The Analysis And Research Of Transformer’s Shielding Method

With the increase of transformer capacity, enhancing the leakage magnetic fieldwill enhance, and significantly increase the stray loss of core structures and oil tank. Inthe most, the stray loss is from the eddy current loss. In order to avoid localoverheating problems which caused by the loss, reduce the magnetic leakage flux intothe metal structural parts, by mean of installing shielding in oil tank wall. But when theshielding structure is unreasonable, errors of the shielding effect often occur, even leadto local overheating. thereby affect the safe operation of transformer. Therefore,studying of the leakage magnetic field,determination of reasonable shielding way andthe structure for the transformer is necessary.Firstly this article introduces the Maxwell’s equations of electromagnetic fieldtheory, the finite element method for solving electromagnetic field problems isdiscussed. Then the transformer leakage magnetic field is analysised, then understandthe reason of leakage magnetic field occur.Illustrate type of magnetic leakage field thatwill be researched in this paper, Describe the effect from leakage magnetic field to thetransformer.Electrical shielding, magnetic shielding, electromagnetic shielding are thecommon method in shield form for transformer. In order to analyze the effect ofdifferent transformer shielding incourse of the application.Based on the differentoutput wire on the high side, select two products and go on analysis. Model parametersof the two transformers are the same basically. Just because the high-voltage wire isdifferent forms (one end part outgoing line, another central line), caused two kind ofshielding method respectively (electrically shielded and magnetic shielding).In order to obtain the distribution of leakage magnetic field and loss structuralparts, the magnet model is established and carry out electromagnetic simulation. At thesame time, the simulation results are analyzed. Summarize the shielding effect ofdifferent structural characteristics. Base on these, obtain some guiding conclusion intransformer shielding design.