Doug Tucker Tyler Butikofer Study Purpose Outage of the southern - - PowerPoint PPT Presentation

Natural Gas Disruption Task Force Findings

January 15, 2020

Doug Tucker Tyler Butikofer

▪ Outage of the southern line of the El Paso Natural Gas Pipeline in the Desert Southwest

• Identify transmission constraints and potential

unserved load using the PCM

• Identify potential voltage and stability risks in the

Southern California and Arizona areas using a power flow and dynamic program

• Identify the threshold for unavailable gas-fired

capacity before experiencing unserved load, and voltage or dynamic stability constraints

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Study Purpose

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Work Flow

WECC Gas-Electric Interface Study Unavailable Generation List from Gas- Electric Interface Study Apply Generation List to 2028 ADS PCM Phase 1 V2.2 and run case

Identify Worst hour for Unserved Load Export August 24, 7:00 to 8:00 PM from 2028 ADS PCM Phase 1 V2.2 in PSLF format

Run 2028 ADS PCM with Northern California units in service

PCM Work PF Work

Model generation unavailable and identify the threshold for having unserved load Starting at the Eastern Arizona border and moving toward California, model generators unavailable Is there unserved load?

No

Unserved load threshold identified

Yes

Starting at the Eastern Arizona border and moving toward California, model generators unavailable Has a voltage/ dynamic stability issue occurred?

No

Voltage/dynamic stability limit identified

Yes

Solve the export hour In PSLF

▪ Power flow took PCM output on August 24, 7:00 p.m. to 8:00 p.m.

• Set generation and loads in power flow
• System losses are different between PCM and

power flow models

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Load and Loss Differences

Model Generation Load System Losses PCM 153,964 150,796 3,167 Power Flow 153,963 149,990 3,941

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Path Comparisons for Stating Case

Path Number and Name Power Flow Flows (MW) PCM Flows (MW) Path Limits (MW) 3 Northwest – Canada

• 1,792
• 2,083
• 3,150

15 Midway – Los Banos 838 861 2,000 22 Southwest of Four Corners 7,098 7,279 2,325 27 IPP DC Line 883 881 2,400 46 West of Colorado River (WOR) 7,098 7,279 11,200 49 East of Colorado River (EOR) 3,200 3,332 10,100 50 Cholla – Pinnacle Peak 529 567 1,200 51 Southern Navajo 70 62 2,800 65 Pacific DC Intertie (PDCI) 913 913 3,220 66 California Oregon Intertie 731 1,033 4,800

For Path 15, the transfer limit ranges from 2,000-3,265 MW for north-to-south direction. For the purpose of this study, the limit was set at 2,000 MW.

▪ Generation taken out was indicated by the WECC Gas-Electric Interface study ▪ Generation was removed from the New Mexico/Arizona boarder moving west

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PCM Study Assumptions

▪ Once 10,688 MW of gas-fired capacity was lost in Arizona, 264 of unserved load was

• bserved in Arizona

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Unavailable Capacity and Unserved Load of Threshold PCM Case

Path Number and Name Flow (MW) Limit (MW) 1 Alberta – British Columbia 1,000 1,000 15 Midway – Los Banos 2,000 2,000 22 Southwest of Four Corners 1,512 2,325 27 IPP DC Line 1,307 2,400 30 TOT 1A 650 650 46 West of Colorado River (WOR) 1,496 11,200 49 East of Colorado River (EOR)

• 3,339
• 10,100

52 Silver Peak – Control 17 17 65 Pacific DC Intertie (PDCI) 2,457 3,220 66 COI 549 4,800 83 Montana Alberta Tie Line 325 325

For Path 15, the transfer limit ranges from 2,000-3,265 MW for north-to-south direction. For the purpose of this study, the limit was set at 2,000 MW.

▪ Generation taken out was indicated by the WECC Gas-Electric Interface study ▪ Generation was removed from the New Mexico/Arizona boarder moving west ▪ Post Transit Simulation was used in power flow simulations

• PSLF was used to study the snapshot and is unable to

run a simulation of this magnitude

• Allowed some of the equipment to switch on or off
• Generation lost was re-dispatched through the system

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Power Flow Assumptions

▪ Path 3 Northwest - Canada, has exceeded (-3153 MW) its path rating of -3150 MW ▪ Path 83 MATL, is 29 MW over its limit

• Because this is a phase shifter, the operators would

control this flow. The 29 MW would flow down Path 3.

▪ Voltage at a 345-kV bus in Colorado dropped to 0.937 from 1.41 pu (10%) ▪ Observed 467 buses with at least a 5% change or greater

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~6800 MW of Generation Lost

▪ Path 3 and Path 15 have exceeded the max ratings of -3150 and 2000 MW ▪ The system has lost 77 Generation units ▪ Voltage at a 345-kV bus in Colorado dropped by 17.6% ▪ Observed 1724 buses with at least a 5% or greater change

• 362 bus are over 10% change

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~8513 MW of Generation Lost

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Path Flow with ~8513 MW of Generation lost

Path Number and Name Pre-Flow Post-Flow Path Limit 3 Northwest – Canada

• 1,792
• 3,572
• 3,150

15 Midway – Los Banos 838 2,350 2,000 22 Southwest of Four Corners 1,038 1,288 2,325 27 IPP DC Line 883 883 2400 46 West of Colorado River (WOR) 7,098 2,226 11,200 49 East of Colorado River (EOR) 3,200

• 2,436

10,100 50 Cholla – Pinnacle Peak 529 485 1,200 51 Southern Navajo 70 1,718 2,800 65 Pacific DC Intertie (PDCI) 913 3,100 3,220 66 COI 731 2,327 4,800

For Path 15, the transfer limit ranges from 2,000-3,265 MW for north-to-south direction. For the purpose of this study, the limit was set at 2,000 MW.

▪ Started with the case that has lost ~5315 MW

• f generation.

▪ Created a dynamics file to run the following Contingencies

• Single Palo Verde outage
• Loss of the Bi-Pole PDCI

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Contingencies Runs

▪ No TPL-001 dynamic Voltage Criteria was violated in either contingency ▪ Frequency dropped to 59.905 for the loss of the single Palo Verde Unit ▪ Path 3 Northwest – Canada: increases to ~- 3130 MW with a limit of -3150 MW ▪ Path 15 Midway – Los Banos: increases to ~1800 MW with a limit of 2000 MW

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Palo Verde Contingency Results

▪ No TPL-001 dynamic Voltage Criteria was violated in either contingency. ▪ Not a Frequency Event. ▪ Loss 44 MW of load in the New Mexico area ▪ Path 3 Northwest – Canada: increases to ~-3130 MW with a limit of -3150 MW ▪ Path 15 Midway – Los Banos: increases to ~2700 MW which has exceeded the limit of 2000 MW ▪ Path 26 Northern to S California: increases to ~4000 MW which has a limit of 4000 MW

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Bi-Pole PDCI Contingency Results

▪ Before the total loss of 24,000 MW

• Transmission constraints were observed
• The PF analysis shows at approximately 8,300

MW, the Western Interconnection is potentially at risk of low voltages

• The PCM shows at approximately 10,600 MW,

potential risk of unserved energy

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Summary

▪ Natural gas, and fuel availability, should be considered when planning the bulk power system as illustrated by this extreme scenario

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Recommendations

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Report Approval

Request for approval of the 2019 NGDTF Reliability Assessment Report

Contact:

Doug Tucker dtucker@wecc.org Tyler Butikofer tbutikofer@wecc.org

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