Investigation of a sinusoidaly supplied transformer under linear and non-linear loading conditions

This paper investigates the effects of harmonics on core and windings of a sinusoidal supplied transformer for two different loading conditions: linear and nonlinear. When harmonics exist, transformer variables, such as core resistance current, magnetic inductance current and excitation current, become non-sinusoidal. This means that the core resistance and magnetic inductance shows nonlinearity under harmonics conditions. In addition, core loss (P_fe), magnetizing reactance reactive power loss (Q_xm), primary and secondary windings resistance power losses (P_cu1, P_cu2) and primary leakage reactance power losses (Q_cu1, Q_cu2) can be obtained. In effects, these nonlinear variations lead to extra power loss and currents in transformer, which should be taken into account during transformer design.