300MW单元机组汽包水位控制系统分析、设计与仿真.doc123

华中科技大学文华学院毕业设计（论文）题目：300MW单元机组汽包水位控制系统分析、设计与仿真学生姓名：陈正学号：090204011101学部（系）：机械与电气工程学部专业年级：09级热能与动力工程指导教师：周慧职称或学位：硕士2013年5月18日华中科技大学文华学院毕业设计（论文）I300MW单元机组汽包水位控制系统分析、设计与仿真摘要锅炉给水控制系统是火力发电厂非常重要的控制子系统，稳定的汽包水位是汽包锅炉安全运行的重要指标。火电厂给水系统构成复杂，汽包水位受到机组负荷、汽包压力、温度、给水量等多项参数的影响：不同负荷阶段，给水设备不同，又需要采取不同的控制方式。目前使用的火电厂给水控制系统存在着各自的不足之处，往往难以满足火电机组复杂工况的要求。针对这些情况，为了保证汽包水位维持在要求值，本文首先分析了给水控制对象的动态特性，在此基础上设计出了采用汽动调速泵、电动调速泵、调节阀三者结合的汽包水位控制系统，低负荷时通过改变旁路调节阀的开度来调节给水量，用单冲量控制系统控制汽包水位；高负荷时通过改变给水泵转速改变给水量，用串级三冲量控制系统控制汽包水位，保证对汽包水位蒸汽流量和给水流量的准确测量。给水调节阀、汽泵、电泵之间，单冲量系统和三冲量系统之间都能实现无扰切换，既能满足机组全程控制要求，又有良好的调节性能和运行经济性。关键词：锅炉给水控制；三冲量控制系统；单冲量控制系统华中科技大学文华学院毕业设计（论文）IITheDesignOfBoilerFeedwaterControlSystemOfThe300MWThermalPowerUnitAbstractFeedwaterControlSystemisoneofthemostimportantcontrolsysteminathermalPowerplant.Stabilizationofthedrumlevelisoneofessentialparameterwhichindicatedsafeoperationofthedrumboiler.Drumlevelisaffectedbytheunitload,pressandtemperatureofthedrum,feedwaterfluxandetc.Becauseofusingdifferentequipmentatdifferentstages,itshouldapplydifferentcontrolmethods.Theeffectoffullrangefeed-watercontrolsystemdoesnotoftenbesatisfiedwhenpowerunitisindifficultsituationbecauseofitsimperfect.Inordertomaintainthelevelofthedrumwaterinrequestedvalue,Basingonanalysisoffeed-watercharacterfirstly,thissystemadoptstimingwhichismovedbysteamandelectromotion-timingpumpandadjustingvalve.Itutilizesbypassvalvestoregulatethefeed-waterandusessingleimpulsetocontrolthelevelofdruminlowerload.Atthehighloadcondition,changetherotatingspeedofsteamorelectricityfeedwaterpumpstoensurethewaterlevelofthedrum,usingthreeimpulsetocontrolthelevelofdrum.Thelevelofsteamandfeed-watercanbemeasurednicety.Non-disturbanceswitchingcanberealizedamongfeed-watervalves,steamandelectricitydrivenpumps,singleandthreeimpulse.Thatnotonlymeettherequirementsofthewhole-coursecontroloftheunit,butalsoensurethesatisfactoryregulatingperformanceandoperatingeconomics.Italsohaveniceregulateperformanceandcirculatingeconomy.Keywords:Boilerfeed-watercontrol;Three-elementcontrolsystem;Single-elementcontrolsystem目录摘要··························································································IABSTRACT················································································II1绪论·························································································11.1课题背景及其意义···································································11.2锅炉给水控制系统的发展和现状·················································11.2.1西门子公司全程给水系统设计方案[6-8]·····································21.2.2ABB贝利公司全程给水系统设计方案[9,10]·································41.2.3FOXBORO公司全程给水系统设计方案[11-13]······························52汽包锅炉给水控制系统·································································82.1锅炉给水全程自动控制系统的概念[14]···········································82.2给水全程自动控制系统的任务[15]·················································82.3给水全程自动控制系统的要求[15,3]············································82.4给水控制对象的动态特性[15-17]····················································92.4.1给水量扰动下水位变化的动态特性········································102.4.2蒸汽流量扰动下水位变化的动态特性·····································102.4.3炉膛热负荷扰动下水位变化的动态特性··································112.5给水全程控制的基本方案[15-18]···················································122.5.1单冲量给水控制系统·························································122.5.2单级三冲量给水控制系统···················································132.5.3串级三冲量给水控制系统···················································142.6300MW机组全程给水自动控制系统的设计与分析[15]······················152.6.1信号测量········································································156.2给水控制系统结构·······························································162.6.3系统工作原理··································································162.6.4控制过程中的跟踪与切换···················································172.6.5逻辑信号的形成·······························································182.7给水RB分析········································································182.7.1给水泵RB的定义······························································182.7.2给水泵RB过程·································································182.7.3给水泵RB逻辑分析···························································193汽包水位控制系统的MATLAB仿真·············································203.1控制系统的分析和整定··························································203.2汽包水位控制系统SIMULINK模型设计······································203.3汽包水位控制系统仿真··························································21结论··························································································23参考文献····················································································24致谢·························································································25华北电力大学本科毕业设计（论文）11绪论1.1课题背景及其意义随着电力需求的增长，我国的火力发电开始向建设大容量、高参数的大型机组方向发展。扩大单机容量可使发电容量迅速增长以适应生产发展的需要，同时可使基建投资下降、设备费用降低、减少运行费用以及节约金属材料消耗。但是，火电机组越大，其设备结构就越复杂，自动化程度要求也越高。我国最近几年新建的300MW，600MW火电机组基本上都采用国内外最先进的分散控制系统（DCS），对全厂各个生产过程进行集中监视和分散控制。汽包水