Supercritical unit DEH side primary frequency modulation method

Abstract

The invention discloses a supercritical unit DEH side primary frequency modulation method. The method includes the following steps that firstly, the deviation value between the rated rotation speed and the feedback rotation speed of a turbine unit is obtained; secondly, the deviation value obtained from the first step is calculated through a speed diversity factor function, and a calculated result and a power command are superposed; thirdly, the deviation value between the superposed value obtained from the second step and the feedback power of the turbine unit is obtained; fourthly, the deviator value generated after PID calculation is conducted on the deviation value obtained from the third step and the deviation value is obtained; and fifthly, the deviator value obtained from the fourth step is calculated through a main steam pressure modification function, the main steam pressure modification value is obtained and input into an execution mechanism, and therefore the turbine unit is controlled to run. By the adoption of the method, the primary frequency modulation function of the unit can be safely input for a long time, the primary frequency modulation performance of the unit is excellent, and the method is of great significance in safety and reliability of a power grid and a power plant.

Description

technical field [0001] The invention relates to the field of steam turbine regulation systems, in particular to a primary frequency regulation method on the DEH side of a supercritical unit. Background technique [0002] The grid frequency is the basis for the balance between power generation and load. When the power generation is equal to the load, the frequency of the grid is stable; when the power is greater than the load, the frequency of the grid rises; Reduced frequency. [0003] Primary frequency regulation refers to an automatic control process in which once the frequency of the grid deviates from the rated value, the control system of the unit in the grid will automatically control the increase or decrease of the active power of the unit, limit the change of the grid frequency, and maintain the stability of the grid frequency. When the frequency of the power grid increases, the primary frequency regulation function requires the unit to use its heat storage to quick...

AI Technical Summary

Problems solved by technology

[0011] The performance of the coordinated control system is not good. The primary frequency regulation function is an important function upstream of the coordinated control system. A coordinated control system with excellent performance is undoubtedly the basis for the optimization of primary frequency regulation. Many units have poor performance of the primary frequency regulation function because of the performance of the coordinated control system. Poor; the speed measurement is incorrect. The turbine speed is theoretically consistent with the grid frequency, but there is a certain delay. The turbine speed fluctuates, causing the turbine adjustment door to shake, the unit operation stability decreases, and the primary frequency modulation performance is poor; the frequency signal should be checked by the entire network , frequency signal, and there is a certain delay and fluctuation; the heat storage of the DC furnace is small, and the primary frequency modulation cannot be sustained. When the primary frequency modulation is inconsistent with the AGC change direction, the performance will deteriorate. There is a phenomenon of reverse regulation in the system; there is a deviation between the DEH door adjustment command and the power, and the correctness of the primary frequency regulation is not enough; at present, many units are operated by sliding pressure, and the steam turbine door is kept at a large opening, and the performance of primary frequency regulation is poor. The linearity is not good, the unit is running close to full load, the frequency regulation performance is poor when the control door is almost fully opened, and the performance is not good when the grid frequency changes slightly; the supercritical unit does not have heat storage like a drum furnace, so the power of the unit changes when the control door changes Very small, and the steam pressure changes greatly, which cannot meet the initial load changing requirements of the power grid

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