This utility, like other similarly registered NERC entities, is required to comply with the NERC Standard PRC-026-1 which ensures that their load-responsive protective relays do not to trip in response to stable power swings. Stable power swings are system disturbances such as faults or generator switching that should not cause protective devices to operate, but sometimes can, leading to undesirable tripping. Commonwealth helped the utility comply with this standard by gathering all relevant relay settings associated with the elements identified by ISONE as being covered by PRC-026. Commonwealth identified the relevant relay functions at each element terminal according to Attachment A of PRC-026-1. Commonwealth performed the required analysis specified in PRC-026-1 and classified each relay as compliant or non-compliant. Commonwealth recommended potential mitigation actions for use in a Corrective Action Plan (CAP) for non-compliant relays. The utility will now develop a CAP for non-compliant relays.
Commonwealth also can develop a CAP if desired. Commonwealth can propose and check changes to the setting required to make the relays compliant. Commonwealth offers its sophisticated analysis capabilities to help determine when avoiding all possible intrusions into the stable operating area is not prudent. Commonwealth provided a timely PRC-026 study which helped the utility avoid compliance violations and potential fines. Commonwealth utilized Aspen’s One-liner for this project. Commonwealth’s thorough understanding of the PRC-026-1 Standard, ensured a complete report without much effort or intervention by the client.