Failure Risk Assessment of Medium-Voltage Distribution Lines in the Central Area of Japan

In the Chubu area of Japan, where major industries are densely located, medium-voltage distribution lines are designed to provide high lightning protection to enhance power supply reliability. However, minimizing investment costs is essential to maintain these medium-voltage distribution lines. We analytically assess the lightning performance of distribution lines in low-power-demand areas using XTAP, specifically when middle-phase arcing horns are omitted. In addition, we evaluate the effects on the risk of lightning damage for poles lacking lightning protection equipment when threephase transformers are removed, in response to changing customer needs. Using data on the frequency of lightning strikes and the cumulative frequency distribution of lightning current peaks in the Chubu area, we assessed the risk of multiphase flashover occurrence and the failure risk of the lightning-arrester elements, finding both measures to be effective.