Power system protection and resilient metrics

During a real-time power system event, a system operator needs to conservatively reduce operating limits while the changing system conditions are analyzed. The time it takes to develop new operating limits could affect millions of transmission system users, especially if this event is classified by NERC as a Category D type event (extreme events resulting in the loss of two or more bulk electric system elements). Controls for the future grid must be able to perform real-time analysis, identify new reliability risks, and set new SOLs (System Operating Limit) for real-time operations. In this paper we are developing “Resilience Metrics” requirements that describe how systems operate at an acceptable level of normalcy despite disturbances or threats. We consider the interdependencies inherent in critical infrastructure systems and discuss some distributed resilience metrics that can be in current supervisory control and data acquisition (SCADA) to provide a level of state awareness. This level of awareness provides knowledge that can be used to characterize and reduce the risk of cascading events. A “resilience power system agent” is proposed that provides attributes to measure and perform this metrics.