wind energy
DESCRIPTION
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WIND ENERGY
Energy available in the wind over the earth’s surface is estimated to be
1.6x107 K.W
The problems associated with Utilizing wind energy
(i) The energy is available in dilute form
(ii) (ii) The availability of the energy varies
Means of storage have to be devised if a continuous supply of power is required
Wind millKinetic
energy of movi
ng air
Mechanical
energy
Machine
/Generator
Classification of wind mills
Wind mills
Horizontal Windmills
Single Bladed
Double Bladed
Multi Bladed
Vertical Windmills
Darrieus rotor
Savonius rotor.
Horizontal Axis single blade Wind mills
Wind Turbine Cost Breakdown
1 propeller type Wind Mill
2 propellers type Wind Mill
3 propellers type
Holland type
Sail type
Multi-blade
Vertical axis wind turbines
Straight wing type
Darrieus type
Cup type
S- paddle type
Savonius type
Crossflow type
Lift and drag
Stalling effect
Pitch angle
Wind Surveys
1. Instrumentation – Wind direction sensors
2. Data recording systems- Strip chart
3. Type of data- Wind speed and directional-hourly averages
4. Data reporting – Wind Frequency curves, Daily, Weekly,
Monthly
Wind direction sensors
Strip chart
Strip chart
Site Selection Consideration
1. High annual average wind speed
2. Availability of anemometry
3. Availability of Wind V(t) curve at proposed site
4. Wind Structure at the proposed site
5. Altitude of the proposed site
6. Distance to Roads and Railways
7. Nearness of site to local center/user
8. Nature of ground
9. Favorable Land cost
Anemometer
Methods of Generating Synchronous Power from WTGs
Rotor Generator The conversion systems
Constant Speed Variable pitch Fixed Ratio gear
AC Generator
Constant Speed Variable pitch Two stage ratio gear
AC Generator
Rotor Generator The conversion systems
Constant Speed Fixed pitch Variable Ratio gear
AC Generator
Variable Speed Fixed pitch DC Generator/DC Motor /AC generator
Rotor Generator The conversion systems
Variable Speed Fixed pitch AC Generator/ Rectifier/DC motor/ AC generator
Variable Speed Fixed pitch AC Generator/ Rectifier/ Inverter
Rotor Generator The conversion systems
Variable Speed Fixed pitch Direct Converter (Matrix Converter)
Variable Speed Fixed pitch Wound Rotor Induction Generator
Rotor Generator The conversion systems
Variable Speed Fixed pitch Wound Rotor Induction Generator and Cycloconverter circuit in the rotor circuit
Induction Generator
Two Types of Induction Generator
1. Normal Type (Non-Isolated)
2. Isolated Type (Self Excited)
Normal Type (Non-Isolated)
Normal Type (Non-Isolated)
Isolated Type (Self Excited)
Controls
1. Orientation of the rotor
2. Start up and cut-in
3. Varying Pitch of the blades
4. Generator output monitoring
5. Shutdown and cut out owing to malfunction or very high winds
6. Maintenance Mode
Controls
Controls
Power in the Wind :
Po = 0.5*ρ *A* Cp*v3
Where
ρ = density of air
v= wind speed
Cp= efficiency factor or Power Coefficient
A= Cross-sectional area of turbine disc
Maximum wind turbine efficiency - the Betz limit
The power developed by the wind turbine is
Power =(P1 - P2 ) * At *Ut
where At is the turbine disc area
Volume flow continuity
Au *Uu = Ad *Ud = At *Ut
Force on the turbine
F = m*Uu -m*Ud
Power extracted by the Turbine:
PT = F*Ut =m(Uu –Ud )*Ut