................................113
3.Waiver of "Significant Impact"Status............................................................114
4.Procedures........................................................................................................115
5.Progress Reports..............................................................................................116
5.1.Initial Progress Report ...............................................................................116
5.2.ComprehensiveProgress Report...............................................................116
5.3.SupplementalProgress Reports ................................................................119
5.4.Review of Progress Reports ......................................................................119
6.Informal Reports Presented at TSS Meetings................................................120
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1.Introduction
This document is intended to provide the policies and procedures for notification and
reliability assessment requirements related to projects planned within the Western
Interconnection.WECC members are expected to be in full compliance with this WECC
document on Progress Report Policies and Procedures.
2.Policies
Entities sponsoring new generation are project sponsors and may be WECC members
or non-WECC members.Insofar as a non-WECC member sponsoring a generation
project requests interconnection to the Western Interconnection,the WECC member
accountable for generation interconnection administration (Interconnecting Utility)shall
take reasonable steps as the Interconnecting Utility to facilitate,and when applicable,
shall assist in the implementationof the policies and procedures specified herein.
Projects subjectto these policies and procedures include:
·All generation projects (200 MW or greater)connected to the transmission
system through step-up transformers.In the context of these policies and
procedures,such projects include,but are not limited to,new generation plants,
generation repower or upgrades that may significantly alter the operation of the
generation facilities.
All new and upgraded transmission facilities with (voltagelevels over 200 kV).
Such projects include,but are not limited to,new transmission facilities,
transmission re-designs or upgrades,permanentremoval of existing
transmission facilities,or other changes (e.g.,operating procedures)that may
significantly alter the operation of the transmission facilities.
Any facilities below these thresholds that may have a significant impact on the
reliability of the Western Interconnection.
The project sponsor or Interconnecting Utility shall begin providing appropriate
notification of projects in accordance with the procedures stated herein to WECC soon
after the project sponsor has made the project public.25 The project sponsor or
Interconnecting Utility is encouraged to make the project public at the earliest possible
date.
25 A project sponsor can make a project public via trade journals,news releases,public notice in a
newspaper,information released in an open public forum,issuance of a significant permit (air quality or
water rights)by a government agency to the project sponsor or notification to the interconnecting utility
that the project will be moving beyond the system impact study phase.
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The project sponsor or Interconnecting Utility shall perform technical studies to ensure
the reliable operation of the Western Interconnection when the project is placed in
service.The project sponsor or Interconnecting Utility shall provide comprehensive
progress reports of the technical studies to WECC in accordance with the procedures
stated herein.In the event WECC members have reliability-related concerns with a
project,the project sponsor or Interconnecting Utility shall be responsible for addressing
the concerns under the auspices of WECC's Technical Studies Subcommittee (TSS)in
accordance with the procedures outlined herein.Project sponsors are encouraged
voluntarilyto solicit interest in forming a study review group as the venue for performing
the technical studies and developingthe comprehensiveprogress report.
3.Waiver of "Significant Impact"Status
The sponsor(s)of transmission projects with operating voltages26 200 kV and above
and are not seeking a path rating may request waivers of the WECC Project
Coordination Process.The request must either provide documentation of how the
project is being coordinated in another forum,or provide an explanationof why the
project is not expectedto have any significant impact to the operation of the WECC
interconnected electric system.Project sponsors can request the waiver according to
the followingprocess:
1.The project sponsor includes a list of projects for which waiver is requested in a
separate section in its Annual Progress Report to the TSS with a copy to WECC
staff.If the request for waiver is needed before the next Annual Progress Report
is to be submitted,the project sponsor submits a request to WECC staff with
copy to TSS.
2.The followingproject information shall be included,as a minimum:
a.Project name
b.Project purpose
c.Brief Project description,including expectedtermination points
d.Expected date of release to operations
e.Expected operating voltage
f.Either:
i.Description of how the Project,has been coordinated through a
transmission planning forum,such as a Subregional Planning Group
(SPG),the Transmission Expansion Planning Policy Committee (TEPPC),
26 For transformer banks the operating voltage refers to the low side of the transformer bank.
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or some other appropriate forum27.The description should include
references to any transmission studies performed.
OR
ii.Explanationof why the Project is not expectedto have a significant impact
on the operation of the WECC interconnected electric system.
The followingquestionsmay be considered in determining whether a
project has significant impact to the WECC interconnected system:
Are there any impacts to other systems-have studies demonstrated?
·Is there any impact on flow of energy on other systems?
·Are any WECC transfer paths impacted?
·Is some kind of flow control device needed or required as a part of the
project?
·Is the project connected to other utilities systems?
·Do disturbances impact other entities?
3.WECC staff posts the list of projects and notifies the PCC,TEPPC,and TSS.
The waiver is granted unless a letter from a WECC member opposing the waiver
is received within 30 days.
4.Any WECC member(s)that believes the project should not be granted a waiver
must submit a letter to the PCC chair with a copy to the project sponsor and
WECC staff within 30 calendar days of the posting of the list.The letter must
outline the reason(s)for not granting the waiver and include a request that the
project proceeds with the Project Coordination Process.
