某超超临界660MW燃煤机组FCB试验不成功原因分析及改进

Cause Analysis and Improvement of an Unsuccessful FCB Test on 660 MW Ultra-Supercritical Coal-Fired Unit

对某超超临界660 MW燃煤机组在首次甩负荷试验时,超速保护动作跳机原因进行分析,得出上汽西门子机组/Ovation系统组合DEH甩负荷控制逻辑较复杂及控制器站间通讯点扫描时间较长,使在发电机解列信号发出后,高中压调阀跳闸电磁阀收到跳闸指令时间较长,进而调阀关闭时间滞后,造成机组超速跳机。对此,提出增加发电机解列后直接使高中压调阀跳闸电磁阀失电1 s,缩短发电机解列信号发出后跳闸电磁阀接收信号时间,使得快速甩负荷试验成功。

Cause analysis is made for the trip of over-speed protection action in the first FCB test on one 660 MW ultra-supercritical coal-fired unit. As indicated,in the SAIC Siemens /Ovation system combined unit,DEH load shedding control logic is complex and the scan time of communication points between controller stations is long. Consequently,after the generator's splitting signal is issued,the trip electromagnetic valve in low-/medium-voltage adjusting valve receives the trip command after a longer time,then adjusting valve closes with time lag,causing the unit over-speed trip. Therefore,this paper proposes to directly de-energize the trip electromagnetic valve for 1s after the generator's splitting to shorten signal-receiving time and ensure the FCB test success.