Method and device for reducing pressure fluctuation of turbine main steam valve closing test

Abstract

The embodiment of the present application provides a kind of method and device for reducing pressure fluctuation of steam turbine main steam valve closing test, belong to steam turbine main steam valve test field.The method comprises: obtaining the main steam pressure of steam valve in the closing test process;Calculate the pressure change difference of main steam pressure and preset pressure, the preset pressure is the main steam pressure of steam valve under the stable load state of steam turbine;According to the pressure change difference, adjust the experimental action in the closing test process, so that the main steam pressure approaches the preset pressure.The present application can effectively reduce the fluctuation of main steam pressure, can control the fluctuation of main steam pressure in the relatively small range, can ensure the safe operation of unit, has strong reference significance for the safe operation of the same type unit after localization reform.

Description

Technical Field

[0001] This invention relates to the field of steam turbine main steam valve testing, specifically to a method for reducing pressure fluctuations during a steam turbine main steam valve closure test, a device for reducing pressure fluctuations during a steam turbine main steam valve closure test, an electronic device, and a computer-readable storage medium. Background Technology

[0002] During normal operation, the turbine's high- and intermediate-pressure main steam valves and regulating valves remain open. To prevent valve jamming due to salt deposits or oxide scale buildup, and to prevent valve malfunctions caused by faulty hydraulic actuators or quick-closing solenoid valves in the safety control system, which could lead to load shedding or turbine overspeed during shutdown, regular loosening and closing tests must be performed on each valve. According to the operating procedures and work permits, loosening and closing tests are conducted on each valve within the specified load range to ensure normal valve operation.

[0003] After the DCS operating system of the steam turbine unit was upgraded, the current shutdown test will cause the main steam pressure to continue to rise. The continued rise in main steam pressure will cause the unit's superheat and regulating stage temperature to drop, and the possibility of steam carryover will increase, seriously threatening the safe operation of the unit. Summary of the Invention

[0004] The purpose of this invention is to provide a method and apparatus for reducing pressure fluctuations during the main steam valve closure test of a steam turbine, thereby solving the problem that current closure tests for modified steam turbine units cause the main steam pressure to continue to rise.

[0005] To achieve the above objectives, the present invention provides a method for reducing pressure fluctuations during steam turbine valve closure tests, the method comprising:

[0006] Obtain the main steam pressure during the valve closure test;

[0007] Calculate the pressure difference between the main steam pressure and the preset pressure, where the preset pressure is the main steam pressure of the steam valve under stable load conditions of the steam turbine.

[0008] Adjust the experimental actions during the shutdown test based on the pressure difference to bring the main steam pressure close to the preset pressure.

[0009] Preferably, the experimental actions include at least one of the following: the opening and closing rate of the steam valve, the experimental interval duration, and the boiler combustion rate.

[0010] Preferably, adjusting the experimental actions during the shutdown test based on the pressure change difference includes:

[0011] Calculate the magnitude of the main steam pressure change based on the pressure change difference;

[0012] Determine the reduction range of the valve opening and closing rate to match the change range of the main steam pressure;

[0013] Reduce the valve switching rate according to the decrease in the valve switching rate.

[0014] Preferably, adjusting the experimental actions during the shutdown test based on the pressure change difference includes:

[0015] The rate of increase of the main steam pressure is calculated based on the pressure change difference.

[0016] If the rate of increase of the main steam pressure exceeds the rate of increase threshold, the boiler combustion rate is reduced.

[0017] Preferably, if the rate of increase of the main steam pressure does not exceed the rate of increase threshold, the opening and closing rate of the steam valve is reduced so that the main steam pressure approaches the preset pressure.

[0018] Preferably, adjusting the experimental actions during the shutdown test based on the pressure change difference includes:

[0019] Set the experimental interval for two valves that are continuously closed in the experiment;

[0020] At the moment when the previous steam valve closing experiment ends and the experiment interval is reached, determine whether the pressure change difference at that moment has decreased to within the pressure stability range;

[0021] If the pressure change difference at that moment decreases to within the pressure stability range, the closing test of the next steam valve begins.

[0022] If the pressure difference at that moment does not decrease to within the pressure stability range, increase the experimental interval until the pressure difference decreases to within the pressure stability range, and then begin the closing experiment of the next steam valve.

[0023] Preferably, it further includes:

[0024] The rate of increase of the main steam pressure is calculated based on the pressure change difference;

[0025] If the rate of increase of the main steam pressure far exceeds the rate of increase threshold, reduce the boiler combustion rate and the opening and closing rate of the steam valves.

