A new multi-variable predictive control method for thermal power unit load

Abstract

The invention discloses a novel thermal power generating unit load multivariable predictive control method. According to the method, novel performance indexes are provided by being specific to characteristics of great inertia of a boiler, slow process response and the like, and a multivariable predictive control method of a unit load control system is designed according to the indexes. The performance indexes of the method are designed on the basis of the relation among unit output power, single-step predicted deviations of main steam pressure and deviation change rate. During process controlling, when demands of outside loads are changed, the valve opening degree of a turbine is adjusted to change inlet steam quantity of the turbine, the main steam pressure is changed to release stored heat of the boiler so that a unit can rapidly respond to the outside load demands, meanwhile, the boiler burning ratio is rapidly adjusted to meet the outside load demands and meanwhile, prevent the deviation between the main steam pressure and a set value from exceeding a limit, the set value can be tracked, stable operation of the unit can be maintained, and the stability of the load control system and the operating efficiency of the unit can be improved.

Description

technical field [0001] The invention belongs to the technical field of thermal automatic control, and in particular relates to a novel thermal power unit load multivariable predictive control method. Background technique [0002] At present, the decentralized control system (DCS) is commonly used in thermal power units. The load control system adopts the control method of load command feedforward and proportional integral differential feedback. The steam pressure fluctuates greatly, causing other important parameters of the unit such as main steam temperature, boiler drum water level, furnace negative pressure and oxygen content to fluctuate greatly, so that the unit cannot quickly meet the external load demand, and the unit cannot Stable economic operation. Therefore, it is of great significance to study and design advanced fast load response control algorithms. [0003] When the ordinary multivariable predictive control method is applied to the load coordination control ...

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Problems solved by technology

[0003] When the ordinary multivariable predictive control method is applied to the load coordination control system, there is a large amount of calculation, and the project cannot realize online real-time control; at the same time, it cannot realize the dynamic coordination between the boiler side and the turbine side in the control process, that is, when the external load demand changes , by changing the main steam pressure in a short period of time, the boiler heat storage is released to meet the load demand, and at the same time, when the boiler side control control action is followed up, it can ensure that the main steam pressure tracks the change of the pressure setting value

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