等腰三角形界面缺陷对复合绝缘子电场分布的影响

Influence of Isosceles Triangle Interface Defects on Electric Field Distribution of Composite Insulators

复合绝缘子内部界面缺陷引起的故障对电网的安全稳定运行造成了极大威胁。为研究不同形状的缺陷及其尺寸和水气浸入对绝缘子电场分布的影响,本文提出了一种包含曲率半径参数的等腰三角形缺陷模型,建立了500 kV复合绝缘子三维模型,并使用COMSOL对不同形状、尺寸和水气比例的缺陷进行电场仿真和对比。结果表明:等腰三角形缺陷模型能更好地反映出缺陷向低压侧发展的趋势;缺陷的尖端曲率半径对气隙没有明显影响,但水隙存在尖端效应;随着缺陷中水分含量的上升,场强最大值逐渐增大。在尖端效应和水气浸入的作用下,低压侧尖端的场强严重畸变,增大了局部放电可能性,使其向低压侧发展的速度加快。

The faults caused by internal interface defects of composite insulators is a great threat to the safe and stable operation of power grid. In order to study the influence of different shapes of defects and their sizes and moisture immersion on the electric field distribution of insulators, an isosceles triangle defect model including tip curvature radius parameter was proposed. A 3D model of 500 kV composite insulator was established, and the electric field of defects with different shapes and sizes and moisture ratio were simulated and compared by the COMSOL. The results show that the isosceles triangle defect model can better reflect the tendency of defect developing to the low voltage side. The tip curvature radius of defect has no obvious effect on the air gap, but there is a point effect in the water gap. With the increase of moisture content in the defect, the maximum electric field strength increases gradually. Under the action of point effect and moisture immersion, the electric field strength at the tip of low voltage side is distorted severely, which increases the possibility of partial discharge and accelerates its development to the low voltage side.