A study on improvement of multiphase flashover analysis in medium-voltage line caused by lightning and its application to the reduction of lightning outage rate

2022 Fiscal Year Final Research Report

• Project/Area Number: 17K06317
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Power engineering/Power conversion/Electric machinery
• Research Institution: Shonan Institute of Technology
• Principal Investigator: Sekioka Shozo 湘南工科大学, 工学部, 教授 (60410031)
• Project Period (FY): 2017-04-01 – 2023-03-31
• Keywords: 雷サージ / 配電線 / フラッシオーバ

Outline of Final Research Achievements

The multiphase flashover in medium-voltage line in Japan has been studied based on experiment and numerical simulation. This study simulates a direct lightning strike to the top of concrete pole of the line. The medium-voltage line in Japan is non-grounding system. Most of single-phase flashovers in the lines are naturally recovered due to low fault current. Thus, more than two-phase flashover causes a line fault.
This study has proposed an unbalanced insulation method in the medium-voltage line to reduce the multiphase flashover. The insulation levels among phases are different in the proposed method. The first flashover occurs on the lowest insulation insulator, and waveform on the other phases becomes lower and stepwise after the flashover. As a result, the number of more than two-phase flashover becomes smaller.

Free Research Field

電力工学、高電圧工学、電気回路論

Academic Significance and Societal Importance of the Research Achievements

発電容量が小さな再生可能エネルギーは配電線に連系されることが多く、配電線の電力品質向上が求められている。本研究では雷により配電線における供給支障を生じさせる多相フラッシオーバについて、その発生メカニズムを実験および数値計算シミュレーションにより明らかにするとともにコストをかけることなく実施可能な低減対策について提案を行った。実験データは工学的フラッシオーバモデルおよび雷事故率計算手法の高精度化に寄与することが期待できる。