Micro-SynchrophasorsforDistribu4onSystems

Dr.Alexandra(Sascha)vonMeierDirector,ElectricGridResearch,CaliforniaIns6tuteforEnergyandEnvironmentAdjunctProfessor,Dept.ofElectricalEngineeringandComputerScienceUniversityofCalifornia,Berkeleyvonmeier@berkeley.edu

Micro-synchrophasors(µPMUs)forDistribu4onSystems

Three-year,$4.4MARPA-EOPEN2012project(2013-2016)ResearchpartnersCIEE,UCBerkeley,LawrenceBerkeleyLab,PowerStandardsLabFieldinstalla6onsatRiversidePublicU6li6es,SouthernCaliforniaEdison,PacificGas&Electric,AlabamaPower,GeorgiaPower,TennesseeValleyAuthority

TRADITIONALPMUNETWORKTransmissionSystem

μPMUNETWORKDistribu6onSystem

BTrDBserver

µPMU

µPMU

µPMU

µPMU

µPMU

(Yourpla\ormhere)

Micro-synchrophasornetworkconcept:Createvisibilityfordistribu4oncircuitsbehindthesubsta4ontosupportintegra4onofdistributedresources

GeneralProjectObjec4ves•  developanetworkofhigh-precisionphasormeasurementunits(µPMUs)

tomeasurevoltagephaseangletowithin0.01o

•  understandthevalueofvoltagephaseangleasastatevariableonpowerdistribu6onsystems

•  exploreapplica6onsofµPMUdatafordistribu6onsystemstoimproveopera6ons,increasereliability,andenableintegra6onofrenewablesandotherdistributedresources

•  evaluatetherequirementsforµPMUdatatosupportspecificdiagnos6candcontrolapplica6ons

•  developT2Mopportuni6es

10-6 10-3

0.1o 1o 1 cycle

time scale in sec

GPS time stamp: differential absolute

clock accuracy

10-9 1

nanosecond microsecond millisecond

PowerStandardsLabµPMU

SCADA measurements

instrument sampling rate 512/cycle

phasor measurements

reported 120/sec

•  builtonPQube3powerqualityrecorder•  capableofpowerqualitymodewith512samplespercycle•  timestampingtonsprecision,µsaccuracywithGPS•  measuresvoltage&current,magnitude&angle(12channels)•  100V~690Vinput•  120samplespersecondinPMUmode(eachchannel)•  localdatabuffering+batching(2min),backupstorage•  connec6vityviaEthernet,4Gwireless

www.powerstandards.com

•  smallervoltageangledifferences•  morenoiseinmeasurements

•  differentX/Rra6os(reactance/resistanceofdistribu6onlines)

•  unbalancedthree-phasesystems•  distribu6onnetworkmodelstendtohavepoorfidelity•  fewmeasuringpointscomparedtonetworknodes•  lackofaccessandtoolstointegratewithotherdata,e.g.smartmeters

→verysmallsignal-to-noisera6o

→commonapproxima6onsrela6ngvoltagephasorstoimpedancesandpowerflowsarenotokay

→hardtodoafull“statees6ma6on”

Challengesfordistribu4onsynchrophasorsascomparedtotransmission:

Other Services

Other Services

Other Services

LocalBuffer

LocalBuffer

LocalBuffer

LocalBuffer...

Chunk Loader

Field Datacenter / Cloud Clients

BTrDBCluster

Distillate Framework Cluster

PlottingService

HTTP

MATLAB

IPython

etc ...

