基于波形不对称特征的变压器励磁涌流识别新方法

通过对变压器各种情况下波形特征的分析,提出一种利用平行四边形平行度检验变压器是否发生励磁涌流的新方法。当励磁涌流时,波形呈现出严重的上下及前后半波不对称,构成出的四边形很不规则;而变压器发生内部故障时,所构成的四边形则近似为平行四边形,所以通过平行度的大小可以有效区分变压器励磁涌流和内部故障。动模试验分析结果表明,该方法是可靠的,即使对轻微匝间故障也有足够的灵敏度。

A Novel Method to Identify Inrush Current Based on Asymmetric Characteristics of Waveform

Analyzing the waveform characteristics of transformer in various situations, this paper proposes a new method to identify whether inrush currents happen in transformer. When inrush current happen, the waveform is in asymmetry on up and down or left and right so seriously that an irregular quadrilateral appears. In contrast, while internal faults happen, the quadrilateral is out of shape only slightly. Therefore, the degree of parallelism of quadrilateral could be taken as an index to identify inrush currents and internal faults. The experimental results indicate that the proposed method is reliable, and sensitive even to the turn to turn faults of low level.