Today’s LiveWire Spotlight examines NERC’s latest Lessons Learned; a “teachable moment” where extreme cold weather disrupted BES breaker operations, threatening electric system reliability.  It describes an outage that began when an air blast circuit breaker locked in the closed position in an outdoor substation at dangerously low temperatures (45° F with wind-chill).  A single inflexible seal hardened by age allowed air to leak out of the blast mechanism faster than the air compressor could keep up with

Protection System Misoperations continue to be a leading cause of BES service loss and are among NERC’s top reliability concerns.  Severe penalties may be levied if an outage occurs, and it is found that an equipment owner did not act upon this Lesson Learned.