DeWind Brochure D8 2 Eng

8/12/2019 DeWind Brochure D8 2 Eng

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AnevolutionarydesignthatsharesmanysystemsprovenontheD8-2000DFIG.

WinDrivetechnologyhasprovenitself inotherdemandingpowerandindustrialapplications

whereit hasestablishedaMTBFof morethan39years.Thesynchronousgeneratorhasalonghistoryof useindieselgeneratorsystemsachievinga MTBFof45years.

Generatesat mediumvoltageand capableof operating witha broadpower factorrange andinherent LVRTcapability.

Removesthe needfor Power Conversion Electronicsand providesdampening of loadtransients.

Providesa lighterand stifferstructure.

Improvesreliability andremovestheneedfor extrapackages for LVRT.

Built onproventechnology

Establishedtrack record

ofnewcomponents

synchronousgenerator

Useof VoithWinDriveTechnology

Useofcarbonfibersparinrotorblade

NoPowerConversionElectronics

F ea tu r e B en ef it


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Optimization StepsThrough the first year of operation DeWind engineerscollected largeamountsof operatingdata to enable further optimization of the performance of the Wind Turbine,including:

Tuningpitch controller to optimizeresponse to highlyturbulent wind conditions

Optimizing theWinDriveto aerodynamic performanceand drive trainefficiency

Minimizing transients duringthesynchronizationprocesstherebyassuringsmoothramp-up

Optimizingcut-in and ramp-up processesmitigatingflicker and/or other grid phenomena

D8.2 Power Performance CurveThe Power Curve tests were performed by an accreditedwind turbine performance test engineering consultant tomeasureandcertifythepowercurve, inaccordancewiththeguidelines published in IEC 61400-12. The resultingmeasured power curve demonstrates that the D8.2 meetsand/or exceeds thewarranted publishedpower curve.

D8.2 Power QualityPowerquality measurementswereperformedtoIEC61400-21 standards by a recognized power quality testingorganization, producingthefollowingconclusions:

Enhanced Voltage-Ride-Through(VRT) performanceresulting fromthe inherent characteristics of thesynchronousgenerator

Eliminatedsignificant transients duringthe synchronizationprocess thanks to theSmart-Control algorithm

Reducedshort-livedvoltage variationsresulting fromthefavorable Flicker coefficient.

D8.2 SynchronizationFigure2showsatypicalsynchronizationprocedurerampingto rated conditions. The synchronization is smooth with nosignificant transients. Theactivepower(brown)traceshowsthe point of breaker close, with the subsequent ramp-up

slope controlled by the pitch control function (black) of thecontrol system.Anindustry-provencontrol unitautomaticallycontrols thesynchronizationprocess. This behavior is typicalfor a synchronous-generator-based power plant, and, is nottypical forwindturbinesof traditional design.

D8.2 CertificationDeWind has achieveda Statement of Compliance for Designassessment from DEWI-OCC to IEC 61400 for both the 50 &60Hz D8.2 Turbines.

D8.2 Reactive Power CapabilitiesOneofthe key D8.2 designgoals wasfor the D8.2 tohavetheability toproducesignificantreactivepower. Figure3illustratesthe results of the tests, which confirmthe ability of the windturbine to deliver 1MVARof reactive powerat ratedoutput.

Summary

I

Figure 3: D8.2 PQ Stability capabilities measured

Figure 2: Synchronization Process

n summary, theCuxhaven demonstrationof theDeWindD8.2performanceconfirms that theD8.2turbinemeets thevision of itsdesigners. TheD8.2producesexcellent powerperformance,power quality, reactive power and reliability. By April 2009theDeWindD8.250HzTechnologyDemonstratorhasoperatedfor over7600hrsand produced morethan 6.4GWh of energy.

P

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Active Power

ActivePower 2 MWActivePower 2 MW

-986Kvar-986Kvar

D8.2 ReactivePower CapabilityDFIG ReactivePower Capability

986Kvar986KvarReactive Power

under-excitedReactive Powerover-excited

Power

StabilityCurve

102030405060708090100110

40,0

18,0

16,0

14,0

12,0

10,0

8,0

6,0

6,0

30,0

20,0

10,0

0,0

2000450

400

350

1600

1400

1200

1000

800

600

1500

1000

500

0

Datalog_071129_162000.svw

PitchAngle [*]Wind SpeedNacelle[m/s]WinDrive OutputSpeed [rpm] ActivePower[kW]WinDriveInputSpeed[rpm]

For further info on Dewind Co. , Please contact(949) 250-9491 or dewind .hq@dewindco .com


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SummaryDirect-connecting utility-scale wind turbines on distributiongrids, asa part of the distributed power solution, continuetorise in popularity in the US. Although site configuration is

simplified, grid integration of thedistributed utility-scalewindturbines presents a new set of technical issues unique to adistributed grid installation. This case study overviewsummarizes some of the experience gained from direct-connecting a single DeWind D8.2 to a 12.47 kVdistributionline near Sweetwater, Texas.

IntroductionIn late 2007 DeWind began installing the first DeWind D8.260Hzwindturbinein theUS,forTexasStateTechnical College(TSTC), completing the project in 2008. TSTCutilizes theturbineasatechnologydemonstrator,asatrainingplatformfor the TSTCWind TechnicianAssociate Degree Program, and

asa revenue generator for the college.Theturbineis locatedneartheRoscoeHighSchool onCountyRoad 608, approximately one mile fromthe distribution grid,ona relatively flat site, asshown inFigure 1.

The DeWind D8.2 2 MW turbine for this project is directlyconnected without a step-up transformer to a 12.47 kV

mediumvoltagedistributionline. TheDeWindD8.2featuresahydrodynamic converter, whichconvertsvariable speedinputfromthewindturbinerotor to a constant synchronous-speedoutput, uniquely enabling the mediumvoltage generator toconnect directly to the grid.

