20180329PAC to Staff UT Q707SIS.pdf

PAciFICORP
TRANSMISSION
System Impact Study Report
Large Generator Interconnection
System Impact Restudy Report
Completed for
("Interconnection Customer")
Q0707
Proposed Point of Interconnection
Existing Shirley Basin 230 kV Substation
February 9,2018
PACIFICORPTRANSMISSION
System Impact Study Report
TABLE OF CONTENTS
1.0 DESCRIPTION OF THE GENERATING FACILITY ...............................................3
2.0 SCOPE OF THE STUDY ......................................................3
3.0 TYPE OF INTERCONNECTION SERVICE ...............................................4
4.0 DESCRIPTION OF PROPOSED INTERCONNECTION...............................................4
4.1 Other Options Considered...............................................6
5.0 STUDY ASSUMPTIONS.........................................................6
5.1 Energy Resource (ER)Interconnection Service................................................7
5.1.1 Requirements 7
5.1.2 Cost Estimate 14
5.1.3 Schedule 15
5.1.4 Maximum Amount of Power that can be deliveredinto NetworkLoad,with No Transmission
Modifications(for informationalpurposes only)15
5.1.5 Additional Transmission ModificationsRequired to Deliver 100%of the Power into Network
Load (for informationalpurposes only)16
6.0 PARTICIPATION BY AFFECTED SYSTEMS..............................................16
7.0 APPENDICES ..........................................................16
7.1 Appendix 1:HigherPriority Requests ..............................................17
7.2 Appendix 2:Property Requirements.............................................18
7.3 Appendix 3:Study Results................................................20
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1.0 DESCRIPTION OF THE GENERATING FACILITY
("Interconnection Customer")proposed interconnecting 250 MW of new generation to
PacifiCorp's ("Transmission Provider")Shirley Basin 230 kV substation located in Carbon
County,WY.The project ("Project")will consist of 14 Vestas V110 2.0 and 53 Vestas Vl36 4.2
turbines for a total output of 250 MW at the Point of Interconnection.The requested commercial
operation date is November 1,2020.
The restudy of this Project is performed due to the staging of the Energy Gateway West project.
Specifically,while the entire Gateway West project has a longer developmenttimeline,the Aeolus-
Bridger/AnticlineD.2 segment of the project (500 kV segment from the planned Aeolus substation
to the planned Anticline substation)now has an expected 2020 in-service date.The earlier
availabilityof the D.2 segment materiallychanges certain modeling assumptions that could impact
the cost or timing of the interconnection of certain projects whose previous studies depended on
Gateway West in its entirety.
Interconnection Customer will NOT operate this generator as a Qualified Facility as defined by
the Public Utility Regulatory Policies Act of 1978 (PURPA).
The Transmission Provider has assigned the Project "Q0707."
2.0 SCOPE OF THE STUDY
The interconnection system impact restudy shall evaluate the impact of the proposed
interconnection on the reliability of the transmission system.The study will consider Base Case as
well as all generating facilities (and with respect to (iii)below,any identified network upgrades
associated with such higher-queued interconnections)that,on the date the interconnection system
impact study is commenced:
(i)are directlyinterconnected to the transmission system;
(ii)are interconnected to Affected Systems and may have an impact on the interconnection
request;
(iii)have a pending higher queued interconnection request to interconnect to the transmission
system and have a planned in-service date of December 2020 or earlier;and
(iv)have no Queue Position but have executed an LGIA or requested that an unexecuted
LGIA be filed with FERC.
This interconnection system impact study will consist of a short circuit analysis and a power flow
analysis.The study will state the assumptions upon which it is based;state the results of the
analyses;and provide the requirements or potential impediments to providing the requested
interconnection service,includingpreliminaryindication of the cost and length of time that would
be necessary to correct any problems identified in those analyses and implement the
interconnection.The study will also provide a list of facilities that are required as a result of the
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Interconnection Request and a non-binding good faith estimate of the cost responsibility and a
non-binding good faith estimated time to construct.
Based on the engineeringjudgement,the stability results for this project are not expected to change
and hence the restudy of stability analysis was not performed.
