CMWG 11/15/21 - CIMView

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CMWG 11/15/21

Table of Contents

Executive Summary

ERCOT presented on the RUC for congestion on 9/21/21.  Turns out it wasn’t very mysterious after all; the units in Houston were for Houston voltage collapse and the units in DFW and San Antonio were for WESTEX export relief.  

The discussion on possible fixes for the issue where short term derates of transmission line ratings get carried into far future CRR network models was discussed and 4 solutions were presented.  This should get resolved in a few months, then implementation will take about a year.

The argument about whether ERCOT should move a resource node if the point of interconnection changes continued.  Morgan Stanley and DC Energy are against it, transmission companies are for it, we’ll see who wins in WMS.



  • RUC for congestion on 9/21/2021
    • ERCOT reported that their previous report on the RUC for congestion on 9/21/21 was somewhat incorrect.  The units in Houston were RUC’s to prevent Houston voltage collapse, there were units in Dallas/Fort Worth and San Antonio that were RUC’d to relieve the WESTEX generic Transmission Constraint (GTC).
    • ERCOT also reported that the forecasts for the RUC hours were pretty good.
  • Long Term Model Improvement Suggestions
    • There were five options identified:
      1. Do nothing
      2. TSPs submit 2 separate Network Operations Model Change Requests (NOMCRs), one a derate and one with a later start a rerate
      3. Set an end date for derate NOMCRs
      4. Add a flag that designates a NOMCR as temporary and use that flag on derate NOMCRs
      5. Implement derates via the outage scheduler
    • Choices 3  4 and 5 require system changes
    • Choices 3 and 5 were preferred by ERCOT
  • NPRR1099 (Changing Resource Node locations when the POI changes)
    • ERCOT presented some examples showing how the Resource Node would move under the NPRR and without the NPRR.
    • In some cases it would result in a noticeable change in price for CRRs that are connected to it.
    • DC Energy and Morgan Stanley still don’t like it.
    • Transmission companies love it because they no longer have to maintain models with incorrect outdated equipment that is no longer there.
    • ERCOT will present for endorsement at the next WMS (hopefully with examples of why carrying non-existent equipment in the model is a bad thing)
  • RENA Update
    • No one asked any questions about the revenue neutrality in August

Discussed Issues