Towards Supervisory Protection Using Energy Functions for Relay Misoperations in a Stressed Power System During Blackout

Relay misoperations in power systems, especially during stressed conditions can initiate a cascade potentially leading towards a blackout. A typical event that aggravates a cascade is a trip decision by distance relays to faults in zone 3. We examine the use of energy functions as a discriminant in such scenarios to supervise the action of distance relays, in particular, to distinguish between load encroachment and zone 3 faults. The scenarios are tested on two individual test beds, the 39 bus New-England Test System (NETS) and a portion of the Western Electricity Coordinating Council (WECC) system. NETS is used to analyze and assess the choice of energy functions for protection, whereas the WECC system is used for an actual blackout simulation in the South Western United States corridor. Analysis on these test systems depict on how energy functions can help in detecting and potentially avert costly relay misoperations.