Logic control method and system for preventing regulating stage pressure fluctuation

Abstract

The invention discloses a logic control method and system for preventing regulation stage pressure fluctuation, and relates to the field of coal power plant machine front pressure control, and the method comprises the steps: collecting historical frequency modulation data, and extracting a data set with stable unit load after frequency modulation as a high-control-valve instruction coefficient; after the system sends out a primary frequency modulation action instruction, front pressure control is carried out; after the pressure in front of the unit is controlled, calling a corresponding high control valve instruction coefficient according to the load of the unit, and controlling a high control valve by switching a pressing plate based on the high control valve instruction coefficient; and the unit load state after frequency modulation is collected in real time, and the high control valve instruction coefficient is adjusted according to the load state. According to the method, the primary frequency modulation action is added after the primary frequency modulation control action, and the high control valve is controlled based on the formulated high control valve instruction coefficient, so that the unit load is more stable.

Description

Technical Field

[0001] The invention relates to the field of pressure control in front of coal power plants, and in particular to a logic control method and system for preventing pressure fluctuations at a regulating stage. Background Art

[0002] In coal-fired power plants, according to the analysis of the unit operating conditions and the design principles of each main parameter, the pre-machine pressure control method should be the most stable control method for the unit's main steam pressure, regulating stage pressure and load control. At present, when the unit load is less than 300MW, the single valve control method, and the total valve position command is about 13%, after a frequency modulation control action, even if the control method is the pre-machine pressure control method, the main steam pressure, regulating stage pressure and load control will fluctuate greatly, which brings huge hidden dangers to the safe operation of the unit at low load, and brings great trouble to the operating personnel to control the stability of each main parameter of the unit when the unit is in abnormal working conditions.

[0003] In order to solve the problem that the pre-machine pressure control mode is affected by the primary frequency regulation automatic control, resulting in the instability of the unit main steam pressure, regulating stage pressure and load control. The present invention provides a logic control method and system to prevent the regulation stage pressure fluctuation, change the primary frequency regulation control strategy of the pre-machine pressure control mode, and continuously track the logic primary frequency regulation control effect after the transformation to meet the power grid primary frequency regulation load control and the safe and stable operation requirements of the unit. Summary of the invention

[0004] In view of the above-mentioned problems, the present invention is proposed.

[0005] Therefore, the problem to be solved by the present invention is that after a frequency modulation control action, even if the control mode is the pre-machine pressure control mode, the main steam pressure, the regulating stage pressure and the load control will fluctuate greatly.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a logical control method for preventing pressure fluctuations in the regulating stage, which includes collecting historical frequency modulation data, extracting a data group in which the unit load is stable after the frequency modulation as a high-pressure regulating valve command coefficient; when the system issues a frequency modulation action command, performing pre-machine pressure control; after the pre-machine pressure control, the corresponding high-pressure regulating valve command coefficient is retrieved according to the unit load, and the high-pressure regulating valve is controlled by switching the pressure plate based on the high-pressure regulating valve command coefficient; real-time collection of the unit load status after the frequency modulation, and adjustment of the high-pressure regulating valve command coefficient according to the load status.

[0007] As a preferred solution of the logical control method for preventing regulation stage pressure fluctuations described in the present invention, the frequency modulation data includes the unit load, turbine speed, valve control mode, valve opening and unit load status after frequency modulation during frequency modulation.

[0008] As a preferred solution of a logical control method for preventing regulation stage pressure fluctuations described in the present invention, wherein: the extraction of the data group in which the unit load is stable after frequency modulation as the high-regulating valve command coefficient includes, feature screening of the collected historical frequency modulation data, and screening out the data group with the feature that the unit load is in a stable state after frequency modulation; coefficient selection of the screened data group includes, if the valve control mode in the data group is single valve control, then using the opening of the single valve control as the high-regulating valve command coefficient; if the valve control mode in the data group is multi-valve control, then extracting the high-regulating valve opening therein, and using the high-regulating valve opening as the high-regulating valve command coefficient.

[0009] As a preferred scheme of the logical control method for preventing pressure fluctuations in the regulating stage described in the present invention, the pre-machine pressure control includes controlling the feed water flow rate by adjusting the speed of the feed water pump according to the load demand of the unit, and then adjusting the steam generation of the boiler to control the steam pressure; before the turbine is operated, the excess steam is led out through the bypass system to maintain the pressure balance between the boiler and the turbine.

