20171218PAC to Staff Attachment Utah_DPU 1.pdf

PACIFICORP
A MIDAMERICAN ENERGY HOLDlNG$COMPANY
Spring &Summer 2017
TOT 4A/TOT 4B Operating Curve
System Operating Limit
(Check Cases)
January 26,2017
Revision 1.0
Y PACIFICORP
A MIDAMERICAN ENERGY HOLDlNGS COMPANY TOT4A-4B SOL Study Plan
Table of Contents
1.INTRODUCTION..............................................2
2.STUDY ASSUMPTIONS...............................................6
3.OPERATING CRITERIA..............................................11
4.STUDY AREA ...............................................11
5.NOMOGRAM CURVE,GREAT DIVIDE l15 KV OPEN POINT ............................................12
6.NOMOGRAM CURVE,PLATTE 115 KV OPEN POINT ...........................................14
7.CONCLUSION..............................................15
8.APPENDIX A:WYOMING SHUNT CAPACITOR SWITCH SETTINGS.................................16
9.APPENDIX B:DYNAMIC STUDY RESULTS...............................................18
Figure 1:Eastern Wyoming Scheduling Areas...............................................2
Figure 2:Actual 2016 Spring and Summer Flows ...............................................4
Figure 3:2017 TOT 4A/4B Operating Curve,Data rom WECC Facility Rating Report -Standpipe In-Service with
Bairoil to Great Divide 115 kV line open at Great Divide .............................................5
Figure 4:2017 TOT 4A/4B Operating Curve,Data rom WECC Facility Rating Report -Standpipe In-Service with
Platte to Whiskey Peak 115 kV line open at Platte................................................6
Table 1:Path FlowDefinition ...............................................7
Table 2:Check Case Points with Great Divide 115 kV Open Point.............................................12
Table 3:Check Case Points with Platte l15 kV Open Point.............................................14
Page i slanuary 26,2017
PACIFICORP
A MIDAMERICAN ENERGY HOLDlNGS COMPANY
TOT4A-4B SOL Study Plan
1.INTRODUCTION
The TOT 4A/TOT 4B Operating nomogram defines the simultaneous operating transfer capability
of these two paths and is used to ensure that scheduled and actual flows do not exceed rated
capability.Figure 1 shows the eastern Wyomingtransmission system and lines that make up the
TOT4A and TOT4B transmission paths.
Yellowtail PAC YellowtailSouth:Maxec2k3DryMFork
Frannie RiverPacifiCorpEastSherida
Wyoming Transmission Garland
MDU Sherid
Oregon Wyodak
Basin North Wyoming Carr 271 8 MW N
Buffalo
Draw
Hughes
Grass TOT4B Barber DCr ey
Creek Creek
<230 kV Existing Kaycee eno
230 kV Existing
345 kV Existing Thermopolis \Pu pkin
\Bu es Teckla
Badwater Midwest ockl e 1BuffaloHead3ButtesRollingHill
99MW 1185MWea.
TOT4A Yellow Cake i
oPinedale W op Ch1e nMWind
y Latig r T.O.W.
Naughton Load Paradise CaspeÁmasa 811DM 200.2 MW
tlantic RootCreek 80
Chimney Butte Big Piney Jonad City WyoCm gmload spence MW
East Wyoming
Chappel Ba roil TOT4 Difficulty
To
puluTo 3MK Creek Labar Mustang n o.Shidey Basin
To Treasureton Trona Bridger West ""Dunlap 111 MW
/Limit:2400 MW Aeolus (Future)Evanston 4 _
Kemmerer -'Bridger (PAC Freezeout
7 Mile HillWiest0Limit:N na
iaces Fork Palis de
1472 MW)
Platte
andpipe 118.5 MW
Foote 135 MWBirchcreekCreek
To Ben Lomond Mtn wind onument Mansfac e e High Plains -99 MW
Railroad
MonumentWest RL
t
6r gs/FH T m4 4B Limit:
Limit:475 MW (thermal limit)Nomogram
Figure 1:Eastern Wyoming SchedulingAreas
PacifiCorp implemented a new TOT 4A/4B nomogram on April 1,2013 based on a rating study that
was approved in the spring of2013.Operating studies were performed for the 2013 spring,2013
summer,2014-2015 winter,2015 spring &summer,and 2016 spring &summer operating seasons.
This study considered four check cases and verifies that the system can be reliablyoperated during
the 2017 spring and summer operating seasons using the approved 2017 TOT 4A /TOT 4B
Operating Nomogram.The nomogram points studied and verified for this study are from the 2013
rating study nomogram that included Standpipe substation and Standpipe synchronous condenser
Page 2 slanuary 26,2017
PACIFICORP
A MIDAMERICAN ENERGY HOLDlNGS COMPANY
TOT4A-4B SOL Study Plan
in-service.The study considered several improvements to the Wyoming230 kV transmission
system that have been placed in-service.The improvements considered for the 2017 spring and
summer SOL study are:
(1)A new 80 MW wind farm at Amasa,which is a new 230 kV substation between Dave
Johnston and Difficulty.The in-service date for this wind farm is October 2016.
