Numerical location of unknown single line-to-ground faults on a 70 KV subtransmission system

This paper presents a work to locate, numerically, the unknown single line-to-ground faults on an existing 70 KV subtransmission system. First the paper describes a method to determine the location of the faults by using SIMPOW, a power system simulation software developed by ABB Power Systems AB, Sweden. Based on the models of components in the network analyzed, a model for the whole system is constructed. The simulation is then performed with a three-step approach so that the amount of computational work is dramatically reduced. The results from each step are presented in the paper. It is concluded that the proposed method is an efficient and reasonable approach to locate unknown transient faults on a large system when reliable data of the network are available.