硅橡胶复合绝缘子运行寿命的试验研究

为评估运行中硅橡胶复合绝缘子安全寿命,提高供电可靠性,从上海电网中实际运行的线路上,选取运行年限>10a的110kV硅橡胶复合绝缘子作为试验研究样品绝缘子,通过对其表面特性及工频和冲击电压的试验研究,并辅助硅橡胶材料的微观试验,分析和探讨硅橡胶复合绝缘子运行寿命特性、电气和机械性能的综合因子老化规律,评估运行中硅橡胶复合绝缘子安全运行状态。研究结果表明:在硅橡胶材料表面特性正常的情况下,其工频和冲击电压试验的干、湿闪电压较接近并与外绝缘结构有关;当硅橡胶材料表面特性老化时,其干、湿闪络电压出现差值,表现出与材料表面特性有关。

Test Research on Operation Life of Silicon Rubber Composite Insulators

In this paper, the researching-test specimens of 110 kV silicone rubber (SR) composite insulators are sampled from 110kV power transmission system of East Shanghai Electrical Power Supply Co. which had been operated over 10 years. The operation life, electrical and mechanical characteristics of operating aged SR composite insulators as well as phenomena of SR aged caused by multi-factors are discussed and analyzed based on surface characteristic test of SR composite insulators, power frequency voltage test, impulse voltage test, electric-microscope and scan electric-microscope inspection. Safe operation life of SR composite insulators may be evaluated according to these results of tests in this paper. The fruits of research and tests proves that dry flashover voltages of power frequency voltage test and impulse voltage test are a little different from wet flashover voltages of power frequency voltage test and impulse voltage test. The range depends on external-insulation structure of SR composite insulators if the insulators are normal. But the range becomes larger when the insulator is aged and polluted because flashover voltages depends on surface characteristic of SR composite insulators. At the same time, low-density contamination that adhered to the SR jacket of composite insulators tightly, aging micro-crack on the surface of insulator SR jacket and many granules that filled in the SR material are verified by surface resistance test, electrical microscope and scan electrical microscope inspection. On the other hand, eyeballing and hand feeling lets us know that the aged SR material is much fragile, color is fading, surface is crackle and metallic connector is rust badly. Relative to 20 years safe operation life design of normal SR composite insulator, these specimens show that their aging is not deviant. The reason causing SR early aging and aging principle may be researched more detailed in the future. It is proposed that this batch of SR composite insulators should be replaced as soon as possible in this paper.