汽轮机DEH转速控制模式下的节能优化

降低运行成本、提质增效、节能减排是目前火电行业的迫切需求。阐述汽轮机组数字式电液控制系统（digital electric-hydraulic control system，DEH）在转速控制模式下普遍存在的启机暖机时间长、暖机不充分、汽缸温升率较难控制以及甩负荷后操作复杂、转速难以稳定、短时间内重新并网困难等问题。从汽轮机调节汽门、控制机构入手，分析机组启动暖机的加热过程及甩负荷后的动态过程，对比现有技术的利弊，总结得出在机组启动过程中阀位函数设置不合理、甩负荷后DEH转速控制模式与旁路阀门特性不匹配是导致上述问题的根本原因。提出一种汽轮机DEH转速控制模式下的变阀位函数的优化方法，该方法能够实现自动暖机和机组甩负荷后的快速并网，在提高机组安全性的同时，保障机组的经济性，极大减轻了运行人员的工作压力及工作量。

Energy-Saving Optimization of Steam Turbine DEH under Speed Control Mode

Currently thermal power industry calls for the operation cost reduction, quality and efficiency improvement as well as energy-saving and emission reduction urgently. In this paper, the problems that have been existing in digital electric-hydraulic control system (DEH) speed control mode widely are discussed in terms of long start-up duration, inadequate warming-up process, difficult control over cylinder temperature rise rate, the complex operation, unstable speed and unsuccessful re-connecting to the grid in a short time after load rejection. Starting with the regulating valve and control mechanism of steam turbine, the heating process and dynamic process after load rejection are analyzed. By comparing the pros and cons of the existing techniques, the unreasonable settings of valve position function during the start-up process and the mismatch between DEH speed control mode and bypass valve characteristics after load rejection are concluded as the root causes of the above problems. At last, an optimization method of variable valve position function in steam turbine DEH speed control mode is proposed, which can realize automatic warming-up and fast grid-connection of the unit after load rejection. Therefore it can improve the security of the unit while maintaining its economic performance. In addition, the operators' workload is greatly reduced and their stress at work is relieved.