1 ieee psrcc wg 24 -modification of commercial fault ...€¦ · type-3 wind generator model...
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IEEEPSRCCWG24- ModificationofCommercialFaultCalculationPrograms
forWindTurbineGeneratorsNeedfortheWG
Dr.SukumarBrahma,ClemsonUniversityWGChair
Scope2
1. TosurveyWTGmanufacturerstodeterminewhatparameterstheycouldprovidethatcouldbeusedbysteadystateshortcircuitprogramdevelopersinvarioustimeframes.
2. Usetheresultofthissurveytoprepareareportthatcanbeusedbysteadystateprogramdeveloperstorefinetheirmodels.
Motivation• TypeIIIandTypeIVwindturbinegenerators(WTGs)connectthroughinverters.
• Highlynonlinearresponseofinverterstofaults.• Conventionalphasordomainshortcircuitanalysisassumes– Linearresponseofsources(TheveninEquivalent)– Loadcurrentsnegligiblecomparedtofaultcurrents.
• Theseassumptionsarenolongervalid.• Invertercontrolsareproprietary– hampersemtpmodelingaswell.
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FaultResponse- I4
Gear Box DFIG
C
RSC GSC
Ps,Qs
Pr,Qr
Ecap
Crow bar
Wind Turbine
Coupling Inductor
Controls
Grid
AC/DC DC/AC
• TypeIIIWindTurbineGenerators(WTGs)canhavethemostcomplexbehavior–– oldermodelscrowbarforclose-infaultstoprotecttheconverter
circuit– behaviorsimilartoinductiongenerators.– current-controlledmodefordistantfaults.– canswitchfromonemodetoanotherduringfault.– newermodelscanavoidcrowbaraltogether.
FaultResponse- II5
• TypeIVWTGsandPVconnecttothesystemthroughinverters– responsedeterminedsolelybyinverter.– typicalfeatures– currentcontrolled,purelypositivesequence
current.– lowvoltageridethroughcanbeimplemented– changeinpower
factorduringfault.– completelynonlinearresponse- voltagecontrolledcurrent
source.
Wind Turbine
PMSG
Controls
Ps, QsGrid
MSC GSC
PV
FaultResponse– FullConverter6
• Timeforcontroltotakeoverisdifferentfordifferentmodels.• Noticepurelypositivesequencecurrentwithmagnitudecomparableto
loadcurrent.
Model – 1 (Clemson)
Model - 2 (PSRCC C17 WG report)
A-G Fault3-ph Fault
ShortCircuitBehavior- Example7
• 8– bus4.16kVbalanceddistributionsystem– 3-phfaultatbus3.• Inverter-connectedPVwithLVRTatbuses1,5,6.• Duringfaultpowerfactoranglesatthesebusesareapproximately57,54,and
41degreesleading (generatingkVar).• Conventionally,forsynchronousgenerators,ΔVi
(1)/ΔIi (1) equalsthesourceimpedanceofthegeneratoratbusi,whichhasalargereactiveangle.Inthiscasetheangleis1330.Clearlylinearitydoesnothold.
• TotalfaultcurrentangleusingVPF-3/Zbus(3,3) isverydifferent(almost1800)fromtheobservedcurrent-angle.Anglesofvoltagescalculatedusingthiscurrentinjectionarealsowidelydifferentthanmeasuredvalues.
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2 3
5
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Fault
WGRecommendation8
1. PSRCCWG24hasconsultedwithallstake-holders(utilities,softwaredevelopers,EPRI,consultants)andcomeupwiththefollowingdatarequirementsfrommanufacturersfordifferenttime-frames:
2. EPRIhasalsocontributedfieldtestedgenericmodelsthatcanbeusedinsteadoftables– caution– thesedonotmimicalldesigns.
• Invertersareungrounded– donotcontributezero-sequencecurrents.