3.0 TYPE OF INTERCONNECTION SERVICE
The Interconnection Customer has elected to have the interconnection studied as an Energy
Resource (ER).
4.0 DESCRIPTION OF PROPOSED INTERCONNECTION
The Interconnection Customer's proposed Generating Facility is to be interconnected to the
existing Shirley Basin 230 kV substation.Figure 1 below,is a one-line diagram that illustrates the
interconnection of the proposed Generating Facility to the Transmission Provider's Shirley Basin
substation.
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Df6culty
8 1 M 34
Point of 84/112/140 MVA
Interconnection 230 -34.5 kV
Z =9%
Shirley Basin TSubstation 8
34.5 kVQ0707
Substation
I
230 kV
Dunlap
Miles
|||Î
Aeolus
Substation
500 -Q0706 500 -
230 kV 230 kV
Tranf.Tranf.Freezeout
Figure 1:Simplified System One Line Diagram
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4.1 Other Options Considered
The followingalternative options were considered as potential points of interconnection for this
Project:None per Interconnection Customer.
5.0 STUDYASSUMPTIONS
All active higher priority transmission service and/or generator interconnection requests
with an in-service date as of December 2020 or earlier will be considered in this study and
are listed in Appendix 1.If any of these requests are materiallymodified or withdrawn,the
Transmission Provider reserves the right to restudy this request,and the results and
conclusions could significantlychange.
For study purposes there are two separate queues:
o Transmission Service Queue:to the extent practical,all network upgrades that are
required to accommodate active transmission service requests will be modeled in
this study.
o Generation Interconnection Queue:Interconnection Facilities associated with
higher queued interconnection requests with an in-service date of December 2020
or earlier will be modeled in this study.
The Interconnection Customer's request for energy or network resource interconnection
service in and of itself does not convey transmission service.Only a Network Customer
may make a request to designate a generating resource as a Network Resource.The
provision of transmission service may require additional studies and the construction of
additional upgrades.
This study assumes the Project will be integrated into the Transmission Provider's system
at the Shirley Basin point of interconnection.
The Interconnection Customer will construct and own any facilities required between the
Point of Change of Ownership and the Project unless specifically identified by the
Transmission Provider.
Generatortripping may be required for certain outages.
.All facilities will meet or exceed the minimum Western Electricity Coordinating Council
("WECC"),North American Electric Reliability Corporation ("NERC"),and the
Transmission Provider's performance and design standards.
The Energy Gateway West,Aeolus-Bridger/AnticlineD.2 500 kV line from the proposed
Aeolus substation to the proposed Anticline substation and ancillaryprojects are assumed
in service in 2020.
Remedial Action Scheme (RAS)that will arm approximately 640 MW of generationfor
the followingoutages is assumed to be in-service.
o Aeolus -Bridger/Anticline500 kV line
o Aeolus 230/500 kV transformer
o Anticline 345/500 kV transformer
o Future Anticline -Populus 500 kV line
o Future Populus 500/345 kV auto transformer
o Future Aeolus -Clover 500 kV line
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o Future Clover 500/345 kV auto transformer
PacifiCorp reserves the right to restudy the Project if any of the mentioned assumptions
are changed or any of the required mitigations are not in-service at the time of
mterconnection.
This report is based on information available at the time of the study.It is the
Interconnection Customer's responsibility to check the Transmission Provider's web site
regularlyfor Transmission System updates at http://www.pacificorp.com/tran.html
5.1 Energy Resource (ER)Interconnection Service
Energy Resource Interconnection Service allows the Interconnection Customer to connect its
Generating Facility to the Transmission Provider's Transmission System and to be eligible to
deliver electric output using firm or non-firm transmission capacity on an as available basis.
5.1.1 Requirements
5.1.1.1 GeneratingFacility Modifications
Transmission Provider will require the facility to operate in voltage control mode with the ability
to deliver power output to the Point of Interconnection within the range of +/-0.95 power factor.