5.WECC staff posts the letter opposing the waiver and notifies the PCC,TEPPC,
and TSS.
6.The PCC chair determines if the waiver will be granted within 20 calendar days of
posting the letter opposing the waiver.If the project sponsor is also the PCC
chair,such determination will be made by the PCC vice chair.
4.Procedures
The followingprocedures cover requirements for reporting project status and technical
studies.The purpose of these project progress and study reports is to encourage early
communication of plans and to maintain flexibilityfor changes during the period of
advanced planning.These reports should contain enough meaningful data to stimulate
27 If the project is being coordinated through a transmission planning forum,the sponsor shall provide an
open invitation for participation to all WECC members and other interested stakeholders.
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constructive discussion with the intent to share information and experience with WECC
members.
5.Progress Reports
5.1.Initial Progress Report
Soon after a project is made public,the project sponsor or Interconnecting Utility
shall submit,in electronic form if possible,the Initial Progress Report to the
WECC Technical staff and to TSS members.The content of the Initial Progress
Report will depend on the design status of the system upgrade,addition,or
project,but at a minimum should include:
1.A brief physical description of the project,including points of interconnection,
equipmentcapacities and voltages,and expected ratings.
2.The planned operating date.
3.The project status,including where the project is situated in the planning
process and a tentative schedule for completion.
4.Facility owner(s)name,a contact person including title or position,address,
telephonenumber and email address that can answer questionsand
comments or direct them to persons who can provide responses.
To the extent applicable,the project sponsor or Interconnecting Utility should
coordinate the Initial Progress Report submittal requirements with data reporting
requirements of the Project Coordination Process.
5.2.Comprehensive Progress Report
The purpose of the ComprehensiveProgress Report is for the project sponsor to
demonstrate that the project sponsor has met its obligationsto be compliantwith
the NERC Reliability Standards and WECC Criteria.
After the project is made public,at a point that would allow opportunity for WECC
member review and input,the project sponsor or Interconnecting Utility shall
submit the ComprehensiveProgress Report to the WECC Technical staff and
TSS members.The project would be considered in compliance with these
procedures if the ComprehensiveProgress Report was submitted at a point in
the developmentprocess that would allow changes to the Plan of Service,if so
indicated by WECC member review and input.
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The content of the ComprehensiveProgress Report should include,at a
minimum (1-5):
1.The requirements specified under the Initial Progress Report.
2.A one-line and geographic diagram of the project showing points of
interconnection,metering points,adjacentpath locations,and control area
boundaries.
3.Models and data that can be used by transmission planning software
programs.28 This may include a block diagram,transfer functions,equations,
and completedescriptions of the software modeling needed to study the new
facility using power flow and transient stability computerprograms.This
information is not required if the necessary models are already available in
the power flow and stabilityprograms.
4.A project milestone schedule that covers the current period through initial
operation of the project.This schedule should be sufficiently detailed to allow
for monitoring by the TSS members.
5.A summary of transmission studies performed,or information on where the
transmission studies can be located.With respect to impacts on other
systems,the specific contingencies in the followingtable must be evaluated:
Figure 1:Contingenciesand Performance Requirements for Assessment of Impacts on Other
Systems
Failure of a circuit breaker o All facilities shall be operating within their thermal,
associated with a Remedial Action voltage and stability limits,and Cascading or
Scheme to operate when required,uncontrolled separation shall not occur.
following:1)the loss of any o Planned or controlled interruption of electric supply to
element without a Fault;or 2)a customers (load shedding),the planned removal from
service of certain generators,and/or the curtailment ofpermanentphase-to-ground Fault,contracted Firm (non-recallable reserved)electricwithNormalClearing,on any power transfers is allowed.transmission circuit,transformer or
bus section.
28 Modeling guidelines can be found in the WECC Data Preparation Manual
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A non-three-phase Fault with All facilities shall be operating within their thermal,voltage
Normal Clearing on common mode and stability limits,and cascading or uncontrolled
Contingency of two adjacent separation shall not occur.
circuits29 On separate towers.Planned or controlled interruption of electric supply to
customers (load shedding),the planned removal from
service of certain generators,and/or the curtailment of
contracted Firm (non-recallable reserved)electric power
Transfers is allowed.
A common mode outage of two Cascading shall not occur.
generating units connected to the
same switchyard.
If the sponsor is planning to go through the Path Rating Process,then the
ComprehensiveProgress Report must also include the following(6-11):
6.A statement describing the Transfer Capability associated with the project,
including the impact on other systems,the impact on existing transfer path
ratings,and the project sponsor'scompliance with the NERC Reliability
Standards and WECC Criteria.This statement should include a declaration
that indicates if the project will require (or not require)obtaining an accepted30
transmission path rating (or rerating).
7.A description of the interconnected-system conditions and or requirements on
which the proposed Transfer Capability rating is based and/or required by the
project.
8.The operating conditions including flows on key transmission lines and paths,
load levels,and generation status that allow the project to operate within the
guidelinesdefined in the NERC Reliability Standards and WECC Criteria.