Timeframe1,2,3(unit-secondsorcycles) FaultType:Positivesequence
voltage(asspecifiedinitem3)(pu)
Positivesequencecurrent(pu)
Positivesequencecurrentanglewithrespectto
positivesequencevoltage(deg)
1.00.90.80.70.60.50.40.30.20.1
Timeframe1,2,3(unit-secondsorcycles) FaultType:Negativesequence
voltage(asspecifiedinitem3)(pu)
Negativesequencecurrent(pu)
Negativesequencecurrentanglewithrespectto
negativesequencevoltage(deg)
1.00.90.80.70.60.50.40.30.20.1
Implementation9
1. Findfaultcurrentatbusi asVPF-i /Zbus(i,i) – thiswillnotmatchtheactualfaultcurrentbecauseofnonlinearfaultresponsefromrenewables.
2. Adjustcurrentsfromrenewablesbasedonthecalculatedterminalvoltages– usetablesprovided,oruseagenericmodelforthisstep.
3. Adjusttotalfaultcurrentbasedonadjustedcurrentinjectionsfromrenewablesandrecalculatevoltages.
4. Repeatsteps2and3untilthesuccessivevoltagesarecloseenough.
EvangelosFarantatos,Ph.D.Sr.ProjectManager
TransmissionOperations&PlanningR&DGroupEPRI
Panel“Modelingofconverter-interfacedrenewablesourcesforshortcircuitstudies”2019IEEEPESGeneralMeeting
Atlanta,GAAugust5,2019
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GenericShort-CircuitModelsofWindTurbine&PhotovoltaicSolarGeneration
Motivation,Challenges&Needs• Continuouslyincreasingpenetrationlevelofinverterbasedresources(IBR),predominantlyrenewables(TypeIII,TypeIVWTGs&PVs)
• Complexfaultresponse• Differssignificantlyfromsynchronousgeneratorshort-circuitcurrent(SCC)
• Accurateshort-circuitmodelsforprotectionstudies• Performanceoflegacyprotectionschemes(distanceprotectionetc.)
InverterBasedResources
Gearbox
Grid
Step downtransformer
Windturbine
iPMSG
Stator-Side Converter
Grid-Side Converter
ig
IL , PLType III WTG
Slip ringsGearbox
GridStator power
Rotor -Side Converter
Grid-Side Converter
Rotor power
Transformer
Windturbine
Crowbar
Chopper
Type IV WTG
Solar PV
InverterBasedResourcesFaultResponseCharacteristicsSynchronous Generator
Type IV WTG
• SCC magnitude close to nominal load current (typically 1.1-1.5 pu)
• Initial transient (typical duration 0.5-1.5 cycles) –uncontrolled response – controller “reaction time”
• Fault current can be capacitive, inductive or resistive• Typically low negative sequence current contribution• No zero sequence current
InverterBasedResourcesShort-CircuitModeling
Synchronous generator classical short circuit model (voltage source behind an impedance) is not applicable
•EPRI Project 173.09 “Impact of Renewables on System Protection” • IEEE PSRC WG C24 “Modification of Commercial Fault Calculation Programs for Wind Turbine Generators”
EPRIWind/PVPhasorDomainShort-CircuitModel
•Voltage controlled current source• Iterative solution (nonlinear behavior)
• considers the impact of controls on the short circuit response• respects inverter current limits
InverterGenericControlModeOptionsFunction ControlMode Performance/Description
