Fanghong Guo • Changyun Wen Yong-Duan Song
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2.2DistributedFinite-TimeAverageConsensusAlgorithm.......
2.4.3.1Projectionoperator(Case1)............
3.3.2Distributedsecondarycontrollerdesign...........
3.3.2.1Finite-timevoltagerestoration...........
4.2.2.2DistributedVUC..................
4.2.2.3Distributedcooperativesecondarycontrolscheme
4.2.2.4StabilityanalysisofdistributedVUC.......
4.3.1Testingoftheoveralldistributedcontrolsystemundervari-
4.3.1.1CaseA:Communicationfailure..........
4.3.1.2CaseB:Contributionlevelvariation.......
4.3.1.3CaseC:BackupDGplug-and-play........
4.3.2Systemstabilityandperformance..............
4.3.3Comparisonswithcentralizedsecondarycontrolin[65]..
4.3.4Distributedvoltageunbalancecompensationusingnegative
5.4.1Distributedprojectedgradientmethod(DPGM).......
5.5.2.1Generatorplug-and-play..............
5.5.2.2Loadplug-and-play................
5.5.3Casestudy3:ImplementationonIEEE30-bustestsystem.
5.5.4Casestudy4:Comparisonwithheuristicsearchmethod..
6.3.1Distributedsynchronousoptimizationalgorithm.......
6.3.2Distributedsequentialoptimizationalgorithm........
6.3.3Virtualagent.........................
6.4Convergenceanalysis.........................
6.4.1Distributedsynchronousalgorithm..............
6.5EconomicDispatchinMulti-AreaPowerSystem..........
6.5.2.1Casestudy1:Distributedsynchronousalgorithm.
6.5.2.2Casestudy2:Distributedsequentialalgorithm..
6.5.2.3Casestudy3:Distributedsequentialalgorithm withrandomcommunicationstrategy.......
6.5.2.4Casestudy4:Fastgradient............
7.3HierarchicalDecentralizedEconomicDispatch...........
7.3.1DistributedalgorithminChapter5..............
7.3.2Hierarchicaldecentralizedalgorithm.............
7.3.3Convergenceanalysis.....................
7.3.3.1Problemdecomposition..............
7.3.3.2Dummyagent...................
7.4.1.1Casestudy1:Withoutgeneratorconstraints...
7.4.1.2Casestudy2:Withgeneratorconstraints.....
7.4.1.3Casestudy3:Varyingload............
7.4.1.4Casestudy4:Plug-and-playcapability......
7.4.1.5Casestudy5:Comparisonwithdifferent
7.4.1.6Casestudy6:Fastgradient............
7.4.2IEEE118-bustestsystem..................
8.3.1Distributedalgorithmwithsynchronouscommunication..
8.3.2Distributedalgorithmwithsequentialcommunication....
8.4CaseStudies.............................
8.4.1Distributedoptimization...................
8.4.1.1Distributedoptimizationwithsynchronouscom-
8.4.1.2Distributedoptimizationwithsequentialcommunication......................
9.2.1DistributedadaptivecontroloftheMG...........
9.2.2Stabilityanalysisofthedistributedsecondarycontrolwith communicationtimedelay.................. 166
9.2.3Distributedevent-triggeredoptimizationoftheMG..... 167
ListofFigures
1.1Centralized,decentralized,anddistributedcontrolscheme..... 4 1.2GeneralstructureoftheMG..................... 7
1.3HierarchicalstructurefortheislandedMGcontrol[28,29,30]... 8
2.1Illustrationofsynchronousoptimization...............
2.2Illustrationofsequentialoptimization................
2.3Illustrationofprojectionoperator...................
2.4IllustrationofprojectioninCase1with2-dimensionexample....
2.5IllustrationofprojectioninCase2with2-dimensionexample....
3.1SchematicdiagramofagenericislandedMG............
3.2Theschemeofalocalprimaryinvertercontroller..........
3.3DistributedsecondarycontroldiagramofanislandedMG......
3.4Thediagramoftheproposedsecondarycontroller..........
3.5Simulationtestsystem........................
3.6ThevoltageoutputofthetestislandedMG..............
3.7TherealpoweroutputofthetestislandedMG............
3.8ThefrequencyoutputofthetestislandedMG............
3.9ThesecondaryfrequencycontrolinputofthetestislandedMG...
3.10Comparisonbetweentheproposedmethodandtheapproachin[54] 50
4.1DistributedvoltageunbalancecompensationinanislandedMG...
4.2Illustrationofsecondarycompensationintimedomain.......
4.3Flowchartofdistributedcooperativesecondarycontrolscheme...
4.4Simulationtestsystem........................
4.5TheaverageconsensusprocessofUCR...............
4.6VoltageunbalancefactorsofeachDGandSLB...........
4.7RealandreactivepoweroutputsoftheMGsystem.........
4.8FrequencyoutputoftheMGsystem.................
4.9TheunbalancedcompensationreferencesofeachDG........
4.10Amplitudeofnegativesequencecurrent...............
4.11VoltageunbalancefactorsofeachDGandSLBin[65].......
4.12DistributedvoltageunbalancecompensationinanislandedMGusingnegativesequencecurrentfeedback...............
4.13ThevoltageunbalancefactorofeachDGandSLBusingnegative sequencecurrentfeedback......................
4.14Amplitudeofnegativesequencecurrentusingnegativesequencecurrentfeedback.............................
5.1Smartgridsystem...........................
