Adaptive protection coordination scheme for distribution network with distributed generation using ABC

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ScienceDirect

JournalofElectricalSystemsandInformationTechnology3(2016)320–332

Adaptive

protection

coordination

scheme

for

distribution

network

with

distributed

generation

using

ABC

A.M.

Ibrahim

,

W.

El-Khattam

,

M.

ElMesallamy

,

H.A.

Talaat

a_{FacultyofEngineering,AinShamsUniversity,Egypt} b_ABB,Egypt

Received13October2015;accepted5November2015 Availableonline2August2016

Abstract

ThispaperpresentsanadaptiveprotectioncoordinationschemeforoptimalcoordinationofDOCRsininterconnectedpower networkswiththeimpactofDG,theusedcoordinationtechniqueistheArtificialBeeColony(ABC).Theschemeadaptstosystem changes;newrelayssettingsareobtainedasgeneration-levelorsystem-topologychanges.Thedevelopedadaptiveschemeisapplied ontheIEEE30-bustestsystemforbothsingle-andmulti-DGexistencewhereresultsareshownanddiscussed.

©2016ElectronicsResearchInstitute(ERI).ProductionandhostingbyElsevierB.V.ThisisanopenaccessarticleundertheCC BY-NC-NDlicense(http://creativecommons.org/licenses/by-nc-nd/4.0/).

Keywords:Adaptiveprotection;ArtificialBeeColony;Directionalovercurrentrelay;Distributiongeneration;Optimalcoordination

1. Introduction

Theelectricalpowersystemmaybesubjectedtomanytypesof faultsduringitsoperationthat candamage the equipmentconnectedtothissystem,sothe importanceofdesigningareliableprotectivesystemarises,inorderto achievesuch reliability,aback-up protective schemeisprovided incaseof any failureinthe primary protection. Theback-upschemeshouldnotoperateunlesstheprimaryfailstotaketheappropriateaction,whichmeansitshould operateafteracertaintimedelayknownascoordinationtimeinterval(CTI),givingthechancefortheprimaryprotection tooperatefirst.Theabovementionedscenarioleadstotheformulationoftheprotective relaycoordination, which consistsofselectionofasuitablesettingofeachrelaysuchthat theirfundamentalprotectivefunctionismetunder thedesirablequalitiesofprotectiverelaying,namelysensitivity,selectivity,reliability,andspeed(Anderson,1999). However,introducingDGintothepowersystemterritorieschangestheexistingprotectionscheme.AlthoughDGhasa lotofadvantagesonsystemdesignandoperation(Griffin,2000),alsoithasnegativeeffectsaswell,oneofthesenegative

∗_{Correspondingauthor.}

E-mailaddresses:[email protected](A.M.Ibrahim),[email protected](W.El-Khattam), [email protected](M.ElMesallamy),[email protected](H.A.Talaat).

PeerreviewundertheresponsibilityofElectronicsResearchInstitute(ERI).

http://dx.doi.org/10.1016/j.jesit.2015.11.012

2314-7172/©2016ElectronicsResearchInstitute(ERI).ProductionandhostingbyElsevierB.V.ThisisanopenaccessarticleundertheCC BY-NC-NDlicense(http://creativecommons.org/licenses/by-nc-nd/4.0/).

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effectsisitseffectonsystemprotection,especiallythedisturbancecausedtotheexistingrelaycoordination(Girgis

andBrahma,2001).Thisdisturbanceiscausedbythechangeinvalueanddirectionofboththesystem’spowerflow

