Analysis Of Harmonic Loss And Thermal Problems On Transformer

Harmonic is one of steady state disturbances which can influence the electric powerquality.In the modern power system,with the development of power electronictechnology and electrified railway and the extensive use of industrial electricalequipment,more harmonic are get into the power system,and bring serious consequencesto the electric power quality.Transformer plays an important role in the power system,andhas accessed to a wide range of applications in every domain of electric powerengineering.Because of the reason of technology and economy,single capacity of thetransformer become bigger and bigger,thus more attention is bring up to theloss,temperature rise and the hottest of transformer.The harmonic current of powersystem can make the transformer’s copper loss and stray loss increases,the outer shell,silicon steel sheet and some fasteners fever,and can cause transformer noise increases,reduce transformer rated capacity,life and reliability.Therefore analysis of harmonic lossand thermal problems on transformer has the important practical significance.This thesis analyzes the winding loss,hysteresis loss and eddy current loss intransformer caused by harmonic generation.With the theory of electromagnetic field intransformer and the finite element analysis theory,we make an analysis on the magneticleakage in transformer,and the magnetic field distribution, harmonic loss and temperaturerise of transformer iron core, winding and other structural parts,by establishing thethree-dimensional model of transformer.Then we obtain the the relationship between thetransformer’s loss and temperature rise and harmonic frequency, and the distribution ofthe core of main channel’s axial magnetic field density,and the distribution of hot spots ofwinding and iron core.That has a vital significance to reducing the loss of the transformer,prolonging the service life of the transformer, and guaranteeing the safe and stableoperation of power system.