5.2Flowchartofdistributedeconomicdispatch.............
5.3Graphreconfigurationillustrationexample..............
5.4Thecommunicationgraphoftestpowersystem...........
5.5Simulationresultsof6-buspowersystem..............
5.6Simulationresultswithgeneratorplug-and-play...........
5.7Graphreconfigurationofgenerator1plug-and-play.........
5.8Simulationresultswithloadplug-and-play.............
5.9SimulationresultsofIEEE30-bussystem..............
5.10EvolutionoffitnessvaluesinGAmethod..............
6.1Twodifferentcommunicationstrategies...............
6.2Flowchartofdistributedsynchronousoptimization.........
6.3Adiagramoftheproposeddistributedsequentialoptimization...
6.4Illustrationofvirtualagent......................
6.5IEEE30-bustestsystem.......................
6.6Simulationresultswithdistributedsynchronousalgorithm.....
6.7Simulationresultswithdistributedsequentialalgorithm.......
6.8Simulationresultsofdistributedsequentialalgorithmwithrandom communicationstrategy.......................
6.9Simulationresultsofdistributedsequentialalgorithmwithfastgradientmethod.............................
7.1Hierarchicaloptimizationstructure..................
7.2Hierarchicaloptimizationstructureforeconomicdispatch......
7.3IEEE30-bustestsystem.......................
7.4Simulationresultswithoutgeneratorconstraints...........
7.5Simulationresultswithgeneratorconstraints.............
7.6Simulationresultsofproposedalgorithmwitha2-hourloadprofile.
7.7Simulationresultswithgeneratorplug-and-play...........
7.8Simulationresultswithdifferent α
7.9Simulationresultsoffastgradientmethod..............
7.10SimulationresultsinIEEE118-buspowersystem..........
8.1Thesmartpowersystem.......................
8.2Illustrationof PDpricing
8.3Flowchartofdistributedoptimizationalgorithmineachagentwith synchronouscommunication.....................
8.4Illustrationexampleoftwooptimizationalgorithms.........
8.5Communicationgraph........................
8.6Simulationresultsofdistributedoptimizationwithsynchronous communication............................
8.7Distributionofagentsconductingoptimizationduringsequential communicationprocess........................
8.8Simulationresultsofdistributedoptimizationwithrandomsequentialcommunication..........................
8.9Simulationresultsofdistributedoptimizationwithdeterministicsequentialcommunication........................
8.10Comparisonbetween P and PDpricing strategy...........
8.11Theperformanceofdifferentderivativegains............
9.1ThedynamicequivalentcircuitmodeloftheMGsystem[50]....
ListofTables
2.1IllustrationexampleofAlgorithm2.1................
4.1ParametersofDGanditsprimarycontroller.............
4.3CommunicationgraphreconfigurationinCaseA..........
4.4CommunicationgraphreconfigurationinCaseC..........
4.5Voltageunbalancefactorsoutputwithdifferentconsensustime...
5.1Illustrationexampleoftotalloaddemanddiscovery.........
5.6LoadparametersinIEEE30-bus...................
5.7SimulationresultsofIEEE30-bustestsystem............
Preface
Asthemainbuildingblockofthesmartgridsystems,microgrid(MG)integrates anumberoflocaldistributedgenerationunits,energystoragesystems,andlocal loadstoformasmall-scale,low-andmedium-voltagelevelpowersystem.Ingeneral,anMGcanoperateintwomodes,i.e.,thegrid-connectedandislandedmode. Recently,inordertostandardizeitsoperationandfunctionality,hierarchicalcontrolforislandedMGsystemshasbeenproposed.Itdividesthecontrolstructureinto threelayers,namely,primary,secondary,andtertiarycontrol.Theprimarycontrol isbasedoneachlocaldistributedgeneration(DG)controllerandisrealizedinadecentralizedway.Inthesecondarylayer,thefrequencyandvoltagerestorationcontrol aswellasthepowerqualityenhancementisusuallycarriedout.Inthetertiarycontrol,economicdispatchandpowerflowoptimizationissuesareconsidered.However, conventionallyboththesecondaryandtertiarycontrolarerealizedinacentralized way.Therearecertaindrawbackstosuchcentralizedcontrol,suchashighcomputationandcommunicationcost,poorfaulttoleranceability,lackofplug-and-play properties,andsoon.Inordertoovercometheabovedrawbacks,distributedcontrol isproposedinthesecondarycontrolandtertiaryoptimizationinthisbook.
Inthesecondarycontrol,restorationsforbothvoltageandfrequencyinthedroopcontrolledinverter-basedislandedMGareaddressed.Adistributedfinite-timecontrolapproachisusedinthevoltagerestorationwhichenablesthevoltagesatall theDGstoconvergetothereferencevalueinfinitetime,andthus,thevoltageand frequencycontroldesigncanbeseparated.Then,aconsensus-baseddistributedfrequencycontrolisproposedforfrequencyrestoration,subjecttocertaincontrolinput constraints.Theproposedcontrolstrategycanrestorebothvoltageandfrequencyto theirrespectivereferencevalueswhilehavingaccuraterealpowersharing,undera sufficientlocalstabilityconditionestablished.
