Trends in power system simulation for relay testing

Operational experience with protective relays is limited by the number of system events that occur. For many years, both the users and suppliers of protective relays have relied on relay testing to define the capabilities of power system protection under load, transient system disturbance, and fault conditions. The use of secondary injection test kits and artificial transmission lines (ATLs) was well established by the 1950's. The authors identify the trends in relay testing since that date and demonstrate how increasingly sophisticated power system modelling techniques can be used to evaluate protective scheme performance in the most demanding modern applications.