Simulation of power-system fault currents and voltages for protective-equipment testing

Artificial transmission lines have been successfully used in the past for protective-gear testing. However, the great increase in the power-system fault levels and transmission voltages experimented with in recent years has made it impractical and uneconomical to simulate correctly the high fault currents and time constants now encountered by means of artificial transmission lines. The paper describes two circuits to produce synthetically the fault currents and voltages required for protective-relay testing. Results obtained from small-scale models of the test circuits are illustrated and discussed.