(undernormaloperation)andshort-circuitscurrent(underfaultconditions)(BarkeranddeMello,2000).Theimpact ofDGdependsonDGs:size,location,technologytype,andmethodofinterconnectionwiththepowersystem(Brahma

andGirgis,2004).Duetooftheseimpacts,thesettingofallprotectionrelayshavetobecheckedtoensurethatno

mis-coordinationhappenedinthesystem,andiftherewas,theoptimalprotectiverelays’settingshavetobedetermined andsetagain,theseleadstotheintroductionofadaptiveprotectionscheme.Oneofthetechniquesthatcanbeusedto gettheoptimalsettingsistheABC;whichwasintroducedinKarabogaandBusturk(2007),thatwasmotivatedbythe intelligentbehaviorofhoneybees.ABCasanoptimizationtoolprovidesapopulation-basedsearchprocedureinwhich individualscalledfoodspositionsaremodifiedbytheartificialbeeswithtimeandthebee’saimistodiscovertheplaces offoodsourceswithhighnectaramountandfinallytheonewiththehighestnectarwhichistheoptimalsolutionis selected.

2. Coordinationproblemformulation

DOCRcoordinationproblemcanbeformulatedasoptimizationproblem,wheretheobjectivefunctiontobe min-imizedisthesumoftheoperatingtimesoftherelaysconnectedtothesystemfunctioninitsTimeDialSettingTDS

(Urdanetaetal.,1988).Theaboveproblemcanbeformulatedmathematicallyas:

min

i



jTijprimary (1)

whereT_ijistheoperatingtimeoftheprimaryrelayiforafaultj.

Inthiswork,thefollowingformulaisusedtoapproximatelyrepresenttheOCRcharacteristics(IEC60255-3):

T =K1 TDS MK2+_K3 (2) where M= I IP (3)

Iisrelaycurrent,Ip istherelay’spickupcurrent andK1,K2,K3areconstantsdepending onthetypeofthe relay

simulated.

Thecoordinationproblemissubjecttothefollowingconstraints(Urdanetaetal.,1988):

1) Coordinationcriteria:inordertoachieveareliableprotectionsystem,theprimaryprotectionhastobebackedupby anotherprotectionscheme.Thetwoprotectiveschemesshouldbecoordinatedtogether,i.e.,apredefinedCTI col-lapsesbeforethebackupschemecomesintoaction.ThisCTIdependsuponthetypeoftherelays(electromechanical ormicroprocessorbased),speedofthecircuitbreakers,andothersystemparameters.

Tbackup−Tprimary≥CTI (4)

2) Relaysettingsbounds:themaintargetofDOCRcoordinationstudyisthecalculationofitsTDSandIP.

TDS_imin≤TDS_i≤TDS_imax (5)

Inthispaper,thecoordinationproblemisaddressedasalinearoptimizationone,i.e.,ABCisusedtosolve coordi-nationproblemoffindingTDSoftherelaysforagivenIP’s.AlsoitshouldbeclearthatABCiscapableofaddressing bothlinearandnon-linearoptimizationproblems.

3. ArtificialBeeColonyABC

ArtificialBeesColonyalgorithm (KarabogaandBusturk, 2007)wasproposedfor solving numerical optimiza-tionproblems,itwasusedinrelaycoordinationinUthitsunthornetal.(2012).ABCshowsgreatresultsinDOCR coordinationinElMesallamy(2014).Thecolonyofartificialbeescontainsthreegroupsofbees:employedbeesand unemployedbees:onlookersandscouts.Firsthalfofthecolonyconsistsofemployedartificialbeesandthesecond halfconstitutestheartificialonlookers.Theemployedbeewhosefoodsourcehasbeenexhaustedbecomesascoutbee. Thepositionofafoodsourcerepresentsapossiblesolutiontotheoptimizationproblemandthenectaramountofa foodsourcecorrespondstothequalityorfitnessoftheassociatedsolution.Thenumberoftheemployedbeesisequal tothenumberoffoodsources,eachofwhichalsorepresentsasite,beingexploitedatthemomentortothenumberof solutionsinthepopulation.Inartificialbees’algorithm,thestepsgivenbelowarerepeateduntilastoppingcriterion issatisfied.

