NPRR593  Clarification of Generic Transmission Limit Posting Requirements

This Nodal Protocol Revision Request (NPRR) creates and defines the term "Generic Transmission Constraint" (GTC) to distinguish between the transmission constraint itself and the value of the transmission constraint’s Generic Transmission Limit (GTL); and modifies the definition of GTL to be consistent with this clarification. This NPRR also clarifies the posting requirements for GTCs and GTLs, as current Protocol language does not specify what GTC- or GTL-related information should be posted on the Market Information System (MIS). In practice, ERCOT posts only the predicted GTL values based on its Day-Ahead analysis. ERCOT has not posted background details on the GTCs it uses currently; given that they are artifacts of the Zonal market and are considered common knowledge. As additional GTCs are added to the ERCOT system, it is important that the details behind a GTL and its derivation are made transparent to the Market before the GTC goes into service.