Fault current constrained impedance-based method for high resistance ground fault location in distribution grid

Abstract

Fault locating technology is crucial to the safe operation of a distribution grid. Impedance-based method is quite promising in fault locating due to its low cost and easy implementation. However, this method suffers from low precision when locating high resistance ground fault. This paper proposes a fault current constrained impedance-based fault location method. This method establishes location equations via the assumption that fault resistance consumes zero reactive power. First, this method adds the Thevenin equivalent to the downstream network after the fault. Second, the increment of fault current caused by distributed generations is quantified. These efforts provide an exact estimation of fault current, leading to a higher locating precision when encountering a high resistance ground fault. Simulations based on IEEE-34 node network show that the proposed method outperforms the traditional impedance-based method in precision significantly. Moreover, the proposed method does not need to distinguish fault type in advance, and is compatible to different fault scenarios.