Issues and opportunities for testing numerical relays

This paper reviews the use of modern relay test sets, real-time playback simulators and real-time digital simulators for testing numerical relays. The issues concerning the generation of data for testing relays are examined. Types of tests that can be performed on numerical relays are also reviewed. A procedure for identifying critical tests is discussed. A procedure for testing relays by using recorded data is also described. The paper demonstrates that there is a need for the relay manufacturers to provide facilities in their relays for testing them by using the data acquired by numerical devices installed in the system