Thenthedistributedcontrolstrategyisalsoemployedinthesecondaryvoltage unbalancecompensationtoreplacetheconventionalcentralizedcontroller.Theconceptofcontributionlevel(CL)forcompensationisfirstproposedforeachlocalDGto indicateitscompensationability.Atwo-layersecondarycompensationarchitecture consistingofacommunicationlayerandacompensationlayerisdesignedforeach
localDG.Atotallydistributedstrategyinvolvinginformationsharingandexchange isproposed,whichisbasedonfinite-timeaverageconsensusandnewlydeveloped graphdiscoveryalgorithm.
Inthetertiarylayer,adistributedeconomicdispatch(ED)strategybasedonprojectedgradientandfinite-timeaverageconsensusalgorithmsisproposed.Bydecomposingthecentralizedoptimizationintooptimizationsatlocalagents,ascheme isproposedforeachagenttoiterativelyestimateasolutionfortheoptimization probleminadistributedmannerwithlimitedcommunicationamongneighbors.It isshownthattheestimatedsolutionsofalltheagentsreachconsensusoftheoptimal solutionasymptomatically.Besides,twodistributedmulti-clusteroptimizationmethodsareproposedforalarge-scalemulti-areapowersystem.Wefirstproposetodivide allthegeneratoragentsintoclusters(groups)andeachclusterhasaleadertocommunicatewiththeleadersofitsneighboringclusters.Thentwodifferentschemesare proposedforeachagenttoiterativelyestimateasolutionoftheoptimizationprobleminadistributedmanner.Itistheoreticallyprovedthattheestimatedsolutionsof alltheagentsreachconsensusoftheoptimalsolutionasymptomatically.Inaddition, anovelhierarchicaldecentralizedoptimizationarchitectureisproposedtosolvethe EDproblem.Similartodistributedalgorithms,eachlocalgeneratoronlysolvesits ownproblembasedonitsowncostfunctionandgenerationconstraint.Anextracoordinatoragentisemployedtocoordinateallthelocalgeneratoragents.Besides,it alsotakestheresponsibilityforhandlingtheglobaldemandsupplyconstraint.Inthis way,differentfromexistingdistributedalgorithms,theglobaldemandsupplyconstraintandlocalgenerationconstraintsarehandledseparately,whichwouldgreatly reducethecomputationalcomplexity.Itistheoreticallyshownthatunderproposed hierarchicaldecentralizedoptimizationarchitecture,eachlocalgeneratoragentcan obtaintheoptimalsolutioninadecentralizedfashion.
Adistributedoptimalenergyschedulingstrategyisalsoproposedinthetertiary layer,whichisbasedonanewlyproposedpricingstrategynamed PDpricing.Conventionalreal-timepricingstrategiesonlydependonthecurrenttotalenergyconsumption.Incontrasttothis,ourproposedpricingstrategyalsotakestheincrementalenergyconsumptionintoconsideration,whichaimstofurtherfillthevalleyload andshavethepeakload.Anoptimalenergyschedulingproblemisthenformulated byminimizingthetotalsocialcostoftheoverallpowersystem.Twodifferentdistributedoptimizationalgorithmswithdifferentcommunicationstrategiesareproposedtosolvetheproblem.
Authors
FanghongGuo receivedhisB.Eng.degreeinautomationsciencefromSoutheast University,Nanjing,China,inJuly2010,M.Eng.degreeinautomationscience& electricalengineeringfromBeihangUniversity,Beijing,China,inJanuary2013,and Ph.D.degreeinsustainableearthfromEnergyResearchInstitute@NTU,InterdisciplinaryGraduateSchool,NanyangTechnologicalUniversity,Singapore,inNovember2016.HeiscurrentlyascientistinExperimentalPowerGridCenter(EPGC), AgencyforScience,TechnologyandResearch,Singapore.Hisresearchinterestsincludedistributedcooperativecontrol,distributedoptimizationonmicrogridsystems, andsmartgrid.Hereceivedthe2015NationalAwardforOutstandingSelf-financed ChineseStudentsStudyAbroadin2015.
ChangyunWen receivedhisB.Eng.degreefromXi’anJiaotongUniversity,Xi’an, China,in1983andhisPh.D.degreefromtheUniversityofNewcastle,Newcastle, Australia,in1990.FromAugust1989toAugust1991,hewasaresearchassociate andthenpostdoctoralfellowatUniversityofAdelaide,Adelaide,Australia.Since August1991,hehasbeenwithSchoolofElectricalandElectronicEngineering, NanyangTechnologicalUniversity,Singapore,whereheiscurrentlyafullprofessor.Hismainresearchactivitiesareintheareasofcontrolsystemsandapplications, autonomousroboticsystems,intelligentpowermanagementsystems,smartgrids, cyber-physicalsystems,complexsystemsandnetworks,model-basedonlinelearningandsystemidentification,signalandimageprocessing.
Dr.Wenisanassociateeditorofanumberofjournalsincluding Automatica, IEEETransactionsonIndustrialElectronics and IEEEControlSystemsMagazine Heistheexecutiveeditor-in-chiefof JournalofControlandDecision.Heserved IEEETransactionsonAutomaticControl asanassociateeditorfromJanuary2000 toDecember2002.Hehasbeenactivelyinvolvedinorganizinginternationalconferencesplayingtherolesofgeneralchair,generalco-chair,technicalprogramcommitteechair,programcommitteemember,generaladvisor,publicitychairandso on.HereceivedtheIESPrestigiousEngineeringAchievementAward2005fromthe
InstitutionofEngineers,Singapore(IES)in2005.HereceivedtheBestPaperAward ofIEEETransactionsonIndustrialElectronicsin2017.
