风沙环境下绝缘子闪络特性及机理研究

Study on Flashover Characteristics and Mechanism of Insulator in Wind-sand Environment

风沙环境中绝缘子会发生不正常的闪络现象从而严重威胁输电线路运行安全。为了深入理解风沙环境下绝缘子的闪络特性,文中利用实验的手段研究了风速、沙流量以及沙粒直径对绝缘子闪络特性的影响规律。实验结果发现风速对绝缘子闪络电压的影响是非线性的,随着风速的增加,绝缘子闪络电压呈现先升后降的趋势;同时发现增加沙流量和增大沙粒粒径均会降低绝缘子闪络电压。为进一步理解风沙环境下的绝缘子闪络机理,通过理论推导与试验验证相结合的方式证明气流场中绝缘子闪络过程受到气吹效应和低气压效应共同作用;通过仿真分析发现沙流量增加使得绝缘子附近电场畸变加剧,增大沙粒直径使得沙粒周围空间最大电场强度增加,导致电场不均匀度增大并降低了闪络电压。

Insulators in the wind-sand environment will have abnormal flashover phenomenon,which seriously threaten the safe operation of the power transmission line.For in-depth understanding the flashover characteristics of insulators in wind-sand environment,the effect law of wind speed,sand flow and sand diameter on the flashover characteristics of insulators are studied by means of experiment in this paper.It is found by the experimental results that the influence of wind speed on the insulator flashover voltage is nonlinear.As the wind speed increases,the flashover voltage of the insulator shows the tendency of rising first and then falling.At the same time,it is found that the increase of sand flow and sand diameter will reduce the flashover voltage of insulators.In order to understand the flashover mechanism of the insulator further,it is proved by the combination of theoretical derivation and experimental verification that the flashover process of insulator in the airflow field is affected by both air-blowing effect and the lowpressure effect.It is found through simulation analysis that the increase of sand flow will increase the electric field distortion around the insulator.Increase of the diameter of the sand keeps the maximum electric field strength increased around the sand,which leads to an increase unevenness in electric field and a decrease in the flashover voltage.