Intelligent microgrid energy management system.doc

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1、1Summary.2Chapter 1 Introduction.41.1 Research background and significance of the subject.41.2 Intelligent Microgrid Classification.61.3 Research Status at Home and Abroad.72.1 System design of household photovoltaic microgrid.92.1.1 Environmental parameters.92.1.2 PV module parameters.112.1.3 Syste

2、m planning and design.122.1.4 Capacity selection of bidirectional inverter.132.1.5 battery capacity selection.142.2 Summary of this chapter.16Chapter 3 Intelligent Microgrid Operation Control Strategy.163.1 Distributed power supply operation control strategy.173.1.1 PQ Control.173.1.2 VF Control.183

3、.1.3 droop control.203.2 Microgrid Coordinated Control Strategy.213.2.1 Master-slave control.213.2.2 Peer control.233.2.3 Hierarchical control.233.3 Summary.24Chapter 46k W Intelligent Microgrid Energy Management System.254.1 Energy Management System Control Logic.254.2 Energy Management System Soft

4、ware.264.3 Energy Management System Testing.294.3.1 Battery charge and discharge control.294.3.2 System grid-connected power generation control.304.4 Intelligent microgrid system monitoring of five operating modes314.4.1 Photovoltaic direct supply mode.314.4.2 Energy feedback mode.354.4.3 Battery Po

5、wer Mode.364.4.4 External power supply mode.384.4.5 Load Limit Mode.404.5 Summary.42Chapter V Conclusions and Prospects.43References.442SummaryWith the rapid development of the social economy,the demand forelectricity in industrial production and residential life is increasing,andthe large-scale pow

6、er system of centralized power generation andlong-distance high-voltage transmission has become increasingly prominent asthe scale of the power grid expands.The cost is high and the operation isdifficult,and it is difficult to meet the increasingly high reliability anddiverse power demand of users.A

7、t the same time,the traditional energy crisisand the environmental pollution caused by it have become the focus of theworlds attention.It is imperative to vigorously develop clean energy.Smartmicro-grid can make full use of new energy and can make up for the shortcomingsof large power grids.Therefor

8、e,it has become a research hotspot in variouscountries in recent years.This paper takes the household photovoltaic storage smart microgrid asthe research object,and focuses on its operation control and energymanagement.The specific research contents are as follows:(1)Designed a household photovoltai

9、c power generation microgridsystem.Including:6k W photovoltaic panels,two sets of 12V,200 Ah batteries,photovoltaic grid-connected inverters 6k W,bidirectional inverters 6 k W andlocal AC loads.(2)In-depth study of intelligent micro-grid operation controlstrategy,including distributed power control,

10、micro-grid coordinatedcontrol,and proposed a control strategy combining master-slave control andhierarchical control.The PQ control strategy is adopted when the maincontroller is connected to the network.The VF control strategy is adoptedwhen the network is off-network,so that the smart micro-grid c

11、an be connectedto the grid and run on an island,the mode switch is seamlessly connected,and the modes are flexible.(3)Designed a 6kW photovoltaic storage intelligent microgrid system,developed a photovoltaic storage intelligent microgrid energy managementsystem software,realized intelligent microgri

12、d measurement and control,protection,mode switching,power control,load control,energy storagemanagement and other functions.Under the five operating modes of photovoltaicdirect supply mode,energy feedback mode,battery power supply mode,externalpower supply mode,and load limiting mode,the 6kW wind an

13、d light storageintelligent microgrid system runs experiments,and obtains multiple operatingcurves and power quality data.The validity and stability of the operationalcontrol strategy and energy management system adopted in this paper are furtherverified.Keywords:household photovoltaic smart microgri

14、d,operational control strategy,energy3management4ChapterChapter 1 1 IntroductionIntroduction1.11.1 ResearchResearch backgroundbackground andand significancesignificance ofof thethe subjectsubjectHuman development has benefited from the development and utilizationof energy.However,in terms of energy

15、types,it is still dominated bytraditional fossil fuels such as coal and petroleum.Thousands of years ofusing energy habits have led to the accumulation of shortcomings in the useof traditional energy sources,and the problem of energy shortages has becomeprominent.Moreover,the large-scale use of trad

