一起500kV电容式电压互感器的故障处理及原因分析

Treatment and Analysis of 500kV Capacitor Voltage Transformer Fault

针对一起500kV线路电容式电压互感器(CVT)二次电压异常的故障,通过现场试验和解体检查,查明造成CVT二次电压异常的原因是由于CVT中补偿电抗器两端并联的保护避雷器故障,绝缘下降所致。通过相量定性分析了CVT中的保护避雷器故障后CVT二次输出电压数值偏小、相位超前的原因;并结合设备试验数据,定量分析了二次输出电压随负载的变化情况。

As for the abnormality of secondary voltage of 500kV capacitor voltage transformer (CVT)in operation,it is checked clearly by way of site inspection and disassembly at factory that the cause for such abnormality is due to the protection arrester with both ends of the compensation reactor in CVT fault and insulation strength reduction of arrester.The reasons that the secondary voltage value of CVT is small and the phase lead in CVT are qualitatively analyzed by the phasor.Combined with the test data of the equipment,the secondary output voltage of fault CVT with load is quantitatively analyzed.