A fan blade vibration monitoring system and method based on fiber optic ethernet

Abstract

The application discloses a fan blade vibration monitoring system and method based on an optical fiber Ethernet, which comprises various measuring points on a fan, a local control cabinet, a fan MCC cabinet, optical fibers, a network gate, an Ethernet, a server, a client, an optical fiber network switch and an SIS server; the various measuring points on the fan are used for collecting physical signals and transmitting the physical signals to the local control cabinet; the fan MCC cabinet provides power supply for the local control cabinet through a cable; the local control cabinet transmits data to the network gate through the optical fibers; the network gate 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. The application screens out the data of abnormal blades by the local control cabinet in combination with the characteristic frequency and the vibration amplitude of blade tip vibration, and thus realizes real-time monitoring on the running state of the fan blades, visualization of the fan running point, online real-time monitoring and analysis diagnosis of mechanical faults.

Description

Technical Field

[0001] This invention belongs to the field of thermal power generation technology, specifically relating to a wind turbine blade vibration monitoring system and method based on fiber optic Ethernet. Background Technology

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

[0003] Therefore, it is necessary to monitor the operating status of the induced draft fan in real time and directly, and to 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, so as to optimize the induced draft fan operating speed adjustment strategy and provide early warning of induced draft fan vibration faults.

[0004] Through research on the project, corresponding blade vibration monitoring devices, wind turbine bearing and casing vibration monitoring devices, wind turbine operating point monitoring systems, and intelligent fault diagnosis systems were developed. These systems enable simultaneous monitoring of the above parameters and fault diagnosis on a single platform. By monitoring the wind turbine's condition over a long period, the vibration patterns and influencing factors of the blades are analyzed, and feasible operation and maintenance adjustment strategies are formulated to reduce the occurrence of blade cracking faults and improve the safety and stability of wind turbine operation. Summary of the Invention

[0005] The purpose of this invention is to provide a wind turbine blade vibration monitoring system and method based on fiber optic Ethernet to improve the safety and stability of wind turbine operation.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A wind turbine blade vibration monitoring system based on fiber optic Ethernet includes various measuring points on the wind turbine, a local control cabinet, a wind turbine MCC cabinet, fiber optic cable, network gateway, Ethernet, server, client, fiber optic network switch, and SIS server.

[0008] Each measuring point on the wind turbine is used to collect physical signals and transmit them to the local control cabinet. The wind turbine MCC cabinet provides power to the local control cabinet through a cable. The local control cabinet transmits the data to the network gateway through optical fiber. The network gateway transmits the data to the fiber optic network switch through Ethernet. The fiber optic 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, through which the physical signals collected by each measuring point on the fan are transmitted to the local control cabinet.

[0010] A further improvement of the present invention is that the vibration acquisition part of each measuring point on the wind turbine includes a rotor vibration monitoring system and a blade vibration monitoring system. The acquisition components of the rotor vibration monitoring system and the blade vibration monitoring system include a key phase sensor system, a shaft vibration acquisition system and a blade tip timing acquisition system. The key phase sensor system includes key phase measuring points and key phase sensors. The shaft vibration acquisition system includes a casing vibration sensor. The blade tip timing acquisition system includes four blade tip sensors arranged along the circumferential side of the blade tip and one blade tip sensor arranged at the blade tip.

[0011] A further improvement of the present invention is that four blade tip sensors are arranged along the circumferential side of the blade's leading edge, 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 in parallel to the acquisition system. A key phase measuring point is set on the wind turbine shaft and equipped with one key phase sensor as a reference point for sampling the blade's circumferential angle and the entire cycle.

[0012] A further improvement of this invention is that it adopts a full-cycle acquisition mode, that is, one rotation of the rotor is taken as one sampling cycle. Within a single cycle, the rotor vibration monitoring system and the blade vibration monitoring system collect 256 sampling points at equal phase intervals, and 17 acquisition cycles are extracted as the analysis data segment.

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

[0014] A further improvement of this invention is that the vibration of the rotor blades is monitored by the blade tip timing method, the blade tip sensor is an eddy current sensor, and the blade tip sensor is arranged with equal arc on the casing.

