Q5Power Generation Sources
Question
Q.5. Define wind energy conversion systems.
Answer
A Wind Energy Conversion System (WECS) is the complete assembly of equipment that captures the kinetic energy of moving air using rotor blades and converts it into mechanical shaft power, which a generator then converts into electrical energy.
A Wind Energy Conversion System (WECS) is defined as the complete system of components that converts the kinetic energy present in wind into useful electrical energy. The wind's kinetic energy causes the rotor blades (aerodynamically shaped like airfoils) to rotate, which turns a low-speed shaft; this is connected through a gearbox (in geared turbines) to increase rotational speed, driving a high-speed shaft coupled to an electrical generator (induction or synchronous), which produces electrical power that is conditioned by power-electronic converters and fed to the grid.
The power extractable from wind is given by P = ½ ρ A v³ Cp, where ρ is air density, A is the swept area of the rotor, v is wind speed, and Cp is the power coefficient (efficiency of conversion, limited to a theoretical maximum of 59.3% by the Betz limit). A WECS also includes a yaw mechanism (to orient the rotor into the wind for horizontal-axis machines), a pitch control system (to regulate blade angle for power/speed control), a braking system, a tower, and a nacelle housing the drivetrain and generator. WECS may be classified as grid-connected (feeding power directly into the utility grid) or stand-alone/hybrid systems (used with battery storage or diesel/solar backup for remote locations).