Visual identification and positioning method and device for operation process of last-stage blade of steam turbine

Abstract

This invention discloses a visual recognition and positioning method and device for the operation of the last-stage blades of a steam turbine. The method includes: obtaining the number of low-pressure long blades in a complete revolution; using the edge of the key phase mark of the turbine shaft system as the zero position of rotor rotation; recording the time difference between two pulses of the original shaft system key phase signal through hardware circuitry; when the rotor begins the next revolution, outputting a square wave signal corresponding to the number of low-pressure long blades in the hardware circuitry, and using the falling edge of this square wave signal to drive the visual recognition system; introducing a drive enable signal based on the square wave signal and the single-blade recognition time of the visual recognition system; as the unit continues to rotate, when all drive enable signals become low, the visual recognition system completes the visual recognition of the entire revolution of blades and synchronously outputs the drive sequence number of all blades; and organizing the visual recognition results of the entire revolution of blades according to the order of the drive sequence numbers.

Description

Technical Field

[0001] This invention belongs to the field of power equipment, and particularly relates to a visual recognition and positioning method for the operation of the last stage blade of a steam turbine. Background Technology

[0002] With economic development, the digital and intelligent transformation of power plants has become an essential path for power companies to ensure safe production operations, improve production and operational efficiency, and achieve energy conservation and emission reduction.

[0003] Power plants face the challenge of deep peak shaving. For power plants in northern regions, there is also a need for increased heating capacity during the winter heating season to alleviate the pressure on residential heating. However, both peak shaving and heating capacity expansion conditions deviate significantly from the design conditions provided by the turbine manufacturers. Under these non-design conditions, the low-pressure cylinder inlet steam flow is low, the steam vortex on the blade surface is enhanced, and the dynamic stress of the low-pressure last-stage blades increases accordingly, increasing the risk of blade fracture. Blade safety issues have attracted widespread attention.

[0004] During turbine operation, the last-stage long blades rotate at high speed. To check their operational status, visual recognition is used to monitor their safety. However, this process requires blade positioning to ensure that the entire long blade is covered during visual recognition. Therefore, it is essential to incorporate a blade positioning system into the visual recognition process. This system serves two purposes: firstly, to ensure that the entire circumference of the long blade is covered during each visual recognition session; and secondly, to facilitate comparison of blade safety status after each subsequent visual recognition. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of the prior art by disclosing a visual recognition and positioning method and device for the operation of the last stage blade of a steam turbine. The method and / or device of this invention can ensure that the entire long blade is covered each time a visual recognition is performed, and can also facilitate the comparison of the blade's safety status after the next visual recognition.

[0006] On the one hand, the objective of this invention is achieved through the following technical solution:

[0007] A visual recognition and positioning method for the operation process of the last stage blade of a steam turbine, the method comprising:

[0008] S1: Obtain the number of low-pressure long blades in the entire circle;

[0009] S2: Use the edge of the key phase mark of the turbine shaft system as the zero position of rotor rotation;

[0010] S3: Record the time difference between two pulses of the original shaft key phase signal through hardware circuitry;

[0011] S4: Based on the data obtained in steps S1 to S3, when the rotor starts the next rotation, a square wave signal corresponding to the number of low-pressure long blades is output in the hardware circuit, and the falling edge of this square wave signal drives the vision recognition system to work.

[0012] S5: Based on the square wave signal generated in step S4 and the single-blade recognition time of the vision recognition system, a drive enable signal is introduced.

[0013] S6: When the drive enable signal is high, the falling edge of the square wave signal is valid; when the drive enable signal is low, the falling edge of the square wave signal cannot drive the vision recognition system to work.

[0014] S7: When the vision recognition system starts collecting data for each lap of the blades, all drive enable signals are at a high level by default. Each time the vision recognition system is driven, it provides a feedback signal indicating successful drive, the corresponding drive enable signal goes low, and the specific drive sequence number is recorded simultaneously.

[0015] S8: As the unit continues to rotate, when all drive enable signals go low, the vision recognition system completes the visual recognition of the entire circle of blades and synchronously outputs the drive sequence number of all blades.

[0016] S9: Based on the visual recognition results corresponding to the drive serial number, organize and obtain the visual recognition results of the entire blade circle.

