3D Finite Element Analysis of the Stray Loss in Power Transformer Structure Parts

Yan Li,Longnv Li,Bo Zhang,Yongteng Jing

doi:10.4236/epe.2013.54b207

Abstract

In order to analyze the leakage magnetic field and stray loss in power transformer, leakage magnetic field and stray loss in structure parts of a power transformer are calculated by three-dimensional (3-D) non-linear time harmonic finite element method (FEM). The results show that stray loss and loss density in structure parts are large and which may lead to local overheating and affect performance of the transformer. The magnetic shields are used to reduce the stray loss and loss density of power transformer. Effects of these shields on stray loss and loss density of structure parts are discussed. The results show that stray loss and local overheating can be reduced and eliminated effectively by adding magnetic shields. It provides some references for the analysis of stray loss and optimization design in transformer.

Highlights

Power transformer is the core of energy conversion and transmission in power network, which is the most important and expensive equipment
The results show that stray loss and loss density in structure parts are large and which may lead to local overheating and affect performance of the transformer
The results show that stray loss and local overheating can be reduced and eliminated effectively by adding magnetic shields

Summary

Introduction

Power transformer is the core of energy conversion and transmission in power network, which is the most important and expensive equipment. With the increase of capacity of the transformer, the magnetic leakage field is increasing which may enlarge the stray loss in the structure parts of power transformer. In the large power transformer, leakage magnetic field generated by the winding current will produce losses in the metal structure parts, and these losses is part of the transformer load losses, it often tend to local overheating because of its unevenly distribution. According to the continuity condition of B/H between silicon steel sheet and air, the permeability of magnetic shields along lamination direction (y-direction) can be described as the following equation: Clamp. The eddy current generated in the silicon steel sheet near the winding side can not be ignored, the model of conductivity:. The average eddy current loss of time-harmonic field can be governed by following equation: pe.

Verification of Calculation Method

Calculation and Analysis of Loss

Calculation and Analysis of Loss by Adding Magnetic Shields

Magnetic Shields Effect on Structure Parts of Leakage Magnetic Field

Findings

Conclusions