抑制高压直流瓷和玻璃绝缘子铁帽电解腐蚀的保护锌环设计

Designing for the Protection Zinc Ring to Suppress Electrolytic Corrosion of Porcelain and Glass Insulators' Iron Caps on HVDC Transmission Lines

近年来,中国多条高压直流输电线路瓷绝缘子出现铁帽腐蚀现象。结合现场腐蚀情况,对铁帽腐蚀的机制及危害进行了深入的理论分析和试验研究。从概率统计学角度进行考虑,结合铁帽电解腐蚀模拟试验结果、现场腐蚀绝缘子年均腐蚀电荷量的测量结果以及不同类型绝缘子的铁帽结构尺寸,对3种典型铁帽结构直流瓷和玻璃绝缘子自带锌环的结构尺寸进行了优化设计,并采用Auto CAD软件计算了不同结构、不同吨位绝缘子锌环的尺寸及质量。研究结果表明:直流瓷和玻璃绝缘子铁帽电解腐蚀的主要危害是加速绝缘件表面积污,降低绝缘子的污闪电压,在铁帽帽檐安装保护锌环能够解决其电解腐蚀问题。模拟试验结果证明了所述锌环设计方案的有效性和可行性。

In recent years, electrolytic corrosion on porcelain insulators’ iron caps has occurred in many HVDC transmission lines in China. With the corrosion situation on site taken into consideration, the mechanism and harmful effects of iron caps’ electrolytic corrosion were studied and analyzed in this paper. On the basis of probability and statistics, the structures and sizes of zinc rings for three typical categories of insulators were designed optimally according to the electrolytic corrosion simulation test results, field measurement results of corroded insulators’ annual quantity of electric charge and the iron cap structures of different kinds of insulators. Meanwhile, the sizes and weights of zinc rings on insulators of different tonnages and structures were calculated by means of AutoCAD. The results indicate that the main harmful effect of iron caps’ electrolytic corrosion is that it accelerates pollutant accumulation and decreases the pollution flashover voltage. Installing zinc ring can solve the corrosion problem of iron cap and the test results of insulators with zinc rings verify the effectiveness and feasibility of the zinc ring design methods proposed in the paper.