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1、学本科生毕业设计说明书(毕业论文)题目:村镇供水厂电气及仪表控制系统设计学生姓名:学号:1专业:自动化班级:自动化2班指导教师:V村镇供水厂电气及仪表控制系统设计摘要根据村镇的供水的要求,设计了一套电气及仪表控制的变频恒压供水系统。变频恒压供水控制系统由变频器、压力传感器、水泵机组、数字显示仪表等组成。供水厂为远在方圆15Km外的几十个村庄供水,供水厂由加压站和水源井群组成,水源井群由3眼井组成。先把水源井中的水注入加压站的蓄水池中,然后由加压泵从蓄水池通过变频调速控制为用户供水。蓄水池包含三台潜水泵电机控制水位,依据水位的不同,
2、启动不同台数的潜水泵,功率大一台的应采用降压启动。同时包含三台加压水泵电机,它们组成变频循环运行系统,控制柜应能根据用户需求的供水压力供水,采用变频器实现对加压水泵的软启动和变频调速,实现任意一台水泵的的变、工频切换及两台水泵之间的自动启动与停止,压力传感器检测当前水压信号,送入变频器与设定值比较,进行PID运算,从而控制变频器的输出电压和频率,进而改变水泵的转速来改变供水量,最终保持管网压力稳定在设定值附近,实现恒压供水。关键词:恒压供水;变频器;PID控制;变频调速;仪表V内蒙古科技大学毕业设计说明书(毕业论文)RuralWa
3、terSupplyPlantElectricalandInstrumentationControlSystemDesignAbstractAccordingtotherequirementoftheruralwatersupply,Designasetofelectricalandinstrumentcontroloffrequencyconversionconstantpressurewatersupplysystem.Frequencyconversionconstantpressurewatersupplycontrolsy
4、stembyfrequencyconverter,pressuresensor,pumpingunit,Digitaldisplayinstrument,etc.Watersupplyplantfordozensofvillagesinfangyuan15kmoutsidethewatersupply,Watersupplyplantiscomposedofpressureandwaterwellgroup,SourcewellgroupconsistsofthreeWells.PutwaterWellswaterinjectio
5、npressureinthereservoir,Thenthepumpwaterfromthereservoirthroughthefrequencycontrolofmotorspeedcontrolforusers.Reservoircontainsthreesubmersiblepumpmotorcontrolwaterlevel,Accordingtothewaterlevelisdifferent,Startthedifferentsetsofsubmersiblepump,Poweroffreshmanshouldad
6、optstep-downstartup.Atthesametimecontainsthreepressurizedwaterpumpmotor,Theyarecomposedofvariablefrequencycycleoperationsystem,controlcabinetshouldbeabletosupplypressurewatersupplyaccordingtouserrequirements,Frequencyconverter,isadoptedtorealizeofpressurizedwaterpumps
7、oftstartandfrequencycontrolofmotorspeed,Implementasapumpofvariable,powerfrequencyswitchingandautomaticstartandstop,betweenthetwopumps,Currenthydraulicpressuresensorsignal,IntotheinvertercomparedwiththesetvaluetoPIDarithmetic,Tocontroltheoutputvoltageandfrequencyofthei
8、nverter,Canmakeabigdifferencetothespeedofwaterpumpmotortochangewatersupply,Eventuallymaintainstabilityofthepipenetworkpressu