500kV电容式电压互感器顶端接地对分压电容C_2的影响

The Affect of 500kV CVT′s Top Terminal Grounding on the Dividing Capacitance C_2

在新建变电站的验收中,发现电容式电压互感器(CVT)顶端接地对分压电容C2的测量值产生了影响。通过对测量C2时原理接线图的分析,知道由于顶端接地,每次测得的电容值C2均需要除以校正系数K值后,方能够得到准确的实际值,再进行前、后数据比较,可以保证每次所测得的电容值前、后具有可比性,并能够准确地判断CVT的绝缘状况是否良好。

In the acceptance test of new built substation, it is found that the 500kV CVT＇ top terminal grounding will affect the dividing capacitance Cz. Through analysis on the connection principle of measurement, it is concluded that, due to such grounding, the reality value of C2 must be corrected by a coefficient K. In each measurement, the measured value of C2 should be divided by K, and the values gotten from different measurements should be compared and analyzed, thus the insulation of CVT can be determined accurately.