Fan blade vibration monitoring system and method based on optical fiber Ethernet

Abstract

The invention discloses a fan blade vibration monitoring system and method based on an optical fiber Ethernet. The system comprises all measuring points on a fan, a local control cabinet, a fan MCC cabinet, an optical fiber, a gatekeeper, the Ethernet, a server, a client, an optical fiber network switch and an SIS server. Each measuring point on the fan is used for collecting physical signals and transmitting the physical signals to the local control cabinet, the fan MCC cabinet provides a power supply for the local control cabinet through a cable, the local control cabinet transmits data to the gatekeeper through an optical fiber, and the gatekeeper transmits the data to the optical fiber network switch through the Ethernet. And the optical fiber network switch connects the server, the client and the SIS server together through the Ethernet. According to the invention, the local control cabinet is combined with the characteristic frequency and the vibration amplitude of the blade tip vibration to screen out the data of the abnormal blade, so that the real-time monitoring of the operation state of the fan blade, the visualization of the operation point of the induced draft fan and the online real-time monitoring, analysis and diagnosis of mechanical faults are realized.

Description

Technical Field

[0001] The invention belongs to the technical field of thermal power generation, and in particular relates to a fan blade vibration monitoring system and method based on optical fiber Ethernet. Background Art

[0002] The existing vibration measurement points of the steam-driven induced draft fans in a thermal power plant are installed outside the casing, which makes it impossible to intuitively and accurately obtain the vibration status of the fans. In addition, for a long time, the blades of the induced draft fans of the two units have experienced resonance during variable speed operation, and there is a risk of cracking.

[0003] Therefore, it is necessary to conduct real-time and direct monitoring of the operating status of the induced draft fan, and comprehensively analyze the vibration characteristics of the induced draft fan at different speeds, such as blade vibration, bearing vibration, casing vibration, and fan operating point status, to optimize the induced draft fan operating speed adjustment strategy and to provide early warning of induced draft fan vibration failures.

[0004] Through research on the project, we have developed corresponding blade vibration monitoring devices, fan bearing and casing vibration monitoring devices, fan operating point monitoring systems, and intelligent fault diagnosis systems, which enable the simultaneous monitoring of the above parameters and fault diagnosis on a single platform. Through long-term monitoring of the fan status, we analyze the blade vibration patterns and influencing factors, formulate feasible operation and maintenance adjustment strategies, reduce the occurrence of blade cracking failures, and improve the safety and stability of fan operation. Summary of the invention

[0005] The object of the present invention is to provide a fan blade vibration monitoring system and method based on optical fiber Ethernet, so as to improve the safety and stability of the fan operation.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A wind turbine blade vibration monitoring system based on optical fiber Ethernet, including various measuring points on the wind turbine, a local control cabinet, a wind turbine MCC cabinet, optical fiber, a network switch, Ethernet, a server, a client, an optical fiber network switch and a SIS server;

[0008] Each measuring point on the fan is used to collect physical signals and transmit them to the local control cabinet. The fan MCC cabinet provides power to the local control cabinet through cables. The local control cabinet transmits data to the network switch through optical fiber. The network switch transmits data to the optical network switch through Ethernet. The optical network switch then connects the server, client and SIS server together through Ethernet.

[0009] A further improvement of the present invention is that it also includes connecting pipelines, and the physical signals collected by each measuring point on the fan are transmitted to the local control cabinet through the connecting pipelines.

[0010] A further improvement of the present invention is that the vibration collection part of each measuring point on the fan includes a rotor vibration monitoring system and a blade vibration monitoring system, the collection components of the rotor vibration monitoring system and the blade vibration monitoring system include a key phase sensor system, a shaft vibration collection system and a blade tip timing collection system, the key phase sensor system includes a key phase measuring point and a key phase sensor, the shaft vibration collection system includes a casing vibration sensor, and the blade tip timing collection system includes 4 blade tip sensors arranged along the circumferential side of the front end of the blade and a blade tip sensor arranged at the rear end of the blade.

