1、Fundamentals of Electro-Magnetic Transients in Electric Networks and EMT ProgramsDharshana Muthumuni, Ph.D, P.EngManitoba HVDC Research CentreWinnipeg, ManitobaCanadaWind PowerPSCAD is a choice of major wind farm vendors, utilities, consultants and researchers:Investigate new generation technologyDe

2、sign novel control conceptsLow voltage fault ride-through requirementsHarmonics and power quality issuesSub synchronous resonance problemsPower electronic designFiltersFault contribution and protection of wind farm equipmentWind PowerDifferent machine types and connectionsInduction machine Type IOpt

3、i-slip controlled induction machine Type IIDoubly fed induction machine Type IIISynchronous machine Type IVPM machine “Type V”Wind turbine and controlsAerodynamic modelPower coefficientPitch controlMaximum power trackingWind models Ramps, gusts, noiseInduction MotorsA doubly fed induction machine is

4、 popular in wind farms due to its flexible operation under variable wind conditions. PSCAD is used by wind farm developers and researches to design the complex control functions of the DFIGDoubly Fed Induction Machine in Wind farmsWind PowerDoubly-fed Induction MachineMost popular among wind manufac

5、turersDetailed model can be implemented only in emt-type (PSCAD) simulations.AdvantagesIndependent P and Q controlSpeed controlReactive power control is possible“Lower rating for the converter Cost Allows the machine speed to be controlled as the wind speed varies - Stator fluxIdIqTorque IqReactive

6、Power (Q) IdComplex physical phenomena of a DFIG based system can be modeled and the performance of the machine optimized through PSCAD simulationsWind PowerDoubly-fed Induction MachineWind PowerDoubly-fed Induction Machine - Stator fluxIdIqStator phase A axis (stationary)Rotor positionSlip angleD-a

7、xis (rotating)Q-axis (rotating)Wind PowerDoubly-fed Induction MachineCircuit and ModulesRotor side converterWind PowerDoubly-fed Induction MachineCircuit and ModulesEstimation of the stator flux vectorIraaIrbbIrccIra_refIrb_refIrc_refslpangto StatorDQRotoralfabetaABC2 to 3TransformalfabetaDoubly-fed

8、 Induction MachineWind PowerEstimation of rotor current references with PSCAD control blocksd axis and q axisCurrent referencesWind PowerDoubly-fed Induction MachineControl response and the verification of performance of the modelPSCAD Simulation ResultsStep change in wind speedController response : to maintain optimum tip speed ratioReduced power outputConstant reactive powerWind PowerTYPE 1 or 2 Direct connected IMTYPE 3 - DFIGFault recovery responseWind PowerPSCAD examples:Type 1 and type 2 Fault response Starting and soft starting Turbine pi