隔雨伞对淋雨状态下复合支柱绝缘子电场的影响

Study on the Water-cut Shed's Influence on the Electric Field of Composite Post Insulators Under Wet Condition

支柱绝缘子在实际运行的降雨天气下发生闪络是影响电网安全运行的重要因素。对在运行的绝缘子加装隔雨伞是最有效的提高抗雨闪能力的措施。为探究隔雨伞参数的选择方法,文中用有限元法对加装隔雨伞的一大一小伞型复合支柱绝缘子进行建模,研究隔雨伞数量和隔雨伞伸出对一大一小伞型复合支柱绝缘子电场分布的影响,提出沿面平均场强以及空气间隙场强作为2个隔雨伞参数的选择判据。结果表明:安装隔雨伞会使得隔雨伞周围大伞与小伞之间空气间隙场强变大,其自身场强相比没有加装隔雨伞时也会增大。将仿真结果进行对比后,根据场强大小关系推荐选用以空气间隙场强为判据进行参数选择,对隔雨伞的安装以及防雨闪措施有一定的指导意义。

The flashover of post insulators in rainy weather is an important factor affecting the safety of the power grid. For the insulator in operation,installing water-cut sheds is the most effective measures to improve the anti-rain flashover ability. To explore the selection method of water-cut sheds＇ parameters,this paper uses the finite element method to establish a composite post insulator model with water-cut sheds to study the electric field distribution influenced by the number of sheds and the overhangs. The field strength of the surface of the sheds and the field strength of air gap were proposed as the criterion for selecting water-cut sheds parameters. The results show that installing water-cut sheds will make the field strength of the air gap between the nearby big sheds and the nearby small sheds stronger,and water-cut sheds＇ field strength will be stronger. According to the relationship between the field strength of surface and air gap,using the electric field of air gap as the criterion is recommended. This paper has certain guiding significance for the installation of water-cut sheds and the measures of preventing wet flashover.