16、itional fossil fuels has ledto serious air pollution,the occurrence of smog and sandstorms,and frequentnatural disasters.The problem of environmental pollution has already beensolved.New energy sources such as wind and light have the advantages of richtotal,environmentally friendly,and easy to devel

17、op and utilize,which havebecome the focus of attention.Chinas economy still maintains medium-to-high-speed growth,and thedevelopment of almost all industries will increase the need for electricalenergy.At present,Chinas power construction is mainly based on large-scalecentralized power plants compos

18、ed of fire,water and nuclear energy.However,in the long run,there are many problems with such large-scale centralizedpower generation.First of all,the price of coal determines the high costof thermal power,and a large number of high-voltage,ultra-high-voltageelectrical equipment,which determines the

19、 construction cost of the power gridis high;secondly,when the power grid fails,it will cause large-scale poweroutages and poor anti-risk capability.5Through the above analysis,we can easily find that the traditionalpower generation method has reached the bottleneck period in terms of energy,environm

20、ent,and the power grid itself.We need new power generation methodsto solve these problems and improve the power system.Using new energy togenerate electricity is undoubtedly a good prescription.At home and abroad,we are paying more and more attention to the development and utilization ofnew energy.N

21、ew technologies and new equipment for renewable energy havesprung up.Distributed power generation(DG)has thus entered the field ofvision.Distributedpowergenerationreferstotheuseofvariousdecentralized energy sources,including renewable energy sources(such assmall wind energy,solar energy,small water

22、energy,tidal energy,geothermalenergy,biogas,and Biomass energy,etc.)and fossil fuels(mainly naturalgas)that are easily accessible locally.The distributed generation systemcangenerateelectricity,coldandheat,andisanefficientenergyutilizationmethod.Adistributedpowergenerationhashighenergyutilizationeff

23、iciency,widedistribution,lowpollution,flexibleinstallation location,and reduced input and output of power transmission andtransformation equipment.It can reduce the shortcomings of the traditionalpower grid by reducing the pressure of the peak load on the power system.However,distributed power sourc

24、es are uncontrollable for traditional powergrids,which will increase uncertainties in the stable operation of powersystems.In order to reduce the disadvantages caused by DG access to the largepower grid and maximize the advantages of distributed generation of renewableenergy,distributed power genera

25、tion is fully utilized,and distributed powergeneration mostly operates in the form of microgrid.Microgrid is a new term compared to traditional large power grids.Itconsistsofdistributedpower,load,energystoragedevices,energyconversion devices,control devices and monitoring and protection devices.It h

26、as complete functions of transmitting,transmitting,distributing andpowering.Controllable independent system.The microgrid can access thedistribution network on the user side to reduce losses,directly meet userneeds,save electricity costs,and provide higher reliability.The microgridhas the characteri

27、stics of power distribution and local power supply,and theoperation is more stable.When the large power grid fails,it can continueto supply power to the local load and improve the reliability of power supply.Local power generation is used locally,reducing power transmission losseswithout causing too

28、 much impact on large power plants.Power electronics arecommonly used in microgrid control to make power control and harmonicreduction W more convenient.Smart microgrids,or intelligently optimizedmicrogrids,will play an important role in the development of smart grids.6In the power market,the high p

29、enetration of smart microgrids can savepower generation costs,thereby lowering electricity prices and bringingbenefits directly to users.For example,the electricity price during peakhours is high,and the microgrid can transfer excess electric energy to thepower grid to alleviate the power shortage.W

30、hen the electricity is low,theelectricity price is cheap,and the electric energy can be purchased at a lowprice,and the excess electric energy of the power grid is injected into themicro grid.In terms of operation,the intelligent microgrid operates in aflexible manner,which can be connected to the l

31、arge grid to achievegrid-connected operation,and can cut off the connection with the large gridto achieve island operation.The grid-connected standard of the microgrid isonly for the connection point(PCC)between the microgrid and the distributiongrid,not for the specific micro-power supply.Therefore

32、,the microgrid canfreely control the access and disconnection of each micro power supply in thesystem according to its own needs,and truly realizes“plug and play”,real-time interaction and coordinated operation.It is precisely because the smart microgrid can meet peoples needs forenergy optimization

33、,environmental improvement,and smart grid advancement,making it a research hotspot in the electrical field.The intelligentmicrogrids networking form and grid structure are flexible and diverse,including a wide variety of distributed power sources,complex control modes,and varied operating modes,so t