3.1. Initialphase

Swarmsarecreatedrandomlybythefollowingformulaintheinitialphase:

Xij=Xminj+rand (0,1)



Xmaxj−Xminj



(7)

3.2. Employedbeesphase

Eachemployedbeedeterminesafoodsourcerepresentingasite.Eachemployedbeesharesitsfoodsource informa-tionwithonlookerswaitinginthehiveandtheneachonlookerselectsafoodsourcesitedependingontheinformation takenfromemployedbees.Tosimulatetheinformationsharingbyemployedbeesinthedancearea,probabilityvalues arecalculatedforthesolutionsbymeansoftheirfitnessvaluesusingthefollowingequation.Thefitnessvaluesmight becalculatedusingtheabovedefinitionasexpressedinEq.(8).

Pfi =nfiti j=1fiti (8) fiti= ⎧ ⎨ ⎩ 1 a+fi fi≥ 0 1+abs (fi) fi<0 (9)

3.3. Onlookerbeesphase

Onlookersareplacedontothefoodsourcesitesbyusingafitnessbasedselectiontechnique,forexampleroulette wheelselectionmethod.

3.4. Scoutbeesphase

Everybeeswarmhasscoutsthataretheswarm’sexplorers.Theexplorersdonothaveanyguidancewhilelooking forfood.Incaseofartificialbees,theartificialscoutsmighthavethefastdiscoveryofthegroupoffeasiblesolutions.In thesearchingalgorithm,theartificialemployedbeewhosefoodsourcenectarhasbeenexhaustedortheprofitabilityof thefoodsourcedropsunderacertainthresholdlevelisselectedandclassifiedastheartificialscout.Theclassification iscontrolledby“abandonmentcriteria”or“limit”.Ifasolutionrepresentingafoodsourcepositionisnotimproved untilapredeterminednumberoftrials,thenthatsolutionisleftbyitseloyedbeeandtheemployedbeebecomesa scout.

Fig.1.IEEE30bussystem. 4. CoordinationwiththeimpactofDG

TheIEEE30bustestcaserepresentsaportionoftheAmericanelectricpowersystem(intheMidwesternUS)as ofDecember,1961(Univ.WashingtonSeattle,2006).Butasthemaintargetofthispaperisthedistributionlevelto addresstheimpactofDG,thedistributionlevel(33kV)portionsareonlyconsidered.ModifiednetworkoftheIEEE30 BusTestsystemisshowninFig.1;ithas22distributionlevelbusesand29relays(El-KhattamandSidhu,2008),where thesystemismodeledwithallofitsdetailedparameters.Thesystemisfedfromthreeprimarydistributionsubstations (132/33kV)atbuses10,12,and27.Eachprimarydistributionfeederisprotectedbytwodirectionalovercurrentrelays, onerelayateachend.Thesystemmodelisassumedtohave29existingdirectionalovercurrentrelays.Itisassumed thatallrelaysareidenticalandhavenormalinverserelaycurveswhichisrepresentedbyEq.(2)withthefollowing constants0.14,−1,and0.02forK1,K2,andK3,respectively(IEC60255-3typeA).theIpsaresettobe1.75times

the fullloadcurrent,CTI isassumed tobe 0.3sfor each backup-primaryrelaypair. Twocandidate DGlocations areassumedwhicharesubstationbus12andloadbus19.DGlocationsarechosenbasedonenvironmentalandfuel availabilityrestrictions(El-KhattamandSidhu,2008).ThechosenDGtechnologyisasynchronoustype,10MVA capacity,operating nominally at0.9lagging powerfactor, and0.15 p.u. transient reactance based onits capacity

(El-KhattamandSidhu,2008).TheDGispracticallyconnectedtothesubstationbusthroughatransformerwhichis

assumedtohave10MVAcapacityand0.05p.u.reactancebasedonitscapacity.

Twocasesare examinedtoshow theimpactof addingDGonthe settingofthe protective relaysandthe mis-coordinationthatmaybehappen.

1) CaseA:Itisthebasecasewithwell-establishedrelaycoordination,wherethereisnoDGpresentedinthesystem. 2) CaseB:DGisaddedtothesystem,whererelaysmis-coordinationhappened.

