500kV断路器均压电容器介质损耗超标分析

摘要

针对目前变电站中500 kV高压断路器均压电容器在10 kV试验电压下介损试验值超标的现象,对均压电容器的特性进行分析,并在实验室进行了升高试验电压下介质损耗试验.试验数据分析表明:在均压电容器中存在Garton效应.加上现场的高电压及强磁场的干扰,常规10 kV介质损耗试验电压远低于额定电压,很难真实反映均压电容器的绝缘缺陷.而升高试验电压或额定电压下的介损试验可以反映绝缘内部潜在缺陷的类型和发展情况,可以消除Garton效应的影响,更真实地反映均压电容器在运行状况下的介质损耗情况,该方法对于500kV高压断路器均压电容器的现场试验和绝缘分析有较大的参考价值.%To solve the problem of hyper-scaling dielectric loss of grading capacitors for 500 kV high voltage substation breakers under the test voltage of 10 kV, characteristics of the capacitors were analyzed and dielectric loss tests under a higher voltage more than 10 kV were conducted in a laboratory. The experimental data shows that the Garton effect existed in the capacitors is the cause for the problem. In addition to the high voltage and magnetic field interferences, a test with a normal voltage of 10 kV much lower than the rated voltage cannot reflect the real insulation condition of the capacitors. However, by raising test voltage or conducting the test under rated voltage, the influence of Garton effect can be eliminated, and the real insulation condition of capacitors in the normal working environment can be surveyed. This method may provide references for field tests and analyses of grading capacitors of 500 kV breakers.