[0010] As a preferred scheme of a logical control method for preventing regulation stage pressure fluctuations described in the present invention, wherein: the calling of the corresponding high-regulating valve command coefficient according to the unit load includes, based on the unit load demand, retrieving the filtered data group, retrieving the data group in which the unit load during the frequency modulation action is the same as the demand load, recording it as the data group that meets the demand, disassembling the unit load during the frequency modulation action and the unit load after the frequency modulation in all the data groups that meet the demand, making a difference, taking the data group that meets the demand with the smallest difference as the optimal data group that meets the demand, and calling the high-regulating valve command coefficient in the optimal data group that meets the demand as the high-regulating valve command coefficient of the demand load.

[0011] As a preferred scheme of a logical control method for preventing pressure fluctuations in the regulating stage described in the present invention, the control of the high-speed regulating valve by switching the pressure plate based on the high-speed regulating valve command coefficient includes changing the steam flow direction by switching the pressure plate, switching the control regulating valve to the high-speed regulating valve, and controlling the opening of the high-speed regulating valve according to the high-speed regulating valve command coefficient to control the steam pressure entering the turbine, thereby controlling the speed and power of the turbine.

[0012] As a preferred scheme of a logical control method for preventing regulation stage pressure fluctuations described in the present invention, wherein: the adjustment of the high-regulating valve command coefficient according to the load state includes: real-time collection of the unit load after frequency modulation, comparing the unit load variation range with a preset threshold value, if it is lower than the preset threshold value, the unit load state is marked as stable, and the frequency modulation is successful and the unit is put into use; if it is higher than the preset threshold value, the unit load state is marked as swinging, the high-regulating valve command coefficient is adjusted, and the high-regulating valve opening is corrected. If the unit load state is still swinging after correction, the unit operation is stopped and maintenance is carried out.

[0013] Another object of the present invention is to provide a logic control system for preventing pressure fluctuations in the regulating stage, which system performs a high-pressure valve adjustment after a frequency modulation control action.

[0014] To solve the above technical problems, the present invention provides the following technical solutions: a system of a logical control method for preventing regulation stage pressure fluctuations, comprising: a data acquisition module, a front-machine pressure control module, a high-pressure control module and a correction module; the data acquisition module collects historical frequency modulation data, and extracts a data group in which the unit load is stable after the frequency modulation as a high-pressure command coefficient; when the system issues a frequency modulation action instruction, the front-machine pressure control module performs front-machine pressure control; after the front-machine pressure control, the high-pressure control module retrieves the corresponding high-pressure command coefficient according to the unit load, and controls the high-pressure by switching the pressure plate based on the high-pressure command coefficient; the correction module collects the unit load status after the frequency modulation in real time, and adjusts the high-pressure command coefficient according to the load status.

[0015] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the steps of a logic control method for preventing pressure fluctuations of a regulating stage as described above are implemented.

[0016] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of a logic control method for preventing pressure fluctuations in a regulating stage as described above.

[0017] The beneficial effect of the present invention is that after a frequency modulation control action in the existing method, even if the control mode is the machine front pressure control mode, the main steam pressure, the regulating stage pressure and the load control will fluctuate greatly. The present invention adds a frequency modulation action after a frequency modulation control action, controls the high-speed regulating valve based on the formulated high-speed regulating valve command coefficient, and makes the unit load more stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0019] Figure 1 This is a flow chart of a logic control method for preventing pressure fluctuations in the regulating stage in Example 1.

[0020] Figure 2 This is a module structure diagram of a logic control system for preventing pressure fluctuations in the regulating stage in Example 1. DETAILED DESCRIPTION

[0021] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0022] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0023] Example 1, reference Figure 1 , which is the first embodiment of the present invention, provides a logic control method for preventing pressure fluctuations in the regulating stage, including: Figure 1 As shown:

[0024] S1. Collect historical frequency modulation data and extract the data group in which the unit load is stable after frequency modulation as the high-frequency control command coefficient.

[0025] The frequency modulation data includes the unit load, turbine speed, valve control mode, valve opening and unit load status after frequency modulation.

[0026] In an optional embodiment, the present invention takes the frequency modulation data of a power plant as an example: after the unit is started, the pre-machine pressure control mode is put into use, the load is 294.4MW, the turbine speed is 3002.7rpm, the single valve control mode, and the GV1-GV4 valve position is 13%. After one frequency modulation action, the unit load swings, and the swing is obvious when the turbine rotates over 3003rpm. Compared with the load of 299.9MW, the turbine speed is 2997.5rpm, the single valve control mode, and the GV1-GV4 valve position is 13%. After one frequency modulation action, the unit load begins to swing, and the swing is obvious when the turbine speed is lower than 2997rpm. When the load is 306.9MW, the turbine speed is 3002.3rpm, the single valve control mode, the GV1-GV4 valve position is 13%, after one frequency modulation action, the unit load control is relatively stable. When the load is 302.9MW, the turbine speed is 2998rpm, the single valve control mode, the GV1-GV4 valve position is 13%, and the unit load control is relatively stable after the primary frequency modulation is activated. It can be judged that the unit is put into the pre-machine pressure control, the single valve control mode, the GV1-GV4 valve position is 13%, and the unit load begins to swing, which is affected by the continuous action of the primary frequency modulation. When the unit speed is continuously lower than 2997rpm and exceeds 3003rpm, the primary frequency modulation control causes the unit to increase or decrease the load, causing the total valve position command to change. Since the control mode is the pre-machine pressure mode, after the primary frequency modulation action is completed, the unit valve position command is restored to the set value, resulting in the valve position command fluctuation. When the primary frequency modulation is not activated or the action load is small, the load and valve position fluctuations are not obvious. After the coordinated control mode is put into use, after the primary frequency modulation action is completed, the unit main steam pressure, regulating stage pressure and load control are stable. Therefore, it is judged that the load fluctuation is affected by the primary frequency modulation automatic control.

