Supercritical unit feedwater flow wide load stable control system and method

Abstract

The application discloses a supercritical unit water supply flow wide load stable control system and method, and is characterized in that the static water supply flow set value of the supercritical unit is calculated based on the load set value of the supercritical unit, the dynamic water supply flow set value of the supercritical unit is calculated based on the fuel amount dynamic feedforward amount, the main steam pressure value and the main steam pressure set value, the total water supply flow set value of the supercritical unit is calculated in combination with the separator temperature correction coefficient, the stability and the rapid response demand can be met at the same time, the control effect is good under different working conditions and the change of the boiler fuel quality, the stability risk caused by the single control strategy is avoided, and the application is not dependent on the manual operation and judgment, and the technical problems of the insufficient response speed, the limited control precision, the decreased stability and the insufficient automation degree of the traditional supercritical unit water supply flow control method in the wide load regulation process of the unit are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power automation, and particularly relates to a supercritical unit water supply flow wide load stable control system and method. BACKGROUND

[0002] Wide load regulation of thermal power units refers to that, through a series of technical means and optimization design, the thermal power units realize high-efficiency and stable operation under different loads in a wide load range (such as 40% to 100% load, or even lower to the load range of oil-free stable combustion), while minimizing actual energy consumption. This regulation capability is of great significance to improve the flexibility and economy of thermal power units.

[0003] In supercritical units, the control of water supply flow is crucial to ensure the stable operation of the boiler and improve the thermal efficiency. The traditional water supply flow control method mainly includes two types: one is based on load setting, and the other is based on boiler master output. The traditional supercritical unit water supply flow control method has the following problems in the process of wide load regulation of the unit:

[0004] Insufficient response speed: In the process of wide load regulation, due to the large and fast change of load, the traditional water supply flow control method may not be able to respond quickly to such changes, resulting in a lag in the regulation of water supply flow relative to the load demand, affecting the stability and efficiency of the unit.

[0005] Limited control precision: The traditional control method mainly relies on fixed control strategies and parameter settings, which are difficult to adapt to changes in various working conditions in the wide load range, resulting in a large deviation in the control process of water supply flow, affecting the combustion efficiency of the boiler and the steam quality.

[0006] Decreased stability: In the process of wide load regulation, the coupling relationship between various parameters of the unit is complex, and the traditional water supply flow control method cannot effectively handle this coupling relationship, resulting in a decrease in system stability. For example, the mismatch between water supply flow and combustion rate may cause fluctuations in main steam temperature, thereby affecting the safe operation of the unit.

[0007] Low degree of automation: The traditional water supply flow control method relies on manual operation and judgment, and has a low degree of automation. In the process of wide load regulation, the hysteresis and uncertainty of manual operation may further exacerbate the control difficulty and risk.

[0008] In summary, how to solve the technical defects of the traditional supercritical unit water supply flow control method in the process of wide load regulation of the unit, such as insufficient response speed, limited control precision, decreased stability, and low degree of automation, is a technical problem that needs to be solved by those skilled in the art. SUMMARY

[0009] The application provides a supercritical unit feedwater flow wide load stable control system and method, which is used for solving the technical problems of insufficient response speed, limited control precision, decreased stability and insufficient automation degree of the traditional supercritical unit feedwater flow control method in the unit wide load regulation process.

[0010] Therefore, the application provides a supercritical unit feedwater flow wide load stable control system in the first aspect, which comprises a static feedwater flow set value calculation module, a dynamic feedwater flow set value calculation module, a separator outlet temperature correction module and a total feedwater flow set value output module.

[0011] The static feedwater flow set value calculation module is used for calculating the static feedwater flow set value of the supercritical unit according to the load set value of the supercritical unit, and the static feedwater flow is the required feedwater flow of the supercritical unit under stable working conditions.

[0012] The dynamic feedwater flow set value calculation module is used for calculating the dynamic feedwater flow set value of the supercritical unit according to the fuel quantity dynamic feedforward quantity, the main steam pressure value and the main steam pressure set value, and the dynamic feedwater flow is the additional feedwater flow required by the supercritical unit under variable working conditions to overcome the boiler combustion inertia and the pipeline flow inertia.

[0013] The separator outlet temperature correction module is used for calculating the separator temperature correction coefficient according to the separator outlet temperature value and the separator outlet temperature set value.

[0014] The total feedwater flow set value output module is used for calculating the total feedwater flow set value of the supercritical unit according to the static feedwater flow set value, the dynamic feedwater flow set value and the separator temperature correction coefficient.

