Testing the influence of the quality of the supply voltage on the performance of a numerical relay

Abstract

To ensure consistent reliability and proper operation, protective relay equipment must be evaluated and tested. This paper presents the requirements for testing the ac and d.c. auxiliary power supply of protective relays and the test results. The test severity levels, test set-up, test procedures and test report are presented according to the IEC60255-11 Ed.2.0. A numerical relay commonly found in the power distribution systems is used for testing. The tests are carried out to determine the ability of the relay to withstand a variety of disturbances as specified in the international standard.