2MW DFIG FAULT RIDING IMPROVEMENT USING SVC · Figure 1: Block Diagram of DFIG Wind Turbine...

2MW DFIG FAULT RIDINGIMPROVEMENT USING SVC

Saravanan K1, P. Karthik2,T. Rajesh3, Maharajan.D4,

1,4Asst professor, 2,3M.Tech. Student2Power Electronics and Drives,

SRM Institute of Science and Technology,Chennai-603 203, India

[email protected]@[email protected]

[email protected]

July 3, 2018

Abstract

This paper Presents the application of a Static VarCompensator (SVC) connected to a turbine driven DoublyFed Induction Generator (DFIG) is investigated. Now aday most of wind industrial they are using double fedinduction generator. During Short circuit time generatorside voltage sag will be occurred. Power converter currentVdc is too increased and rotor current also increased. Atthe moment tower vibration also increased. However, wecan able to protect wind power plant help with of StaticVar compensator (SVC). When we connected SVC againstof the problem. Short circuit current discharged throughSVC during fault time. And also the wind turbine isun-interruption operation during short-circuit time andimprove voltage regulation and control Power convertcurrent. MATLAB simulation based result using a 2MW

1

International Journal of Pure and Applied MathematicsVolume 120 No. 6 2018, 10677-10691ISSN: 1314-3395 (on-line version)url: http://www.acadpubl.eu/hub/Special Issue http://www.acadpubl.eu/hub/

10677

double fed induction generator based wind generator. Theresult shows good output and support during short circuitcondition.

Keywords: Introduction, DFIG Wind Turbine Model,SVC Block Diagram, Simulation Model and SimulationOutput.

1 INTRODUCTION

Energy consumption increases gradually due to the rapid advancein the industrial sectors, also the deficit in fossil fuel and increasedenergy demand turned the world’s attention towards therenewable energy resources. Wind energy becomes one of themainstream power sources in many countries all over the world.Renewable energy stations are friendly to both consumer andenvironment, due to it requires shorter construction time [1]. Yet,for the grid operators, this large growth in wind energy was not apredicted phenomenon and therefore grid codes for gridintegration of renewable energy were altered to make therenewable work in harmony with the grid. Among the new gridcodes for grid integration of wind energy, Fault Ride Through(FRT) capability during transient conditions and reactive powercontrol during steady-state conditions pose considerablechallenges for variable speed wind turbines [2].

Wind farms are no longer allowed to disconnect during faultsand voltage sag conditions, instead are expected to operate like Theconventional power plants, providing the reactive power supportand to remain connected during system faults [3].

2 DFIG WIND TURBINE

The doubly-fed induction generator (DFIG) system is a popularsystem in which the power electronic interface controls the rotorcurrents to achieve the variable speed necessary for maximumenergy capture in variable winds. Because the power electronicsonly process the rotor power, typically less than 25% of the overalloutput power, the DFIG offers the advantages of speed controlwith reduced cost and power losses. This PLECS demo model

2

International Journal of Pure and Applied Mathematics Special Issue

10678

Figure 1: Block Diagram of DFIG Wind Turbine

demonstrates a grid-connected wind turbine system using all ofPLECS’ physical modeling domains. The system model includes amechanical model of the blades, hub, and shaft, a back-to-backconverter including thermal loss calculations, a magnetic model ofthe three-phase transformer, and the transmission line and grid.Doubly fed generators are one solution to this problem. Instead ofthe usual field winding fed with DC, and an armature windingwhere the generated electricity comes out, there are twothree-phase windings, one stationary and one rotating, bothseparately connected to equipment outside the generator. Thusthe term ”doubly fed. One winding is directly connected to theoutput, and produces 3-phase AC power at the desired gridfrequency. The other winding (traditionally called the field, buthere both windings can be outputs) is connected to 3-phase ACpower at variable frequency. This input power is adjusted infrequency and phase to compensate for changes in speed of theturbine.

3


10679

3 DFIG WIND TURBINE MODEL

d-q equivalent circuit (DFIG):

q-axis circuit

Figure 2: q-axis equivalent circuit of DFI

d-axis circuit:

Figure 3: d-axis equivalent circuit of DFIG

4


10680

Flux Linkage expressions:

Figure 4:

Rotor circuit equation in d-q frame:

Figure 5:

Where, ωψ is the back e.m.f .or speed e.m.f. due to rotation ofaxis.When the angular speed of the d-q frame i.e. ωe = 0