[0015] Optionally, the static feedwater flow set value calculation module comprises a load setting sub-module, a first function sub-module and a first inertia link sub-module.

[0016] The load setting sub-module is used for acquiring the load set value of the supercritical unit.

[0017] The first function sub-module is used for calculating the static feedwater flow set value of the supercritical unit according to the load set value of the supercritical unit.

[0018] The first inertia link sub-module is used for performing first-order inertia link-based filtering processing on the static feedwater flow set value of the supercritical unit.

[0019] Optionally, the dynamic feedwater flow set value calculation module comprises a signal acquisition submodule, a second inertia link submodule, a first PID controller submodule, a first summation submodule, a first multiplication submodule and a constant submodule.

[0020] The signal acquisition submodule is configured to acquire a fuel quantity dynamic feedforward quantity, a main steam pressure value and a main steam pressure set value.

[0021] The second inertia link submodule is configured to perform first-order inertia link-based filtering processing on the fuel quantity dynamic feedforward quantity.

[0022] The first PID controller submodule is configured to acquire a first PID correction quantity of a deviation between the main steam pressure value and the main steam pressure set value.

[0023] The first summation submodule is configured to superimpose the first PID correction quantity and the fuel quantity dynamic feedforward quantity output by the second inertia link submodule to obtain a dynamic fuel quantity.

[0024] The constant submodule is configured to configure a feedwater flow coefficient.

[0025] The first multiplication submodule is configured to multiply the dynamic fuel quantity and the feedwater flow coefficient to obtain a dynamic feedwater flow set value of the supercritical unit.

[0026] Optionally, the preset percentage is 20%.

[0027] Optionally, the separator outlet temperature correction module comprises a separator outlet temperature acquisition submodule, a separator outlet temperature setting submodule, a second PID controller submodule and a second function submodule.

[0028] The separator outlet temperature acquisition submodule is configured to acquire a separator outlet temperature value.

[0029] The separator outlet temperature setting submodule is configured to configure a separator outlet temperature set value.

[0030] The second PID controller submodule is configured to calculate a second PID correction value of a deviation between the separator outlet temperature value and the separator outlet temperature set value.

[0031] The second function submodule is configured to convert the second PID correction value into a separator temperature correction coefficient in a range of 0.8 to 1.2.

[0032] Optionally, the total feedwater flow set value output module comprises a second summation submodule and a second multiplication submodule.

[0033] The second summation submodule is configured to superimpose and sum the static feed water flow set value of the supercritical unit and the dynamic feed water flow set value of the supercritical unit to obtain a total feed water flow;

[0034] The second multiplication submodule is configured to multiply the total feed water flow by the separator temperature correction coefficient to obtain a total feed water flow set value of the supercritical unit.

[0035] Optionally, the dynamic feed water flow set value calculation submodule further comprises an adjustment submodule.

[0036] The adjustment submodule is configured to determine whether a proportion of the dynamic feed water flow set value of the supercritical unit in the total feed water flow set value of the supercritical unit is less than a preset percentage, and if yes, no adjustment is made, and if no, the dynamic feed water flow set value of the supercritical unit is adjusted.

[0037] The second aspect of the present application provides a supercritical unit feed water flow wide load stable control method, which is applied to any supercritical unit feed water flow wide load stable control system provided in the first aspect of the present application, and the supercritical unit feed water flow wide load stable control method comprises the following steps:

[0038] calculating a static feed water flow set value of the supercritical unit according to a load set value of the supercritical unit;

[0039] calculating a dynamic feed water flow set value of the supercritical unit according to a fuel quantity dynamic feedforward value, a main steam pressure value and a main steam pressure set value;

[0040] calculating a separator temperature correction coefficient according to a separator outlet temperature value and a separator outlet temperature set value;

[0041] calculating a total feed water flow set value of the supercritical unit according to the static feed water flow set value of the supercritical unit, the dynamic feed water flow set value of the supercritical unit and the separator temperature correction coefficient.

[0042] Optionally, the total feed water flow set value of the supercritical unit is calculated according to the static feed water flow set value of the supercritical unit, the dynamic feed water flow set value of the supercritical unit and the separator temperature correction coefficient, and then the following steps are further included:

[0043] determining whether a proportion of the dynamic feed water flow set value of the supercritical unit in the total feed water flow set value of the supercritical unit is less than a preset percentage, and if yes, no adjustment is made, and if no, the dynamic feed water flow set value of the supercritical unit is adjusted.