(2)The Standpipe 230 kV substation with the addition of a synchronous condenser with a rating
of+65/-35 MVAR.
(3)Addition of an emergency rating on the Casper to Spence 230 kV line based on
communication with WAPA.
(4)Line rating updates followingthe LiDar line clearance project.
This study assessed four separate TOT 4A /TOT 4B operating curves for Spring and Summer 2017
operation with 1)the Bairoil to Great Divide 115 kV line open at Great Divide without the Platte to
Standpipe dynamic line rating system,2)the Bairoil to Great Divide 115 kV line open at Great
Divide with the Platte to Standpipe dynamic line rating system in-service,3)the Platte to Whiskey
Peak 115 kV line open at Platte without the Platte to Standpipe dynamic line rating system,and 4)
the Platte to Whiskey Peak 115 kV line open at Platte with the Platte to Standpipe dynamic line
rating system in-service.Figure 2 below shows the actual flows on TOT 4A/TOT 4B paths in 2016
during the spring and summer seasons.The flows are compared against the nomogram points
established during the rating study in 2013.
Page 3 Januæy 26,2017
PACIFICORP
A MIDAMERICAN ENERGY HOLDINGS COMPANY
TOT4A-4B SOL Study Plan
2017 Spring&Summer TOT4A &TOT4B NOMOGRAM
Verified nomogram points
(860,600)&(900,600)
¯O~CAF owiMWI
+2:17 Spr ng &Burirner Opera ng Curve .vth P atte norrla open idynaric rat.ng)
-e-2017 Spr ng &Suririer Opera ng Curie wth Great Dv de norria y cpen IDynaric ratng.i
2016 Spr ng Suririer A2ua F co
Figure 2:Actual 2016 Spring and Summer Flows
PacifiCorp has verified that the system meets the required performance metrics for all contingencies
for the nomogram points (715,600)and (900,600)with Great Divide open as shown in Figure 3.
Similarly,PacifiCorp has verified acceptable performance for the nomogram points (765,600)and
(860,600)with the Platte open point as shown in Figure 4.Consistent with operating practice,the
Platte to Standpipe 230 kV line ratings will default to the static ratings anytime the dynamic line
rating system is out of service or not providing an operating benefit.
Page 4 January 26,2017
PACIFICORP
A MIDAMERICAN ENERGY HOLDINGS COMPANY
TOT4A-4B SOL Study Plan
Wyoming System Operating Curve
2017 HeavySpring and 2017 Heavy Summer Loads
Normal Open Point:Great Divide 115 kV
1100
I Verified
1000 Nomogram Points
700
,900,600
600 -
500
400
OF 300
200
100
0
0 100 200 300 400 500 600 700 800 900 1000 1100
I
TOT 4A Flow (MW)
Operating Curve,Platte-Standpipe Dynamic Line Rating with Standpipe Project Upgrades
Operating Curve,Platte-Standpipe Summer Static Rating with Standpipe Project Upgrades
Figure 3:2017 TOT 4A/4B Operating Curve,Data from WECC Facility Rating Repor -
Standpipe In-Service with Bairoil to Great Divide 115 kV line open at Great Divide
Page 5 slanuary 26,2017
PACIFICORP
A MIDAMERICAN ENERGY HOl.DINGS COMPANY
TOT4A-4B SOL Study Plan
Wyoming System Operating Curve
2017 HeavySpring and 2017 Heavy Summer Loads
Normal Open Point:Platte 115 kV
1100
Verified
1000 Nomogram Points
700
o 500
400I-
-300
200
100
0
0 100 200 300 400 500 600 700 800 900 1000 1100
I
TOT 4A Flow (MW)
+Operating Curve,Platte-Standpipe Dynamic Line Rating with Standpipe Project Upgrades
Operating Curve,Platte-Standpipe Summer Static Rating with Standpipe Project Upgrades
Figure 4:2017 TOT 4A/4B Operating Curve,Data from WECC Facility Rating Repor'-
Standpipe ln-Service with Platte to Whiskey Peak 115 kV line open at Platte
2.STUDY ASSUMPTIONS
Four check point cases for the TOT 4A /TOT 4B operating curve check points were developed
using the WECC-approved 2017 heavy spring operating base case (17hsplap_RMOSG)and four
additional check point cases were also developed using the 2017 heavy summer operating case
(17hs2ap).
When the Platte to Standpipe dynamic line rating system is not providing a benefit,the line rating
will default to the summer static continuous /emergency rating of 428/519 MVA,respectively,
consistent with current operating practice.The Platte to Standpipe static line rating has recently
Page 6 slanuary 26,2017
PACIFICORP
A MlDAMERICAN ENERGY HOLDlNGS COMPANY
TOT4A-4B SOL Study Plan
been revised as a result of a LiDAR survey.During summer operation with the dynamic line rating
system in-service,the line loading may be increased to a theoretical maximum of 666 MVA (4
hour)and 680 MVA (30 minute),effectivelyremoving the line as a limitingelement on the path
during ambient weather conditions that are favorable to transmission line thermal operation.
The new Standpipe Substation and Latham 25 MVAr capacitor bank were placed in-service in
2014.The Standpipe synchronous condenser is included in the case and was placed in-service on
10/14/2016.