Point of Common CouplingThePoint-of-Common-Coupling(PCC)is theconnectionpointto the distribution grid, and is equipped with the necessaryprotection to meet theanti-islanding requirements of the gridoperator. At the Sweetwater site, the grid protection isachievedbyarecloserequippedwitharelaythat providesthenecessary over/under voltage, over/under current andover/under frequency protection. The recloser is located onthepoletothe left inFigure 2. Thecabinet, at the baseofthecenterpolehousesthetransfertripequipment,whichprovidestheanti islandingprotectionrequiredbytheutility. Thepoletotheright isownedbytheutilityandprovides theconnectiontotheexistinggridincludingtherevenuemeter.

Distribution Line DetailsFigure3showstheone-linediagramoftheoriginal distributionsystem, including the turbine connection to the distributionfeeder, located approximately 7 miles from the Roscoesubstation.

Four automatically-switched capacitor banks were originallyinstalledonthefeeder asthesoleprovisionforvoltagecontrolon theline. Approximately65%of theminimumload onthefeeder, roughly approximately 0.5 MVA, is located near thesubstation, withthe balanceof the loadlocated at the end of the feeder. The X/R ratio at the PCC is a low 0.3784,contributingtopotentialvoltagerisechallenges.Theminimumloadandelevatedvoltageissuesonthefeeder wereparticular challenges that required solutions. A collaboration of thecustomer and site owner, the grid operator and power engineering design specialists tackled the issues anddevelopedthesolutionthatincludedchanginglineimpedanceand applyingdistribution linevoltageregulationat the69kVsupply line upstreamfrom the 12.47 kVline, resulting in theconfiguration that enables the turbine to operate whileconcurrently enabling the utility to keep thefeeder within anacceptable operatingvoltage.

Implementation of Utility Scale WindPower Generation on Distribution Grids

Figure 1: The Installed DeWind D8.2 at Sweetwater, Texas

Figure 2: Point of Common Coupling Equipment


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Thecharacteristicsof theDeWindD8.2 are acritical part of the solution, since the directly-connected synchronousgenerator provides excellent power quality with a muchbroader reactive power capability than other wind turbineconfigurations on the market today. The ability to providebroadreactivepowersupportis graphically illustratedin thecapability curveof thesynchronous generator (reddashedlineshows stability boundaries) in Figure4. TheBluelineslocated well withintheoperatingregionof thesynchronousgenerator showthe limits of a typical DFIG-based turbine.The DeWind D8.2 can operate with a power factor of 0.9

leading to0.9 lagging at rated power, and can offera muchbroaderrangeofpowerfactorcapabilitywhende-ratedthanthe typical DFIG. This capability is very similar toconventional powerstationsand can beutilized tostabilizeweak electricalgridsand/or tocompensatefor lesscapablewind turbines.

To address the voltage rise phenomena resulting from thelow load on the distribution feeder at Sweetwater, thefollowingactions weretaken:

1.Two sections of thefeeder circuit were upgradedtoalarger conductor. Atotal of14,800feet ofconductor fromthePCCtowards thesub-station werereplacedbytheutility.

2.Avoltageregulatorwasinstalledat theRoscoe substationbythe utility to regulate the voltageand ensurethat thevoltageat the PCCdoesnot violatesystemlimits,

3.The DeWindD8.2turbineprovides reactivepower without de-rating.

The revised one-line diagramof the distribution system isshown in Figure5.

Turbine PerformanceOncethelocal utilitysgridissueswereresolved,aseriesof tests were completed to assure any voltage rise on thedistribution feeder remained within operational limits whenthe wind turbine was operating at rated power. Sincecommercial operation began thedistribution grid has beenstableand availabilityhas beenexcellent.

SummaryThe DeWind D8.2 2 MW turbine at Sweetwater, Texas,demonstratesthecapabilityof theturbinetointerconnect atmediumvoltage without the need for a transformer, whileproviding significant grid support with no additionalequipment, thereby demonstratingthe valueof this type of architecture in utilityscaledistributedwindgeneration.

Rosco

5447 Feet4/0 AAC

19443 feet1/0 ACSR

11821 feet#4 ACSR

5200 feet# 1/0 Copper U/G

DeWind8.2WTG

CAP 1

CAP 2

CAP 3

CAP 4

PCC

Bus 3

Bus 4

277 kW172 kvar

300.0 kvar

300.0 kvar

600.0 kvar148 kW92 kvar

2000.0 kW

600.0 kvar

Rosco

Voltage Reg.5447 Feet4/0 AAC

16457 feet1/0 ACSR

14807 feet4/0 AAC

5200 feet# 1/0 Copper U/G

DeWind8.2WTG

CAP 1

CAP 2

CAP 3

CAP 4

PCC

Bus 3

Bus 4

Bus X

277 kW172 kvar

200.0 kvar

200.0 kvar

600.0 kvar148 kW92 kvar

2000.0 kW0.0 bar

600.0 kvar

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Act ive Power

Act ive Power 2 MW Act ive Power 2 MW

-986Kvar -986Kvar

D8.2 ReactivePower CapabilityDFIG Reactive Power Capability

657Kvar 986Kvar Reactive Power

under-excitedReactive Power over-excited

Power StabilityCurve

For further info on Dewind Co. , Please contact(949) 250-9491 or dewind .hq@dewindco .com

Figure 3: One Line diagram of orginal Distrib ution System

Figure 5: Revised One Line diagram of the Distribution System

Figure 4: Reactive power s upport c apability

Documents

DeWind Brochure D8 2 Eng