JSON / CSV

Analytics with 3rd party tools

Interactive visualization

Wired

Event Detection Service

Other Services

webapp

PMU

PMU

PMU

PMU

Internet

LTE modem

AddressingtheDataChallenge:BerkeleyTreeDatabase(BTrDB)

MichaelAndersen,UCBPresentlystreaming30+µPMUsat120Hz,12streamseach(VandImag&angle)

Sample4me-seriesdata

Frequencyevent

Sample4me-seriesdata

Frequencyevent(PacificDCInter6etrip)viewedinBTrDBploneratdifferent6meresolu6ons

Sample4me-seriesdata

Frequencyeventwithlocaloscilla;ons

Sample4me-seriesdata,showingsynchroniza4onofmagnitudemeasurements

Voltagedisturbancepropaga6onduetoarcflash:about0.0015p.u.atneighboringtransformerBank514and0.0003p.u.atPSL

OmidArdakanianandMichaelAndersen,UCB

Mul4-resolu4on(logarithmic)searchmadepossiblebycapturingsta6s6calfeaturesofdatastreamsatdifferentlevels

datapointsperpixel

minimumvalueduringinterval

OmidArdakanianandMichaelAndersen,UCB

Mul4-resolu4on(logarithmic)searchmadepossiblebycapturingsta6s6calfeaturesofdatastreamsatdifferentlevels

minimumvalueduringinterval

OmidArdakanianandMichaelAndersen,UCB

Mul4-resolu4on(logarithmic)searchmadepossiblebycapturingsta6s6calfeaturesofdatastreamsatdifferentlevels

individualsampleiden;fiedin~200ms

OmidArdakanianandMichaelAndersen,UCB

Architectureforeventsearchanddiagnos4cs

MichaelAndersenandOmidArdakanian,UCB

hVps://eventdetect.lbl.govrecruitexpertsforeventlabelingtobuildreferencelibrary

Modelvalida4on:useultra-preciseμPMUmeasurementstoconfirm,deny,orcorrectexis6ngmodelsofreal-worlddistribu6onnetworks:•  Phase(ABC)connec/vityiden/fica/on.Rela6velystraigh\orward;main

challengeisaccoun6ngformul6pledelta-wyetransformersbetweenmeasurementpointsabsentreliablemodeldata.

•  Linesegmentimpedancecalcula/on.Basedonmeasuredcurrentandvoltagephasorsateachendofthesegment.Trivialinprinciple(V=IZ)yetextremelychallenginginprac6ceduetothree-phaseasymmetryandPT/CTerrorsthatarelargecomparedtochangesalongalinesegment.

•  PT/CTcalibra/on.Essen6alforasubsetofapplica6onsthatdependonhighlyaccurateμPMUmeasurementsatasinglepointin6metocharacterizethesteady-stateofopera6on(“statees6ma6onbased”applica6ons).

Distribu4onSynchrophasorApplica4ons-Overview

Distribu4onStateEs4ma4on:useμPMUmeasurementsinconjunc6onwithotheravailabledata(SCADA,AMI)toes6matethestatevariables(voltagephasors)throughoutanen6redistribu6onnetwork,includingunmonitorednodes.•  LinearizedDSE:Severaltechniquesworkintheory.Sensi6vetonumberand

placementofµPMUs,andhingesonPT/CTcalibra6on.

Topologydetec4on:useμPMUmeasurementstoassesstheconnec6vityortopology(open/closedstateofswitches)ofadistribu6onnetwork.•  ResidualStateEs/ma/onError:requiresprecisestatees6ma6on,seeabove.•  Time-seriessignatureoftopologychanges:leverageshigh-resolu6onviewof

transi6ons.•  SourceImpedancemethod:avariantofthe6me-seriessignatureapproach.

FaultLoca4on:useμPMUmeasurementstopreciselylocatefaults.Requiresvalidatedmodelwithimpedances;sensi6vetonumberandplacementofµPMUs,andhingesonPT/CTcalibra6on.

Distribu4onSynchrophasorApplica4ons,cont’d

Eventiden4fica4on:useμPMUmeasurementstodetectandexplaindisturbanceevents.Reliesonprecision6mestampsandhigh-resolu6on6me-seriesmeasurements,morethanonaccurateabsoluteorcompara6vemul6-loca6onmeasurementsatasinglepointin6me:•  Automa/ceventdetec/onandno/fica/on.ScanµPMUdatabaseandissue

no6fica6onswhenanomaliesoccur,e.g.voltagesags;manyop6onsfordefiningthresholds.

