An AGC control method for 660mw supercritical unit under deep peak regulation

Abstract

The invention belongs to the technical field of AGC (automatic gain control) control and discloses an AGC control method for a 660MW supercritical unit under deep peak-load regulation. The method includes: when a unit load enters a deep peak-load regulation range, subjecting flow of steam pumps to minimum flow limitation; when the flow of each single steam pump is smaller than 435T / H, enabling a steam pump recirculation valve to participate in steam pump inlet flow regulation, slowly opening, and keeping each steam pump operating above minimum output; increasing smoke temperature on a boiler side, and slowly closing a denitrification wide load baffle along with the unit load to keep smoke temperature under a low unit load condition; after the unit load enters the deep peak-load regulationrange, automatically reducing the rate through AGC rate judgment, and enabling boiler master control and steam engine master control PID self-adaption variable-parameter control through AGC control, so that automatic control quality can be improved. Automatic control of the steam feed pump recirculation valve and the denitrification wide load baffle along with the unit load, AGC automatic controlunder deep peak-load regulation, steam engine master control PID self-adaption control and boiler master control PID self-adaption control are realized.

Description

technical field [0001] The invention relates to the technical field of AGC control, and more specifically relates to an AGC control method for a 660MW supercritical unit under deep peak regulation. Background technique [0002] The working medium in the boiler is water, and the critical pressure of water is: 22.115MPA, 374.15°C; at this pressure and temperature, the latent heat of vaporization of water and steam is equal to zero, and there is no two-phase region, that is, water is continuous into steam , and in a single-phase form, it is called the critical point of water, and the pressure of the working fluid in the furnace is greater than this pressure, which is a supercritical boiler. Automatic Gain Control (AGC) is an important part of the Energy Management System (EMS). According to the control target of the power grid dispatching center, the command is sent to the relevant power plant or unit, and the automatic control of the power of the generator is realized through...

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Problems solved by technology

[0005] (1) The recirculation valve of the original steam-driven feed water pump above 330MW adopts manual operation and fully closed mode, which cannot interfere with the inlet flow of the steam-driven feed water pump. The heat is low, which affects the safety of unit operation;

[0006] (2) The original denitrification wide-load baffle is manually controlled by operation, and kept fully open, unable to automatically adjust the flue gas temperature following the load of the unit, so that when the unit is reducing load, the flue gas temperature drops sharply, causing the denitrification to exit, causing the pollutants in the unit to exceed instantaneously. If the hourly average value exceeds the standard, the unit will be forced to shut down;

[0007] (3) The original AGC rate is 6.6MW / min. When entering the deep peak regulation interval, the range is too large, which affects the safety of the unit;

[0008] (4) In the original boiler main control command circuit, the dynamic compensation feedforward of the boiler main control is designed as an energy demand and pressure compensation circuit. In actual operation, the adjustment effect is not obvious, the adjustment lag is large, and the dynamic deviation of the main steam pressure is large;

However, this application only solves the problems existing in the coordinated control of some units, and a solution that can comprehensively solve various problems is still needed

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