单轴燃气-蒸汽联合循环机组FCB控制策略研究与应用

Research and Application of FCB Control Strategy for Single-shaft Gas-steam Combined Cycle Unit

为强化本地支撑电源建设,提高应对突发因素造成的大面积停电事故,广东电网对联合循环机组孤网运行能力及“黑启动”功能提出了明确要求。依托某燃机电厂二期基建调试项目,开展了两套AE94.3A型燃气-蒸汽联合循环“一拖一”单轴式机组快速甩负荷(fast cut back,简称FCB)试验。试验模拟了电网外送回路故障,机组通过快切线路断路器,最终实现了汽机跳闸,燃机快速切负荷、输出功率降至带厂用电的“孤网运行”目的,试验过程各参数变化平稳,主辅机设备均为安全停运,试验取得了较好的效果。通过对汽机旁路系统、锅炉过热/再热减温水系统、汽包液位系统、凝结水及真空系统、轴封系统等的控制策略进行针对性的优化与完善,使得机组具备了完整可靠的FCB功能,显著增强了电源侧供电可靠性。相关经验可供后续同类机组参考。

In order to strengthen local power supply construction and improve the response to large-scale power outages caused by unexpected factors,Guangdong Power Grid has put forward clear requirements for the isolated operation capacity and"black start"function of combined cycle units.It relies on the second phase infrastructure debugging project of a certain gas turbine power plant to carry out two sets of AE94.3A gas steam combined cycle"one driven one"single shaft unit fast cut back(FCB)tests.The experiment simulated a fault in the external transmission circuit of the power grid,and the unit achieved the goal of"isolated grid operation"by quickly switching the circuit breaker of the power grid.The steam turbine tripped,the gas turbine quickly cut off the load,and the output power was reduced to with plant power.During the experiment,all parameters changed smoothly,and the main and auxiliary equipment were safely shut down.The experiment achieved good results.Through targeted optimization and improvement of control strategies for steam turbine bypass system,boiler overheat/reheat cooling water system,steam drum liquid level system,condensate and vacuum system,shaft seal system,etc.,the unit has complete and reliable FCB function,significantly enhancing the reliability of power supply on the power side.Relevant experience can be used as a reference for similar units in the future.