[0011] A further improvement of the present invention is that four blade tip sensors are arranged along the circumferential side of the front end of the blade, and one blade tip sensor, a key phase sensor and a key phase measuring point are arranged at the rear end of the blade; the output dynamic voltage signals of the four blade tip sensors are connected to the acquisition system in parallel, a key phase measuring point is set on the fan shaft, and a key phase sensor is equipped as a reference point for sampling the blade circumferential angle and the entire cycle.

[0012] A further improvement of the present invention is that a full-cycle acquisition mode is adopted, that is, one rotation of the rotor is regarded as one sampling cycle, and within a single cycle, the rotor vibration monitoring system and the blade vibration monitoring system evenly collect 256 sampling points at equal phase intervals, and 17 acquisition cycles are intercepted as analysis data segments.

[0013] A further improvement of the present invention is that the rotor rotation cycle signal is provided with a switch signal by a key phase sensor, with the first key phase signal as the starting point and the next key phase signal as the end point, and the time length of the previous cycle determines the time interval of the sampling points in the next cycle.

[0014] A further improvement of the present invention is that the blade tip timing method is used to monitor the vibration of the rotor blades, the blade tip sensors are eddy current sensors, and the blade tip sensors are arranged on the casing with equal arcs.

[0015] A further improvement of the present invention is that when the blade vibrates, the tip of the blade passes a discretely distributed signal; the torsion of the blade is inferred by taking the multi-cycle phase average value obtained by four tip sensors arranged along the circumferential side of the front end of the blade and the multi-cycle phase average value obtained by one tip sensor arranged at the rear end of the blade, and fault diagnosis is performed based on post-processing analysis.

[0016] A further improvement of the present invention is that the blade torsion angle comparison analysis is based on the multi-cycle average phase signal of four blade tip sensors arranged along the circumferential side of the front end of the blade and one blade tip sensor arranged at the rear end of the blade, and the blade torsion angle is analyzed by analyzing the phase difference between the two phase signals; by comparing the torsion consistency of 19 blades within the period, the abnormal blades are screened out in combination with the characteristic frequency and vibration amplitude of the blade tip vibration for blade crack fault diagnosis.

[0017] A method for monitoring fan blade vibration based on optical fiber Ethernet, comprising:

[0018] By arranging four blade tip sensors along the circumferential side of the front end of the blade on the fan, and arranging one blade tip sensor, a key phase sensor, a key phase measuring point and a casing vibration sensor at the rear end of the blade, the physical quantities collected by these measuring points on the fan are transmitted to the local control cabinet through connecting pipelines. The local control cabinet converts the collected physical quantities into electrical signal data through its various components, and then transmits them to the network switch through optical fiber. The network switch transmits the data to the optical network switch through Ethernet. The server is connected to the optical network switch through Ethernet to store the data transmitted by the network switch. The SIS server is connected to the optical network switch through Ethernet. The client is connected to the optical network switch through Ethernet and accesses the server and SIS server. The local control cabinet combines the characteristic frequency and vibration amplitude of the blade tip vibration to filter out the data of abnormal blades, thereby realizing real-time monitoring of the operating status of the fan blades, visualization of the induced draft fan operating points, and online real-time monitoring and analysis and diagnosis of mechanical faults.

[0019] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0020] The present invention provides a fan blade vibration monitoring system and method based on optical fiber Ethernet. The functions that can be realized by the system include: long-term scientific monitoring and data recording of rotor vibration and blade vibration under the operation state of the fan; monitoring, diagnosis and early warning of rotor misalignment, imbalance, cracks and bending faults; rotor structure rotor-to-static friction fault alarm; stator structure looseness monitoring and alarm; fan bearing operation state monitoring and fault diagnosis; fan blade abnormal vibration, abnormal torsion monitoring and crack early warning. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 The present invention is a flow chart of a fan blade vibration monitoring system and method based on optical fiber Ethernet.

[0022] Figure 2 The present invention is a simplified diagram of the equipment used in a fan blade vibration monitoring system and method based on optical fiber Ethernet.

