Frequency Response Analysis for Transformer Winding with Improved Equivalent Circuit

Frequency response analysis(FRA) is currently one of the most effective methods to diagnose transformer winding deformation. In this paper, the FRA is applied to power transformer in different winding states, in which the equivalent circuit is improved. The geometric model of the transformer with detailed winding is established, and the electrical parameters of the transformer are calculated by magnetic and electric field finite element analysis respectively. The capacitance between the non-adjacent disk and the winding is added in the traditional transformer equivalent circuit and the frequency response curve for different winding states are calculated by using the improved equivalent circuit.

I. Introduction

The power transformer is a critical equipment of the power system, and its reliable and stable operation is essential for the safety of the power grid. Transformer failure may lead to power outage, which will have a serious impact on economic development, manufacturing and daily life [1]. Data shows that transformer winding deformation is a primary factor leading to transformer failures [2]. Therefore, it is of great significance to implement effective detection methods to find winding deformation in time, preventing further deterioration and ensure the safe operation of transformers.