20180329PAC to Staff UT DPU Set 24 (1-10).pdf

1407 W.NorthTemple
ROCKY MOUNTAIN Salt Lake City,UT 84116
POWER
A DMSION OFPAC1FICORP
March 16,2018
Erika Tedder
Division of Public Utilities
160 E 300 S,4th Floor
Salt Lake City,UT 84114
[e-mail](C)
RE:UT Docket No.17-035-40
DPU 24th Set Data Request (1-10)
Please find enclosed Rocky Mountain Power's Responses to DPU 24th Set Data Requests 24.1-
24.10.Provided electronicallyis Attachment DPU 24.4.
If you have any questions,please call me at [phone].
Sincerely,
Jana Saba
Manager,Regulation
Enclosures
C.c.:Dan Kohler/DPU [e-mail](C)
Aliea Afnan/DPU [e-mail] (W)
[e-mail] (W)
Dan Peaco/DPU [e-mail] (C)(W)
Kevin Higgins/[e-mail] (C)
Neal Townsend/UAE [e-mail](C)(W)
Gary A.Dodge/UAE [e-mail] (C)
PhillipRussell/UAE [e-mail] (C)
Philip Hayet/OCS [e-mail] (C)
Béla Vastag/OCS [e-mail](C)
Sophie Hays/UCE [e-mail](C)
Kate Bowman/UCE [e-mail](C)(W)
Emma Rieves/UCE [e-mail](C)(W)
Lisa Tormoen Hickey/[e-mail] (C)
Mitch Longson/Interwest [e-mail] (C)
Nancy Kelly/[e-mail](C)
Jennifer Gardner/WRA [e-mail](C)
Penny Anderson/WRA [e-mail] (W)
Peter J.Mattheis/Nucor [e-mail] (C)
Eric J.Lacey/Nucor eil smxblaw.com (C)(W)
William J.Evans/UIEC [e-mail]
Vicki M.Baldwin/UIEC [e-mail](W)
Chad C.Baker/UIEC [e-mail] (W)
17-035-40 /Rocky Mountain Power
March 16,2018
DPU Data Request 24.1
DPU Data Request 24.1
Refer to the Company's Response to DPU 21.1,Aeolus West Transmission Path Transfer
Capability Assessment (February 2018).The cover page notes that it is a Preliminary
Draft.
a.Please identify all components of the analysis that are preliminary,and which results
may change before the report is finalized.
b.When will the Company be completing the final version of this study?
c.Provide the final version of this study as soon as it is completed.
Response to DPU Data Request 24.1
a.Preliminary results are provided in sections 3.3,4,6 and Appendix B of the report.
The report results will change in the same sections and appendices noted above.
b.All power flow and dynamic stability studies evaluating the interaction between the
Aeolus West and the TOT 4B transmission paths are expected to be completed by
March 30,2018.
c.The final technical study report will be provided upon completion.
17-035-40 /Rocky Mountain Power
March 16,2018
DPU Data Request 24.2
DPU Data Request 24.2
Refer to the Company's Response to DPU 21.1,Aeolus West Transmission Path Transfer
Capability Assessment (February 2018),page 5,stating that the transient stability analysis
is "currently underway."When will the Company be completing this analysis and
providing the results in this docket?
Response to DPU Data Request 24.2
Please refer to the Company's response to DPU Data Request 24.1.
17-035-40 /Rocky Mountain Power
March 16,2018
DPU Data Request 24.3
DPU Data Request 24.3
Refer to the Company's Response to DPU 21.1,Aeolus West Transmission Path Transfer
Capability Assessment (February 2018).Page 11 includes a note stating "UPDATES IN
PROGRESS."
a.Please identify all updates to which this note is referring.E.g.Table 4 of the report,
Appendix B,etc.?
b.When will the Company be completing these updates and providing the results in this
docket?
Response to DPU Data Request 24.3
a.The "UPDATES IN PROGRESS"note on page 11 is applicable to Appendix B.
Please refer to the Company's response to DPU Data Request 24.1.
b.Please refer to the Company's response to DPU Data Request 24.1.
