大型火力发电厂过热汽温控制策略的改进

上海交通大学硕士学位论文大型火力发电厂过热汽温控制策略的改进姓名：刘期彬申请学位级别：硕士专业：控制工程指导教师：袁景淇;刘建江20090701IABSTRACTIIIMPROVEDCONTROLSTRATEGYFORSUPERHEATERSTEAMTEMPERATUREINLARGESCALETHERMALPOWERPLANTABSTRACTInlargethermalpowerplant,superheatersteamtemperatureisoneofthemostimportantparameterforboileroperation.Typically,thetemperaturefluctuationhastobecontrolledwithin+5-10.Thesteamtemperaturecontrolstrategyhasbeenstudiedforyears.AlongwiththewidelyapplicationofDCSsystem,thecascadePIDcontrolmodelhasbeenwidelyadoptedasaclassicalstrategy.However,inmanycases,theeffectseemsnottobesosatisfying.Therearetwomainproblemsremainunsolved:independentcontrolofthetwodesuperheatersandthelongtransientstime.ToovercomethedisadvantagesofthecascadePIDcontrolstrategy,thisarticleprovidedcoordinatedesuperheaterscontrolstrategyandtheSmithpredictorbasedsolutionsbyconsideringfieldcommissioningexperiences.Thesesolutionsareevaluatedonasimulatedpowerplant.Coordinatedesuperheaterscontrolstrategyisusedtosolvetheunbalancebetweentwodesuperheaters.Thevalvepositionofthesecondstagedesuperheaterisusedasthecontrolsetpointofthefirststagedesuperheater.Bythisstrategy,theeffectofanydisturbancehappenedinthesystemwillbeshiftedtothefirststagedesuperheater,andthenthesecondstagedesuperheatercouldbealwayskeptinthemiddlepositionsoastobereadyfordisturbanceinanydirections.Smithpredictorisbasedonthebigdelaycharacteristicofsuperheatersteamtemperature,itcanABSTRACTIIIshortenthecontrolprocessandsoastoimprovethecontrolqualityofthewholesystem.Keywords:Superheatertemperature,cascadePIDcontrol,Smithpredictor,Coordinatecontrol.11.1-[1]1-1DsDPm[2,3]()()()DPMDS1-1Fig.1-1Coalfiredboilerflow2[4]••••••1-2[5]1-2Fig.1-2Boilercontrolobjects3[6,7]1.2[8]+5-10[9,10]1)12Cr1MoV5851059332)3)44)5)1.3PID[11][12,13,14]1)DNEPTT22)BDT2PTNE3)DPTNET2DNEPT5T24)D1.41)2)3)SmithPIDSmith6GESimPanel5.2V6[15,16]2.1SimPanelSimPanelGEDCSGEDCSSimPanel[17]SimPanelDCSSimPanelDCSSimPanelDCSDCSDCSDCSDCS/SimPanelDCS2-1SDPU7DCSDCSDPUDPUDPU...VDPUVDPUVDPU...HMIHMIHMI...HMIHMIHMI...IHMISDPUSDPU...DCSDPUVDPUDPUSDPUDPUHMIIHMI2-1Fig.2-1Distributedsimulationsystem2.21)OC400GEDEHDCSSCADAOC4000[17]OC4000NetWinSimPanelSimPanelNetWinNetWin2)DPUMMIXNETOC4000DPUI/OMMIDPU3)VDPUOC4000DPUVDPUDPUI/OMMIVDPU84)SDPUSimPanelVDPU2.31)SDPU2)3)4)SimPanel2-22-2SimPanelFig.2-2SimPanelsimulationsystemmenuSDPUDPU2-392-3SimPanelFig.2-3SimPanelsimulationsystemoperation2-42-4SimPanelFig.2-4SimPanelsimulationsystemdevicemanagement102.4HeaderHXgr[18]12.5GE330MWDCS1)1018t/h,18.44Mpa[19,20,21]2)()()()()()[19,20,21