界面微气隙大小对复合绝缘子绝缘性能的影响

Influences of Micro-gap's Size at Partial Interface on Insulation Performance of Composite Insulator

为了给复合绝缘子制造、安装和运行提供技术指导,对复合绝缘子界面微气隙周围的场强及电位分布进行了研究。通过对实例中复合绝缘子界面局部微气隙进行三维建模计算,分析微气隙内部场强电位分布、芯棒-护套界面上的场强分布及伞裙边场强电位分布随微气隙大小的变化规律。结果表明,随着界面局部微气隙的变化,复合绝缘子电场、电位分布均发生改变,且气隙越大,气隙附近的场强畸变越严重;气隙大小对电场的影响远大于对电位的影响;存在界面微气隙后,场强畸变最严重的部位是芯棒-护套界面,该处最易发生放电;此外,随气隙的增大,伞裙边场强分布整体呈增大趋势,增加了复合绝缘子界面放电的可能性。

In order to provide technical guidance for composite insulator manufacturing,assembling and operating,the field strength and the potential distribution around a micro gap,which lies at the interface of composite insulators,were researched.A composite insulator with a local micro-gap in interface of high voltage side is modeled in 3Dand the distribution of electric field and potential is analyzed.Then the changing laws of field strength and potential distribution in the micro-gap,at the mandrel-field jacket interface and on the umbrella skirt of test insulator with changing micro-gap size are explored.The result shows that the changing micro-gap size in the interface of mandrel-field jacket,the electric field and the potential distribution of the test insulator will also change together;while the greater gap is,the more aberrant field strength near the gap is;micro-gap has much larger influence on electric field than on potential;the worst aberrant lies at mandrel-jacket interface,where it is easy to discharge under the work voltage;in addition,as the size of micro-gap increases,the field intensity of the umbrella skirt presents a trend of overall increase,which could increase the possibility of flashover on the surface of composite insulator.