(Please see Standard Large Generator Interconnection Agreement,article 9.6.1 and 9.6.2 in
OATT).Any additional reactive compensation must be designed such that the discrete switching
of the reactive device,if required,does not cause step voltage changes greater than ±3%at any
load serving bus on the Transmission Provider's system.
As required by NERC standard VAR-001-la,the Transmission Provider will provide a voltage
schedule for the Point of Interconnection.In general,Generating Facilities should be operated so
as to maintain the voltage at the Point of Interconnection,or other designated point as deemed
appropriated by Transmission Provider.The Transmission Provider may also specify a voltage
and/or reactive power bandwidth as needed to coordinate with upstream voltage control devices
such as on-load tap changers.At the Transmission Provider's discretion,these values might be
adjusted depending on operating conditions.
Generating Facilities capable of operating with a voltage droop are required to do so.Voltage
droop control enables proportionate reactive power sharing among generation facilities.Studies
will be required to coordinate voltage droop settings if there are other facilities in the area.It will
be the Interconnection Customer's responsibility to ensure that a voltage coordination study is
performed,in coordination with Transmission Provider,and implemented with appropriate
coordination settings prior to unit testing.
For areas with multiplegenerating facilities additional studies may be required to determine
whether or not critical interactions,including but not limited to control systems,exist.These
studies,to be coordinated with Transmission Provider,will be the responsibility of the
Interconnection Customer.If the need for a master controller is identified,the cost and all related
installation requirements will be the responsibility of the Interconnection Customer.While study
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costs of subsequent interconnection projects nearby will be the responsibility of the new project,
participation by the Q0707 Project may be required post commercial operation to ensure Bulk
Electric System reliability is maintained.
To facilitate collection and validation of accurate modeling data to meet NERC modeling
standards,PacifiCorp,as the Planning Coordinator,requires Phasor MeasurementUnits (PMUs)
at all new GeneratingFacilities with an individual or aggregate nameplate capacity of 75 MVA or
greater.In addition to owning and maintaining the PMU,the Generating Facility will be
responsible for collecting,storing and retrieving data as requested by the Planning Coordinator.
Data must be collected and be able to stream to Planning Coordinator for each of the Generating
Facility's step-up transformers measured on the low side of the GSU at a sample rate of at least 30
samples per second and synchronizedwithin +/-2 milliseconds of the CoordinatedUniversal Time
(UTC).Initially,the followingdata must be collected:
Three phase voltage and voltage angle (analog)
Three phase current (analog)
Data requirements are subject to change as deemed necessary to comply with local and federal
regulations.
All generators must meet the Federal Energy Regulatory Committee (FERC)and WECC low
voltage ride-through requirements as specified in the interconnection agreement.At low or zero
output levels,the Project must not have reactive power interchange outside of the +/-0.95 power
factor requirement at the POI.PacifiCorp has experienced high voltages in the Wyoming area
when the transmission system is lightly loaded with low wind conditions in the area.With low
wind conditions the wind farms tend to supply reactive power into the transmission system
increasing the voltage.
As the Transmission Provider cannot submit a user written model to WECC for inclusion in base
cases,a standard model from the WECC Approved Dynamic Model Library is required 180 days
prior to trial operation.The list of approved generator models is continuallyupdated and is
available on the http://www.WECC.bizwebsite.
5.1.1.2 Transmission System Modifications
Figure 1 above is a one-line diagram that illustrates the interconnection of the proposed
generating facility and the system improvements required.
A new bay and three new breakers along with associated switches at the existing Shirley
Basin 230 kV substation.
Two new line terminations at Shirley Basin substation,one to interconnect the this Project
and the other to connect the new Shirley Basin -Aeolus 230 kV line required by the
Project.
Addition of two new breakers along with associated switches on the existing bay that
connects Dunlap wind farm to Shirley Basin in order to convert Shirley Basin to full
breaker and half scheme.
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Construction of a new approximately 16.5-mile Shirley Basin -Aeolus 230 kV line with
2-1557 ACSR Potomac.It is noted that the requirement for this Project is a 2-1272 ACSR
conductor;however,the Transmission Provider's master plan identifies 2-1557 ACSR and
therefore the Transmission Provider will be responsible for the incremental betterment cost
of the larger conductor.
