Digital Simulation of Magnetizing Inrush Currents in Three-Prase Transformers

An accurate simulation of magnetizing inrush currents is an important prerequisite for digital protection of power transformers. Generalized analytical expressions have been developed to simulate three-phase inrush currents based on sequence impedance and mutual coupling methods. The digitally simulated waveforms are compared with those obtained experimentally in a laboratory model transformer. There exists a reasonably close agreement between the computed and measured values.