【作者】 赵卫正；

【导师】 梁庆华； 罗磊；

【作者基本信息】 上海交通大学 ， 机械设计及理论， 2012， 硕士

【摘要】 本文对多工况条件下汽轮机阀门组控制性能进行了深入研究,分别对小网工况下的单阀控制、顺序阀运行下多阀协调控制以及甩负荷工况下阀门快关的超速保护进行了性能分析与优化,主要研究内容如下:(1)采用机理建模法建立了小网工况下基于转速反馈的单阀控制仿真模型,分析了小网工况下采用大网工况的控制策略存在的问题,得出转速反馈环节DEH运算延迟时间长造成其不能满足小网工况运行的结论,在此基础上设计了小网工况下基于转速反馈的阀门控制方案,即采用新的转速控制卡件减少运算延迟时间,并对设计方案进行了仿真验证,最后研制了小网工况下转速控制卡件并进行了实验验证;(2)针对目前国内外缺少对顺序阀运行下阀门控制性能的研究的问题,本文提出了在顺序阀运行下减少高压调节阀晃动的优化策略,即通过修改阀门流量特性函数后段斜率减少开度指令变化,进一步指出在满足流量指令与实际流量较好线性度情况下,尽可能地减少阀门流量特性修正曲线后段斜率,能显著减少开度指令变化,使顺序阀调节下阀门晃动减轻,提高顺序阀运行下阀门控制性能,为电厂现场参数整定提供了理论依据;(3)当电网发生故障出现甩负荷等状况时,会引起汽轮机组转速飞升,汽轮机快关阀门通过OPC电磁阀快速关闭高、中压调节阀,实现对机组的超速保护。本章对汽轮机组甩负荷工况下能否通过快关阀门实现超速保护进行了仿真分析,建立了中间再热式汽轮机阀门快速关闭模型,并对其在甩负荷工况下进行了仿真分析,论证了在甩负荷时快关阀门能够实现对机组的超速保护。更多还原

【Abstract】 Valve control performances in steam turbine DEH system under different conditions are studied in this thesis. Firstly, the strategy for single valve control in isolated power network is discussed. Then the coordinated control for multiple valves is analyzed theoretically. Simulation and experimental results are put forward in the paper. Lastly, quick closing technique of the valve for over-speed protection under load rejection is also discussed in detail. The main contents are as follow:(1)A simulation model of single-valve control is built based on rotation speed feedback under the condition of isolated power network, and then the problem that the single-valve control under isolated power network adopts the large power network control mode is analyzed. It makes conclusion that the delay time of DEH rotate speed feedback ceases to be effective in isolated power network condition. Based on the above conclusion, a design of single-valve control under isolated network condition is proposed in this paper, which a new speed control card is adopted of which the delay time is much shorter than DEH system rotation speed feedback. It is showed in simulation results that the design of small grid single-valve control is feasible.(2)An optimization plan is proposed in this paper to lessen valve sloshing in sequent-valve operation. The valve sloshing will be lessened by decreasing the slop of flow characteristics curve with the good linearity of flow command and actual flow.(3)Quick closing technique of the valve for over-speed protection under load rejection is studied in this paper. A simulation model of the valve quick closing is built. Then the performance of valve quick closing under load rejecting test is analyzed on MATLAB platform. Finally, the valve quick closing is proved effective in the load rejection test.更多还原