Electricty Generation

In wind farm, individual turbines are interconnected with a medium volatage (often 34.5KV), power collection system and communication network. At a substation, this medium-voltage electric current is increased in voltage with transformer for connection to the high voltage electric power transmission system. The surplus power produced by domestic microgenerators can, in some juroisdicitions, be fed into the network and sold to the utility company, producing a retail credit for the microgenerators' owners to offset energy costs.

Induction generators, often used for wind power, require reactive power for excitation so substations used in wind-power collection systems include substantial capacitor banks for p.f. correction. Since wind speed is not constant, a wind farm's annual energy production is never as much as the sum of the generator nameplate rating multiplied by the total hours in a year. The ratio of actual productivity in a year to this theoritical
maximum is called capacity factor.For example, a 1 MW turbine with a capacity factor of 35% will not produce 8,760 MW·h in a year (1 × 24 × 365), but only 1 × 0.35 × 24 × 365 = 3,066 MW·h, averaging to 0.35 MW.