A Microcomputer Based Ultra-High-Speed Dostance Relay: Field Tests

This paper describes the field tests of a microcomputer based Symmetrical Component Distance Relay (SCDR). A brief review of the relay operating principle is followed by a description of the field tests conducted by staging faults on a 765 kV transmission line on the AEP system. Performance of SCDR during these tests is analyzed. A newly developed Ultra-High-Speed (UHS) mode of operation for the SCDR is presented, and the performance of the relay in the Ultra-High-Speed mode is illustrated with the data gathered during the field tests.