摘要
某核电厂设计了给水泵跳闸后在无备用给水泵情况下机组将自动甩负荷的控制逻辑,经过分析该控制逻辑存在设计缺陷。机组满功率运行期间,3台给水泵运行,1台备用,在该平台执行泵切换操作期间,存在4台给水泵同时运行情况,若其中1台给水泵跳闸,此时无备用泵可用,将导致机组甩负荷至65%Pn,造成机组出力损失612MW,但是剩下的3台给水泵其实是能满足满功率蒸汽发生器供水需求的。在发生机组甩负荷瞬态后,当前控制逻辑存在较大给水泵意外启动的风险,会导致蒸汽发生器水位波动或威胁给水泵附近人员安全。结合上述实际工程中的设计缺陷,通过全面分析,制定了合理的逻辑优化方案,在模拟机和真实机组上进行了一系列再鉴定工作,确认优化后逻辑能够解决发现的设计缺陷。该控制策略优化的成功实施,消除了机组发生甩负荷瞬态后给水泵误启动风险,降低了机组在特殊工况运行期间由于给水泵跳闸直接引发跳堆的风险,同时也避免了机组在满功率平台执行给水泵切换过程中不必要的甩35%Pn(612MW)负荷风险。
In one nuclear power plant, the automatic load shedding logic is designed in case of no available backup BFP after the trip of a running BFP. Some design defects are found after analysis. In normal full power operation, 3 pumps are running and 1 is in standby. The pumps change-over will lead to 4 pumps in operation at the same time. If one pump trips accidently it will trigger load shedding signal to 65%Pn as no additional pump is available. It will result in a loss of 612MW. But as we know, the rest of 3pumps are enough to provide the feed water to steam generator. The current logic also has a high risk of accidental start of the BFP after turbine load shedding, which will lead to the fluctuation of steam generator water level or threaten the safety of people near the BFP. In combination with the design defects in the above practical engineering, a reasonable logic optimization scheme is developed through comprehensive analysis. A series of reappraisal works are carried out on the simulator and the real unit to confirm that the optimized logic can solve the design defects. The successful implementation of the control logic optimization can avoid BFP false start after load shedding. It reduces the risk of reactor trip caused by BPF trip during special conditions, and also can prevent an unnecessary 35%Pn(612MW) load shedding during pumps change-over in normal full power operation.
作者
何生文
He Shengwen(Taishan Nuclear Power Joint Venture Co.,Ltd.,Guangdong,laishan,529200,China)
出处
《仪器仪表用户》
2022年第8期77-81,104,共6页
Instrumentation
关键词
给水泵
甩负荷
控制逻辑
优化
feed water pump(BFP)
load shedding
control logic
optimization