].3)[19,20,21]4)538~548543[19,20,21]112.61)2)5305350.55355301)528~5482)3)4)MFT2.7122-52-5Fig.2-5PowerplantsuperheatersteamoperationinterfaceABHeaderTypeTypeTrueFalse2-6132-6Fig.2-6Desuperheaterenthalpysimulationloop2-72-7Fig.2-7Desuperheatertemperaturesimulationloop148.8HXgrHXgr2-8142-8Fig.2-8Superheatersimulationlogic1)336MW2)3)4)2.8—GESimPanelSimPanel153.1[22,23,24][25,26,27][28,29]3-1:16T2TT2CT1CT1T3-1Fig.3-1Superheatersteamcascadecontrolstrategy3-2[30,31,32]T2TT2Cd/dtT1T3-2Fig.3-2Superheatersteamdoubleelementscontrolstrategy173.2ABABA3-33-3Fig.3-3FirststagedesuperheatercontrolstrategyAPIDPIDPIDPIDPID181)2)3)RunBackMFT4)ABABA3-43-4Fig.3-4SecondstagedesuperheatercontrolstrategyPIDPIDPIDPID19PID1)2)3)RunBackMFT4)3.31)62)3.420PID[33,34,35]3-13-1PIDTable3-1FieldadjustedPIDparametersDEVKKpTiTdAPID0.468040APID0.154.51300APID0.358.812030APID0.157.22000BPID0.1568050BPID0.154.21600BPID0.358.811530BPID0.157.120001)SimPanel310MW5302)3)54)AB3-53-6213-5AFig.3-5AdesuperheaterSet-Pointchangeresponse3-6BFig.3-6BdesuperheaterSet-Pointchangeresponse221)SimPanel310MW2)5454203)-54)AB3-73-7Fig.3-7Furnacedisturbancefinalstatus3-83-9233-8AFig.3-8Adesuperheaterfurnacedisturbanceresponse3-9BFig.3-9Bdesuperheaterfurnacedisturbanceresponse243.51)20%2)230.3253.6PID264.12-5.4.220%A4-1274-1Fig.4-1Firststagesuperheateroptimizedlogicconfiguration4.3PID4-1284-1PIDTable4-1AdjustedPIDparametersDEVKKpTiTdAPID168040APID0.154.51300APID0.358.812030APID0.157.22000BPID168050BPID0.154.21600BPID0.358.811530BPID0.157.120004.41)SimPanel310MW2)5454203)-54)AB4-24-34-4:294-2Fig.4-2Furnacedisturbancefinalstatusafteroptimization4-3AFig.4-3Adesuperheaterfurnacedisturbancetestcurve304-4BFig.4-4Bdesuperheaterfurnacedisturbancetestcurve4.5PID1)2)3)Smith31SmithSmith5.1SmithSmith1957PIDPI[36,37,38,39]SmithPalmorSmith1.2.Smith[40,41,42,43]WatanabeSmith1.2.[44,45,46]SmithSmithSmithSmithHangCCSmith[47,48,49]WatanabeSmithM(s)M(s)[50]5.2SmithSmithABSmith32SmithA5-11093.9t/h383.095-1Table5-1Spraywatertestresult(%)(t/h)10383.090383.11433.13210383.094.77380.88428.35318.8383.099378.6423.5430383.0914.31376.07418.12550383.0923.86371.31408.537100380.247.71359.9387.5=0.4771*=-*0.425487K1=0.425487=*1.076687K2=1.076687=0.4771*0.425487*=0.203*T=10sDelay=2sT=120sDelay=10sSmith334105-1ABABSmith5-1Fig.5-1FirststagesuperheatersimulationmodelOC4000leadlag120s60s.delaydelay5-2Smith345-2LeadlagFig.5-2Leadlagmoduleparameter120s5-35Smith355-3Fig.5-3Superheatersimulationsystemoperationinterface5.3••••••Runback•Smith36•BSmith5.4PIDAPID5-4PID+-