[0017] According to a preferred embodiment, the visual recognition and positioning method for the operation process of the last stage blade of the steam turbine further includes: S10: verifying the accuracy of blade recognition by comparing the results of visual recognition of adjacent full-cycle blades one by one.

[0018] According to a preferred embodiment, in step S3, the hardware circuit generates a voltage pulse for each revolution of the rotor, which can be used to identify the zero position of the rotor rotation.

[0019] According to a preferred embodiment, in step S3, the rotor rotation speed can be calculated by using the time difference between two pulses of the original shaft key phase signal.

[0020] According to a preferred embodiment, in step S5, the falling edge time interval of the square wave signal is 200-340 microseconds.

[0021] According to a preferred embodiment, in step S5, the recognition time of a single blade by the visual recognition system is greater than the time interval between the falling edges of the square wave signal.

[0022] On the other hand, the present invention also discloses:

[0023] A visual recognition and positioning device for the operation of the last stage blade of a steam turbine, the visual recognition and positioning device includes a drive system, the drive system being configured to drive the visual recognition system to complete the recognition of the entire circumference of the last stage blade of the steam turbine according to the aforementioned visual recognition and positioning method.

[0024] The aforementioned main solution of the present invention and its various further alternative solutions can be freely combined to form multiple solutions, all of which are solutions that can be adopted and are claimed by the present invention. Those skilled in the art, after understanding the solution of the present invention, will realize that there are many combinations based on existing technology and common knowledge, all of which are technical solutions to be protected by the present invention, and will not be exhaustively listed here.

[0025] The beneficial effects of this invention are:

[0026] The last-stage blades of a steam turbine refer to the long blades of the low-pressure last stage of the steam turbine, which operate under harsh conditions, especially under deep peak-shaving conditions. The method and / or apparatus of this invention can ensure that the entire long blade ring is covered during each visual identification, and also facilitate the comparison of the blade's safety status after the next visual identification. Attached Figure Description

[0027] Figure 1 This is a flowchart illustrating the method of the present invention;

[0028] Figure 2 This is a schematic diagram of the square wave signal of the present invention;

[0029] Figure 3 This is a schematic diagram showing the connection between the driving system and the identification system of this invention. Detailed Implementation

[0030] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0031] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0032] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention. In addition, the terms "first," "second," "third," etc., are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0033] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0034] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0035] Furthermore, it should be noted that, unless otherwise specified, the structures, connections, positions, power sources, etc. involved in this invention are all things that a person skilled in the art can know without creative effort based on the prior art.

[0036] Example 1:

[0037] refer to Figure 1 As shown in the figure, a visual recognition and positioning method for the operation process of the last stage blade of a steam turbine is illustrated. The method includes...

[0038] Step S1: Obtain the number of low-pressure long blades in the entire circle.

[0039] Step S2: Use the edge of the key phase mark of the turbine shaft system as the zero position of the rotor rotation.

[0040] Step S3: Record the time difference between the two pulses of the original shaft key phase signal using hardware circuitry.

[0041] Preferably, in step S3, the hardware circuit generates a voltage pulse for each revolution of the rotor, which can be used to identify the zero position of the rotor rotation.

[0042] Preferably, in step S3, the rotor rotation speed can be calculated by using the time difference between two pulses of the original shaft key phase signal.

[0043] Step S4: Based on the data obtained in steps S1 to S3, when the rotor starts the next revolution, a square wave signal corresponding to the number of low-pressure long blades is output in the hardware circuit, and the falling edge of this square wave signal drives the vision recognition system to work.

[0044] Step S5: Based on the square wave signal generated in step S4 and the single-blade recognition time of the visual recognition system, a drive enable signal is introduced, referencing... Figure 2 As shown.

[0045] Preferably, in step S5, the falling edge time interval of the square wave signal is 200–340 microseconds. In step S5, the single-leaf recognition time of the visual recognition system is greater than the falling edge time interval of the square wave signal.

[0046] Step S6: When the drive enable signal is high, the falling edge of the square wave signal is valid; when the drive enable signal is low, the falling edge of the square wave signal cannot drive the vision recognition system to work.

[0047] Step S7: When the vision recognition system starts collecting data for each lap of blades, all drive enable signals are at a high level by default. Each time the vision recognition system is driven, it provides a feedback signal indicating successful drive, the corresponding drive enable signal goes low, and the specific drive sequence number is recorded simultaneously.

