The construction scheme for a dispatching and management technical support system for large-scale wind farms in the provincial dispatching center is dealt with. The key techniques and functions of the system are described in detail and the functional implementation framework of the wind farm on-line power and voltage control formulated by the provincial dispatching center is proposed. Automatic generation control（AGC） and automatic voltage control（AVC） programs of wind farms based on wind power forecast are also discussed. Part of the system functions have been realized in the dispatching center of Western Power Grid in Inner Mongolia.