一起因励磁涌流导致的主变差动保护动作分析与防范措施

Analysis and Prevention Measures of a Differential Protection Action of the Main Transformer induced by Excitation Inrush Current

从电网设备操作的实例出发,对500 k V变压器空载充电过程中产生较大励磁涌流的机理进行了理论分析,揭示出此次主变空载充电为何未能躲过励磁涌流影响而导致主变差动保护动作的真实原因,通过相关的录波、保护动作、并结合现场实际阐述励磁涌流出现的原因及特征,得出了主变差动保护的动作原理,并提出了一些改良和防范的措施。

A differential protection action of the 500 kV main transformer induced by excitation inrush current during the no-load charging process is investigated. The mechanism of the large excitation inrush current during the no-load charging process is analyzed theoretically. Based on the recorder information and the in-situ situation, causes and characteristics of the excitation inrush current are summarized. Also, the principles of the differential protection action of the main transformer is determined. Then, prevention and improvement measures are proposed correspondingly.