A Study on Excitation Inrush Current and Overvoltage Mitigation Strategies Utilizing Phase Selection Control

To address the challenges of system failures and equipment damage caused by excitation inrush currents and overvoltages during no-load energization of high-speed locomotive transformers, a simulation model was developed utilizing PSCAD electromagnetic transient simulation software. This study establishes a no-load switching simulation model for rolling stock transformers within PSCAD, analyzing variations in overvoltage and excitation inrush current amplitudes across different phase angles. Additionally, it compares excitation inrush current amplitudes under varying residual magnetism conditions. A phase-selective control strategy is proposed, integrating the hysteresis characteristics of the transformer core. The model’s accuracy is validated against empirical data obtained from a city train. Employing the Jiles–Atherton hysteresis model, the residual magnetism of the transformer core is quantified. Based on measured data, a relationship curve between switching phase and residual magnetism is fitted, enabling calculation of the optimal closing angle through the phase selection procedure. This approach effectively mitigates overvoltage and excitation inrush current hazards, thereby enhancing the operational safety of the train system.