Today’s LiveWire Spotlight looks at two “teachable moments” where the maintenance of digital systems used by the electric system led to unexpected failures. The first is the “Unavailability of the Transmission Stability Limits Calculation Application” which describes an event where the function was lost twice during a five-hour period. The second is “Tie Line Relay Coordination” which addresses a Misoperation caused by inadequate interaction between two substation owners regarding the maintenance of a relay communications on a 345 kV transmission system tie-line.

Situational awareness and relay Misoperations are two of NERC’s top reliability concerns. Severe penalties may be applied if Registered Entities do not act upon these Lessons Learned – and may even lead to the development of new standards.