Based on the statistic analysis of the installed capacity of built wind farm in China

it is pointed out that the determination of wind farm capacity is mainly affected by political and subjective factors because of lacking technical support. A way of estimating wind farm capacity

ie. considering wake loss

first determining the array of wind turbine generators under the given wind energy resource is presented

then estimating the capacity is determined when the array of wind turbine generators. To do this

the power efficiency of different wind turbines is analyzed

while the concept of reference wind turbine and carries out wake loss experiments using reference wind turbine is introduced. By controlling the average wake loss of wind farm

the array of wind turbines under difference wind velocities is recommended. Using the relationship between the rated power and square of diameter of wind turbine generator

it gives the recommend installation capacity at 50 m height for areas with different wind power density level. The method can provide a reference for determining the installation capacity of wind farm during the early stage of wind farm construction.