Mathematical Modelling and Analysis of Power Transformer during Abnormal Conditions

Abstract

Single phase and three phase power transformer mathematical models are presented. The models allow the simulation of disturbances which cause undesirable relay operation. The simulation results include inrush magnetizing current, internal fault conditions. The transient waveforms generated under different operating conditions are discussed. The simulation is used to illustrate how the proposed transformer modeling enhances the power transformer protection performance, the model is able to differentiate between inrush current and internal fault condition by sensing 2nd order harmonic contents in the primary current waveform. The differential equations are solved and simulated using MatLab/Simulink tool.