An Introduction to Completing a NERC PRC-026 Study for Traditional Generation Applications

The NERC PRC-026-1 reliability standard has recently taken effect and may have an increasingly important role in the development of generator protection settings. The intent of PRC-026-1 is “To ensure that load-responsive protective relays are expected to not trip for stable power swings during non-fault conditions”. This paper is intended to be an introductory overview for completing a NERC PRC-026 study for a synchronous generator facility from the perspective of a system protection engineer. This paper also provides an overview of power system stability and the response of impedance-based relay elements to system swings. Lastly, this paper includes a comparison of applicable traditional impedance based generator protection methods outlined in IEEE Standard C37.102., with the method used to demonstrate compliance with the PRC-026-1 standard.