West Texas Congestion

Chad ThompsonCongestion Management Working GroupAugust 22 2014

Background

• ERCOT has received several inquiries from market participants regarding congestion patterns in West Texas

• This congestion has been influenced by challenges associated with modeling, telemetry, and outage submissions

• ERCOT has been working diligently with stakeholders and the interconnecting transmission companies to develop plans to ensure grid reliability in the region

Outline

• Walkthrough the process of picking up Sharyland load

• Discuss Operational Challenges encountered in the last 10 months

• Discuss “on-going” stakeholder concerns with congestion management practices

Evolution of the Sharyland Area

Evolution of the Sharyland Area

October 2013

Evolution of the Sharyland Area

November 2013

Evolution of the Sharyland Area

December 2013

Evolution of the Sharyland Area

December 2013

Evolution of the Sharyland Area

December 2013

Evolution of the Sharyland Area

May-June 2014

Evolution of the Sharyland Area

August 2014

Evolution of the Sharyland Area

Operational Challenges• Outage Scheduler/Telemetry

– Coyote – Vealmoor (Jun 27-30, Aug 18-19)• Submitted as outage, energized in RT

– Gardendale POI – Pecan Grove (Aug 18-19)• Tie point added on Aug 8

– Triangle (June 6)• When location changed in the model, SCADA had the station de-

energized, but flow was going through the station

• Modeling– Pecan Grove and Triangle– Gardendale POI – Telephone Rd temporary tie– Eiland – Polecat Creek

• Nomenclature– Substation names changing (e.g. Telephone Rd vs Telephone

Pole Rd)– SPP cutover name changes

On-Going Stakeholder Concerns• Inconsistent management of constraints

– 2 % shift factor cut-off• June 18: Skywest – Spraberry overloads Midland East

– Buffalo• June 27-29: Skywest – Salt Flat Rd overloads Midland

East - Buffalo– Operator discretion on when constraints are

activated & deactivated• Especially with this area, continued vigilance to verify

telemetry and model data may result in delays in activating/deactivating constraints

• SCED Constraint Management Transparency Posting on the MIS

Summary• In the last several months, the load in the area has

increased ~300 MW (peak)• Challenges with telemetry have influenced real-

time congestion management decisions• Challenges with scheduling equipment in the

Outage Scheduler has influenced congestion in forward markets (e.g. DAM)

• Oncor/Sharyland built temporary tie to move Sharyland load to the Midland East – Moss 138 kV line

• Continue to use MIS postings for information regarding constraint activation