Addition of one new 230 kV circuit breaker at the proposed Aeolus substation
New line termination at Aeolus substation.
A RAS that will drop the Q0707 Project for the 500 kV outages related to Gateway West,
Segment D.2:
o Aeolus -Bridger/Anticline500 kV line
o Aeolus 230/500 kV transformer
o Anticline 345/500 kV transformer
o Future Anticline -Populus 500 kV line
o Future Populus 500/345 kV auto transformer
o Future Aeolus -Clover 500 kV line
o Future Clover 500/345 kV auto transformer
5.1.1.3 Transmission/Distribution Line Modifications
Construct a new 230 kV transmission line from Aeolus to Shirley Basin.The line will be
constructed using double bundled 1557 ACSR conductor and will be approximately 16.5 miles
long.There will be an additional 0.12 miles of line constructed to allow a swap of line positions
at Aeolus substation.
Install ½"OPGW in place of one of the shield wire positions on H-frame and Three Pole structures
for the entire 16.5 mile line length.
The Transmission Provider shall review the design of the span between the Interconnection
Customer's tie line substation deadend tower and the Shirley Basin substation deadend tower.The
Interconnection Customer shall coil conductor,OPGW and shield wire and line hardware with
sufficient quantities to span between the tie line substation tower and the Shirley Basin substation
tower.The Transmission Provider will construct the span between the tie line substation tower and
the Shirley Basin tower.
5.1.1.4 Existing Circuit Breaker Upgrades -Short Circuit
The increase in the fault duty on the system as a result of the addition of the generation facility
with 14 Vestas V110 2.0 and 53 Vestas Vl36 4.2 wind turbine generators fed through 14 -2,222
kVA and 53 4,700 kVA 34.5 kV -690 V transformers with 5.75 %impedance then fed through
two 230 -34.5kV 83/112/140 MVA step up transformers with 9 %impedance will not push the
fault dutyabove the interrupting rating of any of the existing fault interruptingequipment.
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5.1.1.5 Protection Requirements
The ground mats of the tie line substation and Shirley Basin substation must be tied together so
that metallic control cables can be used between the two facilities.Bus differential relays will be
applied to detect faults on this connection.With this arrangement the Interconnection Customer
must install line relays systems that will detect and clear all faults on the tie lines in 5 cycles or
less.A set of non-pilot step distance line relays that will detect faults on the tie line will also be
applied at Shirley Basin substation.The Interconnection Customer will need to supply and
maintain sets of line relays to be installed at Q0707 collector substation that will detect faults on
the 230 kV line back to Shirley Basin substation.These line relays can be time coordinated with
the relays detecting faults on the transmission network and will not communicate with the line
relays to be installed at Shirley Basin substation for the tie line.
Should the Interconnection Customer desire a potential alternative to the tie line substation in order
to provide adequate protection to its tie line,the Interconnection Customer may petition the
Transmission Provider for an exemption to this arrangement.The Transmission Provider must
review and approve the Interconnection Customer's proposed alternative.Without approval of the
proposed alternative the tie line substation configuration will be required.
Protective relay elements in the line relays at Shirley Basin substation will monitor voltage and
frequency.If the voltage,magnitude or frequency is outside of the normal operation range,this
relay will trip the 230 kV breaker in the tie line substation.
The existing line relays installed for the Dunlap line will continued to be used for that line.The
relays will be reconnected to the new 230 kV breakers.
This GeneratingFacility will need to be controlled by the Aeolus RAS.For the loss of any one of
a number of electrical elements that will be part of the Gateway Transmission projects this Project
will need to be tripped.The Aeolus RAS master will be located at Aeolus Substation.The trip
signal will need to be communicated from Aeolus to Shirley Basin substation.
Line current differential relays will be installed at Shirley Basin and Aeolus substations for the
new Shirley Basin -Aeolus transmission line.
5.1.1.6 Data (RTU)Requirements
In addition to the need for operational data and control at Shirley Basin substation,data for the
operation of the power system will be needed from the collector substation and tie line substation.
