Backpressure control system of large air-cooler unit

Abstract

The invention discloses a background control system of a large air-cooler unit, belonging to an automatic control system of a coal-fired power plant. The backpressure control system comprises a PID (Process Identifier), a backpressure automatic setting module, a feedforward signal, a control parameter variable gain module and a step-switching optimization module; a real-time online optimization logic is set up by dispersing a function module, an integrator module, a selection module, an add and subtract module, a division module, a multiply module and a pulse module in the control system, and an independently automatic control system capable of being tracked dynamically and controlled stably; the backpressure control system solves the technical problems that the backpressure control system of the large air-cooler unit has large overshoot and is difficult to realize automation in the whole course, and can be widely applied to the backpressure control of a steam turbine of the large air-cooler unit.

Description

technical field [0001] The invention relates to an automatic control system, in particular to a back pressure closed-loop automatic control system of a large air cooling unit. Background technique [0002] The back pressure control system of the air-cooled unit mainly calculates the cooling air flow required by the exhaust steam of the condensing turbine through the measured value of the back pressure. , fan speed and steam isolation valve position are adjusted to finally control the back pressure of the turbine to operate within a safe and economical range. [0003] The existing large-scale air-cooled unit back pressure control system basically has the following problems: (1) With the change of ambient temperature and unit load, the operator has to manually increase or decrease the automatic back pressure setting value to meet the needs of unit operation . (2) The speed reduction program of the countercurrent fan in winter will cause a regular disturbance to the back pres...

AI Technical Summary

Problems solved by technology

[0003] The existing large-scale air-cooled unit back pressure control system basically has the following problems: (1) With the change of ambient temperature and unit load, the operator has to manually increase or decrease the automatic back pressure setting value to meet the needs of unit operation

(2) The speed reduction program of the countercurrent fan in winter will produce a regular disturbance to the back pressure control, which is especially obvious under the condition that the load is relatively low and there are few running air-cooling fans

(3) After the air-cooling step is switched, the number of running fans changes, and the back pressure control PID parameters will not match the actual working conditions, resulting in poor regulation performance of the control loop

(4) The setting interval of air-cooling step switching is too short. When the adjustment characteristics of the control loop become worse, it will cause the step sequence to switch back and forth, which will increase the interference on the control loop

The existence of these problems causes the control performance of the back pressure of the steam turbine to decline, and even fails to meet the requirements of the control index, which directly affects the safe and economical operation of the unit.

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