Reactivepower/voltagecontrolduringride-through
Constantpowerfactor Allowsforinverterinjection/absorptionof
reactivepowerbasedonadesiredpowerfactor
ConstantQ Allowsforinverterfixeddesiredvalueofreactive
powerinjection/absorptionVControl Allowsforinvertercontrolof
voltagetodesiredvalueDynamicreactivecurrentcontrolbasedonreference
curve(FRT)
Allowsforreactivecurrentinjectionbasedona
referencecurve(e.g.gridcode)
FRT Curve
CurrentLimiter- PQPriority
Assume:Active Power: 1 p.u.Post fault voltage: 0.7 puControl mode: FRT withslope 2Q priorityIlimit=1.1 pu
Example:Desired Currents:Iactive= 1/0.7=1.43 p.uIreactive=2(1-0.7) = 0.6 p.uItotal=1.55 pu (exceedslimit)
Upon current limiter:Iactive= 0.92 (reduced tosatisfy limit)Ireactive= 0.6 p.uItotal= 1.1 pu
IterativeSolution
DemonstratingResultsType IV WTG - LLG fault (AB) - BUS 1
Type III WTG - LL fault (AB) - BUS 4
•Here, Type IV WTG/Solar model assumeszero negative sequence currentcontribution
•Type III WTG has negative sequencecurrent contribution due to the DFIG statorconnection to the grid
NegativeSequenceControl
ControlMode:DynamicReactiveCurrentInjection(k=2),QPriority
Coupled Decoupled Germancode(k=2)
WTGvariable
EMTP-RVSolution
PhasorDomainSolution
EMTP-RVSolution
PhasorDomainSolution
EMTP-RVSolution
PhasorDomainSolution
Vpos0.710(23.9)
0.710(24.1) 0.719(13.8) 0.720(13.6) 0.720(6.9) 0.720(6.9)
Ipos1.135(-10.7)
1.135(-10.4) 0.898(-30.4) 0.893(-30.9) 0.743(-50.4)
0.743(-50.5)
Vneg0.336(-120.1)
0.337(-117.4) 0.281(-132.9)
0.281(-133.5) 0.213(-118.1)
0.213(-118.0)
Ineg0.063(97.2)
0.030(152.6) 0.296(26.8) 0.305(27.7) 0.407(-28.1)
0.407(-28.0)
1.Coupled: Elimination of negative sequence current injection2.Decoupled: Mitigation of second harmonic oscillation by
injection of negative sequence current3.German Grid Code: Negative sequence current injection
proportional to variation in negative sequence voltage
22.5 MVA Solar Plant: I2 & V2
VDE-AR-N 4120
ModelValidation– 3Approaches1. Generic EMT Models 2. Manufacturer EMT Models
3. Fault Records
Type-IIIWTGWindParkConnectedtoa230-kVSubstation
+VwZ1
230kVRMSLL /_0
PI
+
Line_LATIGO_3BUTTESWP_DFIG1
DFIG AVM110.022MVA230kVQ-control
LFLF1
Slack: 230kVRMSLL/_0Vsine_z:VwZ1
+ Relay_Wind
+ Relay_Transmission
6604_LATIGO
V1:1.00/_-0.00V2:0.00/_102.09V0:0.00/_45.00Va:1.00/_0.00Vb:1.00/_-120.00Vc:1.00/_120.00
11847_THREE_BUTTES
V1:1.00/_0.2V2:0.00/_-89.8V0:0.00/_-89.8Va:1.00/_0.2Vb:1.00/_-119.8Vc:1.00/_120.2
Variable
POI- pu
EMTP-RV PhasorModel
0.825(-39.7) 0.810(-56.4)0.509(1.5) 0.509(0.6)
0.858(105.8) 0.862(98.4)
0.488(0.4) 0.486(0.1)
I +
V +
I -
V -
Phasor Model
EMTP Model
• Windfarmwith66x1.5MWtype-IIIwindturbinegenerators
• B-CphasetophasefaultonthetielinetothePOIsubstation
IEEEPSRC&VendorEngagement
•Goal: Vendor engagement and implementation of the models in commercial platforms (CAPE, ASPEN OneLiner, CYME, Powerfactory, etc).