The Foote Creek DVAr was modeled off-line for all corner point cases.The manual operation of
shunt capacitors at Foote Creek was considered.
The Platte and Mustang 230/115 kV transformers have manual load tap changers (LTC)that can be
adjusted to maintain acceptable voltage levels on the underlying115 kV system.
The definitions of each tabulatedpath are listed in Table 1 below.
Table 1:Path Flow Definition
TOT 4A Metered End
Mustang -Spence 230 kV line Spence
Riverton -Wyopo 230 kV line Riverton
Standpipe -Platte 230 kV line Standpipe
TOT 4B
Buffalo -Carr Draw 230 kV line Carr Draw
Sheridan -Tongue River 230 kV line Sheridan
Spence -Buffalo Head 230 kV line Spence
Casper -Claim Jumper 230 kV line Casper
Riverton -Thermopolis 230 kV line Riverton
Alcova -Raiderville 115 kV line Alcova
Riverton 230 /115 kV Transformer Riverton
Sheridan PRECORP Load Subtracted Sheridan
Page 7 ,Ianuary 26,2017
PACIFICORP
A MlDAMERICAN ENERGY HOLDlNGS COMPANY
TOT4A-4B SOL Study Plan
The followingcontingencies were simulated for each check-point case
1.Loss of Dave Johnston to Amasa 230 kV line (Loss of Root Creek wind as part of LAPS).
2.Loss of Amasa -Difficulty230 kV Line
3.Loss of Difficulty to Shirley Basin 230 kV line.
4.Loss of Freezeout to Shirley Basin 230 kV line.
5.Loss of Freezeout to Standpipe 230 kV line.
6.Loss of Dave Johnston to Windstar No.2 230 kV line.
7.Loss of Casper to Latigo 230 kV line.
8.Loss of Latigo to Windstar 230 kV line.
9.Loss of Dave Johnston to Casper 230 kV line.
10.Loss of Casper to Spence 230 kV line.
11.Loss of Casper to Claim Jumper 230 kV line.
12.Loss of Casper to Riverton 230 kV line.
13.Loss of Mustang to Spence 230 kV line.
14.Loss of Badwater to Buffalo Head 230 kV line.
15.Loss of Buffalo Head -Spence 230 kV line
16.Loss of Jim Bridger to Mustang 230 kV line.
17.Loss of Platte to Latham 230 kV line.
18.Loss of Latham to Echo Springs 230 kV line
19.Loss of Echo Springs -Point of Rocks 230 kV line.
20.Loss of Platte to Standpipe 230 kV line,including generator tripping at Foote Creek and
High Plains.
21.Loss of Foote Creek to Standpipe 230 kV line.
22.Loss of Jim Bridger to Point of Rocks /Rock Springs 230 kV line.
23.Loss of Atlantic City to Wyopo -Riverton 230 kV line.
24.Loss of Buffalo to Carr Draw 230 kV line.
25.Loss of Buffalo to Sheridan 230 kV line.
26.Loss of Buffalo to Kaycee to Midwest 230 kV line.
27.Loss of Sheridan to Yellowtail 230 kV line.
28.Loss of Riverton to Thermopolis 230 kV line.
29.Loss of Badwater to Thermopolis 230 kV line.
30.Loss of Oregon Basin to Grass Creek to Thermopolis 230 kV line.
31.Loss of Yellowtail to Oregon Basin 230 kV line.
32.Loss of Arvada to Dry Fork 230 kV line
33.Loss of Sheridan to Tongue River 230 kV line
Page 8 ,Ianuæy 26,2017
PACIFICORP
A MlDAMERICAN ENERGY HOLDlNGS COMPANY
TOT4A-4B SOL Study Plan
34.Loss of Dave Johnston to Stegall 230 kV line
35.Loss of Dave Johnston to Laramie River 230 kV line
36.Stuck Breaker at Jim Bridger 230 kV bus resulting in N-2 loss of Jim Bridger to Rock
Springs 230 kV line and Point of Rocks to Jim Bridger /Rock Springs 230 kV line.
37.Stuck Breaker at Jim Bridger 230 kV bus resulting in N-2 loss of Jim Bridger to Rock
Springs 230 kV line and Jim Bridger to Mustang 230 kV line.
38.Loss of Windstar -Yellowcake-Antelope Mine -Teckla 230 kV line
39.Loss of Antlantic City -Rock Springs 230 kV line
40.Loss of Jim Bridger -Rock Springs 230 kV line
41.Loss of Wyodak -Carr Draw 230 kV line
42.Loss of Carr Draw -Pumpkin Buttes 230 kV line
43.Loss of Carr Draw -Dry Fork 230 kV line
44.Loss of Foote Creek -High Plains 230 kV line
45.Loss of Wyodak -Osage 230 kV line
46.Loss of Wyodak -Hughes 230 kV line
47.Loss of Wyodak -Donkey Creek 230 kV line
48.Loss of Yellowtail (PAC)-Yellowtail (WAPA)230 kV line
49.Loss of Standpipe synchronous condenser.
