基于暂态负荷的变压器保护一次电流检验方法

Primary Current Test Method for Transformer Protection Based on Transient Load

当测试负荷不足时,一次电流检验电流互感器(TA)二次回路的工作就无法完成,常造成新建变压器保护不能正常投入。为解决这一问题,提出一种采用电动机启动电流或变压器励磁涌流等暂态电流检验TA二次回路的方法。分析了变压器流过暂态负荷时两侧电流之间的关系,并根据不同接线组别对电流进行重构,以使两侧电流呈现比例关系。引入信号相关函数对电流波形进行分析计算,得到变压器两侧TA相对于基准间隔的相角差和变比,从而判定TA二次回路的正确性。该方法在工程现场检验结果与传统稳态负荷检验方法一致,证明了其可行性和正确性。

When test load is insufficient,the current transformer(TA)secondary circuit test by primary current cannot be completed,which often results in the failure of new transformer protection to be put into normal operation.In order to solve this problem,a method for testing TA secondary circuit by using transient current such as motor starting current or transformer magnetizing inrush current is presented.The double-side current relationship of the transformer is analyzed with transient load flowing,and the current is reconstructed according to different wiring groups so that the currents on both sides are proportional.The signal correlation function is introduced to analyze and calculate the current waveform,and the phase angle difference and transformation ratio of TA on both sides of the transformer relative to the reference bay are obtained,thereby determining the correctness of TA secondary circuit.The engineering test results of the proposed method are consistent with that of traditional steady-state load test method,which proves its feasibility and correctness.