HeisafellowofIEEE,wasamemberofIEEEFellowCommitteefromJanuary 2011toDecember2013andaDistinguishedLecturerofIEEEControlSystemsSocietyfromFebruary2010toFebruary2013.
Yong-DuanSong receivedhisPh.D.degreeinelectricalandcomputerengineeringfromTennesseeTechnologicalUniversity,Cookeville,USA,in1992.Hehelda tenuredfullprofessorpositionwithNorthCarolinaA&TStateUniversity,Greensboro,from1993to2008andaLangleyDistinguishedProfessorpositionwiththe NationalInstituteofAerospace,Hampton,VA,from2005to2008.HeisnowDean oftheSchoolofAutomation,ChongqingUniversity,andthefoundingdirectorofthe InstituteofSmartEngineering,ChongqingUniversity.HewasoneofthesixLangley DistinguishedProfessorswiththeNationalInstituteofAerospace(NIA),founding directorofCooperativeSystemsatNIA.Hehasservedasanassociateeditor/guest editorforseveralprestigiousscientificjournals.
Hisresearchinterestsincludeintelligentsystems,guidancenavigationandcontrol,bio-inspiredadaptiveandcooperativesystems,railtrafficcontrolandsafety,and smartgrid.
Chapter1 Introduction
Inthischapter,wefirstpresentthebackground,motivationandobjectivesofthe researchinthisbook.Thensomedetailedliteraturereviewsonmicrogirdaswellas itsstate-of-artcontrolandoptimizationstrategiesareconducted.Finally,themajor contributionsandorganizationofthisbookaresummarized.
1.1BackgroundandMotivation
Thedemandforelectricalenergyisincreasingrapidly.Itisestimatedthatelectricity demandwilldoublebetween2000and2030,withanannualgrowthrateof2.4%, fasterthantheincreaseofanynon-renewableenergysource[1].Hencemorerenewableenergysourcesareneededinfutureenergysystems.TheRenewablesPortfolio StandardsintheUnitedStatessetsagoalofincreasingthepercentageofrenewable energysourcesto33%by2020[2].InEurope,thetargetistoraisetherenewable energypenetrationpercentagefromthecurrentlevelof20%to50%by2050[3].
Therenewableenergysourcesareusuallylocatedinadistributedmanner,e.g., photovoltaic(PV)andwind,asopposedtotheconventionallargecentralizedpower plants.Thisleadstoalargerandmorecomplexnetworkedenergysystem.Itisa largenonlinearhighlystructuredsystemconsistingofanumberofinterconnected distributedgenerators(DGs)orsubsystems.Itisdifficulttoemployacentralized controllertocontrolsuchalarge-scalesystemformanyreasonssuchaslimitedcommunicationcapabilityamongthesubsystemsaswellaslimitedcomputationability inonesinglecontroller.Inordertohandlethisissue,adecentralizedcontrolmethod hasbeenproposedtodesignalocalcontrollerforeachsubsystem.Forsimplicityand familiarity,eachlocalcontrollerisusuallydesignedandimplementedbyignoringthe interactionsfromothersubsystemsandonlyusingitslocallyavailableinformation.
Thisisessentiallyequivalenttoimposingstructuralconstraintsonthecentralized controller.Thuscontrollabilityisrestrictedbythedecentralizedapproachandsystemcontrolperformancesaredeteriorated.Onetypicalexampleoftheconsequences ofthedrawbacksofsuchcontrolstrategyisthewidespreadblackoutofAugust2003 inNorthAmerica[4].Inthataccident,eachsubsystemonlyfocusedonmaintaining itsownsubsystemstabilityandtransferredtheextraloadtoothersubsystems,which madetheoverloadmoresevereandeventuallycausedacascadingcorruption[5].
Notethatcommunicationtechniqueshaveadvancedsignificantlyandhighlyefficientcommunicationnetworksarereadilyavailableinrecentindustrialinfrastructures.Itisnaturalask,Willthesystemcontrolperformancebeimprovedbyletting thelocaldecentralizedcontrollerscommunicatewiththeirneighboringcontrollers? Theanswershouldbepositive.Infact,suchcontrolstrategyisreferredtoasdistributedcontrol,whichhasbeenwidelystudiedandimplementedsuccessfullyin manyotherfieldssuchasprocesscontrol[6],trafficcontrol[7],andsoon.Inthis book,weproposetoapplydistributedcontrolstrategiestoenergysystems,whichallowinformationexchangeamonglocalcontrollersbyestablishingacommunication networktopologyamongthem.Infact,distributedcontrolstrategiescanbeconsideredasatradeoffbetweenthecentralizedcontrolandthedecentralizedcontrolby combiningtheiradvantages.Thecomparisonamongcentralized,decentralized,and distributedcontrolschemeisillustratedin Fig.1.1
Therearealsootherfactorsthatmotivatedistributedcontrol[8],suchasthe deregulationoftheelectricalmarket.Theelectricitymarketisopenfornewsuppliersandconsumerscanchoosetheirownsuppliers.Thelimitationthatthecurrent controlmethodsimposes(lowflexibility,lowresiliencetofaults)alsorequiresthat thecontrolalgorithmforthepowersystemshouldbereconsidered.
