摘要
近年来,随着跨林区输配电线路日益增多,由山火引发的输电线路跳闸事故也频繁发生,严重影响电网安全稳定运行。目前,针对山火导致高压输电线路对地空气绝缘强度降低的问题,已开展较多实验研究,但未考虑火焰燃烧蔓延至杆塔时,线路绝缘子可能存在的最短绝缘距离问题。为研究植被火焰全桥接线-板短间隙条件下的空气击穿机理,文中开展不同植被燃烧条件下线-板间隙击穿特性实验,分析火焰中泄漏电流和击穿电压之间的相位差,并探讨植被火焰条件下间隙的击穿机理。实验测量了不同植被火焰间隙的击穿电压和平均击穿场强。结果表明:增大间隙距离可降低火焰中的感性成分,使整个线-板间隙呈现电容性;植被火焰条件下的线-板间隙击穿过程是多种放电形式共同作用的结果,且击穿时电弧通道的持续时长差别较大;击穿电压与间隙距离呈线性关系。由于稻草植被灰分含量高、结构松散,燃烧时产生的长灰烬颗粒对间隙电场具有较强桥接与畸变作用,导致间隙在稻草火焰条件下的平均击穿场强最小。
In recent years,the growing number of transmission and distribution lines traversing forested areas have led to an increasing frequency of line tripping incidents caused by wildfires,seriously threatening the safe and stable operation of power grids.Although numerous experimental studies have been conducted on the reduction of air insulation strength in high-voltage transmission lines to ground under wildfire conditions,little attention has been paid to the potential reduction in insulation distance when flames reach the transmission tower,particularly around line insulators.To investigate the air breakdown mechanism under conditions where vegetation flames fully bridged the short gap between a conductor and a grounded plate,experiments on the breakdown characteristics of line-to-plate gaps under various vegetation combustion conditions are conducted.The phase difference between leakage current through the flame and applied breakdown voltage is analyzed,and the breakdown mechanism under vegetation flame conditions is discussed.The breakdown voltages and average breakdown field strengths of the gaps under different vegetation flame conditions are experimentally investigated.The results show that:increasing the gap distance reduces the inductive component within the flame,causing the overall line-to-plate gap to exhibit capacitive behavior;the breakdown process under vegetation flame conditions involves multiple discharge mechanisms,and the duration of the arc channel varies significantly during breakdown;the breakdown voltage increases linearly with gap distance.Due to its high ash content and loose structure,straw vegetation produces long ash particles during combustion,which strongly bridge the gap and distort the electric field.As a result,the average breakdown field strength under straw flame conditions is the lowest among the tested vegetation types.
作者
曾毅
王政
杨皓涵
陈天翔
王孟
邵千秋
ZENG Yi;WANG Zheng;YANG Haohan;CHEN Tianxiang;WANG Meng;SHAO Qianqiu(The College of Nuclear Technology and Automation Engineering,Chengdu University of Technology,Chengdu 610059,China;State Grid Sichuan Electric Power Research Institute,Chengdu 610041,China)
出处
《电力工程技术》
北大核心
2025年第6期193-201,共9页
Electric Power Engineering Technology
基金
四川省自然科学青年基金资助项目(2023NSFSC0827)。
关键词
山火
绝缘距离
空气间隙
相位差
击穿机理
击穿电压
wildfire
insulation distance
air gap
phase difference
breakdown mechanism
breakdown voltage
