Title MVA for SCED Input
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Next Step
Status Approved on 09/15/2009
Effective Dates

or per the Nodal Protocol Transition Plan http://www.ercot.com/mktrules/protocols (10/01/09 Nodal Protocols Library)


Date Gov Body Action Taken Next Steps
07/23/2009 PRS Recommended for Approval PRS Impact Analysis Review
09/03/2009 TAC Recommended for Approval ERCOT Board Consideration
08/25/2009 PRS Recommended for Approval TAC Consideration
09/15/2009 BOARD Approved

Voting Record

Date Gov Body Motion Result
07/23/2009 PRS To recommend approval of NPRR188 as submitted. Passed
09/03/2009 TAC Passed
08/25/2009 PRS To endorse and forward the 7/23/09 PRS Recommendation Report and Impact Analysis for NPRR188 to TAC Passed
09/15/2009 BOARD To approve NPRR188 as recommended by TAC in the 9/3/09 TAC Recommendation Report Passed


Status: Approved
Date Posted: Jul 10, 2009
Sponsor: Ebby John on behalf of the Network Data Support Working Group (NDSWG)
Urgent: No
Description: This Nodal Protocol Revision Request (NPRR) removes the Transmission Service Provider (TSP) requirement to provide MVA to be used in Real-Time sequence and Security-Constrained Economic Dispatch (SCED). This NPRR also corrects the use of Common Information Model (CIM) and corrects the Dynamic Rating requirement.
Reason: MVA values from a TSP or any Market Participant are not used within State Estimator solutions except in the case of a Dynamic Rating. The ERCOT Energy Management System (EMS) is not designed to accept MVA values for equipment except as a Dynamic Rating. The ERCOT State Estimator, and subsequently contingency analysis, utilizes MW and Mega Volt-Amperes reactive (MVAr) Inter-Control Center Communications Protocol (ICCP) data to determine an MVA value which then may be passed to SCED if needed. The State Estimator/contingency analysis-determined MVA value is used to compare with the Market Participant provided ratings, including Dynamic Ratings, and is captured as a Real-Time sequence and SCED requirement pursuant to paragraph (1) (b) of Section This NPRR also replaces CIM with Network Operations Model as Common Information Model (CIM) is a format. All MVA ratings are provided and are utilized by ERCOT in maintaining the reliability of the ERCOT Transmission Grid.

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