特高压换流站直流滤波电容器故障分析研究

针对常发的直流滤波器用直流电容器损坏事故,本文对特高压换流站直流滤波电容器事故的机理和原因进行深入的研究,对电容器单元进行了外观和电性能测试、绝缘油色谱试验、电容量介质损耗测量.对解剖后的电容器元件绝缘包封、电容器元件不同温度下直流电压击穿、聚丙烯薄膜不同温度下交直流电压击穿、铝箔等进行了研究试验.通过对故障和完好电容器对比试验研究,发现所测电容器的部分生产工艺和注油工艺不佳造成运行中电容器不稳定,而电阻过于集中,导致电阻器表面绝缘介质过热,容易发生击穿故障,研究结果对提高该类型电容器的运行可靠性具有重要意义.

Study on Fault Analysis of DC Filter Capacitor for UHV Converter Station

As for the frequently happened damage of DC filter capacitor, in this paper, the fault mechanism and reason of DC filter capacitor for UHV converter station are studied and such tests as appearance and electrical performance, chromatography of insulation oil and capacitance dielectric loss of capacitor unit are performed. And such research tests as DC voltage breakdown of insulation entrapment of disassembled capacitor element and capacitor element at different temperature, AC and DC voltage breakdown of polystyrene film at different temperature as well as aluminum foil etc are carried out. It is found throughout comparative test and study between the faulty and good capaci-tors that instability of capacitor in operation is due to weak partial manufacturing process and oil fill-ing process of the tested capacitor, and over concentration of resistance leads overheat of dielectric medium on surface of resistor and easy breakdown. The study result has important magnificence in improving operation reliability of such type of capacitor.