Network protection performance audits

Considering the rapid changes to which transmission and distribution networks are subjected, and the ever-shorter expected useful life of numeric protection relays, the requirement for network protection performance audits as part of the lifetime management of protection systems is becoming a necessity. The capability and availability of steady state single frequency phasor-based power system and protection analysis software packages now make it possible to undertake “wide-area” protection performance audits. The scope of the working group was to cover the possibilities, advantages and requirements for utilising proprietary power system and protection analysis software for undertaking protection performance audits of transmission and distribution systems involving hundreds or thousands of protection devices.