特殊工业粉尘地区复合绝缘子腐蚀失效过程研究

硅橡胶复合绝缘子因其优异的憎水性及憎水迁移性而具备较好的防污闪能力,往往作为应对污闪事故的首选方案。但在部分特殊工业粉尘地区,复合绝缘子在短时间运行后会出现爬电及蚀损现象,并发展为绝缘失效。为研究特殊工业粉尘地区复合绝缘子的腐蚀失效过程,测试了某特殊工业园区内运行的复合绝缘子的表面污秽度及污秽成分、污闪电压梯度、憎水性能及微观性能,并分析了其腐蚀失效过程。主要结论如下:绝缘子表面等值盐密为0.1~0.2 mg/cm²,其污秽成分与化工污源类似;存在自然污秽时绝缘子表面憎水性良好,但其憎水性的减弱、恢复及迁移特性均不能满足运行要求;绝缘失效的起因是电晕放电导致憎水性降低,进而导致伞裙电蚀损,最后发展为绝缘失效。

Corrosion and insulation failure process of composite insulators in special industrial dust area

Because of the excellent hydrophobicity and hydrophobicity migration, silicone rubber composite insulators have an out-standing anti-pollution flashover performance, so they are often selected as the first choice to deal with pollution flashover accidents. However, in some special industrial dust areas, creepage and electric erosion occurs on the surface of composite insulators after short-term operation, which eventually develops into insulation failure. In order to study the corrosion failure process of composite insulators operated in special industrial dust areas, the samples of composite insulators from a special industrial park are taken, and the pollution degree and pollution composition, pollution flashover voltage gradient, hydrophobicity, and microscopic properties of samples are tested. Furthermore, the failure process of the insulators is analyzed. The results show that the equivalent salt deposit density (ESDD) of insulators is about 0.1~0.2 mg/cm², and the pollution composition is similar to that in chemical industry pollution area. With natural pollution on the surface, the hydrophobicity of the insulators is great, but the hydrophobicity loss, recovery, and migration properties cannot meet the operation requirements. The cause of insulation failure is the decrease of hydrophobicity caused by corona discharge. The decrease of hydrophobicity leads to electric erosion of the umbrella skirts, and finally develops into insulation failure.