孙海东,刘斌,姜华,王哲,邢钢
SUN Haidong,LIU Bin,JIANG Hua,WANG Zhe,XING Gang

• 1:内蒙古电力(集团)有限责任公司乌兰察布供电分公司

摘要(Abstract)：

针对一起110kV变压器差动保护越级跳闸事故，分析事故前变电站的运行方式及事故跳闸的经过，通过核对现场接线情况，判断主变压器低压侧电流互感器二次回路接线有误，并对区外相间短路故障造成变压器差动保护误动的两种原因进行了向量计算，判定事故原因为出线发生相间短路故障，断路器跳闸失败，短路故障扩大到主变压器，主变压器低压侧二次电流回路相序接反，造成变压器差动保护装置动作。最后提出加强电流互感器及其二次回路的验收工作、重视差动保护投运后带负荷检查等防范措施建议。
Aiming at a 110 kV transformer differential protection over tripping accident, the operation mode of the substation before the accident and the process of accident trip are analyzed in this paper. By checking the wiring on site, it is judged that the secondary circuit of the current transformer on the low-voltage side of the main transformer is incorrectly wired,and the vector calculation is carried out for two reasons of transformer differential protection maloperation caused by external phase-to-phase short circuit fault. It is determined that the cause of the accident is the phase-to-phase short circuit of the outgoing line, and the circuit breaker failed to trip. The short circuit fault extended to the main transformer, and the phase sequence of the secondary current circuit on the low-voltage side of the main transformer is reversed, therefore causing the action of the transformer differential protection device. Finally, some preventive measures are proposed, such as strengthening the acceptance of current transformers and their secondary circuits, and paying attention to the on-load inspection after the differential protection is put into operation.

关键词(KeyWords)： 变压器;差动保护;电流互感器;相间短路;二次回路;相序
transformer;differential protection;current transformer;phase-to-phase short circuit;secondary circuit;phase sequence

Abstract:

Keywords:

基金项目(Foundation):

作者(Author): 孙海东,刘斌,姜华,王哲,邢钢
SUN Haidong,LIU Bin,JIANG Hua,WANG Zhe,XING Gang

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