核电厂智能化中压厂用电保护研究

Research on Intelligent Medium-voltage Auxiliary Power Protection Methods for Nuclear Power Plants

继电保护二次回路断线是核电厂最常见的故障之一,断线故障对核电机组安全稳定运行带来的挑战不容忽视。从某核电厂一次厂用母线低电压保护误动造成核功率和电功率下降的事件出发,深入分析了继电保护动作的原理和功率下降的根本原因,探讨厂用母线低电压保护设计缺陷,并提出适合核电厂应用的智能化厂用电保护方案,利用智能化保护装置编辑PT断线闭锁逻辑,使低电压保护既能保护母线一次断相的非全相运行工况,又能避免PT断线保护误动。

The secondary circuit disconnection of relay protection is one of the most common faults in nuclear power plants.The challenge of disconnection fault to the safe and stable operation of nuclear power units cannot be ignored.In this paper,based on the nuclear power and power drop caused by incorrect operation of bus low voltage protection in a nuclear power plant,the principle of relay protection action and the root cause of power drop are deeply analyzed.The design defects of low voltage protection for factory bus are analyzed,and an intelligent power protection scheme suitable for nuclear power plant application is put forward.The intelligent protection device is used to edit the PT disconnection blocking logic,so that the low-voltage protection can not only protect the non-all-phase operation condition of the busbar one-time outage,but also avoid the PT disconnection protection malfunction.