Transcript 2. WIND TURBINE MODEL

Wind power
MODELING AND SIMULATION OF WIND TURBINE –
DOUBLY FED INDUCTION GENERATOR (WT-DFIG)
IN WIND FARM USE MATLAB/SIMPOWERSYSTEM
Student
: TRUONG XUAN LOC (MA02B206)
Professor : CHI-JO-WANG
CONTENTS OF TOPIC
1. INTRODUCTION
2. WIND TURNINE MODEL
Wind power
3. DFIG MODEL
4. WIND FARM USING DFIG
5. SIMULATION RESULT
6. CONCLUSION
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1. INTRODUCTION
Wind power
• Now day, wind energy has become a viable solution for energy
production, in addition to other renewable energy sources. One way
of generating electricity from renewable sources is to use wind
turbines that convert the energy contained in flowing air into
electricity.
• With increased penetration of wind power into electrical grids, DFIG
wind turbines are largely deployed due to their variable speed
feature and hence influencing system dynamics. This has created
an interest in developing suitable models for DFIG to be integrated
into power system studies.
1. INTRODUCTION
Wind power
• Up to this moment, the amount of wind power integrated into
large‐scale electric power systems only covers a small part of the
total power system load. The rest of the power system load is for
the largest part covered by conventional thermal, nuclear, and
hydropower plants.
• This paper presents the modeling and simulation of a wind turbine
doubly-fed
induction
generator
in
wind
farm.
The
Matlab/Simulink/SimPowerSystems software is used to develop the
model for simulation of wind power systems
2. WIND TURBINE MODEL
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• The model is based on the steady-state power characteristics of
the turbine. The output power of the turbine is given by the
following equation.
where
• Pm: Mechanical output power of the turbine (W)
• Cp: Performance coefficient of the turbine
• Ρ: Air density (kg/m3)
• A: Turbine swept area (m2)
• Vwind: Wind speed (m/s)
• λ:Tip speed ratio of the rotor blade tip speed to wind speed
• Β:Blade pitch angle (deg)
2. WIND TURBINE MODEL
• Can be normalized. In the per unit (pu) system we have:
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• Performance or power coefficient Cp depends on wind speed, the
speed of the turbine and the pitch of the blades. The power
coefficient of the turbine is given by :
With
•
Fixing the ratio λ and the pitch blades β to their optimum values,
the wind system will provide optimum electrical power.
2. WIND TURBINE MODEL
• This ratio λ, called also the tip speed ratio :
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Where: Ω is the speed of turbine, R the blade radius and v the wind
velocity.
• The coefficients c1 to c6 are: c1 = 0.5176, c2 = 116, c3 = 0.4, c4 =
5, c5 = 21 and c6 = 0.0068. The cp-λ characteristics, for different
values of the pitch angle β, are illustrated below. The maximum
value of cp (cpmax = 0.48) is achieved for β = 0 degree and for λ =
8.1. This particular value of λ is defined as the nominal value (λ_nom
Figure -1- Power
coefficient versus λ
and β
3. DFIG MODEL
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A. Operating Principle of the Wind Turbine Doubly-Fed Induction
Generator
Fig. 2. The wind turbine and the doubly-fed induction generator system
3. DFIG MODEL
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Pm: Mechanical power captured by the
Fig. 3. Active and reactive power
flows
wind turbine and transmitted to the
rotor
Ps: Stator electrical power output
Pr: Rotor electrical power output
Pgc: Cgrid electrical power output
Qs: Stator reactive power output
Qr: Rotor reactive power output
Qgc: Cgrid reactive power output
Tm: Mechanical torque applied to rotor
Tem: Electromagnetic torque applied to
the rotor by the generator
ωr: Rotational speed of rotor
ωs: Rotational speed of the magnetic
flux in the air-gap of the generator, this
speed is named synchronous speed.
