采用交流互感器测量变压器中性点直流分量的方法

A method of measuring neutral point DC component of transformer using AC transformer

提出了一种利用交流互感器检测变压器中性点直流分量的方法。先利用相关系数的饱和识别方法判断交流互感器是否饱和,然后找到变压器中性点交流互感器测得的三次谐波含量与中性点直流分量对应的关系曲线(饱和关系曲线或不饱和曲线)进行查找,最后得到与此三次谐波含量对应的直流分量。比较该直流分量的大小,通过告警或跳闸来保护变压器,防止事故扩大。所提方法不需要增加额外的一次设备,简单易行。

This paper presents a method of measuring neutral point DC component of transformer using AC transformer. First, the method of saturation recognition based on correlation coefficients is used to judge whether the AC transformer is saturated or not. The third harmonics content is measured by the neutral point AC transformer. Through the relation curve （saturated curve or unsaturated curve） between the third harmonics content and neutral point DC component, the DC components corresponding to the three harmonic content can be obtained. Comparing the size of DC component, the expansion of the accident is prevented by alarming or tripping. This method does not need to add an extra equipment, and it is simple and worthy of promotion.