Transformer Winding Deformation Diagnosis Based on Signal Distance

Aiming at the problem that the current frequency response method still lacks an effective tool for consistent quantitative evaluation in data analysis, and the correlation coefficient method cannot judge the deformation of the transformer winding when the measured frequency response curve is the same as the reference frequency response curve with the different amplitude, this paper proposed a new method for diagnosing transformer winding deformation based on signal distance. The method can accurately judge whether the winding is deformed and the degree of deformation according to the mutual distance value [0, 1] by calculating the mutual distance between the measured and the reference frequency response curve. Through simulation and combined with the power industry judgment criteria, the mutual distance degree judgment criteria of transformer winding deformation are obtained. Simulation results show that this method has high sensitivity, reliability and universality.

I. Introduction

Power transformer is an important upstream equipment of power system, and winding deformation of transformer is one of the main causes of damage accidents^[1]. Sweep Frequency Response Analysis (SFRA) is one of the most widely used methods. The frequency response data contains a large number of important information that can reflect the characteristics of the transformer winding and related to deformation ^[2].