17-035-40 /Rocky Mountain Power
March 16,2018
DPU Data Request 24.4
DPU Data Request 24.4
Refer to the Company's Response to DPU 21.1,Aeolus West Transmission Path Transfer
Capability Assessment (February 2018),page l1,stating that "[t]he 2021-22HW base case
was modified to reflect the most recent Foote Creek,High Plains,Top of the World and
Three Buttes wind generationmodeling as per the recent MOD-032 data submittedby each
generator owner."
a.Please describe the nature of the updates to the base case resulting from the new data.
b.Please provided workpapers or summary spreadsheets noting all the base case
assumptions that were changed as a result of this new data.Provide a comparison of
original and revised values.
Response to DPU Data Request 24.4
a.Updates made to the base case relative to the MOD-032 data submittal included
updated feeder impedances,transformer data,and wind turbine model parameters.
The information provided reflected an equivalencedrepresentation of the wind farm
feeders and utilized the most recent second generation -Western Electricity
Coordinating Council (WECC)wind turbine models.
b.Please refer to Attachment DPU 24.4 which includes sheets summarizing base case
assumptions and changes made in developing the D.2 case.Also included are text
files which identifies changes in the dynamic data files for each of the wind farms.
17-035-40 /Rocky Mountain Power
March 16,2018
DPU Data Request 24.5
DPU Data Request 24.5
Refer to the Company's Response to DPU 21.1,Aeolus West Transmission Path Transfer
Capability Assessment (February 2018),page 13,noting that "[t]he 240 MW of new wind
resource in Big Horn Basin was varied with Wyodak generation."
a.Please explain the significance of this statement and describe the interaction between
generation from the 240 MW of wind in Big Horn Basin and generationfrom Wyodak.
b.Does this statement mean that the 240 MW of wind in Big Horn Basin displaced 240
MW of generationfrom Wyodak?
c.Provide all documentation and analysis supporting the reasonableness of this
assumption.
Response to DPU Data Request 24.5
a.The statement was intended to indicate that,under certain extreme circumstances,
such as a combination of very high or very low TOT 4B flows and the 240 megawatt
(MW)facility in Big Horn Basin generating at full output,it is possible that the full
output of the Wyodak generatingfacility may not be required to serve load in the
north Wyoming area and could be adjusted downward.
b.No.Displacement is an interconnection study concept.This study is assessing
transfer capability.
c.Please refer to the Company's response to Data Request DPU 22.5.
17-035-40 /Rocky Mountain Power
March 16,2018
DPU Data Request 24.6
DPU Data Request 24.6
Refer to the Company's Response to DPU 21.1,Aeolus West Transmission Path Transfer
Capability Assessment (February 2018),page 13,noting that "It was assumed that only the
thermal generationat Dave Johnston (717 MW,new)generatingplant in eastern Wyoming
would be adjusted to maintain transfers on the Aeolus West transmission path."By
contrast,the PreliminaryAeolus West Transmission Path Transfer Capability Assessment
(October 2017)allowed both Wyodak and Dave Johnston to redispatch to maintain
transfers (page 12).
a.Please explain why the analysis was conducted differently in the new study.
b.Please provide all documentation and analysis supporting the reasonableness of the
change in assumptions
Response to DPU Data Request 24.6
a.The new wind resource quantities and locations were different for the February 2018
assessment compared to the October 2017 analysis.Upon announcement of the
2017R RFP shortlist,the new generationresources were incorporated into the
February 2018 V2 study and results.
b.Please refer to the list of new generationresources in Table 4 for each assessment,
page 10 of the October 2017 report and page 11 of the February 2018 report.Please
refer to the Company's responses to Data Request DPU 10.24 for a copy of the
October 2017 report and DPU 22.5 for a copy of the February 2018 report.
17-035-40/Rocky Mountain Power
March 16,2018
DPU Data Request 24.7
DPU Data Request 24.7
Refer to the Company's Response to DPU 21.1,Aeolus West Transmission Path Transfer
Capability Assessment (February 2018),page 14,noting that "a new system operating
limit (SOL)will be identified to represent the real time rating restriction to the path."
a.When will this SOL be identified?
b.Who will conduct the analysis to identify this SOL?