J: Combined rotor and wind turbine
inertia coefficient
3. DFIG MODEL
Wind power
The Power Flow
- The mechanical power and the stator electric power output are computed
as follows:
Pm = Tm ωr
Ps = Tem ωs
- For a lossless generator the mechanical equation is:
J.d ωr/dt = Tm – Tem
- In steady-state at fixed speed for a lossless generator:
Tm = Tem
Pm = P s + Pr
- It follows that:
Pr = Pm - Ps = Tm ωr - Tem ωs = - Tm (ωs – ωr). ωs/ ωs =
= -s Tm ωs = -s Ps
- where s is defined as the slip of the generator:
S = (ωs – ωr)/ ωs
3. DFIG MODEL
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B. Control systems
Fig. 4. Turbine characteritics and
tracking characteristic
Fig. 5. Rotor-side and gridside converters and control
systems
3. DFIG MODEL
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Rotor side converter (Crotor)
Fig .6. rotor-side controller.
3. DFIG MODEL
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Grid side converter
Fig. 7.Grid-side controller
3. DFIG MODEL
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Pitch angle control system
Fig. 8. Pitch angle control
The pitch angle is kept constant at zero degree until the speed
reaches point D speed of the tracking characteristic. Beyond
point D the pitch angle is proportional to the speed deviation
from point D speed.
4. Wind Farm Using DFIG
Description of the Wind Farm
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In this section illustrates application of SimPower Systems
software to study the steady-state and dynamic
performance of a 9 MW wind farm connected to a
distribution system.
Fig. 9. Single-Line Diagram of the Wind Farm Connected to a
Distribution System
4. Wind Farm Using DFIG
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SimPower Systems Diagram of the Wind Farm Connected to the
Distribution System
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4. Wind Farm Using DFIG
Generator Data
Control Parameters
5. SIMULATION RESULT
Turbine response to a change in wind speed
Wind power
wind speed is set at 8 m/s, then at t = 5s, wind speed increases suddenly at 14 m/s
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5. SIMULATION RESULT
Wind power
Simulation of grid parameters when the mode of operation is set
to Control Parameters
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Wind power
6. CONCLUSIONS
• The model is a discrete-time version of the Wind Turbine Doubly-Fed
Induction Generator (Phasor Type) of Matlab/SimPowerSystems.
• Operation of DFIG and it’s controls using AC/DC/AC converter. DFIG
wind generator and investigate the effects of wind speed and pitch
angle on voltage, real power and reactive power of a DFIG wind
generator .
• The DFIG is able to provide a considerable contribution to grid
voltage support during short circuit periods. Considering the results it
can be said that DFIG proved to be more reliable and stable system
when connected to grid side with the proper converter control
systems
• The rotor side converter (RSC) usually provides active and reactive
power control of the machine while the grid-side converter (GSC)
keeps the voltage of the DC-link constant.
• we simulated grid side and wind turbine side parameters and the
corresponding results have been displayed.
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REFERENCES
1. Richard Gagnon, Gilbert Sybille, Serge Bernard, Daniel Paré, Silvano Casoria, Christian
Larose. “Modeling and Real-Time Simulation of a Doubly-Fed Induction Generator
Driven by a Wind Turbine”
2. Karim Belmokhtar, Mamadou Lamine Doumbia and Kodjo Agbossou “ Modelling and
Power Control of Wind Turbine Driving DFIG connected to the Utility Grid”
Wind power
3. Ashish Kumar Agrawal. Bahskar Munshi. Srikant Kayal. Under the guidance of Prof. K. B.
Mohanty. Department of Electrical Engineering, National Institute of Technology, Rourkela
‘STUDY OF WIND TURBINE DRIVEN DFIG USING AC/DC/AC CONVERTER’
4. Dr M S R Murty ‘Wind Turbine Generator Model’.
5. MATLAB
SimPowerSystems
User's
Guide,
Version
5.5
(R2011b),
http://www.mathworks.com/access/helpdesk/help/toolbox/physmod/powersys/
6. Matlab Simulink toolbox of the \SimPowerSystems\Distributed Resources Library\Wind
Generation\, the Help file of the model of DFIG (phasor type).
Wind power
THANKS FOR YOUR ATTENTION!