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 .