CaseA. RelayCoordinationfortheOriginalsystem.ThiscaseisconsideredasabasesystemcasewithoutDGsto evaluatethemostoptimalrelaysettings.ABCisusedtofindtheoptimalTDSofthesystem.AMatLabprogramis developedtocalculateshortcircuitandloadflowforthissystem,the3-␾faultsareappliedatthenear-endofeach relay(close-infaults),alsoanotherMatLabprogramisusedtosimulatetheABCtechnique,theconvergenceofABC totheoptimumsolutionareshowninFig.2.AsampleoftheresultsareshowninTables1–3.

CaseB. Inthisscenario,thesystemexperiencesDGoperationinitsterritories.ThepresenceofDGwillchangethe normalpowerflowaswellastheshort-circuitcurrentalloverthesystem,whichisnotrestrictedtotheDGconnected bus.ADGof(10MVA)willbeaddedatbus12thenatbus19andfinallyatboth12and19simultaneously;dueto

Table1

Samplerelaycurrent,faultcurrentandIPforCaseA.

Relay Shortcircuit(A) Loadcurrent(A) Pickup(A)

Primary 1 6352 111.97 195 Backup 19 658 118.44 207 23 363 109.7 191 Primary 5 7003 134.7 235 Backup 9 1065 312.46 546 12 1164 150.11 262 Table2

TDSvaluesofmodified30bussystemwithoutDG.

Relayno. TDS 1 0.3991 2 0.2786 3 0.1909 4 0.347 5 0.1 6 0.241 7 0.3705 8 0.1 9 0.103 10 0.3117 11 0.2309 12 0.211 13 0.3296 14 0.2904 15 0.2394 16 0.1673 17 0.2528 18 0.265 19 0.1795 20 0.1 21 0.1 22 0.2788 23 0.1 24 0.2553 25 0.2635 26 0.149 27 0.1 28 0.1 29 0.1 Table3

SampleofprimaryandbackuprelayoperatingtimeandtheirCTIgotbyABCforCaseA.

Relaypairs ABC

Tprimary(s) Tbackup(s) CTI(s)

1,19 0.78 1.08 0.30

1,23 0.78 1.09 0.32

9,16 0.42 0.75 0.32

200 300 400 500 600 700 800 900 1000 1100 1200 0 5 10 15 20 25 30 35 No of iterations Be st so lu ti on F oun d-m in T im e (s ec )

Fig.2.ConvergenceofABCtotheoptimalsolutionwithoutDG.

thepresenceofDGarelaymis-coordinationhappened.Fig.3showstheCTIforasamplerelaypairsbeforeandafter addingtheDGatbus12,itwasfoundthat18relaypairsarelessthan0.3swhenDGisaddedatbus12,22relaypairs whenDGisaddedatbus19and24relaypairswhenDGsareaddedatbothbus12and19.

Anewrelaycoordinationhastobedoneagain,toevaluatethenewoptimalrelaysettings,ABCtechniqueisused tofindtheoptimalTDSofthesystem.AsampleforthenewTDSsettingsandasampleofthreephasefaultcurrent forallscenariosareshowninTables4and5respectively.

Fig.4showstheCTIforasamplerelaypairswith/withouttheDGatbus12andafterdoingthecoordinationagain.

5. Adaptivecoordinationscheme

Fromtheprevioussectiontheimportanceof adaptiveprotectionarisesasthecoordinationstudy hastobedone everytimeaDGinstalledinthenetworkasproposedinChandranetal.(2014).

TheusedadaptiveschemeinthispaperissimilartothatinABBmicrogrids(2012),butitisvaliduptotwoDGs placedonbuses12and19ofIEEE30bussystem.Thestepsofnormalcoordinationaresimplycarriedoutasdescribed inprevioussection,onlyfourmodesofoperationsareconsidered:

Table4

SampleTDSsettingvaluesafteraddingDGsobtainedbyABC.

