Thermal power generating unit loading control system and method based on continuously adjustable back pressure

The invention belongs to the technical field of thermal power generating unit peaking, and particularly relates to a thermal power generating unit loading control system and a thermal power generating unit loading control method based on continuously adjustable back pressure. The system comprises a high-pressure cylinder, a medium-pressure cylinder, a low-pressure cylinder, a generator, a condenser, a circulation water pump, a control system, a condensate pump, a boiler, and a circulating water pump motor execution unit, and is characterized by further comprising a back pressure continuous adjustment system. The method includes the first step that a logical judgment unit in the control system judges a working situation of a unit, the second step that a back pressure protection sub-system enters an execution stage, the third step that a best back pressure sub-system enters the execution stage and the fourth step that a varying load control sub-system enters the execution stage. In terms of a wet cooling unit, by means of continuous adjustment of circulating water flow, back pressure of the unit can be changed and varying load control for the unit can be achieved to a certain extent. Therefore, the system and the method can change varying load operation characteristics and economical efficiency of the thermal power generating unit.