[0044] Optionally, the adjusting the dynamic feed water flow set value of the supercritical unit comprises:

[0045] The dynamic feed water flow set value of the supercritical unit is adjusted by adjusting the feed water flow coefficient.

[0046] From the above technical solutions, the supercritical unit feed water flow wide load stable control system provided by the present application has the following advantages:

[0047] The supercritical unit feed water flow wide load stable control system provided by the present application calculates the static feed water flow set value of the supercritical unit based on the load set value of the supercritical unit, calculates the dynamic feed water flow set value of the supercritical unit based on the fuel amount dynamic feedforward amount, the main steam pressure value and the main steam pressure set value, and calculates the total feed water flow set value of the supercritical unit in combination with the separator temperature correction coefficient, which can meet the stability and rapid response requirements at the same time, maintain good control effect under different working conditions and boiler fuel quality changes, avoid the stability risk caused by single control strategy, and does not depend on manual operation and judgment, thereby solving the technical problems of insufficient response speed, limited control precision, decreased stability and insufficient automation degree of the traditional supercritical unit feed water flow control method in the wide load regulation process of the unit. BRIEF DESCRIPTION OF DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other related drawings according to these drawings without creative labor.

[0049] Figure 1 The structure diagram of the supercritical unit feed water flow wide load stable control system provided in the embodiments of the present application is shown in the figure.

[0050] Figure 2 The principle block diagram of the supercritical unit feed water flow wide load stable control system provided in the embodiments of the present application is shown in the figure.

[0051] Figure 3 The flowchart of the supercritical unit feed water flow wide load stable control method provided in the embodiments of the present application is shown in the figure. DETAILED DESCRIPTION

[0052] In order to make the personnel in the technical field better understand the technical scheme of the present application, the technical scheme in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0053] For the convenience of understanding, please refer to Figure 1 The present application provides an embodiment of a supercritical unit feedwater flow wide load stable control system, comprising a static feedwater flow set value calculation module, a dynamic feedwater flow set value calculation module, a separator outlet temperature correction module and a total feedwater flow set value output module.

[0054] The static feedwater flow set value calculation module is used to calculate the static feedwater flow set value of the supercritical unit according to the load set value of the supercritical unit. The static feedwater flow is the required feedwater flow of the supercritical unit under stable working conditions.

[0055] The dynamic feedwater flow set value calculation module is used to calculate the dynamic feedwater flow set value of the supercritical unit according to the fuel quantity dynamic feedforward quantity, the main steam pressure value and the main steam pressure set value. The dynamic feedwater flow is the additional feedwater flow required by the supercritical unit under variable working conditions to overcome the boiler combustion inertia and the pipe flow inertia.

[0056] The separator outlet temperature correction module is used to calculate the separator temperature correction coefficient according to the separator outlet temperature value and the separator outlet temperature set value.

[0057] The total feedwater flow set value output module is used to calculate the total feedwater flow set value of the supercritical unit according to the static feedwater flow set value, the dynamic feedwater flow set value and the separator temperature correction coefficient.

[0058] It should be noted that the static feedwater flow set value calculation module collects the load set value of the supercritical unit in real time, and calculates the required feedwater flow set value of the supercritical unit under stable working conditions according to the load set value of the supercritical unit. Specifically, a function model of the load set value of the supercritical unit and the feedwater flow is established, and the load set value of the supercritical unit is substituted into the function model to calculate the static feedwater flow set value. The required feedwater flow of the supercritical unit under stable working conditions (stable parameters such as load and air temperature) is the static feedwater flow. The static feedwater flow can effectively ensure that the boiler feedwater flow adapts to the load of the supercritical unit, so that the boiler does not produce large coal and water imbalance during operation.

[0059] In one embodiment, as Figure 2As shown, the static feedwater flow setpoint calculation module includes a load setting submodule, a first function submodule, and a first inertial element submodule. The load setting submodule is used to obtain the load setpoint of the supercritical unit. The first function submodule is used to calculate the required feedwater flow of the supercritical unit under steady-state operating conditions based on the load setpoint. The first inertial element submodule is used to perform filtering processing on the required feedwater flow of the supercritical unit under steady-state operating conditions based on a first-order inertial element, effectively removing some disturbances.

