Investigation of Small Signal StabilityInvestigationofSmallSignalStabilityforaRenewableEnergyBasedElectricityDistributionSystem
S Dahal N Mithulananthan T SahaS.Dahal,N.Mithulananthan,T.Saha
SchoolofInformationTechnologyandElectricalEngineeringTheUniversityofQueenslandSt.Lucia,QLD4072,Australia
Tuesday,July 27,2010
1
IEEEPower&EnergySocietyGeneralMeeting,Minneapolis,USA
Presentation OutlinePresentation Outline
Background&Objective System Modelling & Small Signal StabilitySystemModelling&SmallSignalStabilityAnalysis
R l d Di i ResultsandDiscussions ConclusionsandFutureworks
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BackgroundBackgroundGlobalIssues
Electricity Market Climate Change Limited ResourcesElectricityMarket ClimateChange LimitedResources
Distributed Renewable
s
Distributedgeneration
RenewableEnergy
o
m
e
CarbonCapture&Storage(CCS)
Nuclear
u
t
c
o
EfficiencyPluginHybridElectricVehicles(PHEV)
O
3
Distributed GenerationDistributedGeneration Usuallylessthan30MW(AEMO,Australia)
NeitherPlannednordispatchedcentrally(as of now)
Location Size(MW)
(asofnow)
1 0.0015to0.1
2 0.1to3
3 4 1 to 63,4 1to6
5,6,7 3to25
8 20andabove
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Future Distribution SystemFutureDistributionSystem
Characteristics Challenges
DifferentGenerationTechnologies Stability,Control
BidirectionalPowerFlow Stability,Protection
Intermittency Dispatch,Regulation,Quality
5
ObjectiveObjective
Tomodelthesystemforstabilityanalysis
i t d l f DG it t k & L d appropriatemodelsofDGunits,network&Load
Toanalysethesystemforsmallsignalstability
ImpactofwindandsolarImpactofpenetration
6
S M d lliSystemModelling&&
SmallSignalStabilityAnalysis
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Generator ModellingGeneratorModellingGenerator Stator Flux RotorFlux RotorInertia Exciter/ Converter/
Dynamics Dynamics Dynamics Governor Inverter
SynchronousGenerator
Generator
Squirrel CageInduction
InductionGenerator
DoublyFed InductionGenerator
Photovoltaic Generator
8
PV System ModelPVSystemModel
DClinkdynamics
dcpvdc PP
dtdvC =
2
2
Decoupledfromsystemdynamicsbyinverter.
9
Network ModellingNetworkModellingComponent ModelComponent Model
Network Admittancematrix
Generator CurrentSource
Loads Impedances
[ ] [ ][ ]VYI =
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Modal AnalysisModalAnalysis
DAE f tDAEsofpowersystems
),(.
yxfx =),(0),(
yxgyxfx
=
Participation factor
relatesthestatesandthemodes anelementofproductofrightandlefteigenvector
ikkiki vp =
11
Modal Analysis (Contd )ModalAnalysis(Contd..)Eigenvalue sensitivityEigenvaluesensitivity showsimpactofsystemparameters(K)oneigenvalue
movementmovement
Proposedsensitivityindex sensitivityofeigenvalue w.r.t.totalactivepower
iTi vP
A
fluctuation
iTi
ii
vP
PSI
. =
=
12
Results & DiscussionResults&Discussion
13
Case Distribution SystemCaseDistributionSystemSG2>5MW(PF Controlled)
SG1>4MW(voltage control)
ExternalGrid
(PFControlled)(voltagecontrol)
InductionGen>2MW System Load(Squirrelcage)
SystemLoad28MW,17MVAR
PVGen(1MW)
DGunitsareunscheduled
14
System EigenvaluesSystemEigenvalues20
25
EigenvalueContribution
10
15
20
Generator ModelOrder
Statevariables
SG1 6 6
-5
0
5
I
m
a
g
i
n
a
r
y
A
x
i
s
SG1 6 6
SG2 6 6
IG 3 3
-15
-10
5 IG 3 3
PV 0 0
T t l 15
-35 -30 -25 -20 -15 -10 -5 0-25
-20
Real Axis
Total 15
Eigenvalues 15
AlleigenvaluesinlefthalfofImaginaryaxis stablesystem
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Oscillatory ModesOscillatoryModes
Modes DampingRatio
Frequency(Hz)
DominantGenerator
1,2 0.26 3.28 PFControlled SG(Bus3)
3, 4 0.23 2.89 Voltage controlled SG (Bus 2)3,4 0.23 2.89 VoltagecontrolledSG(Bus2)
5,6 0.48 2.82 WindGenerator(Bus6)
Oscillatoryfrequenciesof3HzwereobservedWind generator contributes to highly damped modeWindgeneratorcontributestohighlydampedmode
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Penetration & ParticipationPenetration&ParticipationDominant generator
ModesDominantgenerator
Basecase 20%wind 20%solar
1,2 PFControlledSG PFControlledSG PFControlledSG
V l3,4 VoltagecontrolledSG WindGenerator
Voltage
controlledSGWind Generator/
5,6 WindGeneratorWindGenerator/Voltagecontrolled
SGWindGenerator
DominantgeneratorsmayalteraftersignificantpenetrationofwindWindgeneratorinfluencesmorethansolar
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Penetration & SensitivitiesPenetration&Sensitivities
Forincreasedsolarpenetration,sensitivitiesdecreaseforallmodes.
Forincreasedwindpenetration,sensitivitiesmaydecreaseorincrease.p y
Modesdominatedbysynchronousgeneratorsaremoresensitive.
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Time Domain AnalysisTimeDomainAnalysisThree phase fault applied for 70 ms at bus 15
1.004
1.006
Threephasefaultappliedfor70msatbus15.u
.
)
1
1.002Basecase
20%Windpe
e
d
(
p
.
u
0.996
0.99820%Wind
20%Solar
R
o
t
o
r
s
p
0.9940.8 1.3 1.8
R d d i i f l ll d SG b dTime(sec)
Windandsolarpenetrationimprovesdamping
RotorspeeddeviationofvoltagecontrolledSGwasobserved
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Time Domain Analysis (contd )TimeDomainAnalysis(contd.)
R d d i i f PF ll d SG b d
Windandsolarpenetrationhavenoimpactondamping
RotorspeeddeviationofPFcontrolledSGwasobserved
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Conclusions&FutureWorks
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ConclusionsConclusionsThedistributionsystemwithDGunitsexhibitoscillations.y
Frequenciesof3HzwereobservedSG modes are more sensitive than WG modesSGmodesaremoresensitivethanWGmodes
InformationonlocationofcontrollersParticipations are sensitive for wind than solar penetrationParticipationsaresensitiveforwindthansolarpenetration
rotorfluxvariablesofwindgeneratorsareinfluentialS l i d i i i i f i dSolarpenetrationdecreasessensitivitiesofeigenmodes
betterimpactonsmallsignalstabilityPenetrationofrenewablehasgoodimpact
betterdampingofvoltagecontrolledSG
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Future WorksFutureWorks
Loadmodelling
identificationandpropermodellingoftheloads
f llLocationanddesignofcontrollers
Performanceevaluationofthecontrollers
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ThankYouVeryMuch!!
Any Questions are welcomeAnyQuestionsarewelcome
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