A New Correlation-Based Earth Fault Indication Algorithm Using Only Transient Current Measurements

Abstract

A new earth fault indication algorithm based on a new application of the correlation method is proposed, in this paper, for earth faults in unearthed and compensated medium voltage networks. The algorithm uses only the transient components of the fault currents. An inherent relation and features of the fault currents, through the branched feeders and sections of the network, are observed and utilized. The correlation between these currents is found to be a good indicator for the fault incidence. The high correlation can indicate the faulted path, including the faulted feeder and sections. A measurement using lower sampling frequencies, down to 2.5 kHz, can be used without too much effect on the accuracy. A typical medium voltage network is simulated by EMTP-ATP Draw program and many simulation cases are performed to validate the performance of the proposed algorithm and its limitations. The proposed algorithm is found to be suitable for both of unearthed and compensated neutral networks; overhead, cable and mixed networks, with higher fault resistances.