山火引发输电线路间隙放电机理与击穿特性综述

Review on Discharge Mechanism and Breakdown Characteristics of Transmission Line Gap Under Forest Fire Condition

山火发生时火焰的高温、高电导率、多灰烬等使架空输电线路间隙绝缘强度显著下降,可能引发线路跳闸,且重合闸不成功概率大,易导致线路停运的严重事故。近年来,山火频发给电网的安全稳定运行带来了严峻的挑战。为此,对山火引发输电线路间隙放电机理与击穿特性研究进行了综述,分析了国内外模拟输电线路山火试验平台搭建、试验方法、山火条件下输电线路间隙放电机理,间隙交直流电压击穿特性研究现状。分析表明山火模拟试验平台考虑的影响因素多较为单一;因模拟试验的尺度、植被类型、试验方法等的差异,试验结果差异性及分散性较大;火焰燃烧特性及产物对间隙放电的影响机理研究考虑的影响因素较为单一。对指导山火情况下输电线路跳闸防护具有一定的局限性。建议系统开展山火条件下不同尺度、电极类型间隙交直流击穿特性研究,结合试验数据,开展电场、火焰温度、电导率、灰烬及颗粒等因素对间隙绝缘击穿特性影响的单一和综合作用机理研究。

The high temperature, high electrical conductivity and ashes of forest fire flames can greatly reduce the insulation strength of high voltage overhead transmission line gaps, and can cause transmission line trip out, and the probability of successful re-closing is very low, this may lead to the serious accidents of transmission line out of operation. In recent years, frequent occurrences of forest fire bring great challenge to the safe and steady operation of the power grid. The discharge mechanism and breakdown characteristics of transmission line gap under forest fire condition are reviewed in this paper. The study status of the transmission line forest fire simulation test platforms, experimental methods, discharge mechanism and breakdown characteristics of AC and DC transmission line gap under forest fire conditions in China and abroad are analyzed. The analysis indicates that some test platforms only consider single influencing factor; the differences and disparity are large for the differences of the simulation tests＇ dimension, vegetation forms, and experimental methods; the influencing mechanism studies of flame combustion characteristics and products to the gaps＇ discharge also consider single influencing factor. There is a limitation for the guidance of transmission line trip-out prevention under fire conditions. The systematically study of breakdown characteristics of AC and DC transmission line gaps under forest fire conditions with different dimensions and electrodes, and the single and multi-factor influencing mechanism to the gap discharge study with electric field, flame temperature, conductivity, ashes and particles is suggested.