Parameters of Single-Phase Two-Windings Power Transformer

Abstract

The paper presents the fundamental differential equations of single-phase two-windings power transformer. These equations takes into account the mutual leakage induction of primary and secondary windings and permits to built a vector diagram, from which follows such conclusion: no – load voltage of secondary winding is larger than no-load electromotive force of this winding. In the paper have been shown, that primary and secondary windings are coupled by two magnetic fluxes: the main magnetic flux which flows across the magnetic circuit of the ferromagnetic; and other leakage magnetic flux, which flows through the air. Also there is shown that leakage induction of the transformer windings depends on the load factor, if the load factor has minimal value (no-load duty), the leakage inductances are largest, and when the load factor has maximal value (short-circuit duty), the leakage inductances has minimal values. The calculation method of transformer primary and secondary windings leakage inductive reactances is presented. The difference between the short-circuit inductive reactances values, calculated using the classic method and author’s recommended is about 16%.