Compensation adjusting method for main steam pressure of thermal power generating unit

Abstract

The invention relates to a compensation adjusting method for a main steam pressure of a thermal power generating unit. The method comprises: differential and amplitude limit processing is carried out on an offset signal of an actual main steam pressure value and a set value and then processed signal is superposed to a first-level overheating steam temperature set value of a first-level overheating temperature control system, and the main steam pressure is compensated and adjusted by using a first-level overheating temperature-reducing water flow; an offset signal of a second-level overheating steam temperature set value and an actual value is processed by differential, dead zone, and amplitude limit processing and then the processed signal is superposed to a power generating load set value of a cooperation control system; and when a changing rate of the second-level overheating steam temperature offset signal exceeds a dead zone interval, the second-level overheating steam temperature offset is reduced by changing a power generating load. According to the invention, the main steam pressure offset is compensated and adjusted by using the first-level overheating temperature-reducing water flow; and second-level overheating steam temperature protection logic is added to the power generating load control system. Therefore, on the premise that the overheating steam temperature control quality is not reduced obviously, the control quality of the main steam pressure is improved effectively; and the fluctuation amplitudes of the main steam pressure and fuel quantity during the load changing process of the thermal power generating unit are reduced.

Description

technical field [0001] The invention relates to a method for compensating and adjusting the main steam pressure of a thermal power unit by utilizing the desuperheating water flow of a primary superheater, and belongs to the field of control technology. Background technique [0002] Large-capacity thermal power units generally use two-stage water spray desuperheating to adjust the temperature of superheated steam. The first-stage water spray desuperheater is installed in front of the panel superheater to roughly adjust the steam temperature, prevent the tube wall of the panel superheater from overheating, and maintain The secondary water spray desuperheater is in a reasonable working area; the secondary water spray desuperheater is installed in front of the high temperature superheater to precisely adjust the superheated steam temperature. In engineering, it is generally believed that the coupling between the controlled object of superheated steam temperature and the controll...

AI Technical Summary

Problems solved by technology

The superheater desuperheating water control system must ensure the stability of the superheated steam temperature, which is actually equivalent to reducing the available heat storage capacity of the boiler. The smaller the boiler heat storage, the more difficult it is to control the main steam pressure

Under the action of the control system, the fluctuation of the main steam pressure will cause the fluctuation of the boiler fuel quantity, and the fluctuation of the boiler fuel quantity will cause the fluctuation of the superheated steam temperature

Both the main steam pressure and the superheated steam temperature are difficult to control due to the characteristics of large inertia and large delay. The vicious competition between the two will lead to the deterioration of the overall control effect of the unit.

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