[0026] If the rate of increase of the main steam pressure does not exceed the rate of increase threshold, reduce the opening and closing rate of the steam valve.

[0027] Preferably, the steam valve includes a high-pressure main steam valve, a high-pressure regulating valve, and a medium-pressure combined valve.

[0028] The present invention also provides an apparatus for reducing pressure fluctuations during turbine valve closure tests. The apparatus is used to implement the above-mentioned method for reducing pressure fluctuations during turbine valve closure tests. The apparatus includes:

[0029] The acquisition module is used to acquire the main steam pressure of the steam turbine valve during the closure test.

[0030] The calculation module is used to calculate the pressure difference between the main steam pressure and the preset pressure, wherein the preset pressure is the main steam pressure of the turbine steam valve under stable load conditions.

[0031] The adjustment module is used to adjust the experimental actions during the shutdown test based on the pressure difference, so that the main steam pressure approaches the preset pressure.

[0032] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the above-described method for reducing pressure fluctuations during turbine valve closure tests.

[0033] The present invention also provides a computer-readable storage medium having a computer program stored thereon, characterized in that the program, when executed by a processor, implements the above-described method for reducing pressure fluctuations during turbine valve closure tests.

[0034] Through the above technical solution, the present invention has at least the following technical effects:

[0035] This invention can effectively reduce main steam pressure fluctuations and control them within a relatively small safe range, ensuring the safe operation of the unit. It has strong reference value for the safe operation of similar units after localization and modification.

[0036] Other features and advantages of the embodiments of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0037] The accompanying drawings are provided to further illustrate embodiments of the present invention and form part of the specification. They are used together with the following detailed description to explain the embodiments of the present invention, but do not constitute a limitation thereof. In the drawings:

[0038] Figure 1 This is a flowchart of a method for reducing pressure fluctuations during turbine valve closure tests according to one embodiment of the present invention;

[0039] Figure 2 This is a block diagram of a method for reducing pressure fluctuations during turbine valve closure tests, provided by an optional embodiment of the present invention. Detailed Implementation

[0040] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the scope of the present invention.

[0041] Figure 1 This is a flowchart of a method for reducing pressure fluctuations during turbine valve closure tests according to one embodiment of the present invention, as shown below. Figure 1 As shown, a method for reducing pressure fluctuations during turbine valve closure tests includes:

[0042] Step S101: Obtain the main steam pressure of the steam valve during the closing test;

[0043] In this embodiment, the steam turbine is equipped with two high-pressure main steam valves, four high-pressure regulating valves, and two sets of medium-pressure combined valves. The valve sequence of the high-pressure regulating valves is a composite steam distribution method, and the opening sequence of the four high-pressure regulating valves (valve A, valve B, valve C, and valve D) is D-BC-A. Generally speaking, when the high-pressure regulating valves are closed during the closing test, they are gradually closed to 10% at a reference rate of 2% / s, and then the solenoid valve is quickly closed. After the safety oil pressure is released, the high-pressure regulating valve closes quickly. After the feedback of the high-pressure regulating valve being fully closed is received, it automatically opens to the valve position before the start of the test at a reference rate of 2% / s. Therefore, during the test, the main steam pressure is collected by the steam pressure monitoring equipment.

[0044] Step S102: Calculate the pressure change difference between the main steam pressure and the preset pressure, where the preset pressure is the main steam pressure of the steam valve under stable load conditions of the steam turbine;

[0045] In this embodiment, when the main steam valve is closed for its full stroke, the unit's stable load is 400MW, the main steam pressure is 19.51MPa, and the supercritical pressure of the main steam is 23.18MPa; therefore, 19.51MPa is used as the preset pressure for the turbine's stable load.

[0046] Step S103: Adjust the experimental actions in the shutdown test according to the pressure change difference so that the main steam pressure approaches the preset pressure.

[0047] As a further optimization of this embodiment, the experimental actions include at least one of the following: the opening and closing rate of the steam valve, the experimental interval duration, and the boiler combustion rate. That is, the present invention can flexibly select different adjustment methods according to the actual valve closing experimental conditions; for example, one of the methods can be used to adjust the main steam pressure, or a combination of two methods or three methods can be used to adjust the main steam pressure simultaneously.

