基于误差估计的变压器励磁涌流识别原理

提出了一种利用波形特征来区分励磁涌流和内部故障新方法。该方法利用励磁涌流为具有间断角的尖项波这一特征，通过比较半个周期时间窗内的实际波形与两个不同频率的参考波型的相似程度来区分励磁涌流和区内故障。动模实验表明：该方法能够快速切除各种情况下的变压器内部故障，保护动作速度达10～13ms。

A NEW METHOD TO IDENTIFY INRUSH CURRENT BASED ERROR ESTIMATION

A novel scheme is proposed, which is based on error estimation for identification of magnetizing inrush and internal fault conditions in transformers. Because the inrush current is a peaked wave with dead angle, we can discriminate the internal fault current from inrush current by comparing the similarity between actual wave and two reference waves under two different frequency conditions in half cycle. Experiment results indicate that this technique is effective under different fault conditions, and the action speed can reach 10~13ms when internal faults happens in transformers.