AGC control system for 660MW supercritical unit under deep peak regulation

Abstract

The invention discloses an AGC control system for a 660MW supercritical unit under deep peak regulation, belonging to the technical field of AGC control. When the load of the unit is in a deep peak regulation interval, minimum flow limitation is carried out on the flow of a gas pump; when the flow of a single gas pump is smaller than 425T / H, and a re-circulating valve of the gas pump is involved in gas pump inlet flow regulation, is slowly started and is maintained to work over a minimum output; meanwhile, the smoke temperature is increased at a boiler side, and a denitration wide load baffleis slowly turned down along the load of the unit so as to maintain the smoke temperature of the unit under a low load; and when the load of the unit is in a deep peak regulation interval, AGC speed isautomatically reduced through judgment, meanwhile, PID self-adaption and variable parameter control of boiler main control and steam engine main control can be realized through AGC, so that the automatic control quality is improved. According to the AGC control system, the following of the re-circulating valve and the denitration wide load baffle of a steam feed pump along the automatic load control of the unit, the AGC automatic control under deep peak regulation, the steam engine main control PID self-adaption control and the boiler main control PID self-adaption control can be realized.

Description

technical field [0001] The invention relates to the technical field of AGC control, and more specifically, relates to an AGC control system of 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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