核电厂应急厂用设备停运故障分析及改进研究

Failure Analysis and Improvement Study of Emergency Plant Equipment Outage in Nuclear Power Plants

国内某核电厂出现应急厂用设备无法按要求正常停运的问题。通过故障分析及排查验证,确定故障原因为设备停运过程中6.6 kV中压开关盘经由反馈回路对设备驱动控制模件产生了电磁干扰,造成驱动控制模件过流保护动作并使输出指令截止,从而导致开关盘接触器分闸动作中断。根据故障机制,结合国内多个核电厂出现的同类型问题,对截断反馈回路干扰电流、调整开关盘二次回路动作响应时间和改变反馈回路供电方式等3种故障处理方案进行了分析比较,并给出从根本上抑制干扰和消除故障的改进措施。本研究对典型的核电厂设备间电磁干扰问题进行了根本原因分析,给出的处理方案及改进措施能够用于核电厂同类型问题的预防及处理。

In a nuclear power plant in China, the emergency plant equipment could not be shut down normally as required. Through fault analysis and verification, it is determined that the fault is caused by the electromagnetic interference of the 6.6 kV medium voltage switchboard with the drive control module via the feedback loop during the shutdown, which led to the overcurrent protection of the drive control module and cut-off of the output command, resulting in the interruption of the switchboard contactor breaking action. According to the fault mechanism, considering the same type of problems in several domestic nuclear power plants, three fault handling solutions are analyzed and compared, including cutting off the interference current of the feedback loop, adjusting the response time of the secondary circuit of the switchboard and changing the power supply method of the feedback loop, and the improvement measures are provided to fundamentally suppress the interference and eliminate the fault.This study analyzes the root cause of the typical nuclear power plant inter-equipment electromagnetic interference problem, and the treatment plan and improvement measures given can be used for the prevention and treatment of the same type of problem in nuclear power plants.