污秽中CaSO_4对典型瓷、复合绝缘子交流污闪特性影响对比分析

Comparative Analysis of the Effect of CaSO_4 in Contamination on AC Pollution Flashover Characteristics of Typical Porcelain Insulator and Composite Insulator

自然条件下输电线路绝缘子表面积污成分中含有大量的硫酸钙(CaSO_4),而污秽中CaSO_4对不同型式绝缘子的污闪特性有着不同的影响。为此,以7片XWP2-160型瓷绝缘子串和FXBW4-35/70型复合绝缘子为试品,在人工雾室中进行了人工污秽试验,对比分析了CaSO_4对这2种型式绝缘子污耐压、闪络电压梯度及泄漏电流峰值的影响差异。研究表明:随着CaSO_4质量分数的增加,这2种型式绝缘子污耐压和闪络电压梯度均递增,而泄漏电流峰值递减;不同CaSO_4质量分数下,复合绝缘子的闪络电压梯度是瓷绝缘子闪络电压梯度的1.3~1.7倍,说明复合绝缘子耐污闪性能优于瓷绝缘子;此外,在CaSO_4作用下,盐密(SCD)的改变对于瓷绝缘子污耐压的影响程度为复合绝缘子的1.0~1.2倍,而对于闪络电压梯度为0.8~1.0倍,对于泄漏电流峰值为0.2~0.6倍。研究结果可为输电线路外绝缘设计和运行维护提供参考。

A large amount of CaSO4 is contained in transmission line insulator contamination under the natural condition, and CaSO4 in contamination has different effects on the pollution flashover characteristics of various types of insulators. XWP2-160 porcelain insulator and FXBW4-35/70 composite insulators were used as test samples, and lots of artificial pollution flashover tests were conducted in artificial fog chamber to comparatively analyze the pollution withstand volt- age, flashover voltage gradient, and leakage current peak value of the two types of insulators affected by CaSO4. The results show that, with the increase of CaSO4 mass fraction, the pollution withstand voltage and flashover voltage gradient of the two types of insulators will increase, and the leakage current peak value will decrease. With the effect of CaSO4, the flashover voltage gradient of composite insulator is 1.3 to 1.7 times that of porcelain insulator, showing that the withstand pollution flashover of composite insulators is better than that of porcelain insulators. Besides, with the effect of CaSO4, the influence degree of porcelain insulator pollution withstand voltage effect by the change of SCD is 1.0 to 1.2 times that of composite insulator, the influence degree of the flashover voltage gradient is 0.8 to 1.0 times, and the influence degree of the leakage current peak value is 0.2 to 0.6 times. The research results can give a reference to the outdoor insulation design, operation, and maintenance of transmission lines.