1.2ObjectivesandScope
Recently,theintegrationofthedistributedrenewableenergyresourcesisevolving asanemergingandpromisingpowerscenariofortheenergysystem.Smartgrid, asamodernizedelectricalgrid,usesinformationandcommunicationtechnologyto improvetheefficiency,reliability,andeconomicsoftheproductionanddistribution ofelectricity[9, 10, 11].Asthemainbuildingblockofthesmartgrid,microgrid (MG)integratesanumberoflocalDGunits,energystoragesystems,andlocalloads togethertoformasmall-scalepowersystem.Inthisbook,wewillproposesomedistributedcontrolschemesfortheMGcontrol.Recently,inordertostandardizeitsoperationandfunctionality,hierarchicalcontrolforislandedMGsystemshasbeenproposed.Itdividesthecontrolstructureintothreelayers,namely,primary,secondary, andtertiarycontrol.Conventionallyboththesecondaryandtertiarycontrolarerealizedinacentralizedway.However,withthesizeoftheMGgrowing,itbringssome disadvantagessuchaspoordynamicsandhighcomputationalcost.Insteadofusing acentralizedcontroller,wedecomposethecentralizedcontrollerintodecentralized onesandallowthemtocommunicatewiththeirneighboringcontrollers.Inthisway, wecanmakethecontrolsystemmoreflexibleandalsoreliable.
Theresearchobjectivesandscopesaredetailedasfollows:
1.BasedontheMGprimarycontrolmodel,developdistributedsecondarycontrolschemesfortheislandedMG.Thiscontrolstructureallowseachlocalcontroller tocommunicatewithitsneighboringlocalcontrollers.Themainfunctionofthesecondarycontrolistorestorethefrequencyandvoltagevaluestotheirnominalvalues whilekeepingtherealpowersharingaccuracynomatterhowtheloadsvary.
2.Developadistributedsecondarycontrolschemeforthevoltagequalityenhancementproblemsuchasvoltageunbalancecompensation.Theproposedcontrol schemeshouldbeflexibleandmakethecontrollerhavethe“plugandplay”property.
3.Developadistributedtertiarycontrolstructuretosolvetheeconomicdispatch andoptimalenergyschedulingproblemsinthesmartgridsystem.Besides,asthe energysystemhasbecomeainterconnectedlarge-scalesystem,amorepropermulticlusteroptimizationmethodshouldbedeveloped.
Inthefollowing,wewillgivesomeoverviewofrecentresearchonMGaswell asitscontrolstrategies.
1.3Microgrid
AnMGisasmall-scalelowandmedium-voltagelevelpowersystemthatintegrates anumberoflocaldistributedgenerator(DG)units,energystoragesystemsandlocal loadstogether[12, 13].Differentfromtheconventionalsynchronousgenerator(SG), theDGintheMGisinverter-interfacedwithsustainableprimeenergysourcessuch asfuel-cells(FC),photovoltaic(PV),andwindpowergenerators[14, 15].Compared tothetraditionalfossil-fuel-basedpowergrid,benefitsbroughtbyMGincludeless carbonconsumption,fasterdemandresponse,andsoon.
TherearedifferenttypesofMGsreportedintheliterature.Accordingtothebus type,theMGcanbeclassifiedintothreetypes,namely,alternatingcurrent(AC)MG, directcurrent(DC)MG,andhybridAC/DCMG[16].Moredetailedinformationcan befoundin[16, 17, 18].Inthisbook,wemainlyfocusontheresearchofACMG.
ThereareseveralreportedMG-relatedresearchanddevelopmentprojectsaround theworld.InSingapore,EnergyResearchInstitute@NTU(ERI@N),Nanyang TechnologicalUniversity,issettingupSoutheastAsia’sfirstandlargestmicrogrid locatedatSemakauIsland.Itwilldemonstratehowtogenerateelectricityfrommultiplesourcesincludingsolar,wind,tidal,diesel,aswellasintegrateenergystorage andpower-to-gastechnologies[19].ItisalsoreportedthatEnergyMarketAuthority (EMA)inSingaporeispilotingamicrogridtest-bedatthejettyareaofPulauUbin, anislandnorth-eastofSingapore[20].Thistest-bedaimstoassessthereliability ofelectricitysupplywithinamicrogridinfrastructureusingintermittentrenewable energysourcessuchasPVtechnology.
IntheEuropeUnion(EU),theMGresearchhasbeenconductedextensively since1998.Onerecentprojecttitled MoreMicrogrids:AdvancedArchitecturesand ControlConceptsforMoreMicrogrids aimstoinvestigatealternativeMGcontrol strategiesandalternativenetworkdesigns,anddevelopnewtoolsforMGmanagementoperationandstandardizationoftechnicalandcommercialprotocols[21].This isafollow-upprojectoftheproject Microgrids:LargeScaleIntegrationofMicroGenerationtoLowVoltageGrids,whichisthefirstactivityatEUleveldealingindepthwithMG[22].
IntheUS,onewell-knownMGprojectisconductedbyConsortiumforElectric ReliabilityTechnologySolutions(CERTS).Thisprojectexplorestheimplicationsfor powersystemreliabilityofemergingtechnologicalandenvironmentalinfluences.It isreportedthatthisCERTSMGconcepthasbeenfullydevelopedandalaboratoryscaletestsystemhasbeenbuilt[23].
Comparedtothetraditionalpowersystem,MGhasthefollowingadvantages [24]:
1.Itintegratesthedistributedrenewableenergyresources,thusitleadstoless carbonconsumptionandalsoreducesenergycost.
2.Itismoreenergyefficient.SincetheDGsareusuallyclosetotheloads,the powertransmissionlosswillbegreatlyreduced.Alsoithasfasterdemandresponse thanthetraditionalpowersystem.
