中国电机工程学报2011，Vol.31Issue(34)：163-170,8.
500kV输电线路的山火击穿特性及机制研究
Study on Forest Fire Induced Breakdown of 500kV Transmission Line in Terms of Characteristics and Mechanism
摘要
Abstract
Forest fires near power transmission lines always threaten the reliability of transmission lines and safety of power grids.Combining video record of the 500kV transmission line fire induced flashover and breakdown characteristics of rod-plane gap under wood crib fires,the flashover mechanism of 500kV line under forest fires was investigated.Results are as follows： the dielectric resistance increases with the height of flame due to temperature that affects the thermal ionization of alkali mental salts;the breakdown strength of rod-plane gap under wood crib fire is reduced to 23% of that air gap under standard atmosphere;flame temperature,conductivity and particles such as smokes and flying ashes promote the electronic avalanches and streamers development and lead to the dielectric strength reduction of the transmission gap acutely;pre-discharges initiated by flying ashes and smoke are connected to flame tip and promote the burning of fire.Electrical arc enhances the fire intensity and lifts the height of flame.Based on field records and experimental results,it is concluded that flame temperature,flame conductivity and flying ashes are ascribed to factors leading to transmission line flashover due to fire.Measures to reduce transmission line breakdown under forest fire such as increasing height of transmission line conductors above ground,restricting the vegetation species,height and density near transmission line corridors are proposed.关键词
超高压/输电线路/山火击穿/外绝缘Key words
extra high voltage（EHV）/transmission lines/fire induced flashover/external insulation分类
信息技术与安全科学引用本文复制引用
吴田,阮江军,胡毅,刘兵,陈成..500kV输电线路的山火击穿特性及机制研究[J].中国电机工程学报,2011,31(34):163-170,8.基金项目
国家电网公司重大科技项目（SGKJJSKF20090567) （）
