Gas steam combined cycle unit multivariable constrained prediction function load control method

Abstract

The invention discloses a gas steam combined cycle unit multivariable constrained prediction function load control method. The method is characterized by comprising the steps that (1) an original load instruction counter circuit is adjusted, and a primary frequency modulation instruction is superposed onto a load instruction of a gas turbine; (2) a 2*2 controlled object model with gas turbine fuel valve opening and steam turbine inlet adjusting valve opening as input and combined cycle unit actual power and steam turbine main steam pressure as output is built, wherein the controlled object model is expressed by an equation shown in the specification, PW is the combined cycle unit actual power (MW), TP is the steam turbine main steam pressure (MPa), U1 is the gas turbine fuel valve opening (%), U2 is the steam turbine inlet adjusting valve opening (%), G11 is a transfer function with the U1 as input and the TP as output, G12 is a transfer function with the U2 as input and the PW as output, G21 is a transfer function with the U1 as input and the TP as output, and G22 is a transfer function with the U2 as input and the TP as output; in addition, it is ensured that denominators of the G11 and the G12 are the same, and the denominators of the G21 and the G22 are the same after reduction of fractions to a common denominator is carried out on the transfer functions.

Description

technical field [0001] The invention relates to a multivariable predictive function control method for load control of a gas-steam combined cycle unit, which establishes a new multivariable controlled object model, adopts the latest predictive function recursive algorithm, and makes the actual power of the combined cycle unit reach a new level. The standard for the unit's rising and falling load rate is formulated, and the main steam pressure of the steam turbine is stabilized at the set value as soon as possible, which belongs to the field of thermal automatic control. Background technique [0002] Since the implementation of the "Renewable Energy Law" in 2006, new energy power generation technology has received more and more attention, and the proportion of new energy power generation in the power grid has gradually increased. After more than 60 years of development, the gas-steam combined cycle unit has a series of advantages such as high efficiency, high flexibility, low...

AI Technical Summary

Problems solved by technology

[0005] Purpose of the invention: The purpose of the present invention is to provide a load control system for combined cycle units and a steam turbine main steam pressure control system to solve the problem that the traditional combined cycle unit’s rate of load increase and decrease is difficult to reach the standard; the main steam pressure of the steam turbine fluctuates greatly and the traditional Multi-variable limited predictive function control method for load control of gas-steam combined cycle units where predictive control algorithm is difficult to apply to engineering problems

Images