This data can be acquired by installingan Interconnection Customer owned data concentrator at
the collector substation.The data will be transferred to the RTU in Shirley Basin substation via
Interconnection Customer owned fiber on the tie from the collector substation.Listed below is the
data that will be acquired from the collector substation and at Shirley Basin substation.
From Shirley Basin Substation:
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Analogs:
Net Generationreal power
Net Generator reactive power
Interchange energy register
From the Q0707 Collector substation:
Analogs:
Transformer #1 real power
Transformer #1 reactive power
Real power flow through 34.5 kV line feeder breakerTl-1
Reactive power flow through 34.5 kV line feeder breaker Tl-1
Real power flow through 34.5 kV line feeder breakerTl-2
Reactive power flow through 34.5 kV line feeder breaker Tl-2
Real power flow through 34.5 kV line feeder breakerTl-3
Reactive power flow through 34.5 kV line feeder breaker Tl-3
Real power flow through 34.5 kV line feeder breakerTl-4
Reactive power flow through 34.5 kV line feeder breaker Tl-4
Real power flow through 34.5 kV line feeder breakerTl-5
Reactive power flow through 34.5 kV line feeder breaker Tl-5
Transformer #2 real power
Transformer #2 reactive power
Real power flow through 34.5 kV line feeder breakerT2-1
Reactive power flow through 34.5 kV line feeder breaker T2-1
Real power flow through 34.5 kV line feeder breakerT2-2
Reactive power flow through 34.5 kV line feeder breaker T2-2
Real power flow through 34.5 kV line feeder breakerT2-3
Reactive power flow through 34.5 kV line feeder breaker T2-3
Real power flow through 34.5 kV line feeder breakerT2-4
Reactive power flow through 34.5 kV line feeder breaker T2-4
Real power flow through 34.5 kV line feeder breakerT2-5
Reactive power flow through 34.5 kV line feeder breaker T2-5
Average Plant Wind speed
Average Plant Atmospheric Pressure (Bar)
Average Plant Temperature (Celsius)
Status:
230 kV breaker Tl
34.5 kV collector circuit breaker Tl-1
34.5 kV collector circuit breaker Tl-2
34.5 kV collector circuit breaker Tl-3
34.5 kV collector circuit breaker Tl-4
34.5 kV collector circuit breaker Tl-5
230 kV breaker T2
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34.5 kV collector circuit breaker T2-1
34.5 kV collector circuit breaker T2-2
34.5 kV collector circuit breaker T2-3
34.5 kV collector circuit breaker T2-4
34.5 kV collector circuit breaker T2-5
From the tie line substation:
Status:
230 kV breaker
5.1.1.7 Substation Requirements
The Project will require new 230kV breaker-and-a-half bays at Shirley Basin substation,a
Transmission Provider owned control house at the Interconnection Customer's collector
substation,and a new 230kV line position at Aeolus substation.The ground grids of the tie line
substation and Shirley Basin substation must be connected.The followingmajor equipment has
been preliminarily identified for this Project:
Shirley Basin Substation:
5 -230kV circuit breakers
8 -230kV CCVT's
13 -230kV disconnect switches
9 -230kV surge arresters
Aeolus Substation:
l -230kV circuit breaker
3 -230kV CCVT's
3 -230kV disconnect switches
3 -230kV surge arresters
Collector Station:
l -Control house
l -125 VDC battery system
The Interconnection Customer will provide a separate graded,groundedand fenced area along the
perimeter of the Interconnection Customer's collector substation for the Transmission Provider to
install a control house for metering equipment.This area will share a fence and ground grid with
the Generating Facility and have separate,unencumbered access for the Transmission Provider.
AC station service shall be provided by the Interconnection Customer.DC power for the control
house will be supplied by the Transmission Provider.
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5.1.1.8 Communication Requirements
OPGW fiber will need to be installed on the new transmission line from Aeolus substation to
Shirley Basin substation.This is a redundantpath for the Aeolus RAS.The existing line contains
OPGW which is the primary communication feed.At both Shirley Basin substation and Aeolus
substation a second DMX fiber node and channel bank will be installed for redundancy.At Shirley
Basin substation the existing network router needs to be upgradedwith additional ports.The router
at Shirley Basin substation will have ports for the commercial meters.