[0027] The collected historical frequency modulation data are subjected to feature screening, and a data group having the feature that the unit load after frequency modulation is in a stable state is screened out.

[0028] The coefficient selection for the filtered data group includes: if the valve control mode in the data group is single valve control, the opening of the single valve control is used as the high-pressure valve command coefficient.

[0029] If the valve control mode in the data group is multi-valve control, the high-adjustment valve opening is extracted and used as the high-adjustment valve command coefficient.

[0030] S2. After the system issues a frequency modulation action command, it performs pressure control in front of the machine.

[0031] After the system issues a frequency modulation action command, it controls the feed water flow rate by adjusting the speed of the feed water pump according to the load demand of the unit, and then adjusts the steam generation of the boiler to control the steam pressure.

[0032] Before the steam turbine is operated, excess steam is led out through the bypass system to maintain the pressure balance between the boiler and the steam turbine.

[0033] S3. After the pressure control in front of the machine, the corresponding high-pressure control valve command coefficient is called according to the unit load, and the high-pressure control valve is controlled by switching the pressure plate based on the high-pressure control valve command coefficient.

[0034] Retrieving the corresponding high-throttle command coefficient according to the unit load includes: based on the unit load demand, retrieving the data group after screening, retrieving the data group whose unit load during the frequency modulation action is the same as the demand load, recording it as the data group that meets the demand, disassembling the unit load during the frequency modulation action and the unit load after the frequency modulation in all the data groups that meet the demand, making a difference, taking the data group that meets the demand with the smallest difference as the optimal data group that meets the demand, and retrieving the high-throttle command coefficient in the optimal data group that meets the demand as the high-throttle command coefficient of the demand load.

[0035] Controlling the high-pressure regulating valve by switching the pressure plate based on the high-pressure regulating valve command coefficient includes changing the steam flow direction by switching the pressure plate, switching the control regulating valve to the high-pressure regulating valve, and controlling the opening of the high-pressure regulating valve according to the high-pressure regulating valve command coefficient to control the steam pressure entering the turbine, thereby controlling the speed and power of the turbine.

[0036] The switch pressure plate is added to the coordination control screen. When the unit is switched to the front pressure control mode, the operator can manually switch the primary frequency modulation action to the high throttle command coefficient to enhance the adaptability of the primary frequency modulation control.

[0037] S4. Collect the load status of the unit after frequency modulation in real time, and adjust the high-frequency control command coefficient according to the load status.

[0038] After frequency modulation, the unit load is collected in real time, and the unit load variation range is compared with the preset threshold. If it is lower than the preset threshold, the unit load status is marked as stable, and the unit is put into use after successful frequency modulation; if it is higher than the preset threshold, the unit load status is marked as swinging, and the high-pressure valve command coefficient is adjusted to correct the high-pressure valve opening. If the unit load status is still swinging after correction, the unit is stopped and repaired. The unit load swing may be caused by a blockage in the unit pipeline.

[0039] Example 2, reference Figure 2, which is the second embodiment of the present invention, and is different from the first embodiment in that: a system of a logic control method for preventing regulation stage pressure fluctuations, comprising a data acquisition module 100, a front pressure control module 200, a high-pressure control module 300 and a correction module 400; the data acquisition module 100 collects historical frequency modulation data, and extracts a data group in which the unit load is stable after the frequency modulation as a high-pressure control command coefficient; when the system issues a frequency modulation action instruction, the front pressure control module 200 performs front pressure control; after the front pressure control, the high-pressure control module 300 retrieves the corresponding high-pressure control command coefficient according to the unit load, and controls the high-pressure control by switching the pressure plate based on the high-pressure control coefficient; the correction module 400 collects the unit load status after the frequency modulation in real time, and adjusts the high-pressure control command coefficient according to the load status.

[0040] If the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc., which can store program codes.

[0041] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0042] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering or, if necessary, processing in another suitable manner, and then stored in a computer memory.