3.Itcanprovidehighpowerquality.AstheDGsareusuallyinterfacedwith
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“The volume is one that challenges our present individual indifference to the Russia of today and of the future.”
Springf’d Republican p11a My 30 ’20 1100w
“It should not be neglected by anyone interested in commercial or other relationships with Russia.” Reed Lewis
Survey 44:50 Ap 3 ’20 220w
In this story of dual personality a man, Langdom Kirven, after excessive fatigue and brain-fag, loses himself and consciousness, and wakes up in a hospital another man. In the morning he had said good-bye to his wife and little son and taken a train to New York. The new man is a crook and a criminal, albeit a genius. After seven years his one-time bosom friend and business partner, Spencer Ellis, finds him on a bench in the park, a down and out tramp. Ellis recognizes Kirven and implores him to return to his old life. But there is no memory in Kirven, now John Gorham, and Ellis is at last forced to believe that the external resemblance hides a strange personality. But he gives Gorham a chance to retrieve his fall in fortunes, which the latter does with bold and doubtful business methods. He also falls passionately in love with Naomi, Ellis’ cousin. One morning after another crisis, John Gorham has fled with all memory of himself and a bewildered Kirven awakens in the latter’s office. After this a succession of alternations follows, each one leaving the subject and his friends more bewildered and perplexed than ever. At last an eminent physician finds the way out. The split personality can be unified by a complete realization of the situation and henceforth Langdom Kirven can go through the remainder of his life whole, although cursed with a continuous memory.
“Somewhat melodramatic and rather long drawn out, but cleverly managed. Will appeal to those who read for plot interest.”
Booklist 17:157 Ja ’21
“It is a difficult piece of work which is admirably well done.” D. L. M. Boston Transcript p7 Ag 18 ’20 580w
“Miss Davis has handled her material very well indeed, with much ingenuity of invention and with commendable care in the working out of her great amount of detail and complication. The novel is a good piece of literary workmanship in construction and development.”
N Y Times 25:321 Je 20 ’20 420w
DAVIS, PHILIP, and SCHWARTZ, BERTHA,
comps. Immigration and Americanization. $4 (1½c) Ginn 325.7
20–4542
The book is a compilation of selected readings, on the title subject. It “aims to cover the field of immigration and Americanization from every possible point of view, subject to the limits of a single volume. It is particularly designed to meet the needs of high schools, colleges universities, and chautauquas, which have been frequently at a loss in recommending to the student, investigator, official, or general public a handbook on these twin topics.” (Preface) The selections have been arranged chronologically and include some of the most recent contributions on the subject from writers including Jane Addams, Edward Everett, Henry Cabot Lodge, Emily Greene Balch, Edward A. Steiner, E. A. Goldenweiser, Paul U. Kellogg, John Mitchell, Edward Alsworth Ross, Edward T. Devine, Lillian D. Wald, J. E. Milholland, Samuel Gompers, Woodrow Wilson, Franklin K. Lane, Louis D. Brandeis, Theodore Roosevelt. The contents are in two parts. In book 1 the selections are classified under: History; Causes; Characteristics; The new immigration; Effects; Immigration legislation. Book 2 contains: Americanization: policies and
programs; Distribution; Education; Naturalization and citizenship; Americanism. There is an appendix, a bibliography and an index.
Booklist 17:51 N ’20
“The book should be of value to both the general reader and the special student.”
Boston Transcript p11 My 22 ’20 200w
“The compilers have exercised diligence and judgment, but with a few exceptions the selections lack the ‘human touch.’ It would appear that an undue proportion of space is allotted to the new immigration, even admitting that from the standpoint of the present time and the Americanization worker greater emphasis is justifiable.” G: M. Stephenson Mississippi
A British work designed to meet the rapid development of the knitted fabrics industry and to supply the demand of new firms for information. Contents: Development of the knitted fabric; Knitting
and weaving compared; Latch needle knitting; Types of knitting yarns; Systems of numbering hosiery yarns; Calculations for folded knitting yarns; Bearded needle knitting; Setting of knitted fabrics; Various knitting yarns; Winding of hosiery yarns; Circular knitting; Colour in knitted goods; Colour harmony and contrast; Defects in fabrics. There are sixty-one illustrations and an index.
DAVIS, WILLIAM STEARNS. History of
France; from the earliest times to the treaty of Versailles. il *$3.50 (2c) Houghton 944
19–19268
For descriptive note see Annual for 1919.
“Professor Davis has the knack of vivid and fluent narrative. The tale reads well and is interesting. The author makes the great figures of French history appear living.” C. H. C. Wright
Am Hist R 26:313 Ja ’21 580w
Booklist 61:163 F ’20
“An interesting feature of the story is that which tells of the relation of France to the crusades. There is an extremely interesting account of life in France in the feudal ages. The story of the revolution is told rapidly, but with great brilliancy. As a single volume history of France this must take its place in the foremost rank.” E. J. C.
Boston Transcript p6 Ja 3 ’20 550w
“Though one can clearly discern the author’s purpose of presenting his facts fairly and with due justice to all, he has not perfectly understood the spirit and ideals that have made France. Early and mediæval France cannot be judged by the ideals of modern American Protestantism.”