[0060] The additional feedwater flow required by a supercritical unit under varying operating conditions (variations in parameters such as load, feedwater, and air temperature) to overcome the combustion inertia of the boiler and the flow inertia of the pipeline is called the dynamic feedwater flow. In one embodiment, such as... Figure 2 As shown, the dynamic feedwater flow setpoint calculation module includes a signal acquisition submodule, a second inertial element submodule, a first PID controller submodule, a first summation submodule, a first multiplication submodule, and a constant submodule. The signal acquisition submodule acquires the dynamic feedforward of fuel quantity, the main steam pressure value, and the main steam pressure setpoint. The dynamic feedforward of fuel quantity is the additional fuel quantity added to the corresponding fuel quantity under steady-state load to overcome boiler inertia. The dynamic feedforward of fuel quantity is a pre-acquired parameter. The second inertial element submodule performs filtering on the dynamic feedforward of fuel quantity based on a first-order inertial element. The first PID controller submodule provides a first PID correction for the deviation between the main steam pressure value and the main steam pressure setpoint. The first summation submodule superimposes the first deviation with the dynamic feedforward of fuel quantity output from the second inertial element submodule to obtain the dynamic fuel quantity. The constant submodule configures the feedwater flow coefficient. The first multiplication submodule multiplies the dynamic fuel quantity with the feedwater flow coefficient to obtain the dynamic feedwater flow setpoint for the supercritical unit. The dynamic fuel quantity feedforward, after being smoothed and filtered by the second inertial link submodule, is summed by the PID correction of the deviation between the main steam pressure value and the main steam pressure setpoint, and then summed by the first summing submodule to form the dynamic fuel quantity. The dynamic fuel quantity and the feedwater flow coefficient of the constant submodule are multiplied by the first multiplication submodule to obtain the dynamic feedwater flow setpoint of the supercritical unit.

[0061] The separator outlet temperature correction module calculates the separator temperature correction coefficient based on the separator outlet temperature value and the separator outlet temperature setpoint. In one embodiment, such as... Figure 2As shown, the separator outlet temperature correction module includes a separator outlet temperature acquisition submodule, a separator outlet temperature setting submodule, a second PID controller submodule, and a second function submodule. The separator outlet temperature acquisition submodule is configured to acquire the separator outlet temperature value. The separator outlet temperature setting submodule is configured to configure the separator outlet temperature setting value. The second PID controller submodule is configured to calculate the second PID correction value of the deviation between the separator outlet temperature value and the separator outlet temperature setting value. The second function submodule is configured to convert the second deviation value into the separator temperature correction coefficient in the range of 0.8-1.2. The separator outlet temperature value and the separator outlet temperature setting value are input into the second PID controller submodule to generate the separator temperature correction signal in the range of 0-100%, and then the second function submodule is used to convert the separator temperature correction signal into the separator temperature correction coefficient in the range of 0.8-1.2.

[0062] The total feedwater flow rate setting value output module is configured to calculate the total feedwater flow rate setting value of the supercritical unit according to the static feedwater flow rate setting value of the supercritical unit, the dynamic feedwater flow rate setting value of the supercritical unit, and the separator temperature correction coefficient. In one embodiment, as shown, Figure 2 The total feedwater flow rate setting value output module includes a second summation submodule and a second multiplication submodule. The second summation submodule is configured to superimpose and sum the feedwater flow rate of the critical unit in the stable operating condition and the feedwater flow rate of the supercritical unit in the variable operating condition to obtain the total feedwater flow rate. The second multiplication submodule is configured to multiply the total feedwater flow rate by the separator temperature correction coefficient to obtain the total feedwater flow rate setting value of the supercritical unit. The control system further performs wide load stable control according to the total feedwater flow rate setting value of the supercritical unit.

[0063] In one embodiment, the dynamic feedwater flow rate setting value calculation module further includes an adjustment submodule. The adjustment submodule is configured to determine whether the proportion of the dynamic feedwater flow rate setting value of the supercritical unit in the total feedwater flow rate setting value of the supercritical unit is less than a preset percentage, and if so, no adjustment is made, and if not, the dynamic feedwater flow rate setting value of the supercritical unit is adjusted. Specifically, the dynamic feedwater flow rate setting value of the supercritical unit is adjusted by using the feedwater flow rate coefficient configured by the adjustment constant submodule. In one specific embodiment, the preset percentage is 20%.

[0064] The supercritical unit feed water flow wide load stable control system provided by the application can meet the requirements of stability and rapid response, can maintain good control effect under different working conditions and changes of boiler fuel quality, avoids the stability risks caused by single control strategy, and does not depend on manual operation and judgment, and solves the technical problems of insufficient response speed, limited control precision, decreased stability and insufficient automation degree of the traditional supercritical unit feed water flow control method in the wide load regulation process of the unit.

