变压器励磁涌流的相移比较鉴别方法

A NEW METHOD TO IDENTIFY INRUSH CURRENT BY PHASOR COMPARISON

为了满足现代变压器保护动作快速性的要求,针对变压器铁心饱和的过程中具有非线性特性,提出了一种利用相移比较的短数据窗算法。该方法利用前一段波形估计出的基波相量经移相后与后一段波形估计的相量相比较来判别故障和励磁涌流,并给出了具体的故障判别方案。动模试验表明:该方法原理简单、易于实现,能够迅速、可靠地切除各种情况下变压器的内部故障。

To meet the need of rapid action character in modem power transformer protection, this paper puts forward a new short window algorithm by phasor comparison. Based on the nonlinearity of transformer＇s core, the method can discriminate fault currents from inrush currents by comparing the two phasors. The first one is formed by shifting the fundamental phasor evaluated from the current data window. The latter is the phasor evaluated from the next data window. Detailed scheme for fault identification is also presented. The dynamic test shows that the new method with simple principle and easy implementation can rapidly and reliably cut all the inner faults in the power transformer.