5


10681

4 SIMULATION RESULTS

In this paper simulation by double fed induction generator.Simulation Model circuit shown in the figure 6. We design 2MWDouble fed induction generator connected to Power transformer575V/25KV. Static var compensator connected across withgenerator output. In double fed induction generator wound rotorused and control power converter help with of Pulse withmodulation. Grid voltage which convert AC to DC and DC to ACand connected to rotor winding. While starting condition Werequired 3m/s. Wind speed measuring devices by usingAnemometer. There are two type of Anemometer used our windtechnology first one ultrasonic anemometer second one Cupanemometer. Anemometer to measure Wind speed, air densityand wind direction. Double fed induction generator outputPrimary RPM Signal to connected to Power converter. Powerconverter request current generated based on the generator RPM.Double fed induction generator design by two of winding woundare Low speed winding and high speed winding. During low windspeed time we get output from low speed winding. If wind speedis high, we get output from High speed winding. There are threerotor blade used. The rotor blade made was fiberglass. When weget 3m/s wind speed available. Then wind plant will be started.The double fed induction generator output voltage 575V, 60Hz.We used two type of pitch control in wind technology are, ACpitch system and DC pitch system. All pitch motor to control byPosition controller.

5 SIMULATION RESULTS AND

DISCUSSION

During Running time, the wind plant affected with Short circuit.That time the wind plant is going to interruption operation andPower converter current is increase. Generator rotor current alsoincrease. At the moment tower Transversal tower vibration andlongitudinal tower vibration increase finally all electricalcomponents will be damaged, how to resolve these issue belowillustrated simulation for 2MW wind power plant using Doubly

6


10682

Figure 6: Simulink model of DFIG with SVC

fed induction generator.

Figure 7: Generator out power with SVC and Without SVC

7


10683

Figure 8: Generator output voltage using SVC

Figure 9: Converter output DC voltage using SVC

8


10684

Figure 10: Stator output Voltage (Short circuit)

Figure 11: Generator Reactive Power using SVC

9


10685

Figure 12: Static Var Compensator Output

Figure 13: Rotor Speed output during short circuit time.

10


10686

Figure 14: Generator Output current during Short-circuit andNormal Output using SVC.

Figure 15: Converter output voltage with SVC and Rotor Speed.

11


10687

Figure 7: During Short circuit time Generator has going tostop mode. Due to Phase A, Phase B, Phase B and groundshort-circuited at time 5.019. Now We connected static Varcompensator against of the problem. In this short-circuit currentdischarged to SVC reactor. Then wind power plant is runningnormally. Generator out as already illustrated figure.

Figure 8: At Short circuit time 5.019 that time generatoroutput voltage sag has occurred. Due to these reason outputpower will be reduced and all electrical components hasmalfunction. So We connected SVC then problem has resolved asalready generator output chart illustrated figure.

Figure 9: During Short circuit time The power converter directcurrent will be increase due to three phase fault applied on the line.In mean time power converter dc link voltage increased and AllPower semiconductor temperature will have increased. However,we can able to resolve these issue help with Static var compensator.

Figure 10: Short circuit time Stator voltage increased up to30Pu. After connected SVC. Then Stator voltage reduced.

Figure 11 & 14: During Short circuit time Generator reactivepower will be increased and current also increased. That time allinsulation damaged. Wind turbine is going to stop mode operation.So, we connected static Var compensator the wind turbine continuesgoes to Run mode.

Figure 13: At Short circuit time Rotor speed is reduced 0.19Pu. After connected SVC The Rotor speed is Increased

Figure 15: During Short circuit time Rotor current is increasedthat time tower vibration also occurred. Rotor current increasedup to 2Pu. Due to these reason damping vibrations increased. SVCdoes not control rotor current. Only Controlled by STATCOM.

12


10688

6 PARAMETER TABLE

7 CONCLUSION

In this paper, the effect of static VAR compensator on the DFIG-based wind turbine has been investigated. The results veried thatby applying SVC, the Converter Vdc current and of DFIG duringfault condition is decreased. So, the operation time Fault currentdischarged through Static Var Compensator and power convertercurrent also reduced. Generator voltage sag also arrested. TheStatic Var compensator delivery output is good and control voltagesag. The wind power plant continues operation during short circuittime. The simulation output performed using 2MW doubly fedinduction generator and good output.

13


10689

References

[1] Hinrichsen, E. N., Nolan, P. J “Stability of Wind TurbineGenerators”, IEEE Power Engineering Review, Vol. PER-2,Issue, 8, (1982).

[2] R. A. J. Amalorpavaraj, P. Kaliannan, and U. Subramaniam,“Improved fault ride through capability of DFIG based windturbines using synchronous reference frame control baseddynamic voltage restorer”, ISA Trans., vol. 70, no. 1, pp.465474, Jul. 2017.

[3] J. Morren and S. W. H. D. Haan, “Ridethrough of windturbines with doubly-fed induction generator during a voltagedip”, IEEE Trans. Energy Convers., vol. 20, no. 2, pp. 435441,Jun. 2005.

14


10690

10691

10692

Date post:	15-Mar-2020
Category:	Documents
Upload:	others
View:	15 times
Download:	0 times

2MW DFIG FAULT RIDING IMPROVEMENT USING SVC · Figure 1: Block Diagram of DFIG Wind Turbine...

Documents