50.Loss of Windstar -Glenrock 230 kV line
51.Loss of Yellowtail -Rimrock 161 kV line
The rating study did not identify and stability issues,dynamic analysis was performed on few
critical contingencies.Due to unavailabilityof a 2017 heavy summer case with dynamics data,a
2016 heavy summer operating case with available dynamics in PSS/e was used to perform the
analysis.This case was tuned and modified to represent the 2017 heavy summer transmission
system topology and load conditions.The TOT 4A and TOT 4B flows were stressed to the
nomogram points (765,600)with open point at Platte.The followingcontingencies were simulated
in dynamic analysis.
(1)3-ph fault at Dave Johnston 230 kV bus with loss of Dave Johnston Unit 4
(2)3-ph fault at Standpipe with loss of Standpipe -Platte 230 kV line (Foote Creek and High
Plains tripped as part of RAS)
(3)3-ph fault at Dave Johnston 230 kV bus with loss of Dave Johnston -Amasa 230 kV line.
(Root Creek wind farm tripped as part of RAS)
(4)3-ph fault at Platte 230 kV bus and loss of all switched shunts at Platte.
Page 9 ,Ianuæy 26,2017
PACIFICORP
A MIDAMERICAN ENERGY HOLDlNGS COMPANY
TOT4A-4B SOL Study Plan
(5)Stuck breaker at Jim Bridger 230 kV bus with loss of Jim Bridger -Rock Springs 230 kV
line and Jim Bridger -Point of Rocks -Rock Springs 230 kV line
(6)1-ph fault at Platte 230 kV and loss of Standpipe -Platte 230 kV line with unsuccessful
reclose.
(7)1-ph fault at Dave Johnston 230 kV bus with the loss of Dave Johnston -Amasa 230 kV
line with unsuccessful reclose.
The Standpipe remedial action scheme will trip generation at the 34.5 kV feeder level at Foote
Creek and High Plains in conjunctionwith tripping of the Platte to Standpipe 230 kV line if the pre-
outage flow on the Platte to Standpipe 230 kV line is above 370 MVA and the line is open for more
than two (2)seconds.The Standpipe remedial action scheme was implemented in May 2015.
For loss of the Amasa to Difficulty230 kV line or loss of the Difficultyto Shirley Basin 230 kV
line,all Dunlap generation will trip if post-contingency voltage at Shirley Basin 230 kV bus is less
than 0.85 per unit for 20 cycles.
Page 10 ,Ianuary 26,2017
PACIFICORP
A MIDAMERICAN ENERGY HOLDlNGS COMPANY
TOT4A-4B SOL Study Plan
3.OPERATING CRITERIA
Svstem Normal (NERC/WSCC Categorv A):
All bus voltages should be within 0.95-1.05 per unit.All line and transformer loadings should be
less than 100%of continuous rating.Solution calculation should enable automatic transformer tap
changing and switchable shunt device action.Generation is changed manuallyto adjust TOT4A/4B
flow to set transfer levels.Automatic phase shifter adjustments are locked during solution;
however,they may be adjusted manuallyto control or otherwise adjust pre-contingency TOT4A/4B
power flow.
Outage Conditions (NERC/WSCC Category B,C,and D):
All bus voltages should be within 0.90-1.10 per unit.All line and transformer loadings should be
less than 100%of continuous rating or an established emergency rating.PSS/e contingency
analysis program was used to run the contingencies listed above.Select shunt devices are allowed to
switch,as there are a large number of automatically switched capacitors in the Wyomingarea.
4.STUDY AREA
All buses and branches will be monitored in the followingcontrol areas:
WAPA UM -AREA 63
MONTANA -AREA 62
WAPA RM -Bighorn Zone 750
Black Hills Zone 751
Eastern WY Zone 753
Western Nebraska Zone 756
PACE -WY NO EA Zone 650
WY SO WE Zone 651
WY EVAN Zone 653
WY OVER Zone 660
WY TRONA Zone 668
WY CENT Zone 679
WY NE IN Zone 68
Page 11 ,Ianuæy 26,2017
PACIFICORP
A MIDAMERICAN ENERGY HOLDlNGS COMPANY
TOT4A-4B SOL Study Plan
5.NOMOGRAM CURVE,GREAT DIVIDE 115 KV OPEN POINT
This section describes the tests for two points on the TOT 4A /TOT 4B nomogram with the Bairoil
to Great Divide 115 kV line open at Great Divide using the 2017 heavy spring operating base case
and 2017 heavy summer operating base case.In this system configuration,load on the 115 kV
transmission system at Bairoil and Whiskey Peak is served radially from Platte.
The Platte 230/115 kV transformer with an LTC is used to regulate the voltage in order to maintain
the acceptable voltage performance on the underlying115 kV system.
The followingpoints were studied to verify acceptable system performance (Refer to Figure 3):
Table 2:Check Case Points with Great Divide 115 kV Open Point
Without Platte -Standpipe Dynamic Line Rating
Season CASE TOT4A TOT4B LIMITATION
(MW)(MW)
Spring la 715 600 Standpipe-Platte 230 kV line at 92%of continuous rating
Summer 2a 715 600 Standpipe-Platte 230 kV line at 98%of continuous rating
With Platte -Standpipe Dynamic Line Rating
Season CASE TOT4A TOT4B LIMITATION
Spring lb 900 600 None
Summer 2b 900 600 None
*These operating points were selected from the WECCapproved TOT4A /TOT4B nomogram.
