一起500 kV油浸式电抗器故障调查及防范措施分析

作为电力系统重要的无功补偿设备,高压并联电抗器能够补偿输电线路的电容效应,具有调节无功和电压的作用。运行中电抗器故障将对输电网络的安全稳定构成严重威胁,因此分析其故障成因对维护电网安全具有重要意义。针对一起500 kV油浸式高压并联电抗器故障,基于油色谱中特征气体成分分析、气体含量比值计算、特征气体增长趋势分析及返厂前设备特征气体计算等方法对其故障成因进行剖析。然后通过直流电阻、绝缘及介损、振动、噪声和温升试验等诊断试验进一步排查,综合运用绕组检查、铁心检查、连接部位检查、样品检测分析等研判出本次事故原因为电抗器铁心硅钢片间绝缘不良。最后提出了相应的防范措施,为同类型高压并联电抗器的制造工艺管控、故障诊断和运行维护提供参考。

Fault analysis and preventive measures for a 500 kV oil-immersed reactor

As an important reactive power compensation device in a power system,the high voltage shunt reactor has the function of compensating for the capacitance effect of a transmission line,regulating reactive power and voltage.A reactor fault in operation will pose a serious threat to the safety and stability of the power grid,and so it is of great significance to analyze the cause of a fault for the maintenance of power grid security.A fault on a 500 kV oil-immersed high voltage shunt reactor is analyzed based on the component analysis of characteristic gas in the oil chromatogram,the calculation of gas content ratio,the trend analysis of characteristic gas and the characteristic gas calculation of the device before return to the factory.Diagnostic tests of DC resistance,insulation and dielectric loss,vibration,noise and temperature rise etc.are carried out for further investigation,and it is concluded that the cause of the accident is poor insulation between silicon steel sheets of reactor core,this being achieved by employing winding inspection,core inspection,connection part inspection,sample detection and analysis.Finally,corresponding preventive measures are presented,providing reference for process control,fault diagnosis and maintenance of the same type of high voltage shunt reactor.