Relay TDS(DGatbus12) TDS(DGatbus19) TDS(DGatbus12&19)

Primary 1 0.43 0.48 0.45 Backup 19 0.20 0.26 0.24 23 0.11 0.12 0.19 Primary 5 0.1 0.1 0.1 Backup 9 0.1 0.15 0.14 12 0.22 0.29 0.25 Table5

Threephasenearendfaultcurrentseenbyprimaryrelaysinallscenariosinamperes.

Relayno. Faultcurrent(NoDG) Faultcurrent(DGatbus12) Faultcurrent(DGatbus19) Faultcurrent(DGatbus12and19)

1 6352 6584 6921 7138 2 6804 7099 6967 7252 3 6906 7241 7502 7818 4 7099 7449 7707 8038 5 7003 7876 7360 8282 ModeI:NoDG ModeII:DGatbus12 ModeIII:DGatbus19

ModeIV:DGsatbuses12and19

5.1. Requirementsofadaptiveprotectionscheme 5.1.1. Substationmastercomputer

Themastercomputer isthemaincomponent of thisscheme,it communicateswithalltherelaysinthe system choosingthe correct settingsfor eachrelay usingcommunication module,alsothe mastercomputer monitors the systemforanytopologicalchanges.

5.1.2. Microprocessorrelays

Tofollowinstruction,readinformation,communicatewiththeoutsideworld,storesettingsandswitchbetween them.Microprocessor-basedrelayfirmwareshouldevaluatetheneedtoapplyupdatedfirmware.Whilemanyfirmware updatesmaynotbecriticaltotherelayprotectionfunctions,updatedfirmwarethatcorrectscriticalprotectionfunctions shouldbegivenpriority(NorthAmericanElectricReliabilityCorporationNERC,2013).

5.1.3. Communicationfacility

Animportantpartofwide-scaleAdaptiveProtection isthecommunicationsystemrequiredtotransmitdataand commandsbetweensubstation’scomputerandrelays.IECandIEEEhavestandardcommunicationprotocolsfordigital relaysthatshouldbeadoptedbyalloftherelays’manufacturers,promotingtheuseandsecurityofthemoreadvanced featuresofdigitalrelays,thecommunicationcouldbethroughtheinternet(ZacharyZaremski,2012).

5.2. Proposedadaptiveprotectionscheme

1. Themastersubstationcomputer periodicallychecksthestatusofDGsconnectedtobus 12and19todetectthe currentmode,andselectsthecorrectsettingssavedondigitalrelaysthatcouldhaveuptosixgroupsofsettings. 2. ThecommunicationswiththemicroprocessorrelaysandDGscouldbethroughGSMusingcommunicationmodule

thatareconnectedtothemainsubstationcomputer.

3. In case of communicationfailure dueto any unexpectedcircumstancesa default groupof settings havetobe setinordertomaintainminimumreliabilityofprotectionscheme.Thegroupsettingsnumber(5)isassignedto communicationfailuremode.

4. Only5settingsarestoredintherelayswhiletherestgroupisspare. Setting1:modeInoDG

Setting2:modeIIDGatbus12 Setting3:modeIIIDGatbus19

Setting4:modeIVDGsatbuses12and19 Setting5:communicationfailure

Setting6:spare

Fig.5showstheproposedadaptiveprotectionscheme

6. DGloadingeffects

DifferentDGloadingswillaffecttherelaycurrentwhichwillrequirenewsettingsfortherelaypickupcurrentIp.

InthissectiontheDGloadingsistakenintoconsideration,acompleteloadflowstudieshavebeencarriedoutfor loadingtheDGby(40,60,80and100%)of itscapacity.Ithastobementionedthatfrompractical pointof view

(CumminsPowerGenerationwhitepaper, 2007); loadingupto30%ofDGcapacitywereneglectedtoprotectthe

SynchronousDGenginefromdamage.FourmodesofoperationareshowninTable6. ModeI:loadingcondition1withnoDG.

