基于虚拟磁通与差动电流特性识别变压器励磁涌流

IDENTIFICATION OF TRANSFORMER MAGNETIC INRUSH CURRENT BASED ON VIRTUAL FLUX AND DIFFERENTIAL CURRENT CHARACTERISTICS

在定义虚拟磁通的基础上,根据虚拟磁通对于差电流的曲线在发生励磁涌流和发生内部短路故障情况下在中心对称性上具有明显区别的特征,提出了一种基于计算虚拟磁通的识别励磁涌流和内部短路故障的方法。虚拟磁通只需要根据绕组端电压测量值就可以容易计算。虚拟磁通与差电流的关系曲线的中心对称性特征只需要1个至2个工频周期就可以准确判断。在硬件实现差动保护控制模块的基础上进行了动模试验,结果表明所提出的新方法可以快速、可靠地识别励磁涌流和内部短路故障。

Based on the definition of virtual flux given in this paper, a new method for identifying the magnetic inrush current with internal short circuit fault is proposed. It is achieved by calculating the virtual flux from measured voltage at winding terminals and judging from the centrosymmetry of the virtual flux versus differential current curve. This is because the curve in the case of the internal short circuit fault is almost centrosymmetric. The calculation of the virtual flux is easy and the time needed for the judgment is only one to two power periods. After developing a hardware control module, dynamic power system tests are carried out and the results show that the proposed method is reliable and efficient in distinguishing the magnetic inrush current from the short circuit fault current.