ERCOT Reports Inadvertent Disabling of Contingencies in August Network Operations Model
October 8, 2018 Email This Story Copyright 2010-17 EnergyChoiceMatters.com
Reporting by Paul Ring • email@example.com
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In a market notice, ERCOT reported that, at 23:56 on August 14, 2018, ERCOT implemented Downstream Production Changes (DPC) to add contingency definitions to the Network Operations Model (2018Aug.L2) that had been requested by a Transmission Service Provider (TSP).
ERCOT said in the market notice that, "Due to the significant number of transmission elements involved in the contingency definitions, ERCOT replaced the normal manual process and used an automated import tool to systematically apply the changes to the Energy Management System (EMS). The software tool had a defect that in this unique case resulted in the disabling of 947 existing single circuit contingencies out of approximately 7300 total contingencies. ERCOT identified the error at approximately 22:30 on August 21 during preparations for the next Network Operations Model load (2018Aug.L3). The contingencies were re-enabled as part of the normal model load process at 23:55. Thus, the error resulted in the disabling of the 947 single-circuit contingencies in EMS from August 14 at 23:56 to August 21 at 23:55."
ERCOT said in the market notice that, "ERCOT has investigated the impacts that this error may have had on transmission congestion in real-time and has determined that only 6 of the inadvertently disabled contingencies could have led to additional real-time congestion. None of the disabled contingencies impacted the assessment of the voltage stability limits for the Rio Grande Valley or for the Houston-area Import and the error did not directly impact Day-Ahead Market (DAM), Reliability Unit Commitment (RUC), or Congestion Revenue Rights (CRR) processes. ERCOT is unable to accurately determine the impact to dispatch and pricing for Security-Constrained Economic Dispatch (SCED) and will not be performing a price correction. ERCOT has confirmed that the software defect with the import tool has not previously impacted real-time operations as this was the first instance of using it on a DPC. A solution to the defect in this tool has been developed and changes to validation procedures for DPCs have been implemented. ERCOT will discuss the issues described in this Notice in greater detail at the October meetings of the Wholesale Market Subcommittee (WMS) and the Reliability and Operations Subcommittee (ROS)."