ModeII:loadingconditionsfrom2to5withDGatbus12. ModeIII:loadingconditionsfrom6to9withDGatbus19.

ModeIV:loadingconditionsfrom10to25withDGsatbothbuses12and19.

Itwasfoundthatsomeofrelaycurrentsofdifferentloadingconditionsat40,60and80%ofDGcapacityexceed theIpbasedonthe100%DGloadingwhichmayleadtofalsetripifsettingsof100%DGloadingareadopted.Thus

thesystemsecuritywillbeviolated.Table7showsasampleoftheseconditionsastheencircledrelayscurrentat40, 60and80%ofDGloadingexceedstheIpcurrentbasedon100%ofDGloading.Fig.6showsthenumberofpossible

relaysfalsetrip.

Proposedoptimumsettingsforadaptiveprotectionschemetobestoredintherelays

- Tosolvethedescribedissueforallloadingconditionsthepickupcurrentsaresetbasedonmaximumrelaycurrent thatmaypassatdifferentloadingofDGforeachmodemultipliedby1.5.

Fig.5.Proposedadaptiveprotectionscheme.

Table6

DifferentloadingconditionsofDGsatbus12and19.

Mode Loadingcondition DGatbus12loading

as%ofitscapacity DGatbus19loading as%ofitscapacity ModeI 1 0 0 Mode II 2 40 0 3 60 0 4 80 0 5 100 0 Mode III 6 0 40 7 0 60 8 0 80 9 0 100 Mode IV 10 40 40 11 40 60 12 40 80 13 40 100 14 60 40 15 60 60 16 60 80 17 60 100 18 80 40 19 80 60 20 80 80 21 80 100 22 100 40 23 100 60 24 100 80 25 100 100

Table7

Securitycheck:ModeIIIDGatbus19withloadingconditions6,7,8and9andtheIpcurrentbasedonthe100%loading.

- Forcommunicationfailuremode;thesettingisbasedonIpequals1.5timesthemaximumrelaysloadcurrentthat

maypassinallconditionsforallmodes.

- Theprimaryandbackuprelaysshortcircuitcurrentsused inTDSoptimizationaretakenas themaximumshort circuitofthefourmodestoensureselectivityoftheprotectionscheme.

0 1 2 3 4 5 6 Co nd i on 1 Co nd i on 2 Co nd i on 3 Co nd i on 4 Co nd i on 5 Co nd i on 6 Co nd i on 7 Co nd i on 8 Co nd i on 9 Co nd i o n1 0 Co nd i o n1 1 Co nd i o n1 2 Co nd i o n1 3 Co nd i o n1 4 Co nd i o n1 5 Co nd i o n1 6 Co nd i o n1 7 Co nd i o n1 8 Co nd i o n1 9 Co nd i o n2 0 Co nd i o n2 1 Co nd i o n2 2 Co nd i o n2 3 Co nd i o n2 4 Co nd i o n2 5 Possibl e nu mbers of re lay false trip

Fig.6.Securitycheck.

Table8

DOCR’sIpmodessettings.

Relayno. Ip(A)