[0048] Specifically, when adjusting the opening and closing rate of the steam valve in the closing experiment, the experimental actions during the closing experiment are adjusted according to the pressure difference, including:

[0049] Step a101: Calculate the change range of the main steam pressure based on the pressure change difference;

[0050] Step a102: Determine the reduction rate of the steam valve opening and closing rate that matches the change in main steam pressure;

[0051] In this embodiment, the reduction in the valve switching rate corresponds to a range of variation. The calculated range of variation is determined, and then the corresponding reduction in the valve switching rate is selected. For example, it can be divided into six ranges: 5%-7.5%, 7.5%-10%, 10%-12.5%, 12.5%-15%, 15%-17.5%, and 17.5%-19%.

[0052] Step a103: Reduce the valve switching rate according to the reduction in the valve switching rate.

[0053] In this embodiment, for example, the main steam pressure collected is 22.46 MPa. At this time, the change range is 15.18%, and the corresponding reduction in the valve switching rate is 50%. When the switching experiment is carried out at a reference rate of 2% / s, the adjusted valve switching rate is 1% / s. The reduction in the valve switching rate corresponding to each range of change is obtained by fitting multiple tests.

[0054] Specifically, the boiler combustion rate during the shutdown test is adjusted, and the experimental actions during the shutdown test are adjusted according to the pressure difference, including:

[0055] Step c101: Calculate the rate of increase of the main steam pressure based on the pressure change difference;

[0056] Step c102: If the rate of increase of the main steam pressure exceeds the rate of increase threshold, reduce the boiler combustion rate.

[0057] As a further optimization of this embodiment, if the rate of increase of the main steam pressure does not exceed the rate of increase threshold, the opening and closing rate of the steam valve is reduced, that is, the adjustment steps of steps a01-a03 are adopted to make the main steam pressure approach the preset pressure.

[0058] Specifically, when adjusting the experimental interval in the shutdown experiment, the experimental actions during the shutdown experiment are adjusted according to the pressure change difference, including:

[0059] Step b101: Set the experimental interval for the two valves that are continuously closed in the experiment;

[0060] Step b102: After the previous steam valve closing experiment ends and the experiment interval time is reached, determine whether the pressure change difference has decreased to the pressure stability range;

[0061] Step b103: If the pressure difference decreases to the pressure stability range, begin the closing test for the next steam valve;

[0062] If the pressure difference does not decrease to the pressure stability range, increase the test interval until the pressure difference decreases to the pressure stability range, and then start the closing test for the next steam valve.

[0063] In this embodiment, after a control valve has just completed its closing test, the main steam pressure of the unit will still fluctuate. This means that the unit's flow command and load need several cycles of oscillation to return to their original values. Based on historical data from single control valve closing tests, it is known that it takes approximately 10 seconds for the main steam pressure to stabilize after a single control valve's closing test. Therefore, in this embodiment, 10 seconds is used as the test interval for two consecutive valves undergoing closing tests. However, the test interval varies under different test conditions. Therefore, the test interval can be increased; for example, if the pressure difference has not decreased to the stable pressure range, the initially set test interval can be increased in steps of 1-2 seconds. This ensures that the main steam pressure stabilizes only after the previous control valve has completed its closing test before the next control valve's closing test can proceed.

[0064] As a further optimization of this embodiment, the present invention preferably adopts a combination of methods to regulate the main steam pressure. For example, when the steam pressure rise rate exceeds or far exceeds the rise rate threshold, a combination of adjusting the switching rate (steps a01-a03), the experimental interval duration (steps b01-b03), and the boiler combustion rate (steps c01-c02) is adopted; when the steam pressure rise rate is lower than the rise rate threshold, a combination of adjusting the switching rate (steps a01-a03) and the experimental interval duration (steps b01-b03) is adopted.

[0065] In this embodiment, during the shutdown experiment, by adjusting the opening and closing rate of the steam valve, the experimental interval, and the boiler combustion rate, the pressure rise during the partial closure of the high-pressure regulating valve was relatively stable and the amplitude was small. During the entire test, the lowest main steam pressure was 18.96 MPa and the highest was 19.96 MPa. After the test, the main steam pressure was 19.08 MPa, which was about 0.56 MPa different from the pre-test (19.64 MPa). The pressure fluctuation amplitude was controlled within 1 MPa, which can ensure the safe operation of the unit.

[0066] Secondly, this invention also has strong reference value for the safe operation of similar units after localization and modification.