From Shirley Basin substation,single mode fiber is to be run to the tie line substation.All
communications at the tie line substation and collector substation including the OPGW fiber on
the line between the two is the responsibility of the Interconnection Customer.The Interconnection
Customer is to supply 1 DNP3 SCADA circuit from the collector substation to the Shirley Basin
substation with all the required SCADA points.Four Mirrored bit channels will be installed on the
two fiber paths to Aeolus substation and feed the Aeolus RAS controller.
The Interconnection Customer shall install a data concentrator (SEL-2411 or Transmission
Provider approved device)to transfer data between the collector substation and the Transmission
Provider's RTU located in Shirley Basin substation.The Transmission Provider will input and
hold the second level passwords for the SEL-2411 or Transmission Provider approved device.
Password control ensures the Transmission Provider is aware of and is accepting of the changes
being requested by the Interconnection Customer.
5.1.1.9 Metering Requirements
InterchangeMetering -Shirley Basin substation:
The Point of Interconnection metering will be located at Shirley Basin substation and rated for the
total net generation of the Project.The metering will be designed to include back-feed metering.
The Transmission Provider will specify and order all interconnection revenue metering,including
the instrument transformers,metering panels,junction box and secondary metering wire.The
primary metering transformers shall be combination 230kV,1000/5,CT/VT extended range for
high accuracy metering.
The metering design package will include two revenue quality meters,test switch,with DNP real
time digital data terminated at a metering interposition block.One meter will be designated a
primary SCADA meter and a second meter will be used designated as backup with metering DNP
data delivered to the alternate control center.The metering data will include bidirectional KWH
KVARH,revenue quantities includinginstantaneous PF,MW,MVAR,MVA,includingper phase
voltage and amps data.
An Ethernet connection is required for retail sales and generation accounting via the MV-
90 translation system.
Collector Substation 00707:
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Revenue metering is required for each of the two customer power transformers and will be located
on the high side of each of the step-up transformers.The primary metering transformers shall be
combination 230kV,500/5,CT/VT extended range for high accuracy metering.
The Transmission Provider will design and procure the collector revenue metering panels.The
panels shall be located inside the collector substation control house.The collector substation
metering panel shall include two revenue quality meters,test switches,and all SCADA metering
data terminated at a metering interposition block.
An Ethernet phone line is required for retail sales and generation accounting via the MV-90
translation system.
Station Service/Construction Power
The Project is outside the Transmission Provider retail service territory.Prior to construction the
Interconnection Customer must arrange with Carbon Power &Light permanent station service
load.The Interconnection Customer will need to coordinate with Carbon Power &Lightto submit
a transmission service request to the Transmission Provider for power that will backfeed through
the Transmission Provider's system when the Project is not generating.The Transmission
Provider shall provide a Modbus or DNP output from the bidirectional meters to Carbon Power &
Light for back-feed metering.At Shirley Basin substation the data output shall be trenched from
the meter panel to outside the substation fence.Obtaining all necessary retail service arrangements
are contingent for backfeed approval of the Project.
5.1.2 Cost Estimate
The followingestimate represents only scopes of work that will be performed by the
Transmission Provider.Costs for any work being performed by the Interconnection Customer are
not included.
Energy Resource
Interconnection -Direct AssignmentFacilities
Q0707 Collector Substation -Metering and Control House $952,000
Q0707 Tie Line and Collector Substation -Coordinate Communications $142,000
and Protection &Control
Shirley Basin Substation -Q0707 Line Position and Metering $784,000
Sub-total Direct AssignmentCosts $1,878,000
Interconnection -Network Upgrade Costs
Shirley Basin Substation -Expand to Breaker and a Half $5,472,000
Shirley Basin-Aeolus -Construct 16.5 Mile 230 kV Transmission Line $17,434,000
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Aeolus Substation -New Line Position $2,330,000
Sub-total Network Upgrade Costs $25,236,000
Total Cost -ER Interconnection Service -Interconnection Only $27,114,000
*Any distribution line modifications identified in this report will require a field visit analysis in
order to obtain a more thorough understanding of the specific requirements.The estimate
provided above for this work could change substantially based on the results of this analysis.