9.The potential impacts to transmission facilities including non-simultaneous
ratings and simultaneous path interactions.It is not the purpose of the
ComprehensiveProgress Report to identify mitigation measures or
requirements to mitigate.
29 Adjacent Transmission Circuits are two transmission circuits with separation between their center lines
less than 250 feet at the point of separation with no Bulk Electric System circuit between them.
Transmission circuits that cross,but are otherwise separated by 250 feet or more between their
centerlines,are not Adjacent Transmission Circuits.Transmission circuits that are separated by less than
250 feet for no more than three miles,but are otherwise separated by 250 feet or more between their
centerlines,are likewise not adjacent circuits.
30 Project sponsors or responsible parties desiring to obtain an accepted path rating (or path rerating)
should comply with the detailed procedure contained in the Project Coordination and Path Rating
Processes.
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10.A representativelist of power flow and stability cases run that demonstrate
the project sponsor's compliance with NERC Reliability Standards and WECC
Criteria.
11.Representativepower flow outage results and stabilityplots that demonstrate
the project sponsor's compliance with NERC Reliability Standards and WECC
Criteria.
5.3.Supplemental Progress Reports
The project sponsor or Interconnecting Utility shall submit the Supplemental
Progress Report to WECC staff and the TSS chair every year in which an Initial
Progress Report or ComprehensiveProgress Report is not submitted.These
reports shall be filed annuallyfor projects where there have been no significant
changes in Plan of Service,capacity,or in-service dates since the
ComprehensiveProgress Report was filed.These reports must also include non-
significant additions or revisions to the projects.The Annual Supplemental
Progress Reports,at a minimum shall include:
1.The requirements specified under Initial Progress Report and any additions or
changes related to these requirements.
2.Changes to any or all items specified under the previously submitted
ComprehensiveProgress Report.
In the event of major design changes or project delays that may alter a projects
impact on the overall system,a complete(updated)ComprehensiveProgress
Report must be submitted,in accordance with the procedures for Comprehensive
Progress Reports.
5.4.Review of Progress Reports
The followingprocess shall be used for the review of progress reports:
1.The project sponsor or Interconnecting Utility shall submit the appropriate
progress report in accordance with the respective procedure by March 1 of
each year.
2.WECC staff shall compile and send a report to all TSS members that shows
the date and status of the last ComprehensiveProgress Report for the
various projects and the name of the person who should receive requests for
this report.
3.Members are encouraged to review as many progress reports as possible.
Comments and/or questions concerning progress reports must be directed to
the person named by the project sponsor or the responsible party.Copies of
correspondence relating to the project sponsor'scompliance with NERC
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ReliabilityStandards and WECC Criteria,Policies,and Procedures should be
sent to the TSS chair or his designatedrepresentative.
4.If a progress report is not submitted,or if concerns related to the project have
not been resolved,any reviewing member may request that the TSS review
the project in question by addressing a letter to the TSS chair.Such requests
for TSS review shall be submitted only after extensive efforts have been
made by the reviewing party and the reporting party to resolve the concern.
5.If a TSS review is requested,the TSS chair shall appointan ad hoc
committee to review the project in question.The ad hoc committee shall
report its findings to the TSS on whether the project in question warrants
further review.
6.If further review is necessary,the TSS may then request the project sponsor
or Interconnecting Utility to provide TSS members with studies addressing the
reviewing members'concern or demonstratingthe project sponsor's
compliance with NERC ReliabilityStandards and WECC Criteria,Policies,
and Procedures.
7.The TSS chair will solicit written and verbal comments from TSS members
regarding their review of the progress reports to determine conformance of
the project's performance with NERC Reliability Standards and WECC
Criteria,and the project sponsor'sconformance with WECC Policies and
Procedures.The outcome of the TSS review will provide the basis of the
annual TSS review of progress reports to the PCC.The TSS chair will present
results of the annual TSS review to the PCC at its final meeting of year.
Despite any review for compliance with NERC Reliability Standards that may be
performed under processes described herein,the project sponsor retains the
sole responsibility for compliance with NERC ReliabilityStandards.
6.Informal Reports Presented at TSS Meetings
TSS members shall provide brief written or verbal informal project update reports during
each TSS meeting.
The TSS chair shall select one or more majorprojects of current interest to TSS
members to be reported on at each TSS meeting.These more formal presentations
should be no longer than 15 minutes each,with additional time allowed for questions
and answers.
The presentationscan be oral and/or written and should contain at a minimum:
1.Map showing location,ownership,and voltage.
2.Schematic diagram including majorequipmentratings.
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3.Area load,generation,and interchange schedules used in technical studies.
4.Transfer capability associated with the project and/or effects on other
Transfer Capabilities.
5.Evidence of compliance with the NERC Reliability Standards and WECC
Criteria.
6.Description of the interconnected-system conditions and/or requirements on
which the proposed Transfer Capability Rating is based and/or required by
the project.
Approvedby Planning Coordination Committee July 15,2014
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