[0067] Figure 2 This is a block diagram of a method for reducing pressure fluctuations during turbine valve closure tests, provided by an optional embodiment of the present invention. Figure 2 As shown, an apparatus for reducing pressure fluctuations during a steam turbine valve closure test is disclosed. The apparatus is used to implement the aforementioned method for reducing pressure fluctuations during a steam turbine valve closure test. The apparatus includes:

[0068] The acquisition module is used to acquire the main steam pressure of the steam turbine valve during the closure test.

[0069] The calculation module is used to calculate the pressure difference between the main steam pressure and the preset pressure, wherein the preset pressure is the main steam pressure of the turbine steam valve under stable load conditions.

[0070] The adjustment module is used to adjust the experimental actions during the shutdown test based on the pressure difference, so that the main steam pressure approaches the preset pressure.

[0071] The device for reducing pressure fluctuations during turbine valve closure tests includes a processor and a memory. The aforementioned acquisition module, calculation module, adjustment module, etc., are all stored as program units in the memory, and the processor executes the aforementioned program units stored in the memory to achieve the corresponding functions.

[0072] This invention can effectively reduce the fluctuation of main steam pressure and control it within a relatively small range, ensuring the safe operation of the unit. It has strong reference value for the safe operation of similar units after localization and modification.

[0073] This invention provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the above-described method for reducing pressure fluctuations during turbine valve closure tests.

[0074] The present invention also provides a computer-readable storage medium having a computer program stored thereon, characterized in that the program, when executed by a processor, implements the above-described method for reducing pressure fluctuations during turbine valve closure tests.

[0075] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0076] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0077] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0078] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0079] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0080] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, like read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0081] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0082] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0083] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A method for reducing pressure fluctuations during steam turbine valve closure tests, characterized in that, The method includes: Obtain the main steam pressure during the valve closure test; Calculate the pressure difference between the main steam pressure and the preset pressure, where the preset pressure is the main steam pressure of the steam valve under stable load conditions of the steam turbine. Adjust the experimental actions during the shutdown test according to the pressure difference to make the main steam pressure approach the preset pressure; The experimental actions include at least one of the following: the opening and closing rate of the steam valve, the experimental interval duration, and the boiler combustion rate; Adjusting the experimental actions during the shutdown test based on the pressure difference includes: The rate of increase of the main steam pressure is calculated based on the pressure change difference. If the rate of increase of the main steam pressure exceeds the rate of increase threshold, the boiler combustion rate is reduced. If the rate of increase of the main steam pressure far exceeds the rate of increase threshold, reduce the boiler combustion rate and the opening and closing rate of the steam valve. If the rate of increase of the main steam pressure does not exceed the rate of increase threshold, reduce the opening and closing rate of the steam valve to bring the main steam pressure closer to the preset pressure.

2. The method according to claim 1, characterized in that, Adjusting the experimental actions during the shutdown test based on the pressure difference includes: Calculate the magnitude of the main steam pressure change based on the pressure change difference; Determine the reduction range of the valve opening and closing rate to match the change range of the main steam pressure; Reduce the valve switching rate according to the decrease in the valve switching rate.

3. The method according to claim 1, characterized in that, Adjusting the experimental actions during the shutdown test based on the pressure difference includes: Set the experimental interval for two valves that are continuously closed in the experiment; At the moment when the previous steam valve closing experiment ends and the experiment interval is reached, determine whether the pressure change difference at that moment has decreased to within the pressure stability range; If the pressure change difference at that moment decreases to within the pressure stability range, the closing test of the next steam valve begins. If the pressure difference at that moment does not decrease to within the pressure stability range, increase the experimental interval until the pressure difference decreases to within the pressure stability range, and then begin the closing experiment of the next steam valve.

4. An apparatus for reducing pressure fluctuations during a steam turbine valve closure test, the apparatus being used to implement the method for reducing pressure fluctuations during a steam turbine valve closure test as described in any one of claims 1-3, characterized in that... The device includes: The acquisition module is used to acquire the main steam pressure of the steam turbine valve during the closure test. The calculation module is used to calculate the pressure difference between the main steam pressure and the preset pressure, wherein the preset pressure is the main steam pressure of the turbine steam valve under stable load conditions. The adjustment module is used to adjust the experimental actions during the shutdown test based on the pressure difference, so that the main steam pressure approaches the preset pressure.

5. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the method for reducing the pressure fluctuation during the steam valve closure test of any one of claims 1-3.

6. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by the processor, the program implements the method for reducing the pressure fluctuation during the turbine valve closure test as described in any one of claims 1-3.

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