Control of Idle Losses in Power Transformers of Distribution Electric Networks

For lightly loaded electrical networks and for seasonally changing loads, it is proposed to reduce the idle losses in power transformers by changing the connection scheme of the primary and secondary winding coils provided that the transformation coefficient is constant. In this case, the transformer windings must have branches corresponding to the number of coils on the high and low voltage sides. The quantitative estimates of reducing the idle losses in power transformers by the proposed method are based on the methods of a full-scale experiment using the example of a single-phase transformer and simulation modeling of a three-phase power transformer. Circuit designs for sectioning the windings of power transformers are developed. For automatic control of losses in the transformer, an expression is obtained for reducing the total losses in the transformer by changing the connection scheme of the coils of the primary and secondary windings when the load changes. From a practical point of view, a transformer with a change in the connection schemes of its windings using the proposed method can find application as a power transformer of distribution networks with a voltage of 35, 10 (6)/0.4 kV with a load of less than 20% (summer and cottage villages, seasonal loads of industrial enterprises).