核电厂仪控系统电磁流量计集成控制柜改造

Reformation of Integrated Control Cabinet for Electromagnetic Flowmeter for I&C System in Nuclear Power Plant

针对用于核电厂核取样系统流量测量的涡轮流量计在运行过程中故障频发的问题,进行了流量计换型改造,以电磁流量计替代涡轮流量计进行核取样介质流量测量。首先,对电磁流量计测量原理和基本组成进行了阐述,介绍了在换型改造期间集成控制柜中电磁流量计流量显示异常的现状,并采用示波器对电磁流量计励磁信号和电极信号进行了测试分析,确定了励磁正常但电极信号受到较大干扰的问题。然后,对电极信号干扰源作了较为全面的排查分析及逐一验证,进而提出集成控制柜的整体改造方案,并对改造后的集成控制柜进行了低电导率介质情况下的流量测量准确度测试。测试结果表明,该设计满足现场测量要求。改造后的集成控制柜已在核电厂机组稳定运行,改造效果较好,可为相关行业类似控制柜的设计提供参考。

Due to frequent malfunctions of the turbine flowmeter used for flow measurement in nuclear sampling system of nuclear power plant,electromagnetic flowmeter was used instead of turbine flowmeter for flow measurement of nuclear sampling medium.Firstly,the measurement principle and basic composition of the electromagnetic flowmeter were expounded;The situation of abnormal flow display of the electromagnetic flowmeter in the integrated control cabinet during the transformation was introduced;The excitation signal and electrode signal of the electromagnetic flowmeter were tested and analyzed by oscilloscope.The problem that the excitation is normal but the electrode signal is disturbed greatly was determined.Then,the interference source of the electrode signal was comprehensively analyzed and verified one by one,and then the overall transformation plan of the integrated control cabinet was proposed.The flow measurement accuracy test under the condition of low conductivity medium was carried out,which results show that the design met the requirements of on-site measurement.The modified integrated control cabinet has been in stable operation in the nuclear power plant,and has achieved good results.It can provide reference for the design of similar control cabinets in related industries.