Electric Field Analysis of the Insulation Structure of Power Transformer

Electric field and dielectric conditions were analysed in an oil immersed power transformer. The particularity of the transformer’s design we are dealing with is an attempt to eliminate the stress-control ring above the low voltage (LV) winding. Using the finite element method (FEM) we analysed the steady state electric field that suited conditions during dielectric test with a separate AC source. In the paper is also discussed the evaluation and analyses of other possibilities to form an adequate electric field with simple constructional elements at the ends of the windings. Therefore we evaluated the influence that the radius of conductors, thickness of paper insulation, and additional insulation elements have on electric field strength in the critical places.