Until this field analysis is performed the Transmission Provider must develop the project
schedule using conservative assumptions.The Interconnection Customer may request that the
Transmission Provider perform this field analysis,at the Interconnection Customer's expense,
prior to the execution of an Interconnection Agreement in order to obtain more cost and schedule
certamty.
Note:Costs for any excavation,duct installation and easements shall be borne by the
Interconnection Customer and are not included in this estimate.This estimate is as accurate as
possibly given the level of detailed study that has been completed to date and approximates the
costs incurred by Transmission Provider to interconnect this GeneratorFacility to Transmission
Provider's electrical distribution or transmission system.A more detailed estimate will be
calculated during the Facilities Study.The Interconnection Customer will be responsible for all
actual costs,regardless of the estimated costs communicated to or approvedby the
InterconnectionCustomer.
5.1.3 Schedule
The Transmission Provider estimates it will require approximately 24-30 months to design,
procure and construct the facilities described in the Energy Resource sections of this report
followingthe execution of an Interconnection Agreement.The schedule will be further
developedand optimized during the Facilities Study.
Please note,the Transmission Provider's estimated time to perform the scope of work outlined in
this report may support the Interconnection Customer's requested Commercial Operation date of
November 1,2020.
5.1.4 Maximum Amount of Power that can be delivered into Network Load,with No
Transmission Modifications (for informational purposes only)
Zero (0)MW can be delivered on a firm basis to the Transmission Provider's network loads with
additional transmission modifications.
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5.1.5 Additional Transmission Modifications Required to Deliver 100%of the Power into
Network Load (for informational purposes only)
In order to deliver 100%of the power into Network Load,in addition to the mitigation identified
in section 5.1.1.2,the completion of additional Transmission Provider Energy Gateway projects
and other system improvements would also be required.
6.0 PARTICIPATION BY AFFECTED SYSTEMS
Transmission Provider has identified the followingaffected systems:Tri-State Generation and
Transmission,WAPA
A copy of this report will be shared the each Affected System.
7.0 APPENDICES
Appendix 1:Higher Priority Requests
Appendix 2:Property Requirements
Appendix 3:Study Results
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7.1 Appendix1:HigherPriority Requests
All active higher priority transmission service and/or generator interconnection requests with an
in-service date of December 2020 or earlier were considered in this study and are identified
below.If any of these requests are materiallymodified,the Transmission Provider reserves the
right to restudy this request,as the results and conclusions containedwithin this study could
significantlychange.
Transmission/GenerationInterconnection Queue Requests considered:
Q0542 (240 MW)-QF/NR
Q0706 (250 MW)-ERQ0720*(80 MW -TSR Q2060)*This project has been designated a network resource
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7.2 Appendix2:Property Requirements
Property Requirementsfor Point of Interconnection Substation
Requirementsfor rights of way easements
Rights of way easements will be acquired by the Interconnection Customer in the Transmission
Provider's name for the construction,reconstruction,operation,maintenance,repair,replacement
and removal of Transmission Provider's Interconnection Facilities that will be owned and
operated by PacifiCorp.Interconnection Customer will acquire all necessary permits for the
project and will obtain rights of way easements for the project on Transmission Provider's
easement form.
Real Property Requirementsfor Point of Interconnection Substation
Real property for a point of interconnection substation will be acquired by an Interconnection
Customer to accommodate the Interconnection Customer's project.The real property must be
acceptable to Transmission Provider.Interconnection Customer will acquire fee ownership for
interconnection substation unless Transmission Provider determines that other than fee
ownership is acceptable;however,the form and instrument of such rights will be at Transmission
Provider's sole discretion.Any land rights that Interconnection Customer is planning to retain as
part of a fee property conveyance will be identified in advance to Transmission Provider and are
subject to the Transmission Provider's approval.