It should be noted that the TOT 4B capacity is used principally to serve load north and west of the
TOT 4B cutplane and south of Yellowtail.Anytime the TOT 4B flow is greater than the TOT 4B
load,the remainder will flow from Wyoming to Montana.As long as the Sheridan-Yellowtail 230
kV line flow is monitored to ensure that it is within its capability (limitingelement for high TOT 4B
flow),it ensures that the operation is in a safe operating region inside the nomogram.
Study results indicate acceptable system performance pre-contingency and post-contingency for all
system contingencies considered.With the Bairoil to Great Divide 115 kV line open,load at
Bairoil and Whiskey peak is served from Platte Substation.This configuration results in better
post-contingency voltage at the Spence Substation followingloss of any of the lines between Platte
and Point of Rocks.As post-contingency voltages at Spence limit TOT 4A capacity during the
Page 12 ,Ianuary 26,2017
PACIFICORP
A MIDAMERICAN ENERGY HOLDlNGS COMPANY
TOT4A-4B SOL Study Plan
majority of the contingencies studied,this configuration results in a moderate increase in TOT 4A
capacity as compared to serving the Bairoil and Whiskey Peak loads from Great Divide.The
increase in TOT 4A capacity with the Bairoil to Great Divide line open is only seen with the Platte
to Standpipe dynamic line rating system in service.Without the dynamic line rating system,steady
state thermal capability of the Platte to Standpipe line will limit TOT 4A capacity,resulting in a
decrease in TOT 4A capacity with the Bairoil and Whiskey Peak loads served from Platte.
As per System Performance Regional Business Practice,TPL-001-WECC-CRT-3.1
REQUIREMENTWR5.1,a study was performed to check reactive margin for Case lb (900,600).
The TOT 4A path flow was increased by 5%(TOT4A =945 MW)and the rated TOT 4B capacity
was maintained at 600 MW,all the cases pre and post contingency solved,indicating compliance
with the WR3 requirements.Reactive margin was not tested on Case la and 2a,as reactive
requirements are significantly reduced both pre and post contingency as compared to the reactive
requirements to maintain voltage stability in Case lb and 2b.Case la and lb has lower ratings on
the Platte to Standpipe 230 kV line,resulting in thermal limitations on the line that significantly
limit TOT 4A capability.As reactive margin was demonstrated on Case lb and 2b,the system will
have adequate reactive reserves for all contingencies in Case la and 2a.
Page 13 Januæy 26,2017
PACIFICORP
A MIDAMERICAN ENERGY HOLDlNGS COMPANY
TOT4A-4B SOL Study Plan
6.NOMOGRAM CURVE,PLATTE 115 KV OPEN POINT
This section describes the tests for two points on the TOT 4A /TOT 4B nomogram with the Platte
to Whiskey Peak 115 kV line open at Platte using the 2017 heavy spring operating base case and
2017 heavy summer operating base case.In this system configuration,load on the 115 kV
transmission system at Bairoil and Whiskey Peak is served radially from Great Divide.
The Mustang 230/115 kV transformer with an LTC is used to regulate the voltage in order to
maintain the acceptable voltage performance on the underlying115 kV system.
The followingpoints were studied to verify acceptable system performance (Refer to Figure 2):
Table 3:Check Case Points with Platte 115 kV Open Point
Without Platte -Standpipe Dynamic Line Rating
Season CASE TOT4A TOT4B LIMITATION
Spring 3a 765 600 Standpipe-Platte 230 kV line at 97%of continuous rating
Summer 4a 765 600 Standpipe-Platte 230 kV line at 99%of continuous rating
With Platte -Standpipe Dynamic Line Rating
Season CASE TOT4A TOT4B LIMITATION
Spring 3b 860 600 None
Summer 4b 860 600 None
*These operating points were selected from WECCapproved TOT4A /TOT4B nomogram.
Study results indicate acceptable system performance pre-contingency and post-contingency for all
system contingencies considered.With the Platte to Whiskey Peak 115 kV line open,load at
Bairoil and Whiskey Peak is served from the Great Divide Substation.This configuration results in
an increase in post-contingency voltage stress at the Spence Substation followingloss of any of the
lines between Platte and Point of Rocks,as compared to load service from Platte.
As per System Performance Regional Business Practice,TPL-001-WECC-CRT-3 REQUIREMENT
WR5.1,a study was performed to check reactive margin for case 2b (860,600).The TOT 4A path
rating was increased by 5%(TOT 4A =903 MW)and the rated TOT 4B capacity was maintained at
600 MW,all the cases pre and post contingency solved,indicating compliance with the WR3
requirements.Reactive margin was not tested on Case 3a and 4a,as reactive requirements are
significantly reduced both pre and post contingency as compared to the reactive requirements to
Page 14 Januæy 26,2017
PACIFICORP
A MIDAMERICAN ENERGY HOLDlNGS COMPANY
TOT4A-4B SOL Study Plan
maintain voltage stability in Case 3b and case 4b.Case 3a and 4a has lower ratings on the Platte to
Standpipe 230 kV line,resulting in thermal limitations on the line that significantly limit TOT 4A
capability.As reactive margin was demonstrated on Case 3b,the system will have adequate
reactive reserves for all contingencies in Case 3a.
