直流电压下绝缘子表面电荷分布中“电荷斑”模式的分析与研究

“Charge Speckles” Pattern in Surface Charge Distribution of Insulator under DC Voltage

在对直流电压下缩比气体绝缘金属封闭输电线路(GIL)绝缘子表面电荷进行测量时发现,绝缘子表面通常呈现两种不同的电荷分布,可分别称为电荷分布的"基本模式"和"电荷斑"模式。研究表明,"电荷斑"模式的电荷积聚机理和"基本模式"的不同,无法反映绝缘材料本体特征对电荷积聚的影响规律。为了准确地对电荷积聚特性进行量化表征,需要对"电荷斑"加以分离处理,本文对"电荷斑"形成原因进行分析,利用最大类间方差法对"电荷斑"进行分离,并对分离"电荷斑"以后的基本模式下材料本体的径向电位分布进行量化表征。结果表明,分离电荷斑以后的表征结果和实验结果以及仿真结果具有较好的一致性。

The charge accumulation on the surface of downsized GIL insulators under DC voltage usually presents two different distribution phenomena,which can be called“dominant pattern”and“charge speckle pattern”respectively.The“dominant pattern”is a larger area with uniform and gradient charge distribution,and the“charge speckle pattern”usually consists a number of speckles or stripes.Experiments show that the charge accumulation of the“charge speckle pattern”is different from the“dominant pattern”,which fails to represent the essential characteristics of the charge accumulation of the insulator.In order to quantify the characteristics of charge accumulation accurately,the“charge speckles”need to be separated.In this paper,the reasons for the formation of“charge speckle”are analyzed,the maximum inter-class variance method is proposed to separate“charge speckles”.At last,the“dominant pattern”charge distribution after the separation of“charge speckles”is quantitatively characterized.The analysis shows that the characterization results are in good agreement with the experimental and the simulation results.