INVESTIGATION OF MAGNETIZING INRUSH CURRENT IN TRANSFORMERS .1. NUMERICAL-SIMULATION

Measurements of transformer inrush currents offer important data for a power systems operation and protection. Since inrush currents result from systems transient, it is difficult to observe and analyze. This paper proposes a simple method to simulate the magnetizing inrush currents using real time measurements. The proposed method formulates a simplified model to represent the inrush current under different loading conditions. A digital simulation method is proposed using a PC-AT micro computer. Transformer operating conditions, including transformer loading power factors, switching-on angles, and remanent flux, are also included. The simulation results are compared with experiment results with very good agreements.