Cath World 111:256 My ’20 220w
“His limited space excludes detailed interpretation of separate events, and the author is also compelled to give only the most perfunctory notice to the economic phenomena which are associated with various stages of French history. On the political side, however, the work is reasonably complete, and Professor Davis shows an excellent sense of proportion in laying special stress upon what may be called the revolutionary era of French history.” W: H: Chamberlin
Dial 68:255 F ’20 1500w
Nation 111:109 Jl 24 ’20 300w
New Repub 23:207 Jl 14 ’20 1650w
“The book is much more than a mere history; it is a colorful romance, with a splendid nation as a background, and most of the characters cast in a heroic mold.”
N Y Times 25:303 Je 6 ’20 420w
“The present volume is, so far as we know, the only truly comprehensive history of France. Aside from its comprehensiveness, the text has been clearly and compactly written by one who has an enviable knowledge of sources. ”
Outlook 124:431 Mr 10 ’20 80w
“Though very sympathetic to his subject, and though he often animadverts to the ravages of the Hun in the present when telling of the past, his tone is scholarly and his attitude sufficiently impartial. Mr Davis has added an excellent select bibliography. Unfortunately, there is almost nothing of French literature and art.”
Review 2:285 Mr 20 ’20 280w
“This book becomes at once the standard single-volume history of France in the English language.”
R of Rs 61:335 Mr ’20 100w
“Not the least attractive feature of the book is the excellent diction. Many of the illustrations are reproductions of rare prints and paintings, and they greatly enhance the value of the work, which is, indeed, a modern and trustworthy textbook.”
Springf’d Republican p9a F 29 ’20 140w
DAW, ALBERT W., and DAW, ZACHARIAS
W: Compressed air power. il *$7.50 Pitman 621.5
“A treatise on the development and transmission of power by compressed air for engineers and draughtsmen, and for students of applied science.” (Sub-title) “The compression, expansion, exhaust, and flow of air and gases are very fully dealt with, formulae deduced for making the necessary computations, and practical examples solved to assist those concerned in the design and use of compressed air plant and machines.” (Preface) The book has seventy-five illustrations, forty tables and numerous worked out examples, and is indexed. The authors are members of the Institution of mining and metallurgy [of Great Britain]. N Y P L New Tech Bks p59 Jl ’20 190w
DAWSON, CONINGSBY WILLIAM. Little house.
il *$1.50 (9c) Lane
20–16158
The little house tells its own story. It is a very old and empty little house, as it stands in “Dolls’ House Square” in London, and on the nights of air-raids and bombing, it is a very frightened little house. But it is not too frightened to give shelter to others who are afraid, too, and so one night when “the little lady who needed to be loved, but did not know it,” crept in, with her two little children, they are amply protected. And presently, “the wounded officer who wanted rest,” looking for a haven from the raid sought it too in the little house. Then the officer goes off to war, and the little lady comes to live in the house. After the armistice, the officer returns, and, again in the shelter of the little house, finds the rest he craves more than
ever, and “the little lady” receives the love she needs. And the little house feels that its part in the romance has not been inconsiderable.
“By making the house in question narrate the scenes its walls have witnessed. Mr Coningsby Dawson has aimed, not too successfully, at imparting a Hans Andersen atmosphere to occurrences which have not much in common with the traditional material of fairy-tale.”
Ath p892 D 31 ’20 140w
Booklist 17:157 Ja ’21
“A story which has a real Christmas flavor and which would warm the heart of anybody whatever is ‘The little house.’” Margaret Ashmun
Bookm 52:342 D ’20 120w
“The story has a charm as elusive as the appealing quality that won so many followers for Maude Adams. It is as endearing as ‘Roaming in the gloaming’ or ‘Comin’ through the rye. ’ In it sentiment keeps clear of sentimentality.”
N Y Times p2 S 19 ’20 1000w
“‘The little house’ is really a Christmas story and a very delightful and charming one. The fanciful manner in which the story is told by the old house in which the scenes take place is beautifully conceived and finely carried out.”
Outlook 126:334 O 20 ’20 60w
“Mr Dawson has chosen a rather childish allegory as his method, although, after having read the book, one may look at a house with a slightly more human feeling of childish fancy. The redeeming feature of the book is the atmosphere of old London. Aside from these glimpses of old London, ‘The little house’ is hardly more than a sweet book for sweet people.”
Springf’d Republican p9a O 17 ’20 330w
“For all its pretty sentiment (or, rather, because of it), the whole thing is a pure ‘machine,’ the working of which Mr Dawson has mastered under western influences.”
The Times [London] Lit Sup p781 N 25 ’20 90w
DAWSON, EDGAR. Organized self-government. il *$1.40 Holt 353
20–10285
The object of this volume is to serve as a school text-book in teaching government, organized and political cooperation, the functions of government and the problems to be met by those who perform those functions. It is to arouse the child’s interest in government as a practical subject and to open his eyes to noticing its effects in the street, in the home, in the school. This latter purpose, more especially, is to be accomplished by the suggestions and questions at the end of each chapter. The contents are in five parts. Part I, Elements of self-government, shows how voluntary cooperation depends on parliamentary law, rules and legislation,
rulers and officers, and a constitution. Part II, Self-government in cities, applies these elements to all the details of city government; Parts III and IV do the same for the states and the United States. Part V, Some general ideas about self-government, has chapters on: Socialism and capitalism; Parties and leaders; Organized government; and Real international law. In the appendix some of the accepted principles of political cooperation are discussed, i.e. the short ballot principle; civil service reform; the executive budget; the principle of responsible leadership; etc.
