Three-phase power transmission line phase-to-ground fault responder

摘要

A three-phase power transmission line phase-to-ground fault responder wherein voltage coils of respective responder relays are energized by respective phase-related voltages and wherein current coils of such relays are serially connected across the composite voltage source comprising the three serially composite voltage source comprising the respective phase-related voltages applied in series. In one embodiment the phase-related voltages are proportional to the transmission line phase voltage itself whereas in a second embodiment, less sensitive to location of fault in relation to the instrument takeoff voltage location, the phase-related voltage is the vector sum of voltages of the other two phases.