The dynamic analysis demonstrated that all the simulated contingencies met the criteria described in
TPL-001-WECC-CRT-3.1.The results of the study are shown in Appendix B.
7.CONCLUSION
These check case studies have demonstrated that the TOT 4A and TOT 4B paths can be safely and
reliablyoperated during the WECC 2017 Spring and Summer Operating Seasons using the
approvedTOT 4A /TOT 4B Summer Operating Nomogram.
Page 15 January 26,2017
PACIFICORP
A MIDAMERICAN ENERGY HOLDlNGS COMPANY
TOT4A-4B SOL Study Plan
8.APPENDIX A:WYOMING SHUNT CAPACITOR SWITCH SETTINGS
The Platte 230 kV shunt capacitors will switch out at staggered interval when the voltage is greater
than 1.075 per unit;however,for voltage levels greater than 1.1 per unit,all four (4)Platte 230 kV
shunt capacitors will switch out to alleviate the high voltage.The Latham 230 kV shunt capacitor of
25 MVAr will be switched in at voltage levels below 0.99 per unit and will be switched out at 1.04
per umt.
Page 16 January 26,2017
PACIFICoRP
A MIDAMERICAN ENERGY HOLDlNGS COMPANY TOT4A-4B SOL Study Report
System Protection Control
Relay Location Over Voltage /Operate Time Under Voltage /Operate Time Voltage Close /Operate Time Voltage Trip I Operate Time Trip
X591/A5PD
Atlantic City 230 kV Cap 1.075 pu /8.5Cycles .478 pu /20 seconds .9602 pu /30 Sec 1.052 pu /30 Sec Capacitors
Miners 230 kV Caps 1.075 pu /8.5 Cycles .497 pu /20 seconds 0.985 pu /30 sec 1.0392 pu /30 sec Capacitor
Mustang 230 kV Cap 1 1.075 pu /8.5 Cycles .478 pu /50 seconds .9567 pu /30 Sec 1.052 pu /60 Sec Capacitors
Mustang 230 kV Cap 2 1.075 pu /8.5 Cycles .478 pu /35 seconds .9567 pu /45 Sec 1.052 pu /45 Sec Capacitors
Mustang 230 kV Cap 3 1.075 pu /8.5 Cycles .478 pu /20 seconds .9567 pu /60 Sec 1.052 pu /30 Sec Capacitors
Platte 230 kV Cap 1 1.075 pu /8.5 Cycles .478 pu /20 seconds 0.985 pu /75 Sec 1.0392 pu /30 sec Capacitors
Platte 230 kV Cap 2 1.075 pu /8.5 Cycles .478 pu /35 seconds 0.985 pu /60 Sec 1.0392 pu /45 sec Capacitors
Platte 230 kV Cap 3 1.075 pu /8.5 Cycles .478 pu /50 seconds 0.985 pu /45 Sec 1.0392 pu /60 sec Capacitors
Platte 230 kV Cap 4 1.075 pu /8.5 Cycles .478 pu /65 seconds 0.985 pu /30 Sec 1.0392 pu /75 sec Capacitors
Foote Creek Cap 1 1.098 pu /8.5 Cycles .896 pu for 1 Sec /8.5 Cycles 0.9488 pu /81 *Sec 1.0455 pu /1 8‡Sec Capacitors
Foote Creek Cap 2 1.098 pu /8.5 Cycles .896 pu for 1 Sec /8.5 Cycles 0.9488 pu /71 44 Sec 1.0455 pu /11 7‡Sec Capacitors
Foote Creek Cap 3 1.098 pu /8.5 Cycles .896 pu for 1 Sec /8.5 Cycles 0.9488 pu /61 24 Sec 1.0455 pu /21 6‡Sec Capacitors
Foote Creek Cap 4 1.098 pu /8.5 Cycles .896 pu for 1 Sec /8.5 Cycles 0.9488 pu /51 34 Sec 1.0455 pu /31 5‡Sec Capacitors
Foote Creek Cap 5 1.098 pu /8.5 Cycles .896 pu for 1 Sec /8.5 Cycles 0.9488 pu /41 Sec 1.0455 pu /41Sec Capacitors
Foote Creek Cap 6 1.098 pu /8.5 Cycles .896 pu for 1 Sec /8.5 Cycles 0.9488 pu /31 5‡Sec 1.0455 pu /51 3‡Sec Capacitors