“The book is sure to take its place among the few best ones in its field.”
20–5381
“Mr Dawson builds his thesis that Sinn Fein is Bolshevism by quoting Sinn Fein leaders, and refers the reader to name, page, date of his authority. He goes back to the earliest attempts of Ireland to free herself from England, and traces the whole movement, the influences behind it and the work of the leaders who led, up to today, when the new (Irish) nationalism ‘starting with lofty ideals of national regeneration on the old lines of the ancient culture, begins to seek its inspirations from modern sources of unspeakable corruption.’”—Boston Transcript
Ath p496 Ap 9 ’20 100w
“Will not please those who take the opposite stand, but worth while as a well done presentation of the objections to Ireland’s attitude.”
Booklist 17:24 O ’20
“As a polemical writer Mr Dawson is a comfort because his proofs are not of the unidentified sort so common in the mouths of platform orators. He does not employ vituperation as argument nor blackguarding as punctuation. ‘Red terror and green ’ is a timely, excellent guide book to the present meaning and purpose of Sinn Fein.”
W. R. B.
Boston Transcript p6 Ap 14 ’20 1650w
“So evidently prepared from the standpoint of reactionery British interests as to become propaganda in its most palpable and, therefore, most useless form.” Cath World 112:550 Ja ’21 80w
Reviewed by Preserved Smith
“The intrigues of Casement with the Germans make excellent material for building up a theory that Sinn Fein was part of a German plot, and in a world torn by Bolshevism it is plausible to suggest that Sinn Fein emissaries have been seeking to combine the forces of disorder at home with the agencies of disorder in other countries. But Mr Dawson will not easily convince those who know rural Ireland that its peasantry now bitterly Sinn Fein are now or were ever bolshevistic.” H. L. Stewart
Spec 124:388 Mr 20 ’20 1200w
“The reader will be impressed rather by the care with which the author has followed Irish events than by his insight into the psychic and temperamental change which has affected the Irish people during the period which he reviews.”
The Times [London] Lit Sup p110 F 12 ’20 340w
DAWSON, WILLIAM JAMES.[2] Borrowdale tragedy. *$2 (2½c) Lane
20–19918
The tragedy of the title, altho the central incident of the book, is by no means its central theme. The tragedy is the death of old James Borrowdale, and the subsequent trial of his young wife Flora and her
friend Cecil Twyfold for his murder, of which they are acquitted. The major part of the book, however, is taken up with the love of Cecil and Flora, its development while Flora was still bound and the reaction of the tragedy upon them. The expansion of their characters is along lines contrary to convention, as Cecil expresses it, they have taken the “downward path to salvation,” downward, that is, from the standards of material success that the world sets up. A plea for individual freedom, as opposed to the usages of conventional society, is really the keynote of the book.
“There is an undeniable simplicity in the writer’s style, a genial mellowness that in a tale like this is really extraordinary. There is hardly a writer today that could take the structure of this novel and its strong plea for individualism as opposed to social conventions, with its technically unhappy ending, and not make it despite brilliancy, a hard and cynical book. On the contrary Dr Dawson has written with deep humanness and charm. We have had the fortune to read few novels of the present season with such genuine delight.” S. L. C.
Ours is a simian civilization. If we had not descended from the monkey what would our world be like from the point of view of extraterrestrial beings? If the ant and the bee, or the big cats, or the elephant or any of the other beasts had achieved the hegemony? Such whimsical questions with their conjectures were suggested by a
Sunday afternoon Broadway crowd to the author and his friend Potter. The author’s illustrations are as amusing as his fancies.
“It was a good idea, and Mr Day has a real though immature gift of lightness in treating a solid subject. But his theme is really too big for his ninety pages, and although his thinking is honest and courageous it tends to become unsubstantial.”
Ath p145 Jl 30 ’19 150w
“Aside from the amusing quality there is a basis of shrewd comment.”
Booklist 17:21 O ’20
Boston Transcript p4 O 6 ’20 270w
“No less complete and varied than his estimate of man is Mr Day’s expression of it: a natural blend of wisdom with lightness, humour with profundity, hope with art, economy with abundance, kindliness with malice. The quality that makes possible such alliances is the one most infrequently granted to mortals: Mr Day sees things as they are beneath accumulated centuries of appearances; he cannot, he will not be fooled.” Robert Littell
Dial 69:197 Ag ’20 1300w
“Mr Clarence Day’s whimsicality is quite virile; it is the expression of a naturally ingenuous mind; ‘innocent’ in the Nietzschean sense and not incapable of a certain gentle philosophic malice.”
Freeman 1:358 Je 23 ’20 280w
“The most amusing little essay of the year. ”
Ind 103:318 S 11 ’20 360w
Nation 111:76 Jl 17 ’20 500w
“It ought to interest any lively spirit because of its grace and reasonableness. And it ought to entrap and enlighten any slack soul who may pick it up in search for amusement. Amusing it unquestionably is, but a great deal more than amusing, to follow this grim parallel between the ways of apes and men. ” R. T.
New Repub 23:233 Jl 21 ’20 650w
“While his treatment of the subject is amusingly interesting, it is none the less a serious one. The whole essay is, in fact, a bitter arraignment of our present order of civilization.” Alvin Winston
N Y Call p10 Ag 1 ’20 640w
Review 3:306 O 13 ’20 1400w
Springf’d Republican p11a Ag 22 ’20
500w
Survey 44:450 Je 26 ’20 200w