•Contribution to IEEE PSRC WG C24 “Modification of Commercial Fault Calculation Programs for Wind Turbine Generators”
Timeframe1(secondsorcycles) FaultType:Positivesequencevoltage(asspecified
initem3)(pu)
Positivesequencecurrent(pu)
Positivesequencecurrentanglewithrespectto
positivesequencevoltage(deg)
0.90.70.50.30.1
Contact: [email protected]
Q&A
• EPRI project is conducted in collaboration with Polytechnique Montreal (Prof. Ilhan Kocar, Prof. Jean Mahseredjian, Dr. Aboutaleb Haddadi, Dr. Thomas Kauffmann)
References
Acknowledgements
1. T. Kauffmann, U. Karaagac, I. Kocar, S. Jensen, E. Farantatos, A. Haddadi, and J. Mahseredjian, “Short-circuit model for Type-IV wind turbine generators with decoupled sequence control”, IEEE Transactions on Power Delivery (Early access), DOI: 10.1109/TPWRD.2019.2908686, Apr. 2019
2. T. Kauffmann, U. Karaagac, I. Kocar, S. Jensen, J. Mahseredjian, and E. Farantatos “An accurate Type III wind turbine generator short circuit model for protection applications”, IEEE Transactions on Power Delivery, vol. 32. No. 6, Dec 2017
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Implementation of Converter-Interfaced Generator ModelType-3 Wind Generator Model in Short Circuit Programs
Presented bySherman Chan ASPEN
Converter Interfaced Generator Model
• For solar plants• For Type-4 wind plants• For other generating plants that has a
converter as the interface
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Converter Interfaced Generator Model
• Perfect current source with infinite internal impedance.
• Injects no zero- or negative-sequence fault current now. Negative-sequence current will be added in a future update.
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Converter Interfaced Generator Model
• Within the voltage deadband, the generator maintains constant power.
• The deadband width is adjustable.
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Converter Interfaced Generator Model
• Outside the deadband, control options are:1. Constant power2. Fault-ride-through (FRT) control method3. Constant voltage (by setting the FRT slope to
the impedance of the network as seen from the generator).
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Converter Interfaced Generator Model
• All the control options are subject to a current limit, usually 1.1 or 1.2 pu.
• User can set a lower current limit when the terminal voltage is low.
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Converter Interfaced Generator Dialog Box
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Converter Interfaced Generator Simulation
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Type-3 Wind Generator Model
• Based on EPRI’s phasor-domain model.• Injects positive- and negative-sequence fault
currents, but no zero-sequence current.
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Type-3 Wind Generator Model
The user must decide to simulate:1. The controlled mode, or2. The crowbarred state
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Type-3 Wind Generator Model
The fault current in the controlled mode is usually limited to 1.1 or 1.2 pu.The fault current in the crowbarred state is usually around 5 pu, plus dc offset.
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Type-3 Wind Generator Model Dialog Boxes
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Type-3 Wind Generator Model Simulation
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Voltage Controlled Current Source
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Wasdesignedtosimulatevoltagesourceconverters.
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Short Circuit Models for Wind and PV Generation in CAPE
Presented at 2019 IEEE PES GM Panel Session“Modeling of converter-interfaced renewable sources for
short circuit studies,” August 5, 2019
Donald MacGregorSiemens Industry, Inc.
Ann Arbor, [email protected]
ObjectiveCalculate current contributions from wind and solar generators during external faults. Use a steady-state phasor model. Use manufacturer’s data where possible.
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AG 2019
Three-Phase Fault
Solar Generator
EPRI Test Network
Outline • CAPE Algorithms for Type III, Type IV, and
Voltage-Controlled Current Source• Special Cases• Reporting Options
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CAPE Algorithms for Type III, Type IV, and Voltage-Controlled
Current Source
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Synchronous Generator• A synchronous generator has an internal EMF proportional
to prefault load, or 1.0 pu for a classical flat voltage profile.• After a fault or disturbance, the shunt impedance
immediately decreases from steady-state to subtransient; the EMF is unchanged.
• Fault current Ifault= (Prefault voltage)/ (Thevenin equivalent impedance) at fault bus
• In a linear network, change of Vbus is proportional to Ifault .