Response to DPU Data Request 24.7
a.Per Peak Reliability(PeakRC)guidelines,system operating limit (SOL)studies
should be completed three months prior to the 2020 winter operating season,in
August 2020.Additionally,FAC-013-2 Transfer Capability Assessment studies,
which will involve other utilities within the Western Interconnection will be
completed and accepted by the Western ElectricityCoordinating Council (WECC)by
October 2019.
b.The SOL studies will be performed by PacifiCorp's transmission planning and grid
operations groups,followingPeakRC guideline.
17-035-40 /Rocky Mountain Power
March 16,2018
DPU Data Request 24.8
DPU Data Request 24.8
Refer to the Company's Response to DPU 21.1,Aeolus West Transmission Path Transfer
Capability Assessment (February 2018),page 14.Figure 3 contains a note that it is a
"Preliminary nomogram subject to follow-on analysis."
a.Please describe the scope of the follow-on analysis.
b.When will the Company be completing analysis and providing the results in this
docket?
Response to DPU Data Request 24.8
a.Follow-on analysis will further refine the interaction between the Aeolus West path
and the TOT 4B path under very high or very low TOT 4B flow conditions..
b.Please refer to the Company's response to Data Request DPU 24.1.
17-035-40 /Rocky Mountain Power
March 16,2018
DPU Data Request 24.9
DPU Data Request 24.9
Refer to the Company's Response to DPU 21.1,Aeolus West Transmission Path Transfer
Capability Assessment (February 2018),page 15,noting that "Dynamic stability studies
evaluating a wide range of system disturbances are under way and will be presented in a
follow-on technical report."
a.Please describe the scope of the follow-on technical report.
b.Please identify the "wide range of system disturbances"being evaluated.
c.What is the current status of this analysis?
d.When will the Company be completing analysis and providing the results in this
docket?
Response to DPU Data Request 24.9
a.The follow-on technical report will document the technical studies outlined in DPU
24.8 and as well as the results of dynamic stability analysis.
b.Similar to the technical analysis that provided in the preliminary"Aeolus West
Transmission Path Transfer Capability Assessment"report,which was completed in
October 2017,dynamic stability analysis will be performed on selective critical
outages based on anticipated post fault impact on the wind generationperformance,
especially for the portion of the system with a calculated short circuit ratio of
approximately 1.5.Below is the list of critical transmission outages:
1.Point of Rocks -Latham 230 kV line outage
2.Standpipe -Platte 230 kV line outage
3.Platte -Latham 230 kV line outage
4.Dave Johnston -Casper 230 kV line outage
5.Amasa -Difficulty230 kV line outage
6.Dave Johnston -Amasa 230 kV line outage
7.Shirley Basin -Aeolus 230 kV line outage
8.Freezeout -Standpipe 230 kV line outage
9.Aeolus -Freezeout 230 kV line outage
10.Aeolus -Anticline 500 kV line outage
11.Aeolus -Anticline 500 kV line outage
12.Riverton -Wyopo 230 kV line outage
c.Please refer to the Company's response to DPU Data Request 24.1.
d.Please refer to subpart (c)above.The final technical study report will be provided
upon completion.
17-035-40 /Rocky Mountain Power
March 16,2018
DPU Data Request 24.10
DPU Data Request 24.10
Refer to the Company's Response to DPU 21.1,Aeolus West Transmission Path Transf"er
Capability Assessment (February 2018),Appendix A.The description of the new Aeolus
West path states that "[t]he path rating is 2670 MW East to West based on full Gateway
Project."
a.Please explain the significance of this statement as it relates to the transfer capability
assessment.
b.Was this 2,670 MW transfer limit used in any part of this analysis?
c.Are any other path ratings included in this Appendix A dependent on any components
of the Energy Gateway project?
Response to DPU Data Request 24.10
a.The information provided in Appendix A was gleaned from the most recent Western
Electricity Coordinating Council (WECC)Path Rating catalog.Under the full
Gateway project (Gateway West,Gateway Central,Gateway South)configuration,
the Aeolus West transmission path can achieve a rating of 2670 megawatts (MW),
which was granted by the WECC Planning Coordination Committee (PCC)January
5,2011.
b.As the current analysis is only applicable to the GatewayWest -D.2 Project
(Bridger/Anticline-Aeolus),the 2,670 MW transfer limit for Aeolus West was not
used in the analysis.
c.None of the other path ratings included in Appendix A depended on any components
of the Energy Gateway project.