燃气-蒸汽联合循环机组汽轮机冷态预暖控制策略优化与应用

为了缩短冷态启动过程中联合循环同轴机组汽轮机的启动时间，通过启动锅炉蒸汽对汽轮机提前预暖，解决了机组无法快速响应电网调峰的问题。根据汽轮机冷态预暖系统及机组启动方式，结合机组冷态启动历史过程及数据，进行冷态预暖系统运行特性分析试验、优化后试验及温态启动顺控试验，通过对现有控制逻辑的优化，提出了一种全新的冷态预暖控制策略。结果表明：该策略避免了机组在预暖启动过程中由于预暖管道过热度低，造成热应力准则、紧急切断阀（Emergency Shutoff Valve，ESV）无法满足启动条件、高排逆止阀自动打开以及静止变频启动装置（Static Frequency Convertor，SFC）在燃气轮机与汽轮机啮合过程中自动退出等问题；优化后机组的冷态预暖启动运行过程表明，实现机组全过程无断点的预暖及自启动控制，可有效缩短同轴联合循环机组冷态启动时间约2 h，使机组具备快速灵活的启动方式和应急调峰的能力。

Optimization and application of cold-state preheating control strategy for gas-steam combined cycle unit steam turbine

In order to shorten the startup time of the steam turbine during the cold startup process of the combined cycle coaxial unit, the steam turbine was preheated through the startup of boiler steam, which solves the problem that the unit cannot quickly respond to the peak regulation of the power grid. According to the cold state preheating system of the steam turbine and the startup mode of the unit, combined with the historical process and data of the cold state startup of the unit, the cold state preheating system operation characteristic analysis test, the optimized test and the warm state startup sequential control test were carried out. Based on the optimization of the current control logic, a new cold state preheating control strategy was proposed. Results show that the strategy can avoid the problems that the thermal stress criterion and the emergency shutoff valve (ESV) cannot meet the starting conditions, and the high discharge check valve automatically opens due to the low superheat degree of the preheating pipeline, during the preheating startup process of the unit, as well as the static frequency convertor (SFC) automatically exits during the engaging process of the gas turbine and the steam turbine; the optimized operation process of the unit during cold state preheating startup shows that the realization of the preheating and self starting control without breakpoints in the whole process of the unit can effectively shorten the cold state startup time of the coaxial combined cycle unit by about two hours, so that the unit has fast and flexible startup mode and emergency peak shaving capability.