智能功率变送装置输出共模电压对机组运行的影响

Influence of Common Mode Voltage Output by Intelligent Power Transmitter on Unit Operation

本文针对某电厂1000MW发电机智能功率变送装置4~20mA信号输出回路存在共模电压,超出了DEH系统测量模件的抗干扰能力,DEH系统发电机功率信号测量值大幅跳变,触发热工逻辑,造成机组跳闸的事件进行原因分析,提出抑制共模电压和提高DEH系统抗干扰能力的处理措施,防止再次发生类似事故。

This article analyzes the cause of the unit trip event that there is a common mode voltage on the 4-20 mA signal output circuit of the intelligent power transmitter of 1000 MW generator in a power plant,which exceeds the anti-interference ability of DEH system measuring module,leads to a sharp change of the measured value of the generator power signal of DEH system,and triggers the thermotechnical logic,causing the unit trip,proposes the handling measures to suppress common mode voltage and increase the anti-interference ability of DEH system to prevent the re-occurrence of the similar accident.