Energy gradient utilization system and method for small turbine of thermal power plant

The invention relates to an energy gradient utilization system and method for a small turbine of a thermal power plant. Currently, steam feed pump systems and steam induced draft fan systems have many defects. The system comprises a main steam turbine, a main steam feeding pipe, a main steam feeding regulation valve, a feed pump drive small turbine, a feed pump connection shaft and a feed pump. The system is characterized by further comprising a first steam feeding pipe, a first regulation valve, a first induced draft fan drive small steam turbine, a first induced draft fan connection shaft and a first induced draft fan, wherein one end of the first steam feeding pipe is connected to the feed pump drive small turbine, the other end of the first steam feeding pipe is connected to the first induced draft fan drive small steam turbine, and the first regulation valve is arranged on the first steam feeding pipe. The method comprises the steps that the main steam turbine only provides steam for the feed pump drive small turbine directly, and then a part of steam obtained after acting in the feed pump drive small turbine is directly pumped to the induced draft fan drive small steam turbine to drive the small turbine to act. The energy gradient utilization system and method can conveniently and effectively achieve energy gradient utilization.