Single-Phase Transformer Circuit Solving using Harmonic Interpolation Method

The aim of this paper is to present a way of solving in the time domain an electrical circuit with a single-phase transformer. The considered circuit consists of an AC power supply, a ring-shaped transformer and a resistor in the transformer primary and secondary circuit. Three working regimes of the transformer have been considered – when it is loaded and when it is close to no-load and short-circuit working conditions. Calculations have been made at industrial frequency of 50 Hz using an iterative procedure based on Harmonic Interpolation Method (HIM) and Bertotti’s Statistical Theory of Losses (STL). The obtained results are compared with the results calculated using an equivalent transformer circuit and well-known RL model. The details regarding the calculation procedures, measurement setup and results, the comparison of the calculated results, as well as their appropriate analysis, are presented in this paper.