Performance analysis of surge arrester on high voltage systems using ATP

Lightning strike has been reported to be one of the major factors to cause failures of electrical power system. In this paper a model is designed to investigate lightning overvoltage protection in a complete three-phase scheme of 500 KV substations. The overvoltages originated from direct lightning stroke on a phase of a real model of overhead lines (OHL). Metal oxide surge arrester is used as the protective device against lightning overvoltages. These studies are carried by analyzing the effect of arrester separation distance from the protected equipment such as transformers located at the entrance of the substations. Various system configurations consisting of different arrangements or position of overhead lines and cables are simulated to evaluate the performance of metal oxide arresters at different configurations of electrical substations. All studies are performed using a computer program, Alternative Transient Program (ATP) version of Electromagnetic Transient Program (EMTP). The results obtained from the studies are presented and discussed, and general conclusions and recommendations are addressed for further improvements of the entire protection scheme.