The Interconnection Customer must obtain all permits required by all relevantjurisdictionsfor
the planned use includingbut not limited to conditional use permits,Certificates of Public
Convenience and Necessity,California Environmental QualityAct,as well as all construction
permits for the project.
Interconnection Customer will not be reimbursed through network upgrades for more than the
market value of the property.
As a minimum,real property must be environmentally,physically,and operationally acceptable
to Transmission Provider.The real property shall be a permitted or permittable use in all zoning
districts.The Interconnection Customer shall provide Transmission Provider with a title report
and shall transfer property without any material defects of title or other encumbrances that are
not acceptable to Transmission Provider.Property lines shall be surveyed and show all
encumbrances,encroachments,and roads.
Examples of potentiallyunacceptable environmental,physical,or operational conditions could
include but are not limited to:
1.Environmental:known contamination of site;evidence of environmental
contamination by any dangerous,hazardous or toxic materials as defined by any
governmental agency;violation of building,health,safety,environmental,fire,
land use,zoning or other such regulation;violation of ordinances or statutes of
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any governmental entities having jurisdiction over the property;underground or
above ground storage tanks in area;known remediation sites on property;ongoing
mitigation activities or monitoring activities;asbestos;lead-based paint,etc.A
phase I environmental study is required for land being acquired in fee by the
Transmission Provider unless waived by Transmission Provider.
2.Physical:inadequate site drainage;proximity to flood zone;erosion issues;
wetland overlays;threatened and endangered species;archeological or culturally
sensitive areas;inadequate sub-surface elements,etc.Transmission Provider may
require Interconnection Customer to procure various studies and surveys as
determined necessary by Transmission Provider.
Operational:inadequate access for Transmission Provider's equipment and vehicles;existing
structures on land that require removal prior to building of substation;ongoing maintenance for
landscaping or extensive landscape requirements;ongoing homeowner's or other requirements or
restrictions (e.g.,Covenants,Codes and Restrictions,deed restrictions,etc.)on property which
are not acceptable to the Transmission Provider.
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7.3 Appendix3:Study Results
Power Flow Study Results
A Western Electricity Coordinating Council (WECC)approved 2021-22 Heavy Winter case was
used to perform the power flow studies using PSS/E version 33.7.The study was performed
assuming the Energy Gateway,D.2 500 kV segment from the planned Aeolus substation to the
planned Anticline substation was in-service.The local 500 kV,345 kV,230 kV,and 115 kV
transmission system outages were considered during the study.
N-0 Results:Assuming the Energy Gateway West D.2 segment is in service the followingN-0
thermal or voltage issues were observed in the studies.
The Aeolus -Shirley Basin 230 kV line is overloaded to 102%of its continuous rating under
normal condition.As a result a new 230 kV line from Aeolus -Shirley Basin constructed with 2-
1557 ACSR Potomac/TW is required.(Note:the Q0707 Project identified the need for 2-1272
ACSR;however,the master plan for this area requires 2-1557 ACSR.Therefore,the incremental
betterment cost will be borne by Transmission Provider.The existing 230 kV line cannot be rebuilt
as the existing transmission line cannot be taken out of service.
Injection of approximately 9.0 MVAr into the transmission system was observed if the collector
system was connected with no generation from the Project.The Project shall control the voltage
at the POI within the required voltage range provided by the Transmission Operator.
N-1 Results:Assuming Energy Gateway,Segment D.2 and associated system improvements are
in service,the Platte -Latham 230 kV line overloads above its emergency rating for loss of the
followingelements:
o Aeolus -Bridger/Anticline500 kV line
o Aeolus 230/500 kV transformer
o Anticline 345/500 kV transformer
o Future Anticline -Populus 500 kV line
o Future Populus 500/345 kV auto transformer
o Future Aeolus -Clover 500 kV line
o Future Clover 500/345 kV auto transformer
As such,the Q0707 Project will need to be incorporated into the Aeolus RAS and may be tripped
for the outage of the elements indicated.
N-2 Results:Assuming Energy Gateway,Segment D.2 and associated improvements are in
service,no N-2 thermal or voltage issues were observed in the studies.
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