某核电厂变压器零差保护跳闸案例分析  

Case Analysis of Transformer Zero-Sequence Differential Protection in NPP

作　　者：陆建莺 王丽 LU Jianying;WANG Li(State Nuclear Electric Power Planning Design&Research Institute Co.,Ltd.,Beijing 100095,China)

机构地区：[1]国核电力规划设计研究院有限公司,北京100095

出　　处：《电力勘测设计》2024年第S01期32-37,共6页Electric Power Survey & Design

摘　　要：变压器零序差动保护作为反映变压器单相接地短路故障的主要保护,其误动问题使其应用颇为谨慎。从一起核电厂备用变低压侧零差保护跳闸案例出发,通过查看事件发生时故障录波装置的记录波形和动作时序、查验现场设备实时状态、分析保护跳闸发生前后的零序电流值以及对现场保护整定的定值进行核算,考虑到中压大功率电机启动方式对回路不平衡电流的影响,分析认为本案例保护动作与大功率电机启动方式和变压器零差保护的定值控制逻辑方式有关。又对其他几种零序差动保护原理进行比较,提出在工程实际应用中变压器零序差动保护定值设置时需注意的几点问题。Zero-sequence differential protection of transformer is the main protection principle reflecting the single-phase grounding short circuit fault of transformer,which is applied cautiously.Starting from a case of zero difference protection tripping on the low-voltage side of a backup transformer in a nuclear power plant,by examining the recorded waveform and action timing of the fault recording device at the time of the event,checking the real-time status of the on-site equipment,analyzing the zero sequence current values before and after the protection tripping,and calculating the set value of the on-site protection,considering the impact of the starting mode of the medium voltage high-power motor on the unbalanced current of the circuit,it is analyzed that the protection action in this case is related to the starting mode of the high-power motor and the set value control logic of the transformer zero difference protection.With comparing with several other principles of zero-sequence differential protections,problems which need to be attention in the application of transformer zero-sequence differential protection are put forward.

关 键 词：零序差动保护 零序电流 制动特性 

分 类 号：TM623[电气工程—电力系统及自动化] TM64