补偿电抗器限压MOA对CVT介损测试的影响分析

Effect Analysis of Protective MOA of Compensation Reactor on CVT Dielectric Loss Test

就CVT补偿电抗器限压MOA对CVT介损测试的影响进行分析,得出相关结论:MOA支路的存在会使CVT总电容介损测试结果偏小,严重时会出现负介损的情况。造成该现象的原因是限压MOA支路的存在改变了流入测试电桥Cx端的电流相位。这种由MOA支路引起的测量误差无法通过提高测试电压的方法消除,而且由于MOA器件的非线性伏安特性,提高测试电压还会导致误差不减反增。为了保证CVT整组电容介损测试结果的准确性,建议在测试时拆除限压MOA。

The paper analyzes effect of protective MOA of compensation reactor on dielectric loss test of CVT and draws a conclusion as follow： MOA branch makes the value of dielectric loss test of CVT smaller than the true value; what＇s worse, dielectric loss will be negative in severe cases. The reason of this condition is that the phase of signal current flowing in Cx terminal of electric bridge is changed by protective MOA branch.Such measurement error caused by MOA branch cannot be eliminated by rising up test voltage; in addition,the error may become larger by test voltage rise because of the nonlinear current voltage characteristics of MOA parts. To ensure that the test dielectric loss test result of the entire reactor bank is accurate, it is suggested to remove the protective MOA during dielectric loss test of CVT.