CRR; Operations

Thu, Aug 27, 2020 03:11 PM

W-B112117-08 Update to the Bearkat Generic Transmission Constrain

NOTICE DATE: August 27, 2020

NOTICE TYPE: W-B112117-08 Operations

SHORT DESCRIPTION: Update to the Bearkat Generic Transmission Constraint


DAYS AFFECTED: August 27, 2020

LONG DESCRIPTION: On August 19, 2020, ERCOT updated the limits for the Bearkat Generic Transmission Constraint (GTC) as a result of ERCOT’s review of the Remedial Action Scheme (RAS) at the Bearkat Station to ensure that post-contingency, pre-RAS flows are maintained below thermal cascading Outage criteria.  These updated limits for the no-prior-outage case apply only when this RAS is in service.  Because this RAS may be disabled, ERCOT is modifying the documentation for the Bearkat GTC to add the limits that should be enforced when this RAS is not in service.

In addition, ERCOT has determined that the Voltage Stability Assessment Tool (VSAT) can be used to calculate this post-contingency, pre-RAS flow limit in real-time using actual operating conditions.  ERCOT intends to implement this calculation on or around September 1, 2020.  The updated static limits noted in the Bearkat GTC document will be used until this VSAT calculation is implemented and in the event the VSAT calculation is not available.    

The purpose of this notice is to provide contemporaneous notification to all ERCOT Market Participants of these updates to the Bearkat GTC.  ERCOT has revised the Bearkat GTC document to reflect these changes as of August 27, 2020.

Details associated with all existing GTCs (EMIL ID NP3-766-M, Report ID 11424) can be found on the ERCOT Market Information System (MIS) Grid Transmission page under the Generic Transmission Limits Secured area. Details associated with the Bearkat RAS, which was approved per Market Notice W-B112117-05 Operations, can be found on the MIS Grid Long-Term Planning page under the Approved Remedial Action Schemes (RASs) Secured area.  A Digital Certificate is required to access the MIS Secure Area.

CONTACT: If you have any questions, please contact your ERCOT Account Manager. You may also call the general ERCOT Client Services phone number at (512) 248-3900 or contact ERCOT Client Services via email at

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