光滑导线直流起晕电压判别方法对比分析

Comparisons of Methods for Determining Corona Onset Voltage of Smooth DC Conductors

直流电晕放电会产生空间电荷、离子流场、无线电干扰、可听噪声及电晕损耗等效应,为了研究根据不同的直流电晕放电效应得到的起晕电压差异,搭建了基于同轴圆柱结构的电晕放电起晕电压测试平台,同时测量了不同直径光滑导线电晕放电产生的离子流、合成电场、稳态电晕电流及紫外光子数随电压的变化关系,依据各物理量随电压变化的拐点确定了正、负极性光滑导线的起晕电压。实验结果表明,对于光滑导线,通过不同电晕放电效应借助于拐点法得到的起晕电压基本一致。根据同轴圆柱离子流场的解析公式及起晕场强的经验公式,对导线的起晕电压进行了计算,不同直径的起晕电压的计算结果与测量结果基本一致,最大差异<2.1%。因此,对于实验室内光滑导线起晕电压的确定,建议采用同轴圆柱电极结构对电晕放电效应进行测量,推荐采用拐点法来确定起晕电压。

The multiple corona effects,such as space charges,ionized field,radio interference,audible noise and corona losses,etc,can be generated along with the corona discharge.In order to investigate the differences of corona onset voltages generated by different corona effects,a platform using the cylinder corona cage for determining the corona onset voltage was set up.The ion current densities,ionized fields,steady corona current,and ultraviolet photons from smooth conductors with different diameters were measured simultaneously in the experiments.Comparisons of the corona onset voltages from different corona effects are given through the inflexion-point method.Besides,numerical simulations for the corona onset voltage are also presented on the basis of the analytical formulas for ionized field of cylinder structure and the empirical formulas for onset electric field.The calculated results of the corona onset voltages for different conductors can match the measured ones,and the maximum error is less than 2.1%.Therefore,we proposed to use the cylinder corona cage to measure the multiple corona effects and to use the inflexion-point method to determine the corona onset voltage for the smooth conductor.