Determining Intensity of Radial Deformation and Axial Displacement of Transformer Winding Using Angular Proximity Index

Transfer function method is a widely-used technique to detect mechanical defects of transformer winding. Although TF is emerging as a powerful diagnostics technique, there is still no general guideline for interpreting measured TFs. The present paper is an attempt to diagnose intensity of radial deformation (RD) and axial displacement (AD) of transformer winding through a vector space perspective, using transformer’s transfer function. To determine the intensity of winding deformation or displacement, the angular proximity index is used. The measurement results show the effectiveness of this index. The angular proximity index constructs a nearly linear mapping between any TF curve and its defect intensity. The results are verified using experiments and compared with the other well-known index, i.e., correlation coefficient.

Keywords:

Power transformer , Transfer function (TF) , Radial deformation (RD) , AxiaL displacement (AD) , Vector space model , Arc-cosine similarity measure (ACSM)