Thermal power unit reheated steam temperature control method

Abstract

The invention relates to a thermal power generating unit reheated steam temperature controlling method. According to the operating characteristics of the boiler reheater and the theoretic study on a steam-temperature control system, a state feedback control method based on incremental state observer is adopted, and the concept of an algebraically equivalence observer is used to direct the parameter setting of an incremental state observer; in addition, a special control circuit is arranged in the steam-temperature control circuit to resolve the problems that the process of steam-temperature adjustment is relatively long when the reheated steam temperature set value is changed, non-linearity exists during steam-temperature control, the process of steam-temperature variation is very slow, etc., and variation parameter PID regulator is combined to jointly form a comprehensive reheated temperature automatic adjusting system. The invention is capable to ensure reheated steam temperature control to escape spray water upon large-range load variation, and effectively overcomes the disadvantage of the poor effect of the traditional PID regulation on the control of big lagged object; the reheated temperature control effect is improved remarkably; and a sample is provided for controlling the controlled object with big inertia and serious lagging in relation to reheated steam temperature.

Description

technical field [0001] The invention relates to a method for controlling the steam temperature of a thermal power unit, in particular to a method for controlling the reheated steam temperature of a thermal power unit. Background technique [0002] In the automatic control of modern thermal power plants, the reheat steam temperature affects the safety and stability of the unit and the direct economic benefits of the unit. Therefore, the control of the intermediate reheat unit and the reheat steam temperature is a very important control link. The methods for adjusting the reheat steam temperature are as follows: 1. Adjust the reheater or superheater baffle, and change the reheat steam temperature by changing the flue gas flow rate of the reheater. 2. In an emergency, adjust the temperature quickly by adjusting the water spray. 3. Change the flame center of the boiler by adjusting the swing angle of the burner to change the temperature of the reheater. Since the adjustment pr...

AI Technical Summary

Problems solved by technology

Since the adjustment process of the reheat steam temperature is a link with a large delay, and too much water is used to adjust the reheat steam temperature, it will cause a waste of energy, so the current adjustment of the reheat steam temperature is mainly through the adjustment Flue gas baffle and burner swing angle to achieve

Due to the large delay in the two adjustment methods, there are certain difficulties in the adjustment of the reheat steam temperature.

Especially when the power grid produces a large range of variable loads, it is more difficult to control the temperature of the reheated steam. Sometimes it is necessary to spray water to control the temperature of the reheated steam to a reasonable range, which obviously reduces the economic benefits of the unit.

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