central region of Thailand have wind turbine installation in a large
scale currently. For example, one of the largest wind farms in
Thailand is at Nakhon Ratchasima province with a total capacity
of 207MW [34]. Fig. 5 shows wind rose diagrams of three sites
at a height of 120 m from one-year data of wind direction.
Corresponding to directions of the southwest monsoon and
northeast monsoon, the wind directions at sites S1 and S2