•  Eventclassifica/on.Categorizeevents,e.g.dis6nguishlocally-causedvs.transmission-levelvoltagesagsbycomparingsynchronizedmeasurementsfromdifferentloca6ons.

•  Highimpedancefaultdetec/on.Dis6nguishbetweenfaultsandloadchanges,e.g.arcflashesandmotorstarts,bycomparingsynchronizedmeasurementsfromdifferentloca6ons.

•  FIDVRdetec/on.Fault-induceddelayedvoltagerecovery,duetoaircondi6onersstalling:wehaven’tseenoneyet,butit’sboundtoshowup.

•  Sta/s/caleventcharacteriza/onandlearning.Analysisbasedonlargenumbersofrapidqueries,madepossiblebyexponen6alsearchprocess.

Distribu4onSynchrophasorApplica4ons,cont’d

DistributedGenera4on(DG)andLoadCharacteriza4on:useμPMUstomeasureandunderstand6mevaria6onamongDGandloads,andhowDGaffectsdistribu6onnetworks:•  DisaggregateDGfromload,behindnetmeter•  Detectreversepowerflow.Phaseanglerevealsdirec6onofcurrent.

Notethatcurrentdoesnotcrosszerowhenrealpowerflowreverses,duetothepresenceofreac6vepower.

•  AssessDGimpactsonfeedervoltagemagnitudeandvola/lity.Opportunitytoapplysta6s6calmethods.

•  LoadCharacteriza/on.Assessloadvola6lityandvoltagedependencewithhigh-resolu6onmeasurementsandcorrela6ons.

Distribu4onSynchrophasorApplica4ons,cont’d

Phasor-BasedControl:useμPMUmeasurementstodeterminedesiredPandQinjec6onsorconsump6onbycontrollabledevices.Controlobjec6vesmayinclude,forexample:

•  voltageprofilemanagement•  lossminimiza/on•  ancillaryservicescoordina/on•  balancinggenera/onandloadonamicrogrid•  microgridislandingdecisionsbasedongridbehavior•  assistednetworkreconfigura/onbyphasormatchingacross

switchControldependsasuitablelineariza6onbetweenthephasorprofileandP,Qinjec6onsfortheunbalancedthree-phasecase.

Distribu4onSynchrophasorApplica4ons,cont’d

•  PSLalreadymakingsalesofµPMUhardware

•  Souwareandapplica6ontoolsareinvariousstatesofdevelopment,notquitereadyforcommercialsale

•  Quick-startkitforu6litycustomersmarketedbyPSLthatallowsbasicaccesstoµPMUdataanddis6llatesforvisualiza6on

•  OpensourcecodeforBTrDBavailableonGithub(GPLlicense)

•  Teamhasconductedconversa6onswith25+poten6alcommercializa6onpartnerswhofocusonspecificapplica6onstobesupportedbyµPMUdata

•  Pilotdemonstra6onswithu6litypartnersonspecificapplica6ons

•  Relatedresearchprojectsonspecificapplica6ons:e.g.cybersecurity,PVplanning

•  S6llfounda6onal,cross-cuvngresearchtobedone

TechtoMarketTransi4on

•  Develop,testandrefinespecificdiagnos6ctoolsetsreadyforfieldimplementa6on

•  Transducer(PT&CT)calibra6on

•  Leveragethedis6llatestructure:applyinterac6veanaly6csandmachinelearningtoolsforanewdiagnos6cparadigm

•  Explorecontrolapplica6ons,especiallyfordistributedenergyresources,insimula6onenvironmentsandsmallpilotstudies

•  Buildandenhancepla\ormsforintegra6ngheterogeneousdatastreams

•  Movefromeventdetec6onandforensicstoeventan6cipa6on

•  Extendalgorithmstothethree-phaseunbalancedcase

Con4nuingResearchNeedsandOpportuni4es

26Photo:AlexMcEachern

vonmeier@berkeley.edu