As a clean and renewable energy source, the small hydro plays a very important role in the power system. In China, the total installed capacity of small hydro has been over 55 GW by April 2010, accounting for about 30% of the total installed hydropower capacity. However, there is plenty of abandoned energy in most small hydro plants because of the disordered management and unscientific scheduling methods. Moreover, large amount of transmission overload has posed a great threat to the security and stability of the power grid with a great percentage of small hydro plants, especially in the wet season.