直流电压下复合绝缘子表面电荷积聚的仿真研究

Simulation of Surface Charge Accumulation on Composite Insulator Under DC Voltage

随着特高压电网的建设,复合绝缘子以其优异的性能已被大量采用,然而表面电荷积聚将导致其沿面闪络电压下降,影响电网运行的稳定性。为了研究表面电荷的积聚效应,建立了复合绝缘子二维轴对称模型,并使用COMSOL软件对该模型进行了研究。研究表明:伞群表面是电荷积聚的主要位置,当其积聚电荷的极性不同时,对原电场分布的影响也不同。分析认为,负极性电荷积聚为电子越过伞群向前发展创造了有利条件,缩短了爬电距离,这可能是导致复合绝缘子闪络电压下降的原因;又对表面电荷积聚情况进行了实验测量,结果表明表面电荷积聚将改变电子的积聚位置,确实可能缩短爬电距离。

With the construction of UHV grid, composite insulator has been widely used, however surface charge accumulation will make its flashover voltage drop. In order to study the surface charge accumulation effect, a two-dimensional axisymmetric model of composite insulator is established, and analyze this model with the software COMSOL. The results show that umbrella surface is the main position of surface charge accumulation, when the polarity of accumulated charge is different, the effect to the electric field is different. The negative charge accumulation shorten the creepage distance, it may be the cause of flashover voltage drop. At last, the composite insulator surface charge accumulation were measured, confirmed the presence of surface charge will change the electron accumulation position, it may shorten the creepage distance.