[0023] Figure 3 for Figure 2 AA view structure diagram.

[0024] Figure 4 The present invention is a flowchart of an algorithm for demodulating four groups of dynamic signals in a fan blade vibration monitoring system and method based on optical fiber Ethernet.

[0025] Description of reference numerals:

[0026] 1. Each measuring point on the fan, 2. Connecting pipelines, 3. Local control cabinet, 4. Cables, 5. Fan MCC cabinet, 6. Optical fiber, 7. Network switch, 8. Ethernet, 9. Server, 10. Client, 11. Optical fiber network switch, 12. SIS server;

[0027] 1-1, small steam turbine, 1-2, gear box, 1-3, fan;

[0028] 1-31, blade tip sensor, 1-32, key phase sensor, 1-33, key phase measurement point, 1-34, casing vibration sensor. DETAILED DESCRIPTION

[0029] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0030] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0031] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0032] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0034] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0035] It should be further understood that the term "and / or" used in the present description and the appended claims refers to any and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0036] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0037] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0038] Example 1

[0039] like Figure 1As shown, the present invention provides a wind turbine blade vibration monitoring system based on optical fiber Ethernet, including measuring points 1 on the wind turbine, a local control cabinet 3, a cable 4, a wind turbine MCC cabinet 5, optical fiber 6, a network switch 7, Ethernet 8, a server 9, a client 10, an optical fiber network switch 11 and a SIS server 12; the measuring points 1 on the wind turbine are used to collect physical signals and transmit them to the local control cabinet 3, the wind turbine MCC cabinet 5 provides power to the local control cabinet 3 through the cable 4, the local control cabinet 3 transmits data to the network switch 7 through the optical fiber 6, the network switch 7 transmits data to the optical fiber network switch 11 through the Ethernet 8, and the optical fiber network switch 11 connects the server 9, the client 10 and the SIS server 12 together through the Ethernet 8.

[0040] In this embodiment, the vibration collection part of each measuring point 1 on the fan includes a rotor vibration monitoring system and a blade vibration monitoring system. The collection components of the rotor vibration monitoring system and the blade vibration monitoring system include a key phase sensor system, a shaft vibration collection system and a blade tip timing collection system. The key phase sensor system includes a key phase measuring point 1-33 and a key phase sensor 1-32, the shaft vibration collection system includes a casing vibration sensor 1-34, and the blade tip timing collection system includes 4 blade tip sensors 1-31 arranged along the circumferential side of the front end of the blade and 1 blade tip sensor 1-31 arranged at the rear end of the blade.

[0041] In this embodiment, four blade tip sensors 1-31 are arranged along the circumferential side of the front end of the blade, and one blade tip sensor 1-31, a key phase sensor 1-32 and a key phase measurement point 1-33 are arranged at the rear end of the blade; the output dynamic voltage signals of the four blade tip sensors 1-31 are connected to the acquisition system in parallel, and a key phase measurement point 1-33 is set on the fan shaft, equipped with one key phase sensor 1-32, which serves as a reference point for sampling the blade circumferential angle and the entire cycle.

[0042] In this embodiment, the whole cycle acquisition mode is adopted, that is, one rotation of the rotor is regarded as one sampling cycle. In a single cycle, the rotor vibration monitoring system and the blade vibration monitoring system uniformly collect 256 sampling points at equal phase intervals, and 17 acquisition cycles are intercepted as analysis data segments. The rotation cycle signal of the rotor is provided by the key phase sensor with a switch signal, with the first key phase signal as the starting point and the next key phase signal as the end point, and the time interval of the sampling points in the next cycle is determined by the time length of the previous cycle.

[0043] In this embodiment, the blade tip timing method is used to monitor the vibration of the rotor blades. The blade tip sensor 1-31 is an eddy current sensor, and the blade tip sensor 1-31 is arranged at equal arcs on the casing. When the blade vibrates, the blade tip passes the signal in a discrete distribution; the multi-cycle phase average value obtained by the four blade tip sensors 1-31 arranged along the circumferential side of the front end of the blade and the multi-cycle phase average value obtained by the one blade tip sensor 1-31 arranged at the rear end of the blade are respectively taken to infer the torsion of the blade, and the fault diagnosis is performed based on the post-processing analysis.

