A new method for analyzing the impact of winding mechanical defects on the equivalent circuit parameters of power transformers

Abstract

Condition monitoring of the power transformer winding and diagnose of the fault in its incipient stages can prevent the spread of defect, and as a result, the unexpected exit of the transformer. Correct and accurate perception of the effects of each defect or winding deformation on the detailed or any other model parameters is essential. In this article, a software based on finite element method is used, in order to increase accuracy of the study to model the transformer in healthy and defected cases. Three types of winding mechanical deformation, that is, axial displacement, radial deformation, and disc space variation , have been simulated for different locations and extents. From the simulation of the finite element model in the healthy and other defected cases, R, L, and C matrices are obtained for each case. Each of the above matrices in defected cases has been compared with the corresponding matrix of the healthy case. The amount and manner of the above matrices’ element variations have been investigated in detail, might help the fault classification in terms of the type, extent and location, and risk assessment of using the transformer in the current defective situation.