Lecture No 6: Wind Power Generation
Lecture No 6: Wind Power Generation
Lecture No 6: Wind Power Generation
Wind Energy
Cont:
Cont:
components
Anemometer:
Measures the wind speed and transmits wind speed data to the
controller.
Blades:
Most turbines have either two or three blades. Wind blowing over the
blades causes the blades to "lift" and rotate.
Brake:
A disc brake, which can be applied mechanically, electrically, or
hydraulically to stop the rotor in emergencies.
Controller:
The controller starts up the machine at wind speeds of about 8 to 16
miles per hour (mph) and shuts off the machine at about 55 mph.
Turbines do not operate at wind speeds above about 55 mph
because they might be damaged by the high winds.
Gear box:
Gears connect the low-speed shaft to the high-speed shaft and
increase the rotational speeds from about 30 to 60 rotations per
minute (rpm) to about 1000 to 1800 rpm, the rotational speed
required by most generators to produce electricity.
The gear box is a costly (and heavy) part of the wind turbine and
engineers are exploring "direct-drive" generators that operate at
Types
Types of Wind Turbines
Modern wind turbines fall into two basic groups:
1.
horizontal-axis wind turbines (HAWTs)
2.vertical-axis wind turbines (VAWTs).
.
As the name pertains, each turbine is distinguished by the
orientation of their rotor shafts. The former is the more
conventional and common type everyone has come to know,
while the latter due to its seldom usage and exploitation, is
quiet unpopular. The HAWTs usually consist of two or three
propeller-like blades attached to a horizontal and mounted
on bearings the top of a support tower as seen in Figure.
.
When the wind blows, the blades of the turbine are set in
motion which drives a generator that produces AC electricity.
For optimal efficiency, these horizontal turbines are usually
made to point into the wind with the aid of a sensor and a
servo motor or a wind vane for smaller wind turbine
applications.
Cont:
With the vertical axis wind turbines, the
concept behind their operation is similar to
that of
the horizontal designs.
The major difference is the orientation of the
rotors and generator which are all vertically
arranged and usually on a shaft for support
and stability.
This also results in a different response of the
turbine blades to the wind in relation to that of
the horizontal configurations.
A typical vertical axis design is shown in Figure
Electrical diagram
A small
Quiet revolution
QR5Gorlov type
vertical axis wind
turbine
on the roof of
Colston allin
Bristol, England.
Measuring 3m in
diameter
and 5m high,
it has a nameplate
rating of 6.5kW.
V3
Density = P/(RxT)
P - pressure (Pa)
R - specific gas constant (287 J/kgK)
T - air temperature (K)
kg/m3
Area = r2
m2
Instantaneous Speed
(not mean speed)
m/s
Swept Area: A = R2
Area of the circle
swept by the rotor
(m2).
Wind velocity
1
kineticEnergy ( PAV )V 2
2
1
kineticEnergy PAV 3
2
Cont:
Area ( A) areasweptthebladesoftheturbine
velocity (v ) windspeedinmph
Environmental
Economic Development
Fuel Diversity & Conservation
Cost Stability
No air pollution
No greenhouse gasses
Does not pollute water with mercury
No water needed for operations