Wind Turbine:
Wind energy is converted to electrical energy by wind turbines. Here in
wind turbines the wind’s kinetic energy is captured by the blades on the
rotor of a turbine. Wind makes the rotor blade of the turbine to rotate
proportional to the speed of wind. As rotor blade rotates, rotor rotates
with it. An alternator or electrical generator is mechanically coupled
with the rotor. So with the rotation of the rotor, electricity is
generated.
The amount of mechanical power a wind turbine captures [25, 26] can
be found using:
(5)
Here,
Pm = Captured mechanical power from wind by a
wind turbine.Cp = Wind turbine’s power coefficient of the,
dimension less (theoretical preferred value = 0.59 [7])ρ = Air density in Kg/m3.A = Rotor swept area measured in m2.v = Wind speed in m/s.
The power coefficient Cp is the ratio of turbine
power to wind power and depends on pitch angle and TSR [25]. The
pitch angle is defined as the angle to which the blades of the turbine
are aligned [7]. The TSR is defined as the turbine speed at the tip
of the blade to the wind velocity [25].
TSR= λ=\(\ \frac{\text{ωR}}{v}\) (6)
Here,
ω = Turbine speed.\(v\) = Wind speed.
R= Turbine radius.
From equation (5) it can be said that output power depends on the speed
of wind, rotor area as well as on power coefficient. So if operated at
maximum Cp, the produced power is then maximized.
So it is necessary to operate it with a rotor speed at a constant TSR
[26]. In this work for the simulation is HOMER, AWS HC 3.3kW Wind
Turbine model was used having a rated capacity of 3.3 kW. The
relationship between wind speeds to power output for this wind turbine
model is given in Fig.5 In this experiment single and two units
of this model of wind turbines have been considered. Wind turbines
provide AC supply in the system. The relevant data regarding Wind
Turbine used in this work including different costs, life time etc. are
provided in Table 4 .