一起电流互感器变比超差原因分析及应对措施

Cause Analysis and Countermeasures of a Current Transformer Ratio Out of Tolerance

对一起电流互感器在交接试验中出现变比超差的原因进行分析,根据电流互感器外观检测情况、绝缘电阻测量结果及出厂试验数据复核情况,初步排除电流互感器变比超差为本体异常所致,通过进一步对变比测量原理和影响变比误差因素进行综合分析,得出变比超差原因为铁心存在剩磁。为此提出了通过调整接线方式来消除剩磁的方法,该方法保证了电流互感器变比测量的准确性,同时验证了电流互感器变比超差为剩磁所致这一判断。

The reason for the change ratio of the current transformer in the handover test is analyzed.According to the appearance inspection of current transformer,insulation resistance measurement results and factory test data review,it is preliminarily excluded that the out of tolerance of transformation ratio of current transformer is caused by body abnormality.Through the comprehensive analysis of the transformation ratio measurement principle and the factors affecting the transformation ratio error,it is concluded that the reason for the transformation ratio out of tolerance is the residual magnetism of the iron core.Therefore,a method of eliminating residual magnetism by adjusting the wiring mode is proposed,which ensures the accuracy of current transformer transformation ratio measurement,and verifies the judgment that the excess of current transformer transformation ratio is caused by residual magnetism.