A two-stage coordinated predictive control method for superheated steam temperature of thermal power units

Abstract

The invention discloses a superheated steam temperature two-stage coordination, prediction and control method of a thermal power generating unit. The method designs a two-stage coordination and control algorithm and utilizes a GPC-P (generalized predictive control-proportion) cascade control strategy to respectively achieve the control of first-stage and second-stage desuperheating water spraying and enable the two-stage desuperheating water control to approximately decouple under the situation that a second-stage desuperheating water valve has adjusting allowance, accordingly the adjusting process of the first-stage desuperheating water spraying cannot cause the temperature fluctuation of the outlet of a last-stage superheater; and when the second-stage desuperheating water valve reaches an upper limit or a lower limit, makes full use of the adjusting allowance of the first-stage desuperheating water spraying to assist the second-stage desuperheating water spraying to control superheated steam temperature, and further reduces the deviation between a dynamic state and a steady state of the superheated steam temperature control, thereby improving the control performance of a system.

Description

technical field [0001] The invention belongs to the field of thermal automatic control, and in particular relates to an optimal control method for a superheated steam temperature system, more specifically a two-stage coordinated predictive control method for a thermal power unit superheated steam temperature. Background technique [0002] The superheated steam temperature is directly related to the safety and economy of thermal power unit operation, and is one of the process parameters that need to be monitored during the operation of the unit. [0003] Due to the long pipeline of the superheater and the large inertia and delay of the steam temperature controlled object, the traditional control method is often difficult to achieve a satisfactory control effect. In addition, the superheated steam temperature system of modern large-scale thermal power units is generally equipped with two or more stages of spray desuperheaters, which naturally leads to the problem of coordinate...

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Problems solved by technology

[0004] At present, most superheated steam temperature control systems of thermal power units still adopt the conventional PID (proportional-integral-derivative) cascade control scheme, which is difficult to effectively deal with the large delay characteristics of the steam temperature object, and does not fully consider the relationship between the two-stage water spray control. coordination problem

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