Control method for preventing excessive adjustment of coal feed for boiler in process of varying load

Abstract

The invention discloses a control method for preventing excessive adjustment of coal feed for a boiler in the process of varying load, which is characterized in that a set value of main stem pressure obtained via a sliding pressure function is subjected to inertial filtering by four variable parameter inertial procedures, the change of the set value of the main steam pressure within a varying load starting period of a unit is delayed, the deviation between the set value of the main steam pressure and actual steam pressure within the starting period is reduced, and accordingly the excessive adjustment of coal feed for the boiler in the process of varying load is lessened, and influence of main steam pressure fluctuation on stability of the whole unit is prevented. By the control method, operational stability of the unit can be improved effectively.

Description

technical field [0001] The invention relates to a control method for preventing excessive adjustment of boiler coal supply during load changing, in particular to a control method that uses four inertia links to perform inertial filtering on the set value of main steam pressure and automatically changes the integral time of the boiler load regulator. , effectively reduce the deviation between the fixed value of the main steam pressure and the actual steam pressure in the initial period of unit variable load, and reduce the integral adjustment effect on the steam pressure deviation during this period, so as to prevent excessive coal feed to the boiler during the load variable process The advanced control method of regulation belongs to the field of thermal power engineering and automatic control. Background technique [0002] Boiler load control (also known as the calculation circuit of boiler coal quantity command) determines the amount of coal that should be added to the boi...

AI Technical Summary

Problems solved by technology

The main problem is that in the initial period of unit load change, the main steam pressure fixed value P 0 will follow the load command N 0 The change of sliding pressure changes quickly, while the actual main steam pressure P T Due to the large inertia of the boiler, it is difficult to immediately follow the fixed value P 0 changes, resulting in a large main steam pressure deviation (P 0 -P T ), due to the feedback coal quantity instruction BM CL Just according to the pressure deviation (P 0 -P T ) to adjust, a large main steam pressure deviation will lead to the feedback coal quantity command BM CL There is also a large amount of adjustment

However, resulting in main steam pressure deviation (P 0 -P T ) is not because the amount of coal adjusted by the boiler is not enough (in fact, due to the feed-forward coal amount instruction BM FF The role of boiler coal has enough adjustment), but due to the large inertia and large lag of the boiler, after the boiler burns for a certain lag time, the main steam pressure P T will quickly keep up with the fixed value P 0 The change

Obviously, the feedback coal quantity command BM CL Larger adjustments during the initial period of variable load are incorrect, which will lead to excessive adjustment of boiler coal feed, which will cause repeated fluctuations in main steam pressure and affect the stability of the entire unit

This is one of the most important reasons for main steam pressure fluctuations. So far, there have been no reports on improving boiler load control system solutions for such main steam pressure fluctuations.

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