Ground Fault Location Testing of a Noise-Pattern-Based Approach on an Ungrounded DC System

Finding the phase-to-ground faults in ungrounded distribution systems is very difficult and time consuming. In recent years, the advances in power electronics favor dc distribution, particularly for transportation systems such as ships. Therefore, this paper presents a fault location approach which is based on the pattern recognition of inherent high-frequency noise associated with the switching events of converters. This paper demonstrates the feasibility of the approach through a hardware laboratory test. Specifically, a low-voltage dc system, representative of the salient high-frequency behavior of a real zonal electrical distribution system for ships, was used. Closely matching the results obtained from a computer simulation model of the circuitry, the experimental test results show the ability of the approach to appropriately differentiate various fault locations in the laboratory environment. It is concluded that the approach is feasible and can be applied toward the development of an effective ground fault location system for converter-dominated dc systems.