[0044] In this embodiment, the blade torsion angle comparison analysis is based on the multi-cycle average phase signal of four blade tip sensors 1-31 arranged along the circumferential side of the front end of the blade and one blade tip sensor 1-31 arranged at the rear end of the blade. The blade torsion angle is analyzed by analyzing the phase difference between the two phase signals; by comparing the torsion consistency of 19 blades within the cycle, the abnormal blades are screened out in combination with the characteristic frequency and vibration amplitude of the blade tip vibration for blade crack fault diagnosis.

[0045] Example 2

[0046] like Figure 1 As shown, the present invention provides a fan blade vibration monitoring system based on optical fiber Ethernet, which mainly introduces the components of the fan blade vibration monitoring system. The system includes measuring points 1 on the fan, connecting pipelines 2, local control cabinets 3, cables 4, fan MCC cabinets 5, optical fibers 6, network switches 7, Ethernet 8, servers 9, clients 10, optical fiber network switches 11, and SIS servers 12. Physical signals collected by measuring points 1 on the fan are transmitted to the local control cabinet 3 through connecting pipelines 2, the fan MCC cabinet 5 provides power to the local control cabinet 3 through cables 4, the local control cabinet 3 transmits data to the network switch 7 through optical fiber 6, the network switch 7 transmits data to the optical fiber network switch 11 through Ethernet 8, and the optical fiber network switch 11 connects the server 9, the client 10 and the SIS server 12 together through Ethernet 8 to realize data storage and exchange, thereby realizing real-time monitoring of the operating status of the fan blades and visualization of the induced draft fan operating points, and online real-time monitoring and analysis and diagnosis of mechanical faults.

[0047] like Figure 2 As shown, it is a simplified diagram of the equipment of a fan blade vibration monitoring system based on optical fiber Ethernet of the present invention, which mainly introduces the components of the actual application equipment of the invention, including a small steam turbine 1-1, a gear box 1-2, and a fan 1-3.

[0048] like Figure 3As shown, it is a partial schematic diagram of the equipment applied to a wind turbine blade vibration monitoring system based on optical fiber Ethernet of the present invention, which mainly introduces the layout of the vibration measuring points of the present invention, including a blade tip sensor 1-31, a key phase sensor 1-32, a key phase measuring point 1-33, and a casing vibration sensor 1-34.

[0049] Each part consists of the following:

[0050] 1) Each measuring point 1 on the fan, including fan flow measurement pressure 1, fan flow measurement pressure 2, fan inlet static pressure, fan outlet static pressure, atmospheric pressure, fan casing horizontal vibration, fan casing vertical vibration, fan casing axial vibration, fan blade vibration 1, fan blade vibration 2, fan blade vibration 3, fan blade vibration 4, fan key phase sensor.

[0051] 2) Connecting pipeline 2. Since the present invention mainly describes the fan blade vibration monitoring system, other pipelines will not be introduced one by one. Only the connection lines of the relevant measuring points of the vibration monitoring system are described in detail. The cable of the vibration measuring point is characterized by a diameter of Ф2mm-Ф4.5mm, a twisted pair core wire with an external shield, and the outer layer of the cable is resistant to high temperature and corrosion.

[0052] 3) Local control cabinet 3, which is characterized in that a multi-channel vibration data acquisition device, an atmospheric pressure test module, a PLC, a power distribution, a terminal block, a pressure transmitter, an electromagnetic, a pressure tank and a filter pressure reducing regulator are arranged in the local control cabinet 3, wherein the communication protocol PLC of the local control cabinet 3 adopts TCP / IP protocol data.