[0015] A further improvement of this invention is that when the blade vibrates, the blade tip transmits signals in a discrete manner; the average of multiple-cycle phases obtained by four blade tip sensors arranged along the circumferential side of the blade tip and the average of multiple-cycle phases obtained by one blade tip sensor arranged at the blade tip are respectively used to calculate the blade twisting condition, and fault diagnosis is performed based on post-processing analysis.

[0016] A further improvement of this 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 blade tip and one blade tip sensor arranged at the blade tip. The blade torsion angle is analyzed by analyzing the phase difference between the two phase signals. By comparing the torsion consistency of 19 blades in this cycle, and combining the characteristic frequency and vibration amplitude of the blade tip vibration, abnormal blades are screened out for blade crack fault diagnosis.

[0017] A method for monitoring wind turbine blade vibration based on fiber optic Ethernet, comprising:

[0018] By arranging four blade tip sensors along the circumferential side of the blade tip on the wind turbine, and one blade tip sensor, along with a key phase sensor, key phase measuring point, and casing vibration sensor at the rear end of the blade, the physical quantities collected by these measuring points on the wind turbine are transmitted to the local control cabinet via 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 gateway via optical fiber. The network gateway transmits the data to the fiber optic network switch via Ethernet. The server is connected to the fiber optic network switch via Ethernet to store the data transmitted from the network gateway. The SIS server is connected to the fiber optic network switch via Ethernet. Clients are connected to the fiber optic network switch via Ethernet to access the server and the SIS server. The local control cabinet combines the characteristic frequency and vibration amplitude of the blade tip vibration to filter out data of abnormal blades, thereby realizing real-time monitoring of the wind turbine blade operating status, visualization of the induced draft fan operating point, and online real-time monitoring, analysis, and diagnosis of mechanical faults.

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

[0020] This invention provides a wind turbine blade vibration monitoring system and method based on fiber optic Ethernet. The functions that this system can achieve include: long-term scientific monitoring and data recording of rotor vibration and blade vibration during wind turbine operation; monitoring, diagnosis and early warning of rotor misalignment, imbalance, crack and bending faults; alarm for rotor structure rotor-stationary rubbing faults; monitoring and alarm for stator structure loosening; monitoring and fault diagnosis of wind turbine bearing operation status; and monitoring and early warning of abnormal vibration and abnormal torsion of wind turbine blades. Attached Figure Description

[0021] Figure 1 This is a flowchart of a wind turbine blade vibration monitoring system and method based on fiber optic Ethernet according to the present invention.

[0022] Figure 2 This is a simplified diagram of the equipment used in the wind turbine blade vibration monitoring system and method based on fiber optic Ethernet according to the present invention.

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

[0024] Figure 4 This is a flowchart of the demodulation algorithm for four sets of dynamic signals in a wind turbine blade vibration monitoring system and method based on fiber optic Ethernet according to the present invention.

[0025] Explanation of reference numerals in the attached figures:

[0026] 1. Measuring points on the wind turbine; 2. Connecting pipelines; 3. Local control cabinet; 4. Cables; 5. Wind turbine MCC cabinet; 6. Fiber optic cable; 7. Network gateway; 8. Ethernet; 9. Server; 10. Client; 11. Fiber optic network switch; 12. SIS server.

[0027] 1-1. Small steam turbine; 1-2. Gearbox; 1-3. Fan;

[0028] 1-31, Blade tip sensor; 1-32, Key phase sensor; 1-33, Key phase measuring point; 1-34, Housing vibration sensor. Detailed Implementation

[0029] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0030] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used 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. Therefore, they should not be construed as limitations on this invention.

[0031] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0032] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0033] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

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

[0035] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0036] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0037] The embodiments of the present invention will now be described in detail 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 fiber optic Ethernet, including various measuring points 1 on the wind turbine, a local control cabinet 3, a cable 4, a wind turbine MCC cabinet 5, an optical fiber 6, a network gateway 7, an Ethernet 8, a server 9, a client 10, a fiber optic 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 gateway 7 through the optical fiber 6. The network gateway 7 transmits the data to the fiber optic network switch 11 through the Ethernet 8. The fiber optic network switch 11 then connects the server 9, the client 10, and the SIS server 12 together through the Ethernet 8.

