高压直流输电对山西南部地电场观测影响分析

Effect of HVDC Transmission on Geoelectric Field Observation in the Southern of Shanxi Province

为研究山西南部临汾、夏县地电场受高压直流输电的影响,分析地电场观测受干扰的变化形态与特征,结合高压直流输电干扰的机理,定量计算分析不同换流站接地极对同一台站的影响,以及同一换流站接地极对不同台站的影响。研究表明:①当地电场观测数据受高压直流输电线路干扰时,地电场会出现畸变,较典型形态为方波与两端尖峰叠加方波形态,不同的高压线路,各台站观测到的附加电场信号变化特征有很大的不同;②当高压直流输电线路运行故障而产生大地回路电流时,它对地电场观测数据可能会产生一定的影响,受同一高压直流输电影响的同一台站同一方向上长、短极距观测数据方向一致,干扰幅度基本一致;③当高压直流输电线路运行故障而产生大地回路电流时,不同台站所受干扰随着接地极与台站的距离平方成反比关系,同时还受到台站电导率的影响。

In order to study the influence of HVDC transmission on the geoelectric field in Linfen and Xiaxian seismic station of southern Shanxi Province,the variation patterns and characteristics of the interference on the geoelectric field observation are analyzed.Combined with the mechanism of HVDC transmission interference,the influence of different ground electrode on the same station and the influence of the same ground electrode region on different stations are quantitatively calculated and analyzed.The results show that:When the local electric field observation data are disturbed by HVDC transmission lines,the geoelectric field will be distorted,and the typical forms are square wave and square wave with sharp peak.The variation characteristics of the additional electric field signals observed by different stations are very different for different HVDC transmission lines.@The earth loop current caused by the HVDC transmission line may have certain influence on the observation data of geoelectric field.The observation data of long and short pole distance in the same direction at the same station affected by the same HVDC transmission line have the same direction and the interference amplitude is basically the same.When the HVDC transmission line fault causes the earth loop current,the interference of different stations is inversely proportional to the square of the distance between the ground electrode and the station,and is also affected by the conductivity of the station.