A New Method for Evaluating Fault Reduction Factor in HV Cable System

Grounding fault current distribution and the reduction factor of a power cable is an important parameter for the design of substation ground grid, the correct estimation of the safety conditions (step and touch voltages) in the supplied substation and the interference to the communication system nearby. In this paper, a simplified equivalent model is presented for three single-core cable sheaths, which are two-ends grounded. Both of the cable sheaths with or without applied cross-bonding connection are discussed here. Based on this, the paper presents an original analytical procedure for determination the ground fault reduction factor when a ground fault happens in the substation supplied by HV cable network. The method is proved to be a practical and precise one for evaluating the ground current distribution and the reduction factor in HV cable system