An automated testing system for distance relays

The advent of low-power-requirement electronic distance relays has lead to the possibility of generating low-power test signals for such relays using a minicomputer. Such a test program has been written, for steady-state and transient, i.e. dynamic, testing of distance relays, and the tests performed on an actual relay. The tests are highly automated, with results appearing as "R-X diagram" plots on a CRT screen, and tripping time versus distance-to-fault. It is suggested that this approach can lead to savings in time and expense, as well as increased flexibility, over conventional methods.