[0048] Step S8: As the unit continues to rotate, when all drive enable signals go low, the vision recognition system completes the visual recognition of the entire circle of blades and synchronously outputs the drive sequence number of all blades.

[0049] Step S9: Based on the visual recognition results corresponding to the drive serial number, organize and obtain the visual recognition results of the entire blade ring.

[0050] Preferably, the visual recognition and positioning method for the operation of the last stage blade of the steam turbine further includes: S10: verifying the accuracy of blade recognition by comparing the results of visual recognition of adjacent full-cycle blades one by one.

[0051] Example 2

[0052] refer to Figure 3 As shown in the figure, this embodiment also discloses a visual recognition and positioning device for the operation process of the last stage blade of a steam turbine, the visual recognition and positioning device including a drive system.

[0053] Preferably, the drive system is configured to drive the visual recognition system to complete the recognition of the entire circle of the turbine's last-stage blades according to the visual recognition and positioning method described in Embodiment 1.

[0054] The last-stage blades of a steam turbine refer to the long blades of the low-pressure last stage of the steam turbine, which operate under harsh conditions, especially under deep peak-shaving conditions. The method and / or apparatus of this invention can ensure that the entire long blade ring is covered during each visual identification, and also facilitate the comparison of the blade's safety status after the next visual identification.

[0055] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A visual recognition and positioning method for the operation of the last-stage blades of a steam turbine, characterized in that, The visual recognition and positioning method for the operation process of the last stage blades of the steam turbine includes: S1: Obtain the number of low-pressure long blades in the entire circle; S2: Use the edge of the key phase mark of the turbine shaft system as the zero position of rotor rotation; S3: Record the time difference between two pulses of the original shaft key phase signal through hardware circuitry; S4: Based on the data obtained in steps S1 to S3, when the rotor starts the next rotation, a square wave signal corresponding to the number of low-pressure long blades is output in the hardware circuit, and the falling edge of this square wave signal drives the vision recognition system to work. S5: Based on the square wave signal generated in step S4 and the single-blade recognition time of the vision recognition system, a drive enable signal is introduced. S6: When the drive enable signal is high, the falling edge of the square wave signal is valid; when the drive enable signal is low, the falling edge of the square wave signal cannot drive the vision recognition system to work. S7: When the vision recognition system starts collecting data for each lap of the blades, all drive enable signals are at a high level by default. Each time the vision recognition system is driven, it provides a feedback signal indicating successful drive, the corresponding drive enable signal goes low, and the specific drive sequence number is recorded simultaneously. S8: As the unit continues to rotate, when all drive enable signals go low, the vision recognition system completes the visual recognition of the entire circle of blades and synchronously outputs the drive sequence number of all blades. S9: Based on the visual recognition results corresponding to the drive serial number, organize and obtain the visual recognition results of the entire blade circle.

2. The visual recognition and positioning method for the operation process of the last stage blade of a steam turbine as described in claim 1, characterized in that, The visual recognition and positioning method for the operation process of the last stage blades of the steam turbine also includes: S10: The accuracy of blade recognition is verified by comparing the results of visual recognition of adjacent full-circle blades one by one.

3. The visual recognition and positioning method for the operation process of the last stage blade of a steam turbine as described in claim 1, characterized in that, In step S3, the hardware circuit generates a voltage pulse for each rotation of the rotor, which can be used to identify the zero position of the rotor rotation.

4. The visual recognition and positioning method for the operation process of the last stage blade of a steam turbine as described in claim 3, characterized in that, In step S3, the rotor rotation speed can be calculated by using the time difference between the two pulses of the original shaft key phase signal.

5. The visual recognition and positioning method for the operation process of the last stage blade of a steam turbine as described in claim 1, characterized in that, In step S5, the falling edge time interval of the square wave signal is 200-340 microseconds.

6. The visual recognition and positioning method for the operation process of the last stage blade of a steam turbine as described in claim 5, characterized in that, In step S5, the recognition time of a single blade in the visual recognition system is greater than the time interval between the falling edges of the square wave signal.

7. A visual recognition and positioning device for the operation of the last stage blades of a steam turbine, characterized in that, The visual recognition and positioning device includes a drive system configured to drive the visual recognition system to complete the recognition of the entire circumference of the last stage blades of the steam turbine according to the visual recognition and positioning method according to any one of claims 1 to 6.

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