直流GIL中柱式绝缘子附着金属微粒对表面电荷积聚的影响研究

Effect of Metallic Particles in DC GIL on Surface Charge Accumulation of Insulators

针对直流GIL封闭输电线路中金属微粒污染的现象,在充分考虑金属微粒对绝缘子表面电荷分布影响的基础上,建立了含金属微粒的柱式绝缘子表面电荷积聚时变数学模型,采用COMSOL仿真分别分析了金属微粒、电压幅值、电压极性及其共同作用对直流GIL绝缘子表面电荷积聚动态过程的影响。研究结果表明:绝缘子表面法向电场强度与表面电荷分布密切相关;金属微粒与电极直接接触的绝缘子表面呈现与接触电极相同的电性,与绝缘子中部接触的绝缘子表面位置呈现与微粒所对应电极相反的电性;随着电压幅值的增加,附着金属微粒的绝缘子表面电荷积聚现象愈加严重;随着电压极性的改变,附着金属微粒的绝缘子相同位置处的表面电荷密度大小相等、电性相反;当电压极性发生反转时,绝缘子表面法向电场强度增加、切向电场强度减少。

Aiming at the phenomenon of metal particle contamination in DC GIL closed transmission line and considering the influence of metal particles on the surface charge distribution of insulators,a time-varying mathematical model of surface charge accumulation of column insulators containing metal particles was established.The paper uses COMSOL simulation to analyze the effects of metal particles,voltage amplitude,voltage polarity and their interaction on the dynamic process of surface charge accumulation of DC GIL insulators.Research indicates that the normal electric field strength of the insulator surface is closely related to the surface charge distribution;when metal particles contact with the electrode directly,the insulator surface presents the same electrical properties as the contact electrode,and when contacting with the middle of the insulator,the surface presents the opposite electrical properties;as the voltage amplitude increases,the surface charge accumulation phenomenon of the insulator attached to the metal particles becomes more serious;as the polarity of the voltage changes,the surface charge density at the same position of the insulator to which the metal particles are attached is equal and opposite in electrical polarity;when the polarity of the voltage is reversed,the normal electric field strength of the insulator surface increases and the tangential electric field strength decreases.