34、hat how to achieve fast isolation between themicrogrid and the distribution network,and the grid-connected mode Theseamless switching of the island mode and how to realize the energyoptimization configuration management of each micro power source inside themicro grid have become the most studied pro

35、blems in the field of smart microgrid.Therefore,theoperationcontrolandenergymanagementoftheintelligent microgrid have important research significance.Only by usingadvanced operational control and energy management strategies can theintelligent microgrid be operated economically and stably,so that th

36、e roleof distributed power can be better utilized.1.2 Intelligent Microgrid ClassificationThe smart microgrids are classified according to different standards asfollows:(1)According to the type of energy transmission:1)DC type,each micro-source and load in the micro-grid are connectedto the DC bus,a

37、nd the DC bus is connected to the large power grid via theinverter.72)AC type,the system adopts AC bus operation,directly controls thecommon connection point,and realizes the connection with the large powergrid.3)AC/DC hybrid type,which has both AC bus and DC bus,which respectivelyconnect different

38、types of loads.Compared with the other two,the number ofpower electronic converters is reduced and the energy utilization efficiencyis improved.(2)According to geographical location:1)Island type,used to solve the problem of residential electricity andseawater desalination,avoiding the laying and ma

39、intenance of submarinecables and saving costs.The form of micro power supply is mainly wind,light,firewood and storage,and most of them operate in isolated mode.2)Remote area type,used to solve the problem of lack of electricity,power shortage and poor power quality in remote areas,and build smartmi

40、cro-grid according to the characteristics of local new energy and thedistribution of residents.3)Urban type,primary energy is mainly wind energy and solar energy,andmost of them operate in grid-connected mode to provide green energy forresidential electricity,road lighting and building office.(3)Acc

41、ording to the size of the capacity is divided into:1)Single facility level,single distributed power supply,general loadcapacity less than 2MW,such as residential photovoltaic power generationsystem.2)Multiple facilities,at least 2 types of distributed power sources,with load capacity between 2 and 5

42、 MW,improve system power supply reliability,and apply to buildings and multi-load areas.3)Feeder level and substation level,including multiple distributedpower sources,load capacity above 5MW,intelligent micro-grid connected todistribution network,and subject to dispatch control,high power supplyrel

43、iability,suitable for centralized users,important load areas.1.3 Research Status at Home and AbroadChina began researching microgrids in about 2004.However,thegovernment attaches great importance to the promulgation of the“RenewableEnergy Law of the Peoples Republic of China”and the“Medium and Long-

44、termDevelopment Plan for Renewable Energy”and other policies and regulationsto stimulate the rapid development of microgrids.Leading the development ofdomestic microgrid technology are Tianjin University,Hefei University ofTechnology,Xian Jiaotong University and other key universities,as well asthe

45、Institute of Electrical Engineering of the Chinese Academy of Sciences.They have established their own micro-grid experimental systems and conductedresearch from different angles.From the perspective of power system,TianjinUniversity studies micro-grid planning and design,including DG protection8con

46、trol and operation management.Tianjin University also cooperated withChina Southern Power Grid Corporation and Beijing Sifang Co.,Ltd.to carryout the National 863 Project and MW-class cold and heat power supply formicrogrid project demonstration.Hefei Industry cooperated with Canadianuniversities to

47、 build a microgrid experimental platform containing multipleDGs to study the design,regulation and management of microgrids.The scholarsof Xian Jiaotong University rely on their advantages in the field of powerelectronics to conduct in-depth research on topology and control of powerelectronics in th

48、e microgrid.The Institute of Electrical Engineering of theChinese Academy of Sciences built a 200kVA microgrid experimental platformto analyze the steady-state and transient operation of the microgrid,andachieved important results in terms of steady state,transient calculationmethods and independent

49、 operation control.In recent years,China has built a number of micro-grid technologyapplication demonstration projects,such as Zhangbeis national wind storagedemonstration project,micro-grid construction projects in the rural networksystem of North China and Inner Mongolia Hulunbeier.In 2012,in the“

50、TwelfthFive-Year Plan”formulated by the Energy Bureau,it is planned to build 30micro-grid demonstration projects by 2015,and the actual micro-gridconstruction is in full swing.By the end of 2015,at least 60 demonstrationprojects have been completed.In September 2015,the Energy DistributionBureaus Ac