Reduction of Magnetizing Current of Power Transformer Due to Optimal Location of Concentric Windings

Abstract

Electric power passes several times through transformers on its way from generation to consumers. Therefore, the issue of reducing losses in transformers is very topical. When the transformer is operating under load, the stray magnetic fields of individual windings lead to iron saturation of individual sections of the magnetic circuit or vice versa, unload the magnetic circuit. This affects the magnitude of the magnetizing current under load, and the arrangement of the windings directly effects it. The effect of the mutual arrangement of concentric windings on the value of the transformer magnetizing current under load is investigated. As a primary, first the short-range winding was used, and then the long-range winding was used. The transformer was switched on both of them for the active and inductive loads. Measurement of the magnetizing current under load was made by a patented method with the use of specially calibrated shunts in the primary and secondary circuits. It is revealed that the primary winding of the transformer with concentric windings is optimally arranged further away from the magnetic circuit. This will allow to reduce the magnetizing current when working under load and to reduce iron losses.