Grounding System Tests for Analysis of Fault-Induced Voltages on Communication Cables

To avoid failures of communication lines serving electric power stations during line-to-ground faults, an analysis of the expected voltages must be carried out for each projected station. A method for predicting reliable results without conducting staged-fault tests is described. The technique uses ac current injection at 5 to 10 Hz away from the power-system frequency to simulate a fault condition, and a sensitive detection scheme for measuring the amplitude and phase of secondary voltages and currents in the presence of power-system interference. The method is employed to predict voltage stresses on communication cables in a large multi-station power-system complex.