[0053] 4) Cable 4 is the connecting cable between the local control cabinet 3 and the fan MCC cabinet 5, and is used to supply power to the local control cabinet 3 and control it; the power cable in cable 4 is characterized by a copper core cross-linked polyethylene cable with steel belt armor; the control cables in cable 4 are divided into three categories, which are characterized by copper conductor polyethylene insulation, copper belt sub-screen, PVC sheath, copper belt total screen, flame retardant Class C computer cable, copper conductor PVC insulation, PVC inner sheath, copper belt shielding, steel belt armor, PVC outer sheath, flame retardant grade C and copper core cross-linked polyethylene cable, steel belt armor, flame retardant grade C.

[0054] 5) The fan MCC cabinet 5 is characterized by a voltage level of 380V / 220V, which provides power supply and control power supply for the local control cabinet 3, and has electrical components such as circuit breakers, contactors, thermal relays, releases and current transformers.

[0055] 6) Optical fiber 6, which is characterized by being a multimode optical fiber, the interface type adopts an FC interface, the pigtail adopts a multimode pigtail, and the pigtail type adopts FC-FC.

[0056] 7) Gatekeeper 7, which is characterized as a one-way gatekeeper.

[0057] 8) Ethernet 8, characterized by full-duplex mode and a rate ≮1000Mbit / s.

[0058] 9) Server 9, characterized in that it collects field data through a network interface, and adds a physical isolation network gate 7 between the field data collection point and the server. The server is configured in the information room, and the management functions such as data collection, calculation, storage and analysis are realized from the SIS system through the PI system. The developed software includes online unit status monitoring software, signal analysis software, historical data management software, network communication service software, system configuration software, fault diagnosis software, etc.

[0059] 10) Client 10, which is characterized in that the client 10 accesses the server 9 through a browser, each client logs in through an account and password, and the account has a permission level.

[0060] 11) Fiber optic network switch 11, characterized as a desktop switch, with 12 LAN ports, 1 fiber optic path detector VF45, and 1 12VDC interface.

[0061] 12) SIS server 12, which is characterized by data type analog quantity or HTTP / TCP protocol data, reusing the original unit SIS system.

[0062] 13) Small steam turbine 1-1, characterized by being a back-pressure steam turbine.

[0063] 14) Gearbox 1-2; characterized by a parallel shaft gearbox, a speed ratio of 6.24 (low speed / high speed), a low speed rated speed of 850RPM; a high speed rated speed of 5304RPM.

[0064] 15) Fan 1-3, characterized in that it is an axial flow fan with adjustable stator blades.

[0065] 16) Blade tip sensor 1-31, which is characterized by being an eddy current sensor; four blade tip sensors 1-31 are arranged along the circumferential side of the front end of the blade, and one blade tip sensor 1-31 is arranged at the rear end of the blade. The sensor arranged at the rear end of the blade and the four blade tip sensors arranged at the front end of the blade are located in the same phase plane. The sensor arranged at the rear end of the blade provides auxiliary diagnostic data. A voltage comparator is connected in series at the output end of the eddy current sensor to convert the output signal of the eddy current sensor into a square wave, so that the blade passing signal can be accurately identified.

[0066] 17) Key phase sensor 1-32, which is characterized by being a photoelectric sensor, is installed on the fan bearing box, and the angle between its installation position and the key phase measuring point 1-33 is 50% of the angle between adjacent blades.

[0067] 18) The key phase measuring point 1-33 is characterized in that it is installed at the hub between two blades and is fixed with studs. The convex weight of the key phase measuring point does not affect the dynamic balance of the impeller. The angle between the key phase measuring point 1-33 and the key phase sensor 1-32 is 50% of the angle between adjacent blades.

[0068] 19) Casing vibration sensor 1-34; it is characterized by being an acceleration sensor, which is installed on the base of the induced draft fan casing by using stud punching to measure vibrations in the axial, horizontal and vertical directions. The sensor frequency response range is 1.5 to 15,000 Hz. It is located at the center plane of the fan together with the blade tip sensor 1-31. The blade tip sensor 1-31 is located at the front end of the blade, and the casing vibration sensor 1-34 is located in the middle of the blade. The two are installed in an offset manner.