Inverter-Based Generator
Type III: Doubly Fed Induction Generator
Diagram provided by Electric Power ResearchInstitute, Palo Alto, CA
Inverter-BasedGenerator Type III
Doubly-Fed Induction Generator treated as synchronous withchosen impedance, for currents up to a fixed limit (e.g. 0.5 pu)Magnitudes of other phase currents kept in proportion to first to reach limit; phase angles heldconstant; zero sequence removed
Type III with CrowbarRotor circuit is shorted for overcurrentsMachine becomes an induction generator, with constant EMF behind the given impedance The current limit is set at 999 perunit Optional for all or selected generators
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Type IV Generator with Full-Power Conversion
Diagram and data provided by Electric Power ResearchInstitute, Palo Alto, CA, and by Southern Company, Atlanta, GA.
Type IV Model from LV to MV 12
VLV, ILV
Diagram and data provided by Electric Power ResearchInstitute, Palo Alto, CA, and by Southern Company, Atlanta, GA.
Inverter-Based Generator Type IV13
TYPE IV Power Converter• Start iteration (k) • P = Prefault real power • Desired current Îd = P / |Vd
(k-1)|• Derive quadrature current Îq from the controls
(chosen from Q, PF, V, Fault-Ride-Through)• Limit the d-q (Direct & Quadrature) currents
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TYPE IV Power Converter• Transform Id + j Iq to positive sequence phasor
Ip = (Id + j Iq ) exp j [ arg (Vp (k-1)) ]
• Inject current into faulted network and compute three-phase voltage (Va, Vb, Vc) for iteration (k)
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Type IV Limits of |I|, Id, and Iq• Î = √(Id
2 + Iq2)
• With P control priority, reduce Id with constant Iq, then reduce Î, and finally reduce Iq.
• With Q control priority, reduce Iq with constant Id, then reduce Î, and finally reduce Id.
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Remote-Fault Option• Power penetration into network depends on local load • Without the loads, the computed short-circuit current is
too high at remote buses• Remove generators having Vpu in the dead-band:
VMIN_REMOTE < Vpu < VMAX_REMOTE (e.g. 0.95 < Vpu < 1.1)
• Or remove the dead-band with VMAX_REMOTE = -999 and keep all generators
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Eliminate Neg. & Zero Sequences
| Ia' | | Ia | | Ib' | = A * W * A-1 * | Ib | | Ic' | | Ic |
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Eliminate Neg. & Zero sequences| 0 0 0 | 0seq
W = | 0 1 0 | +seq| 0 0 0 | -seq
| 1 1 1 | A = | 1 a2 a |
| 1 a a2 | a = 1.0 @ 120 deg
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Available DataKey parameters: machine MVA and bus voltageTypes III & IV limits fixed in perunitIdlim = 1.0 Iqlim = 1.0 |I| = 1.1 puTransformer and filter impedances in perunitType IV control mode and priority
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TYPE VCCS: Voltage Controlled Current Source
TYPE VCCS: Voltage Controlled Current Source
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Current and Power Factor are tabulated functions of bus voltage.Different tables apply at specified times.Positive-sequence only.Values are supplied by manufacturer.
Special Cases
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Desired Power Factor not Compatible with Controls
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• Current angle arg(I/V) has a range with no solution. • To help borderline cases to converge, smooth the
differences between iterations using interpolation.• After 20 iterations, inject current at the Iq limit, lagging
the voltage by 90ο. This is the “Iq Injection” state.• After 20 more iterations, remove the generator.
