特殊污秽环境下±660kV直流线路铵盐积污特性

Ammonium Contamination Deposited Characteristics of ±660kV DC Transmission Lines in Special Pollution Environment

银东直流线路是我国自主研发的首条±660kV电压等级的高压直流线路,自投运以来1894号耐张塔多次发生异常放电事故。为了分析1894号杆塔异常放电的原因并得到铵盐的积污规律,对银东线上事故杆塔和参照杆塔的污秽度和污秽成分进行了测量与分析。结果表明:事故杆塔1894号的绝缘子污秽成分中实际运行状态下的等值盐密值最大且上、下表面污秽分布最为均匀,为造成其异常放电的主要原因。污秽成分中铵盐占比表现为沿绝缘子串呈U型分布,且下表面占比高于上表面,极II侧占比高于极I侧,复合绝缘子表面铵盐占比高于钟罩形绝缘子。

The Yin-Dong HVDC transmission line is the first ±660kV HVDC transmission line constructed by China. Since the implementation of Yin-Dong line, abnormal discharge accidents have occurred repeatedly on No.1894 strain tower. In order to analyze the reasons of abnormal discharge of No.1894 tower and get the law of contamination of ammonium salt, we measured and calculated the pollution degree and pollution composition of the accident tower and the reference tower on the Yin-Dong line. The results show that the main reasons of abnormal discharge of No.1894 are its highest ESDD in the actual operating state and lowest non-uniform pollution ration. And the proportion of ammonium salt of the insulators’ surface pollution on No.1894 pole tower is obviously higher than that of other pole towers. The ammonium salt proportion presents a U-shape distribution along the insulators. And the proportion of proportion of ammonium salt on lower surface is higher than that on the upper surface, the polar II is higher than polar I, and the composite insulators are higher than porcelain insulators.