Feasibility study of noise pattern analysis based ground fault locating method for ungrounded DC shipboard power distribution systems

A novel fault locating approach based on noise pattern analysis which utilizes the noise caused by the repetitive switching actions of power electronic converters to solve the difficult fault location problem for ungrounded DC shipboard power distribution systems was previously presented. This paper explores the feasibility of the method in terms of noise level when filtering is applied at the input terminal of the DC-DC converter to attenuate the noise. An investigation based on simulation results from a notional, high-fidelity DC zonal electrical distribution system (DCZEDS) model in PSCAD/EMTDC is first conducted. It reveals that the proposed method remains effective even for a DC system in which the noise level is highly limited and, hence, attenuated. The result is then validated through the analysis based on an experimental small scale DC distribution system which includes shielded power cables and DC-DC converters with low switching frequency to capture the high frequency feature of the notional DCZEDS.