为提高热电联产机组深度调峰工况下的供热稳定性及安全性,本文首先以某35万千瓦超临界燃煤机组为例,分析了旁路供热改造对汽轮机本体及旁路系统的安全边界影响,然后提出了应用于热电联产机组供热高、低旁阀组的联动控制及连锁保护逻辑方案。该方案在高、低旁阀组的供热调节过程中实现了安全参数等级限制,并按报警、闭锁、超驰、保护分级别连锁高、低旁阀动作,同时还考虑了特殊工况下各调节阀的自动与手动切换条件。通过在案例机组的实际应用,该方案有效提高了旁路供热系统运行的安全可靠性,保证机组电负荷降至120.7MW时供热抽汽量仍可达到352.1t/h,增强了机组的深度调峰及热电解耦能力。

In order to improve the heating stability and safety of combined heat and power unit under depth peak load cycling, In this paper, Firstly, the influence of bypass heating transformation on the safety boundary of the turbine and bypass system is analyzed baesd on a 350MW supercritical coal-fired unit. On this basis, the linkage control and protection logic scheme applied to high and low pressure heating bypass valves of combined heat and power unit is formed. The scheme can realize the level limit of security parameters in the heating adjustment process of high and low pressure bypass valves, which can interlock high and low pressure bypass valves according to alarm, lock, overdrive and protection levels. Furtherly, the automatic and manual switching term of each regulating valve under special working conditions is considered. Through the practical application in the case unit, the scheme effectively improves the safety and reliability of the bypass heating system. At last, the lower limit of the unit"s electrical load can be reduced to 120.7MW when the capacity of heat supply can still be maintained at 352.1t/h, enhancing the depth peak load cycling and heat-power decoupling capacity of the unit.

TK02