Type IV Generator Isolated by Open Breakers
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No convergence after 40 steps
Generator Islanded by FaultCompute postfault +seq apparent impedance as Zp = Vp/Ip
If Zp is constant in the first three iterations, the generator is islandedby the fault. Replace arg(Vp) by arg(Vprefault)
when converting (d,q) currents to positive sequence
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Reporting Options
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Reports• Reports show which generators operate and
their current sources: • One-Line Diagram Branch currents and voltages
• Report_IBG Details for single generator
• Report_Active_IBGs List of operating IBGs
• Report_All_IBGs List all IBGs: local and remote
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Report Single GeneratorGenerator status: Switched to limited-Iq injection; Iter 11 Convergence Report THREE_PHASE at 3 Loop Iter bus CCT VP_MV .... P,Q MVA 2 1 8 1 0.26 @ 20.9 17.40 9.17 2 2 8 1 0.37 @ -0.7 18.72 21.93 2 3 8 1 0.42 @ -14.8 14.75 29.47 2 4 8 1 0.44 @ -24.3 10.36 32.92 2 5 8 1 0.44 @ -30.7 6.89 34.29 2 6 8 1 0.44 @ -35.1 4.41 34.74 2 7 8 1 0.44 @ -38.0 2.71 34.81 2 8 8 1 0.44 @ -40.0 1.56 34.76 2 9 8 1 0.44 @ -41.3 0.78 34.67 2 10 8 1 0.44 @ -42.2 0.26 34.59 2 11 8 1 0.44 @ -42.2 0.26 34.59
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Report Active IBGsSummary of controlled generation
Bus Shunt # P,Q MVA Status1 24580 1 1.16, 81.67 Iq injection at current limit2 9634 1 0.00, 0.00 Remote fault3 8869 1 1.13, 80.91 Iq injection at current limit4 8464 1 0.00, 0.00 Remote fault...81 11700 1 0.00, 0.00 Remote fault82 11701 1 0.00, 0.00 Remote fault85 7235 1 0.00, 22.50 Radial line (islanded)86 11728 1 34.99, 14.37 Converged normally...
113 11775 1 0.00, 83.22 Iq injection at current limit114 11779 1 100.87, 41.55 Converged normally
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Summary• EPRI has provided algorithms for fault contributions
from wind and solar generators. • In CAPE, Type III (DFIG) uses a fixed current limit.• Type IV (full-power converter) follows EPRI algorithm.• CAPE has detailed reports for each generator or
summary reports for a large network (e.g. 100 or more wind or solar generators).
Summary• With limited data, user supplies desired real power
and control type.
• Default per-unit parameters give current limits.
• Type VCCS (voltage-controlled current source) uses tables of I-V characteristics.
Discussion
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MohammadDadash Zadeh,Ph.D.,SMIEEE,PEETAP,Irvine,CA,USA
ShortCircuitModelsforWindandPVGenerationinETAP
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Content• ConverterModelforShortCircuitStudies• HigherLevelCurrentLimiter• FaultRightThroughControl• ConverterControlModes• ANSIvsIEC• User-definedModel• Negative-sequenceCurrentInjection
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ConverterModelforShortCircuitStudies• InverterandWTGType4• f()isnonlinear• f()dependsonconvertercontrolsettingsandlimits
• Iterativesolutionvstime-domain• Steady-statevsdynamic
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I1=f(V1,V1Prefault,PPrefault)
I2=0
I0=0
ConverterModelforShortCircuitStudies
• InverterandWTGType3
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I1=f(V1,V1Prefault,PPrefault)
I2=0
I0=0
Z2
Z0
Crowbarnotactivated Crowbarisactivated
SimilartoTypes1&2
ANSI:Crowbarresistanceisadded
IEC:SpecialCalculation
HigherLevelCurrentLimits5
FaultRightThroughControl6
𝐼" = 𝐼"$%"×'()*+,-./0
'(
ConverterControlModes• ReactiveCurrentSupport:Iq ismetfirstandthenId• ActiveCurrentSupport:Id ismetfirstandthenIq• User-DefinedPF:– Id iscalculatedfirst.– Iq iscalculatedbasedontheuser-definedPF.– Id andIq arescaledproportionallytomeetthelimits.
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ANSIvsIEC8
User-DefinedModel• Genericmodelmaynotmeetspecificconverterresponse
• Time-domainsimulationusing– WECCmodel– User-definedmodel
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Negative-sequenceCurrentInjection10
I1=f(V1,V1Prefault,PPrefault)
I0=0
I2=f(V2)
Question?
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