[0069] like Figure 4 As shown, it is a flow chart of the algorithm for demodulating four groups of dynamic signals in a fan blade vibration monitoring system based on optical fiber Ethernet according to the present invention.

[0070] Example 3

[0071] The present invention provides a fan blade vibration monitoring method based on optical fiber Ethernet, comprising:

[0072] By arranging four blade tip sensors 1-31 along the circumferential side of the front end of the blade on the fan 1-3, arranging one blade tip sensor 1-31 and a key phase sensor 1-32, a key phase measuring point 1-33 and a casing vibration sensor 1-34 at the rear end of the blade, the physical quantities collected by these measuring points on the fan 1-3 are transmitted to the local control cabinet 3 through the connecting pipeline 2, the local control cabinet 3 converts the collected physical quantities into electrical signal data through its various components, and then transmits it to the network switch 7 through the optical fiber 6, the network switch 7 transmits the data to the optical fiber network switch 11 through the Ethernet 8, the server 9 is connected to the optical fiber network switch 11 through the Ethernet 8 to store the data transmitted by the network switch 7, the SIS server 12 is connected to the optical fiber network switch 11 through the Ethernet 8, the client 10 is connected to the optical fiber network switch 11 through the Ethernet 8 and accesses the server 9 and the SIS server 12, the local control cabinet 3 combines the characteristic frequency and vibration amplitude of the blade tip vibration to screen out the data of the abnormal blade, thereby realizing the real-time monitoring of the operation status of the fan blades and the visualization of the operation point of the induced draft fan, and the online real-time monitoring and analysis and diagnosis of mechanical faults.

[0073] The present invention provides a fan blade vibration monitoring method based on optical fiber Ethernet. The present invention has novel conception, strong operability, and better solves the problem of online monitoring of fan vibration.

[0074] Example 4

[0075] The existing vibration measurement points of the steam-driven induced draft fans in a thermal power plant are installed outside the casing, which makes it impossible to intuitively and accurately obtain the vibration status of the fans. In addition, for a long time, the blades of the induced draft fans of the two units have experienced resonance during variable speed operation, and there is a risk of cracking.

[0076] Therefore, it is necessary to conduct real-time and direct monitoring of the operating status of the induced draft fan, and comprehensively analyze the vibration characteristics of the induced draft fan at different speeds, such as blade vibration, bearing vibration, casing vibration, and fan operating point status, to optimize the induced draft fan operating speed adjustment strategy and to provide early warning of induced draft fan vibration failures.

[0077] Against this technical background, through on-site surveys, we developed corresponding blade vibration monitoring devices, fan bearing and casing vibration monitoring devices, fan operating point monitoring systems, and intelligent fault diagnosis systems, and proposed a fan blade vibration monitoring system and method based on fiber-optic Ethernet.

[0078] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0079] In addition, it should be understood that although this specification is described in accordance with the implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation modes that can be understood by those skilled in the art. The above content is only to illustrate the technical idea of ​​the present invention, and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A fan blade vibration monitoring system based on optical fiber Ethernet, characterized in that: Including various measuring points on the fan, local control cabinet, fan MCC cabinet, optical fiber, network switch, Ethernet, server, client, optical fiber network switch and SIS server; Each measuring point on the fan is used to collect physical signals and transmit them to the local control cabinet. The fan MCC cabinet provides power to the local control cabinet through cables. The local control cabinet transmits data to the network switch through optical fiber. The network switch transmits data to the optical network switch through Ethernet. The optical network switch then connects the server, client and SIS server together through Ethernet.

2. A wind turbine blade vibration monitoring system based on optical fiber Ethernet according to claim 1, characterized in that: It also includes connecting pipelines, through which physical signals collected at various measuring points on the fan are transmitted to the local control cabinet.