[0040] In this embodiment, the vibration acquisition part of each measuring point 1 on the wind turbine includes a rotor vibration monitoring system and a blade vibration monitoring system. The acquisition components of the rotor vibration monitoring system and the blade vibration monitoring system include a key phase sensor system, a shaft vibration acquisition system, and a blade tip timing acquisition system. The key phase sensor system includes key phase measuring points 1-33 and key phase sensors 1-32. The shaft vibration acquisition system includes a casing vibration sensor 1-34. The blade tip timing acquisition system includes four blade tip sensors 1-31 arranged along the circumferential side of the blade's leading edge and one blade tip sensor 1-31 arranged at the blade's rear end.

[0041] In this embodiment, four blade tip sensors 1-31 are arranged along the circumferential side of the blade's leading edge, and one blade tip sensor 1-31, a key phase sensor 1-32, and a key phase measuring point 1-33 are arranged at the rear end of the blade. The dynamic voltage signals output by the four blade tip sensors 1-31 are connected in parallel to the acquisition system. A key phase measuring point 1-33 is set on the wind turbine shaft and equipped with one key phase sensor 1-32 as a reference point for sampling the blade's circumferential angle and the entire cycle.

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

[0043] In this embodiment, the blade tip timing method is used to monitor the vibration of the rotor blades. The blade tip sensors 1-31 are eddy current sensors, and they are arranged at equal arcs on the casing. When the blade vibrates, the blade tip transmits signals in a discrete distribution. The torsional state of the blade is calculated by taking the average of the multi-cycle phases collected by four blade tip sensors 1-31 arranged along the circumferential side of the blade tip and the average of the multi-cycle phases collected by one blade tip sensor 1-31 arranged at the rear end of the blade. Fault diagnosis is then 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 blade tip and one blade tip sensor 1-31 arranged at the blade tip. The blade torsion angle is analyzed by analyzing the phase difference between the two phase signals. By comparing the torsion consistency of 19 blades in this cycle, abnormal blades are screened out by combining 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, this invention provides a wind turbine blade vibration monitoring system based on fiber optic Ethernet. The system mainly introduces the components of the system, which includes various measuring points 1 on the wind turbine, connecting pipelines 2, a local control cabinet 3, cables 4, a wind turbine MCC cabinet 5, optical fiber 6, a network gateway 7, an Ethernet cable 8, a server 9, a client 10, a fiber optic network switch 11, and a SIS server 12. The physical signals collected by the measuring points 1 on the wind turbine are transmitted to the local control cabinet 3 via the connecting pipelines 2. The wind turbine MCC cabinet 5 provides power to the local control cabinet 3 via the cable 4. The local control cabinet 3 transmits the data to the network gateway 7 via the optical fiber 6. The network gateway 7 transmits the data to the fiber optic network switch 11 via the Ethernet cable 8. The fiber optic network switch 11 then connects the server 9, client 10, and SIS server 12 together via the Ethernet cable 8, realizing data storage and exchange. This enables real-time monitoring of the wind turbine blade operating status, visualization of the induced draft fan operating point, and online real-time monitoring and analysis of mechanical faults.

[0047] like Figure 2 The diagram shown is a simplified equipment diagram of a wind turbine blade vibration monitoring system based on fiber optic Ethernet according to the present invention. It mainly introduces the components of the actual application equipment of the invention, including a small steam turbine 1-1, a gearbox 1-2, and a wind turbine 1-3.

[0048] like Figure 3The diagram shown is a partial schematic of the equipment used in the wind turbine blade vibration monitoring system based on fiber optic Ethernet according to the present invention. It mainly introduces the arrangement of vibration measuring points of the invention, including blade tip sensor 1-31, key phase sensor 1-32, key phase measuring point 1-33, and casing vibration sensor 1-34.

[0049] Each part is composed of the following:

[0050] 1) Measuring points 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, and fan key phase sensor.