Foote Creek Cap 7 1.098 pu /8.5 Cycles .896 pu for 1 Sec /8.5 Cycles 0.9488 pu /21 8‡Sec 1.0455 pu /61 2‡Sec Capacitors
Foote Creek Cap 8 1.098 pu /8.5 Cycles .896 pu for 1 Sec /8.5 Cycles 0.9488 pu /11 7-‡Sec 1.0455 pu /71 44 Sec Capacitors
Foote Creek Cap 9 1.098 pu /8.5 Cycles .896 pu for 1 Sec /8.5 Cycles 0.9488 pu /1 8‡Sec 1.0455 pu /81 4 sec Capacitors
Foote Creek 34.5 kV Feeders 1.1509 4-442 pu for 1 Sec /8.5 Cycles .896 3u for 1 Sec /8.5 Cycles Feeders
Ft.Creek 34.5 kV -Bus Clear |Relay Trip -Protection Clear Ft.Creek
Over Voltage /Operate Time 1.1509 pu for 1 Second /8.5 Cycles 34.5 kV Bus
Under Voltage /Operate Time .896 pu for 1 Sec /8.5 Cycles
Over Frequency I operate Time 60.8 Hz for 3 Cycles /8.5 Cycles
Under Frec uency I Overate Time 58.47 Hz for 9.98 Sec /8.5 Cycles
Foote Creek DVAR Relay Trip -Protection D-VAR Control Ft.Creek
Over Voltage /Operate Time 1.1509 4-098 pu for 1 Sec 3 Cy /8.5 Cy Top of Regulation Deadband 1.04 4-02 pu D-VAR
Under Voltage /Operate Time .896 pu for 1 Sec /8.5 Cycles Bottom of Requiation Deadband .99 -98 pu Control and
Immediate Response -Turn off Cap 1.04 4-03 pu for 2 Sec Protection
Immediate Response -Turn On Cap .97 pu for 2 Sec
Take No Action .91 de pu for 1.5 Sec
Page 17 January 26,2017
Y
PA
C
I
F
I
C
O
R
P
A
MI
D
A
M
E
R
I
C
A
N
EN
E
R
G
Y
HO
l
.
O
l
N
G
S
CO
M
P
A
N
Y
TO
T
4
A
-
4
8
SO
L
St
u
d
y
Re
p
o
r
t
9.
AP
P
E
N
D
I
X
B:
DY
N
A
M
I
C
ST
U
D
Y
RE
S
U
L
T
S
(1
)
3-
p
h
fa
u
l
t
at
Da
v
e
Jo
h
n
s
t
o
n
23
0
kV
bu
s
wi
t
h
lo
s
s
of
Da
v
e
Jo
h
n
s
t
o
n
Un
i
t
4
Il
l
l
l
l
l
l
l
di
O
ØØ
Ø
-
--
I
la
mm
n
-
U-
i
cm
CD
,t
n
m
e-a
il
.--
ru
=
I
i..
I
a..
s
.
i..
I
,
MC
li
l
l
l
l
l
l
l
l
1.
0
2.
0
0
0
0
4.
0
0
0
0
6.
0
0
0
0
8.
0
0
0
0
10
.
0
0
0
TH
U
.
JA
N
26
20
17
16
:
00
TI
H
E
(S
E
C
O
N
O
S
)
Pa
g
e
18
,I
a
n
u
a
r
y
26
,
20
1
7
PA
C
I
F
I
C
O
R
P
A
MID
A
M
E
R
I
C
A
N
EN
E
R
G
Y
HO
L
D
l
N
G
S
CO
M
P
A
N
Y
TO
T
4
A
-
4
8
SO
L
St
u
d
y
Re
p
o
r
t
(2
)
3-
p
h
fa
u
l
t
at
St
a
n
d
p
i
p
e
wi
t
h
lo
s
s
of
St
a
n
d
p
i
p
e
-
Pl
a
t
t
e
23
0
kV
li
n
e
(F
o
o
t
e
Cr
e
e
k
an
d
Hi
g
h
Pl
a
i
n
s
tr
i
p
p
e
d
as
pa
r
t
of
RA
S
)
Il
l
l
l
l
l
l
l
er
*
-r
i
N
I
am
--
I
I
I-
I
I-
I
--
Ioc
IIII
-
Ili
l
l
l
l
l
l
l
l
1.
0
2.
0
0
0
0
4.
0
0
0
0
6.
0
0
0
0
8.
0
0
0
0
10
.
00
[.
0
0
0
0
3.
0
0
0
0
5.
0
0
0
0
7.
0
0
0
0
£4
0
0
0
TI
M
E
(S
E
C
O
N
O
S
)
TH
U
,
JA
N
26
20
1
7
16
:
4
6
Pa
g
e
19
Ja
n
u
a
r
y
26
,
20
1
7
Y PACIFICORP
A MIDAMERICAN ENERGY HOLDlNGS COMPANY TOT4A-4B SOL Study Report
(3)3-ph fault at Dave Johnston 230 kV bus with loss of Dave Johnston -Amasa 230 kV line.(Root Creek wind farm tripped as part of RAS)
lllllllll
-||-
I C
llllllll).0 2.0000 4.0000 6.0000 8.0000 10.000
THU,JAN 26 20 17 16:07TIME(SECONOS)
Page 20 January 26,2017
NE
S
T
E
R
N
EL
E
C
T
R
I
C
I
T
Y
CO
O
R
O
I
N
A
T
I
N
G
CO
U
N
C
I
L
20
1
6
HS
3
OP
E
R
A
T
I
N
G
CA
S
E
OC
T
O
B
E
R
20
,
20
1
5
Te
c
i
n
u
m
i
e
s
IN
T
E
l
-
I
T
I
W
I
W
FI
L
E
:
C:
\
R
i
k
i
n
\
.