3. The wind turbine blade vibration monitoring system based on optical fiber Ethernet according to claim 1, characterized in that: The vibration collection part of each measuring point on the fan includes a rotor vibration monitoring system and a blade vibration monitoring system. The collection components of the rotor vibration monitoring system and the blade vibration monitoring system include a key phase sensor system, a shaft vibration collection system and a blade tip timing collection system. The key phase sensor system includes a key phase measuring point and a key phase sensor. The shaft vibration collection system includes a casing vibration sensor. The blade tip timing collection system includes 4 blade tip sensors arranged along the circumferential side of the front end of the blade and a blade tip sensor arranged at the rear end of the blade.

4. A wind turbine blade vibration monitoring system based on optical fiber Ethernet according to claim 3, characterized in that: Four blade tip sensors are arranged along the circumferential side of the front end of the blade, and one blade tip sensor, a key phase sensor and a key phase measurement point are arranged at the rear end of the blade; the output dynamic voltage signals of the four blade tip sensors are connected to the acquisition system in parallel, and a key phase measurement point is set on the fan shaft, equipped with a key phase sensor as the blade circumferential angle and full cycle sampling reference point.

5. The wind turbine blade vibration monitoring system based on optical fiber Ethernet according to claim 4, characterized in that: The full-cycle acquisition mode is adopted, that is, one rotation of the rotor is regarded as one sampling cycle. Within a single cycle, the rotor vibration monitoring system and the blade vibration monitoring system evenly collect 256 sampling points at equal phase intervals, and 17 acquisition cycles are intercepted as analysis data segments.

6. A wind turbine blade vibration monitoring system based on optical fiber Ethernet according to claim 5, characterized in that: The rotation cycle signal of the rotor is provided by the key phase sensor with a switching signal. The first key phase signal is used as the starting point and the next key phase signal is used as the end point. The time length of the previous cycle determines the time interval of the sampling points in the next cycle.

7. The wind turbine blade vibration monitoring system based on optical fiber Ethernet according to claim 3, characterized in that: The blade tip timing method is used to monitor the vibration of the rotor blades. The blade tip sensor is an eddy current sensor, and the blade tip sensors are arranged in equal arcs on the casing.

8. The wind turbine blade vibration monitoring system based on optical fiber Ethernet according to claim 3, characterized in that: When the blade vibrates, the tip of the blade passes through a discrete distribution of signals. The multi-cycle phase averages obtained by four tip sensors arranged along the circumferential side of the front end of the blade and the multi-cycle phase averages obtained by one tip sensor arranged at the rear end of the blade can be used to infer the torsion of the blade, and fault diagnosis can be performed based on post-processing analysis.

9. The wind turbine blade vibration monitoring system based on optical fiber Ethernet according to claim 3, characterized in that: The blade torsion angle comparison analysis is based on the multi-cycle average phase signal of four blade tip sensors arranged along the circumferential side of the blade front end and one blade tip sensor arranged at the rear end of the blade. The blade torsion angle is analyzed by analyzing the phase difference of the two phase signals. By comparing the torsion consistency of 19 blades in the cycle, the abnormal blades are screened out in combination with the characteristic frequency and vibration amplitude of the blade tip vibration for blade crack fault diagnosis.

10. A method for monitoring fan blade vibration based on optical fiber Ethernet, characterized in that: include: By arranging four blade tip sensors along the circumferential side of the front end of the blade on the fan, and arranging one blade tip sensor, a key phase sensor, a key phase measuring point and a casing vibration sensor at the rear end of the blade, the physical quantities collected by these measuring points on the fan are transmitted to the local control cabinet through connecting pipelines. The local control cabinet converts the collected physical quantities into electrical signal data through its various components, and then transmits them to the network switch through optical fiber. The network switch transmits the data to the optical network switch through Ethernet. The server is connected to the optical network switch through Ethernet to store the data transmitted by the network switch. The SIS server is connected to the optical network switch through Ethernet. The client is connected to the optical network switch through Ethernet and accesses the server and SIS server. The local control cabinet combines the characteristic frequency and vibration amplitude of the blade tip vibration to filter out the data of abnormal blades, thereby realizing real-time monitoring of the operating status of the fan blades, visualization of the induced draft fan operating points, and online real-time monitoring and analysis and diagnosis of mechanical faults.

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