Accident analysis of opposite-side line trip caused by no-load energization of a 220 kV main transformer
ZENG Jingjing1, QI Zhenyu2
1. Nanjing Power Supply Company, State Grid Jiangsu Electric Power Co., Ltd, Nanjing 210019; 2. Extra-High Voltage Branch, State Grid Jiangsu Electric Power Co., Ltd, Nanjing 211100
Abstract：This paper presents an accident where the line protection at the opposite substation operated and tripped as a result of the magnetizing inrush current generated during no-load energization of a 220 kV main transformer. The cause of the protection operation is identified through analysis of protection device reports, fault recorder waveforms and the characteristics of the transformer magnetizing inrush current, in conjunction with the operating conditions of the primary system and relevant transformer parameters. In response to such typical faults, targeted preventive recommendations are proposed to mitigate the impact of main transformer magnetizing inrush current on line protection, so as to enhance the operational stability of the power grid during the commissioning or reinstatement of main transformers.
2026, Vol. 27 
