Improved direct energy balance load coordination control method and system

Abstract

The present invention relates to an improved direct energy balance load coordination control method and system, comprising: using the boiler energy demand command BD as the set value of the PID controller, using the heat signal as the adjusted value of the PID controller, and using the difference between the two Proportional and integral functions are used to change the fuel quantity command, and a new feedforward command is used to adjust the coal combustion quantity command. The new feedforward command includes a load command function, an intelligent overshoot unit, and a steam pressure deviation and coal quantity correction function. . Compared with the prior art, the present invention has the advantages of improving the coordinated variable load capacity of the coal-fired units as a whole, and is also beneficial to the stable control of the main steam pressure.

Description

technical field [0001] The invention relates to the field of automatic control of thermal power generating sets, in particular to an improved direct energy balance load coordination control method and system. Background technique [0002] The thermal power unit is a multi-input multi-output strongly coupled multivariable system, in which the dynamic object characteristics of the boiler and the steam turbine are quite different. The unit load coordinated control system (CCS, Coordinated Control System) needs to coordinate and control input parameters such as boiler coal volume, water supply volume, air volume and steam turbine valve opening, so as to achieve good control quality of main output parameters such as unit load and main steam pressure, and meet the requirements of The requirements of the power grid on the variable load performance of the unit and the safe and economical operation of the unit itself. The direct energy balance (DEB, Direct Energy Balance) control me...

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Problems solved by technology

[0003] However, as the power grid has higher and higher requirements on the variable load performance of the unit, coupled with factors such as large changes in the type of coal used by the boiler and mixed combustion of coal, some deficiencies in the current DEB control have gradually been exposed, mainly including: variable The change of the coal volume lags behind the action of the steam turbine valve adjustment during load, and it will not change until the adjustment stage pressure and the main steam pressure change caused by the steam turbine valve adjustment action, which will easily lead to a large deviation of the steam pressure; the coal volume overshoot adopts the differentiation of the boiler command. When the steam pressure is locked, the overshoot will be reset, which is not conducive to the recovery of the main steam pressure; the feedforward of the coal quantity will also form a steam pressure feedback loop, which will easily lead to loop oscillation; there is no correction coefficient for the calorific value of coal, and it is impossible to make corresponding adjustments according to the change of coal quality. Adjustment; Coal volume adjustment PID does not carry out variable parameter control

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