[0065] Meanwhile, the supercritical unit feed water flow wide load stable control system provided by the application improves the control precision, avoids the operation of the supercritical unit equipment under abnormal working conditions, thereby accelerating the wear and aging of the equipment and shortening the service life of the equipment.

[0066] Meanwhile, the supercritical unit feed water flow wide load stable control system provided by the application avoids the risk of coal water disorder of the existing control system in which the boiler main control output is used as the main line to calculate the feed water flow setting and the separator outlet temperature correction or enthalpy value correction calculation is used as the auxiliary calculation to generate the feed water flow setting when the fuel quality changes greatly, and avoids the technical problem that the feed water flow setting is prone to large fluctuations under the wide load change of the unit or the frequency modulation mode of the unit, thereby causing great risks to the wide load operation of the unit.

[0067] For the convenience of understanding, please refer to Figure 3 In the application, an embodiment of a supercritical unit feed water flow wide load stable control method is provided, which is applied to the supercritical unit feed water flow wide load stable control system provided by the application, and the supercritical unit feed water flow wide load stable control method comprises the following steps:

[0068] Step S1: calculating a static feed water flow setting value of the supercritical unit according to a load setting value of the supercritical unit.

[0069] Step S2: calculating a dynamic feed water flow setting value of the supercritical unit according to a dynamic feed-forward value of the fuel quantity, a main steam pressure value and a main steam pressure setting value.

[0070] Step S3: calculating a separator temperature correction coefficient according to a separator outlet temperature value and a separator outlet temperature setting value.

[0071] Step S4, according to the static feed water flow set value of the supercritical unit, the dynamic feed water flow set value of the supercritical unit and the separator temperature correction coefficient, the total feed water flow set value of the supercritical unit is calculated.

[0072] In one embodiment, after step S4, further comprising:

[0073] Step S5, judging whether the proportion of the dynamic feed water flow set value of the supercritical unit in the total feed water flow set value of the supercritical unit is less than a preset percentage, if yes, no adjustment is made, if not, the dynamic feed water flow set value of the supercritical unit is adjusted. Specifically, the dynamic feed water flow set value of the supercritical unit is adjusted by adjusting the feed water flow coefficient. The preset percentage is 20%.

[0074] The supercritical unit feed water flow wide load stable control method provided in the application is applied to the supercritical unit feed water flow wide load stable control system provided in the application, the principle and the technical effects obtained are the same as those of the supercritical unit feed water flow wide load stable control system provided in the application, and will not be repeated here.

[0075] The above-described embodiments are only used to illustrate the technical solutions of the present application, but not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for some technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A supercritical unit feedwater flow wide load stable control system, characterized by, The static feedwater flow rate setting value calculation module, the dynamic feedwater flow rate setting value calculation module, the separator outlet temperature correction module and the total feedwater flow rate setting value output module are included. The static feedwater flow rate setting value calculation module is configured to calculate a static feedwater flow rate setting value of the supercritical unit according to a load setting value of the supercritical unit, the static feedwater flow rate being a required feedwater flow rate of the supercritical unit under a stable working condition; The dynamic feedwater flow rate setting value calculation module is configured to calculate a dynamic feedwater flow rate setting value of the supercritical unit according to a dynamic fuel quantity feedforward value, a main steam pressure value and a main steam pressure setting value, the dynamic feedwater flow rate being an additional feedwater flow rate required by the supercritical unit under a variable working condition to overcome the inertia of boiler combustion and the inertia of pipeline flow; The separator outlet temperature correction module is configured to calculate a separator temperature correction coefficient according to a separator outlet temperature value and a separator outlet temperature setting value; The total feedwater flow rate setting value output module is configured to calculate a total feedwater flow rate setting value of the supercritical unit according to the static feedwater flow rate setting value, the dynamic feedwater flow rate setting value and the separator temperature correction coefficient; The static feedwater flow rate setting value calculation module includes a load setting sub-module, a first function sub-module and a first inertia link sub-module. The load setting sub-module is configured to obtain a load setting value of the supercritical unit; The first function sub-module is configured to calculate a static feedwater flow rate setting value of the supercritical unit according to the load setting value of the supercritical unit; The first inertia link sub-module is configured to perform a filtering process on the static feedwater flow rate setting value of the supercritical unit based on a first-order inertia link; The dynamic feedwater flow rate setting value calculation module includes a signal obtaining sub-module, a second inertia link sub-module, a first PID controller sub-module, a first summation sub-module, a first multiplication sub-module and a constant sub-module. The signal obtaining sub-module is configured to obtain a dynamic fuel quantity feedforward value, a main steam pressure value and a main steam pressure setting value; The second inertia link sub-module is configured to perform a filtering process on the dynamic fuel quantity feedforward value based on a first-order inertia link; The first PID controller sub-module is configured to perform a first PID correction on a deviation between the main steam pressure value and the main steam pressure setting value; The first summation sub-module is configured to superimpose the first PID correction and the dynamic fuel quantity feedforward value output by the second inertia link sub-module to obtain a dynamic fuel quantity; The constant sub-module is configured to configure a feedwater flow rate coefficient; The first multiplication sub-module is configured to multiply the dynamic fuel quantity and the feedwater flow rate coefficient to obtain the dynamic feedwater flow rate setting value of the supercritical unit.