.
.
\
0
y
n
a
m
i
c
s
\
0
Y
PL
-
4
-
1
PL
T
2
3
0
5
W
S
H
U
N
T
,
a
u
t
CH
N
L
=
27
5
:
CV
O
L
T
67
4
9
9
EL
A
T
H
A
M
23
0
.
0
0
]
1,
50
0
0
-
-
-
-
-
0,
50
0
0
0
|
CH
N
L
=
31
2
:
EV
O
L
T
69
L
4
3
ES
T
N
O
P
[
P
E
23
0
.
0
0
]
1.
5
0
0
0
"'
0,
5
0
0
0
0
|
CH
N
L
=
27
0
:
EV
O
L
T
66
2
5
0
EP
T
RO
C
M
S
23
0
.
0
0
]
]
1,
5
0
0
0
*-
-
-
-
-
-
-
-
-
-
-
0,
5
0
0
0
0
|
a-
I
r
CH
N
L
=
26
0
:
EV
O
L
T
66
2
4
5
EP
L
A
T
T
E
Ll
5
.
0
0
]
]
-
1.
5
0
0
0
---
-
-
0,
5
0
0
0
0
Il
l
l
'
I
l
l
l
l
:
LL
II
I
I
I
I
I
I
I
E
I
Q..
PACIFICORP
A MIDAMERICAN ENERGY HOLDlNGS COMPANY TOT4A-4B SOL Study Report
(5)Stuck breaker at Jim Bridger 230 kV bus with loss of Jim Bridger -Rock Springs 230 kV line and Jim Bridger -Point of Rocks -Rock
Springs 230 kV line
Illllllll
·¯·ru =
m em
--I
ma
i-.-e
I
I
C3
c
Illllllll).0 2.0000 4.0000 6.0000 8.0000 10.00
TIME (SECONOS)THU,JAN 26 2017 16:L1
Page 22 ,Ianuary 26,2017
WE
S
T
E
R
N
EL
E
C
T
R
I
C
I
T
Y
CO
O
R
O
I
N
A
T
I
N
G
CO
U
N
C
I
L
20
1
6
HS
3
OP
E
R
R
T
I
N
G
CR
S
E
OC
T
O
B
E
R
20
,
20
1
5
Te
c
m
s
u
m
i
s
s
IN
T
E
M
N
I
T
I
W
I
B
F[
L
E
:
C:
\
R
i
k
i
n
\
,
.
.
\
0
y
n
a
m
i
c
s
\
0
Y
_
P
l
-
2
-
3
_
P
L
T
-
S
T
N
P
2
3
0
_
U
S
R
C
L
.
o
u
t
CH
N
L
=
30
1
:
EV
O
L
T
67
9
4
6
EF
F
I
E
E
Z
O
U
T
23
0
.
0
0
]
]
1,
5
0
0
0
*-
-
-
-
-
-
-
-
-
-
-
+
0,
5
0
0
0
0
|
a-
I-OI-
-
.
I
r
CH
N
L
=
26
9
:
EV
O
L
T
66
2
4
5
EP
L
A
T
T
E
Ll
5
.
0
0
]
]
-
1,
5
0
0
0
--
-
-
-
-
A
0,
5
0
0
0
0
Il
l
l
l
l
l
l
l
I
(n
I
LL
,
I
Il
l
l
i
'
l
l
l
l
l
0..
WE
S
T
E
R
N
EL
E
C
T
R
I
C
I
T
Y
CO
O
R
O
I
N
A
T
I
N
G
CO
U
N
C
I
L
20
1
6
HS
3
OP
E
R
R
T
I
N
G
CR
S
E
OC
T
O
B
E
R
20
,
20
1
5
Te
e
m
a
a
n
i
e
s
III
T
E
W
I
N
I
T
I
W
I
B
F[
L
E
:
C:
\
R
i
k
i
n
\
,
.
.
\
0
g
n
a
m
i
c
s
\
0
Y
_
P
l
-
2
-
4
_
0
J
-
A
N
S
2
3
0
_
U
5
R
C
L
ou
t
CH
N
L
=
28
2
:
CI
O
L
T
65
3
0
0
EC
M
S
P
E
R
P
P
23
0
.
0
0
]
]
l.
5
0
0
0
0,
5
0
0
0
0
|
CH
N
L
=
29
4
:
EV
O
L
T
67
6
1
4
EM
I
N
O
S
T
A
R
23
0
,
0
0
]
]
1,
5
0
0
0
*-
-
-
-
-
-
-
-
-
0,
5
0
0
0
0
|
c
o
CH
N
L
=
28
5
:
EV
O
L
T
65
4
2
5
EO
N
V
E
J
O
H
N
L
[5
.
0
0
]
]
1,
50
0
0
--
--
0,
50
0
0
0
|
ll
l
l
"
I
l
l
l
l
III
II
I
I
L
I
l
l
l
0..