Ground fault location in radial distribution networks involving distributed voltage measurement

Abstract

Since feeders have complicated laterals connected with unbalanced loads, the location of a ground fault is a challenge in radial distribution networks. Furthermore, lower short-circuit current due to the high value of fault resistance, which is common in the distribution network, will make it even more challenging to identify the fault location. Taking advantage of increasing number of intelligent electronic devices installed in the modern distribution network, the monitoring, and automation of distribution systems can be improved by smart feeder meters. On the basis of the voltage information from the downstream sub-laterals, a novel fault location method involving distributed voltage measurement is proposed in this study. The first step in the proposed method is to identify the fault lateral in the main lateral. In a zero-sequence components network, the position of nodes in the main lateral is iterated to judge if the calculated voltage at the end matches the measured one by a smart feeder meter. The second step is to identify the fault section accurately by combining the voltage information from main lateral or other sub-laterals. Finally, a precise fault location can be attained via an iteration search in the fault section. Two distribution test systems simulated in power systems computer-aided design/electro-magnetic transient design and control with 34-node and 134-node have been employed to evaluate the effectiveness of the proposed algorithm under various ground fault scenarios. The simulation results show that the proposed method is robust since it offered a good performance for ground faults identification with low and high values of impedance occurring at different locations. Furthermore, it is also suitable for the system with distributed generations and dynamic loads.