降雨条件下球电极表面电晕放电特性的试验研究

Experimental Study on the Effects of Raindrops on Corona Discharge on the Surface of Spherical Electrodes

降雨会改变电极表面的电晕放电特性,分别以直径10 cm、20 cm、30 cm及50 cm的均压球为研究对象,在试验室内人工模拟了大、中、小三种不同降雨强度,研究了球电极表面雨滴分布及对电晕放电的影响。研究表明:电晕放电会改变雨滴的形态及位置,使其更接近半球体,位置分布趋于均匀;雨水的存在会使球电极起晕电压明显降低,且表现出一定的极性效应,试验用四种球电极负极性比正极性起晕电压低0~20 k V左右;放电强度会随着球电极直径的增加而减弱,同时随着雨量的增加而增强;雨滴会造成球电极表面电晕放电强度出现间歇性变化;电压降低的过程中,电晕放电强烈程度明显弱于加压过程。电场仿真表明随着雨量增加,电极下表面雨滴径向距离会减小而轴向距离增加,雨滴附近局部场强畸变程度增加,起晕电压降低。

Raindrops remaining on the surface of shielding electrodes will affect corona discharge characteristics.This paper took spherical electrodes with diameters of 10 cm,20 cm,30 cm and 50 cm as research objects to study the distribution of raindrops on the surface of spherical electrodes and its influence on positive and negative corona discharge in heavy,moderate and light rain.Results show that the corona inception voltage of negative is about 0~20 kV lower than positive voltage;the corona discharge will change the shape and position of raindrops and make it more hemisphere-like and even-distributed;the discharge intensity will decrease with the increase of electrode diameter and increase with the enhancement of rainfall;raindrops can cause intermittent change of corona discharge intensity.When lowering the voltage,the intensity of corona discharge is obviously weaker than that of applying voltage.The research show that with the increase of rainfall,the radial distance of raindrop decreases and its axial distance increases,which enhances the local field intensity distortion and lowers the corona voltage.