2. The supercritical unit feedwater flow wide load stabilization control system of claim 1, wherein, The separator outlet temperature correction module includes a separator outlet temperature obtaining sub-module, a separator outlet temperature setting sub-module, a second PID controller sub-module and a second function sub-module; The separator outlet temperature obtaining sub-module is configured to obtain a separator outlet temperature value; The separator outlet temperature setting sub-module is configured to configure a separator outlet temperature setting value; The second PID controller submodule is configured to calculate a second PID correction value of a deviation between the separator outlet temperature value and a separator outlet temperature set value; The second function submodule is configured to convert the second PID correction value into a separator temperature correction coefficient in a range of 0.8 to 1.

2.

3. The supercritical unit feedwater flow wide load stabilization control system of claim 1, wherein, The total feedwater flow rate set value output module comprises a second summation submodule and a second multiplication submodule; The second summation submodule is configured to superimpose and sum the static feedwater flow rate set value of the supercritical unit and the dynamic feedwater flow rate set value of the supercritical unit to obtain a total feedwater flow rate. The second multiplication submodule is configured to multiply the total feedwater flow rate by the separator temperature correction coefficient to obtain a total feedwater flow rate set value of the supercritical unit.

4. The supercritical unit feedwater flow wide load stabilization control system of claim 3, wherein, The dynamic feedwater flow rate set value calculation module further comprises an adjustment submodule. The adjustment submodule is configured to determine whether a proportion of the dynamic feedwater flow rate set value of the supercritical unit in the total feedwater flow rate set value of the supercritical unit is less than a preset percentage, and if yes, no adjustment is made, and if no, the dynamic feedwater flow rate set value of the supercritical unit is adjusted.

5. The supercritical unit feedwater flow wide load stabilization control system of claim 4, wherein, The preset percentage is 20%.

6. A method for wide load stable control of feed water flow of a supercritical unit, characterized in that, The supercritical unit feedwater flow rate wide load stable control method is applied to the supercritical unit feedwater flow rate wide load stable control system of any one of claims 1 to 5, and the supercritical unit feedwater flow rate wide load stable control method comprises: calculating a static feedwater flow rate set value of the supercritical unit according to a load set value of the supercritical unit; calculating a dynamic feedwater flow rate set value of the supercritical unit according to a fuel quantity dynamic feedforward value, a main steam pressure value and a main steam pressure set value; calculating a separator temperature correction coefficient according to a separator outlet temperature value and a separator outlet temperature set value; calculating a total feedwater flow rate set value of the supercritical unit according to the static feedwater flow rate set value of the supercritical unit, the dynamic feedwater flow rate set value of the supercritical unit and the separator temperature correction coefficient.

7. The supercritical unit feedwater flow wide load stabilization control method according to claim 6, characterized by, calculating a total feedwater flow rate set value of the supercritical unit according to the static feedwater flow rate set value of the supercritical unit, the dynamic feedwater flow rate set value of the supercritical unit and the separator temperature correction coefficient, and then further comprising: determining whether a proportion of the dynamic feedwater flow rate set value of the supercritical unit in the total feedwater flow rate set value of the supercritical unit is less than a preset percentage, and if yes, no adjustment is made, and if no, the dynamic feedwater flow rate set value of the supercritical unit is adjusted.

8. The supercritical unit feedwater flow wide load stabilization control method according to claim 7, characterized by, The adjustment of the dynamic feedwater flow rate set value of the supercritical unit comprises: adjusting the dynamic feedwater flow rate set value of the supercritical unit by adjusting a feedwater flow rate coefficient.

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