A Study of Lightning Performance to Multi-grounded System of KEPCO MV and LV Distribution Network

Abstract

This paper presents the indirect lightning performance evaluation of Korea Electric Power Company (KEPCO) medium voltage (MV) and low voltage (LV) lines. The main topic of this paper is to analyze an effect of the grounding systems on the indirect lightning performance of MV and LV distribution lines. To this end, we define the models of the MV and LV distribution systems for the analysis of distribution line surge overvoltage due to lightning. With reference to the data typically adopted by KEPCO, the research describes and motivates the use of the most suitable models of distribution lines, transformers, and surge arresters (SAs) to be implemented in EMTP like simulation environments. The sensitivity of the lightning performance of the distribution lines to different configuration of MV and LV grounding systems, distance between SAs, as well as presence of overhead ground wires is also analyzed. Regarding overvoltage, both the temporary overvoltage and the surge overvoltage are considered. The presence of SAs at the MV terminals of distribution transformers is also considered.