Modesetting1 Modesetting2 Modesetting3 Modesetting4 Modesetting5

1 5.1 4.0 4.6 4.3 4.6 2 4.7 3.9 3.0 3.0 4.1 3 4.5 3.9 3.9 3.9 3.9 4 4.3 3.7 3.7 3.7 3.7 5 4.0 3.5 3.3 3.4 3.5 6 4.6 4.3 3.7 4.0 4.3 7 3.9 3.9 3.2 3.9 3.9 8 5.1 5.2 3.6 4.4 5.2 9 4.6 4.3 3.7 4.0 4.3 10 4.6 4.5 2.9 3.5 4.5 11 4.3 4.2 4.0 4.5 4.5 12 3.9 3.9 3.2 3.9 3.9 13 5.8 7.0 4.8 6.7 7.0 14 5.8 7.0 4.8 6.7 7.0 15 5.1 4.0 4.6 4.3 4.6 16 4.6 4.5 2.9 3.5 4.5 17 4.3 4.8 1.8 2.8 4.8 18 4.3 4.8 1.8 2.8 4.8 19 5.4 4.4 3.1 3.0 4.6 20 4.5 3.9 3.9 3.9 3.9 21 3.7 3.4 3.1 3.3 3.4 22 3.3 3.9 3.5 4.5 4.5 23 4.7 3.9 4.2 4.1 4.2 24 3.1 2.4 2.4 2.3 2.6 25 3.7 3.0 2.9 2.8 3.2 26 5.4 4.7 4.7 4.7 4.7 27 4.8 4.1 4.1 4.1 4.1 28 5.7 4.9 4.9 4.9 4.9 29 3.6 3.1 3.1 3.1 3.1

Table9

DOCR’soptimalTDSmodessettings. Relayno. TDS(s)

Modesetting1 Modesetting2 Modesetting3 Modesetting4 Modesetting5

1 0.40 0.41 0.44 0.44 0.47 2 0.28 0.26 0.37 0.31 0.40 3 0.19 0.12 0.14 0.15 0.14 4 0.35 0.30 0.26 0.39 0.38 5 0.10 0.10 0.10 0.10 0.10 6 0.24 0.26 0.33 0.31 0.33 7 0.37 0.32 0.39 0.38 0.46 8 0.10 0.10 0.10 0.10 0.10 9 0.10 0.10 0.16 0.14 0.16 10 0.31 0.34 0.44 0.40 0.44 11 0.23 0.20 0.29 0.26 0.27 12 0.21 0.21 0.31 0.27 0.27 13 0.33 0.26 0.33 0.32 0.39 14 0.29 0.30 0.37 0.32 0.36 15 0.24 0.21 0.27 0.29 0.31 16 0.17 0.17 0.31 0.19 0.32 17 0.25 0.30 0.43 0.35 0.37 18 0.27 0.25 0.38 0.26 0.38 19 0.18 0.22 0.36 0.30 0.32 20 0.10 0.10 0.10 0.10 0.10 21 0.10 0.10 0.10 0.10 0.10 22 0.28 0.27 0.24 0.41 0.41 23 0.10 0.10 0.23 0.21 0.23 24 0.26 0.21 0.23 0.17 0.17 25 0.26 0.21 0.29 0.32 0.33 26 0.15 0.10 0.10 0.10 0.10 27 0.10 0.10 0.10 0.10 0.10 28 0.10 0.10 0.10 0.10 0.10 29 0.10 0.10 0.10 0.10 0.10 7. Conclusion

ABCissimplyimplementedusingveryfewlinesofcomputercode,anditisageneral-purposealgorithmthatcan beusedforbothlinearandnonlinearoptimizationproblems.Itshowsagreatcapabilityofsolvinghighlyconstrained coordinationproblem.SimulationresultsshowthatABCsucceedstoconvergetofeasibleoptimalsetting.

TheresultsshowthatastheDG’ssizeandnumberchanges,thechanceofrelaysmiscoordinationincreaseswhich requiresanewsettingsforDOCR,oneofthepossiblesolutiontosolvethisissueistouseadaptivecoordination.The proposedadaptiveschemeisapplicableandworkseffectivelyforexistingpowerdistributionsystems,whichlately installDGtogettheirbenefits,protectionsystemfollowthenetworktopologicalchangesandconnectivityofDGto thesystemandswitchesbetweenthepre-calculatedsettinggroupsbasedontheactualoperatingstateoftheDGusing standardcommunicationandprogrammablelogic,thisadaptiveprotectionmayincreaseavailabilityoflocalgeneration andreduceoutagetimeforthecustomerswithoutaneedtochangeexistinghardware,whichleadstotheincreaseof selectivityandsecurityofthesystem.

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