A VSAT study is performed by ramping up generation in one area (in this case the panhandle) and ramping down generation in another area (or ramping up load) until one of two things happens; 1, the study predicts a voltage collapse, or 2) the tool runs out of resources to ramp. At that point the VSAT tool records the flow going across a determined interface and calls it (case 1) the stability limit or (case 2) the dispatch limit. Obviously case 1 is a problem, whereas case 2 isn’t really an issue. However, prior to December 2021, ERCOT would include the result of the VSAT study in the limit setting process for the Panhandle Generic Constraint Limit whether it was the dispatch limit or the stability limit. In December ERCOT started only including the stability limit in its limit setting process for the Day Ahead market. In March 2022 ERCOT will stop including the dispatch limit in the Real-Time market.
- 2/21/22 ERCOT gives presentation on new Panhandle GTC Limit setting procedure.
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