变压器三角形绕组中环流的构造方法

由于Y,d接线变压器中三角形（△）侧绕组电流不易测量,使得变压器差动保护中存在电流相位补偿的问题,由此计算出的差流不能很好地反映本相励磁涌流的特征,也限制了基于等效瞬时电感变化的励磁涌流判据的应用范围。文中根据两侧绕组的电压方程,推导出△侧绕组环流与星形（Y）侧零序电压和电流之间的关系,提出了一种用于构造Y,d接线变压器中△侧绕组环流的方法,该方法与Y侧绕组接地方式无关,具有广泛的适用性。仿真与动模实验验证了该方法的正确性与有效性,结果分析表明,该方法有利于等效瞬时电感的计算及相关励磁涌流判据的实施。

Research on Constructing Algorithm of Circulating Current in Delta Winding of Transformers

For Y-delta connected transformer, the currents in delta winding are not easily measurable. So the problem of current phase compensation has to be considered in the differential protection. However, using the present current phase compensation methods, the calculated differential current cannot really reflect the characteristics of the inrush. At the same time, the application based on the equivalent instantaneous inductance scheme is limited to identify the inrush. In this study, a constructing algorithm of circulating current in delta windings is proposed based on the voltage equations of two side windings. And the relationship between the circulating current and zero-sequence voltage and current in Y side windings is also obtained. The algorithm has nothing to do with the neutral grounding, so that its application is wide. The simulation and experimental results verify that the algorithm is correct and effective to identify the inrush.