Analysis and improvement on the failure of block of magnetizing inrush current criterion in PST—1200U
WANG Chanyuan1, KONG Ming2
1. Danyang Power Supply Company, State Grid Jiangsu Electric Power Co.,Ltd, Zhenjiang, Jiangsu 212000; 2. Zhenjiang Power Supply Company, State Grid Jiangsu Electric Power Co.,Ltd, Zhenjiang, Jiangsu 212000
Abstract：The PST—1200U series transformer protection device based on waveform symmetry principle has an internal threshold value. When the secondary value of excitation inrush current is lower than the internal threshold value of the device, the protection device does not distinguish it from the excitation inrush current and treats it as a general differential current. If the startup setting of differential protection is less than threshold value, it will form a blocking “dead zone” for excitation inrush current, leading to differential protection false tripping of the switch. This article analyzes the reasons for the blocking “dead zone” of excitation inrush current, provides corresponding solutions and verifies them through on-site tests and actual airdrop transformers.
王婵媛, 孔茗. PST—1200U差动保护励磁涌流判据失效原因分析及改进[J]. 电气技术, 2024, 25(11): 81-84.
WANG Chanyuan, KONG Ming. Analysis and improvement on the failure of block of magnetizing inrush current criterion in PST—1200U. Electrical Engineering, 2024, 25(11): 81-84.
2024, Vol. 25 
