覆冰绝缘子串的交流闪络特性和放电过程

为了解长串绝缘子在高海拔下的冰闪特性,在气候室内对XP-70、XWP2-160绝缘子串和FXBW4-110/100合成绝缘子进行了人工覆冰电气试验研究。结果表明:气压对覆冰绝缘子串冰闪电压的影响与污秽绝缘子的相似,3种绝缘子的气压影响指数分别为0.64、0.55和0.69;在不同气压下冰闪电压与绝缘子串长均呈线性关系;绝缘子串覆冰以后的电压分布发生变化且受冰的状态的影响,这个变化是覆冰绝缘子串电气特性下降的主要原因;覆冰绝缘子串的局部电弧发展成完全闪络所需的时间比污秽绝缘子长,且受冰层的融化和冰凌状态的影响;覆冰绝缘子的临界闪络电流大于污秽绝缘子,且与绝缘子串长和类型有关,其原因有待进一步研究。

AC Flashover Performance and Discharge Process of Iced Insulator Strings

The ice flashover performance is one of key issues of the outdoor insulation selection of transmission lines passing icing regions.Based on the artificial icing and electrical tests in the climate chamber,the paper studies the AC flashover performances and mechanism of XP-70 and XWP2-160 insulator strings as well as FXBW4-110/100 composite insulator under the icing condition and in the high altitude region.The experimental results show that the effect of air pressure on the flashover voltages of iced insulator strings is same as the effect on polluted insulators and the exponents of the three types of insulators,and the effects of air pressure on the flashover voltages are 0.64,0.55 and 0.69,respectively.There is a linear relationship between the ice flashover voltage and the length of the insulator string at various air pressures.The voltage distribution of insulator string has changed after icing,which is affected by the ice states.The change is the main reason causing the decrease of electric performance of the iced insulator string.The development of partial arc on iced insulators surfaces needs more time than that on polluted insulators surfaces and is affected by the melting of the ice and shapes of the icicles.The leakage current of the iced insulator is higher than that of polluted insulator,and the leakage current is related with the string length and type of insulators.