[0043] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0044] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A logical control method for preventing pressure fluctuations in a regulating stage, characterized in that: include, Collect historical frequency modulation data, and extract the data group where the unit load is stable after frequency modulation as the high-speed control valve instruction coefficient; When the system issues a frequency modulation action command, the pressure control in front of the machine is carried out; After the pressure control in front of the machine, the corresponding high-pressure control valve command coefficient is called according to the unit load, and the high-pressure control valve is controlled by switching the pressure plate based on the high-pressure control valve command coefficient; Collect the load status of the unit after frequency modulation in real time, and adjust the high-frequency control command coefficient according to the load status.

2. A logic control method for preventing pressure fluctuations in a regulating stage according to claim 1, characterized in that: The frequency modulation data includes the unit load, turbine speed, valve control mode, valve opening and unit load status after frequency modulation.

3. A logic control method for preventing pressure fluctuations in a regulating stage as claimed in claim 2, characterized in that: The extracting of the data group in which the load of the unit after frequency modulation is stable as the high-speed control command coefficient includes performing feature screening on the collected historical frequency modulation data to screen out the data group in which the load of the unit after frequency modulation is stable; The coefficient selection for the filtered data group includes: if the valve control mode in the data group is single valve control, the opening of the single valve control is used as the high-adjustment valve command coefficient; If the valve control mode in the data group is multi-valve control, the high-adjustment valve opening is extracted and used as the high-adjustment valve command coefficient.

4. A logic control method for preventing pressure fluctuations in a regulating stage as claimed in claim 3, characterized in that: The pre-machine pressure control includes, according to the unit load demand, controlling the feed water flow rate by adjusting the speed of the feed water pump, and then adjusting the steam generation of the boiler to control the steam pressure; Before the steam turbine is operated, excess steam is led out through the bypass system to maintain the pressure balance between the boiler and the steam turbine.

5. A logic control method for preventing pressure fluctuations in a regulating stage as claimed in claim 4, characterized in that: The method of retrieving the corresponding high-throttle command coefficient according to the unit load includes: based on the unit load demand, retrieving the filtered data group, retrieving the data group whose unit load during the frequency modulation action is the same as the demand load, recording it as the data group that meets the demand, disassembling the unit load during the frequency modulation action and the unit load after the frequency modulation in all the data groups that meet the demand, making a difference, taking the data group that meets the demand with the smallest difference as the optimal data group that meets the demand, and retrieving the high-throttle command coefficient in the optimal data group that meets the demand as the high-throttle command coefficient of the demand load.

6. A logic control method for preventing pressure fluctuations in a regulating stage as claimed in claim 5, characterized in that: The controlling of the high-speed regulating valve by switching the pressure plate based on the high-speed regulating valve command coefficient includes changing the steam flow direction by switching the pressure plate, switching the control regulating valve to the high-speed regulating valve, and controlling the opening of the high-speed regulating valve according to the high-speed regulating valve command coefficient to control the steam pressure entering the turbine, thereby controlling the speed and power of the turbine.

7. A logic control method for preventing pressure fluctuations in a regulating stage as claimed in claim 6, characterized in that: The method of adjusting the high-pressure regulating valve command coefficient according to the load status includes collecting the unit load in real time after frequency modulation, comparing the unit load variation range with a preset threshold value, if it is lower than the preset threshold value, the unit load status is marked as stable, and the unit is put into use after successful frequency modulation; if it is higher than the preset threshold value, the unit load status is marked as swinging, adjusting the high-pressure regulating valve command coefficient, and correcting the high-pressure regulating valve opening. If the unit load status is still swinging after correction, the unit operation is stopped and maintenance is carried out.

8. A system using a logic control method for preventing pressure fluctuations in a regulating stage as claimed in any one of claims 1 to 7, characterized in that: It comprises a data acquisition module (100), a front-end pressure control module (200), a high-pressure valve control module (300) and a correction module (400); The data collection module (100) collects historical frequency modulation data, and extracts a data group in which the load of the unit is stable after the frequency modulation as a high-speed control valve instruction coefficient; When the system issues a frequency modulation action instruction, the machine front pressure control module (200) performs machine front pressure control; After the pre-machine pressure is controlled, the high-pressure control module (300) retrieves the corresponding high-pressure command coefficient according to the unit load, and controls the high-pressure valve by switching the pressure plate based on the high-pressure command coefficient; The correction module (400) collects the load state of the unit after frequency modulation in real time, and adjusts the high-speed control valve command coefficient according to the load state.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the processor implements the steps of a logic control method for preventing regulation stage pressure fluctuations according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of a logic control method for preventing regulation stage pressure fluctuations according to any one of claims 1 to 7 are implemented.

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