[0051] 2) Connecting pipeline 2: Since this invention mainly describes the wind turbine blade vibration monitoring system, other pipelines will not be described one by one. Only the connection lines of the relevant measuring points of the vibration monitoring system will be 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 external shielding, and the outer layer of the cable can withstand high temperature and corrosion.

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

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

[0054] 5) Fan MCC cabinet 5, characterized by a voltage level of 380V / 220V, provides power and control power to local control cabinet 3, and contains electrical components such as circuit breakers, contactors, thermal relays, trip units and current transformers.

[0055] 6) Fiber 6, characterized by being a multimode fiber, using an FC interface, and employing multimode pigtails of FC-FC type.

[0056] 7) Network gateway 7, characterized as a one-way network gateway.

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

[0058] 9) Server 9, characterized by acquiring field data via a network interface, with a physical isolation gateway 7 added between the field data acquisition points and the server. A server is configured in the information room, and the PI system is used to collect, calculate, store, and analyze data from the SIS system, performing management functions such as data management. Developed software includes online unit status monitoring software, signal analysis software, historical data management software, network communication service software, system configuration software, and fault diagnosis software.

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

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

[0061] 12) SIS server 12, characterized by data types of analog quantities or HTTP / TCP protocol data, utilizing the existing SIS system.

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

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

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

[0065] 16) Blade tip sensor 1-31, characterized as an eddy current sensor; four blade tip sensors 1-31 are arranged along the circumferential side of the blade's leading edge, and one blade tip sensor 1-31 is arranged at the blade's trailing edge. The sensor arranged at the blade's trailing edge and the four blade tip sensors arranged along the blade's leading edge are located in the same phase plane. The sensor arranged at the blade's trailing edge provides auxiliary diagnostic data. A voltage comparator connected in series at the output terminal of the eddy current sensor converts the output signal of the eddy current sensor into a square wave, which facilitates accurate identification of the blade through the signal.

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

[0067] 18) Key phase measuring point 1-33, characterized in that it is installed at the hub between two blades and fixed by drilling with studs. The weight of the protrusion 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; characterized as an acceleration sensor, which is installed on the base of the induced draft fan casing by means of stud drilling, and measures the vibration in the axial, horizontal and vertical directions respectively. The frequency response range of the sensor is 1.5~15000Hz. It is located at the same mid-plane of the fan as 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 a staggered manner.

[0069] like Figure 4 The diagram shown is a flowchart of the demodulation algorithm for four sets of dynamic signals in a wind turbine blade vibration monitoring system based on fiber optic Ethernet according to the present invention.

[0070] Example 3

[0071] This invention provides a method for monitoring wind turbine blade vibration based on fiber optic Ethernet, comprising:

[0072] By arranging four blade tip sensors 1-31 along the circumferential side of the blade tip on the wind turbine 1-3, and one blade tip sensor 1-31, along with 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 wind turbine 1-3 are transmitted to the local control cabinet 3 via connecting pipeline 2. The local control cabinet 3 converts the collected physical quantities into electrical signal data through its various components, and then transmits them to the network gateway 7 via optical fiber 6. The network gateway 7 transmits the data to the fiber optic network switch 11 via Ethernet 8. The server 9 is connected to the fiber optic network switch 11 via Ethernet 8 to store the data transmitted from the network gateway 7. The SIS server 12 is connected to the fiber optic network switch 11 via Ethernet 8. The client 10 is connected to the fiber optic network switch 11 via 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 filter out the data of abnormal blades, thereby realizing real-time monitoring of the wind turbine blade operating status, visualization of the induced draft fan operating point, and online real-time monitoring and analysis and diagnosis of mechanical faults.

[0073] This invention provides a method for monitoring the vibration of wind turbine blades based on fiber optic Ethernet. This invention has a novel concept, strong operability, and effectively solves the problems in online monitoring of wind turbine vibration.

[0074] Example 4

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

[0076] Therefore, it is necessary to monitor the operating status of the induced draft fan in real time and directly, and to 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, so as to optimize the induced draft fan operating speed adjustment strategy and provide early warning of induced draft fan vibration faults.

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

[0078] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the scope of the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0079] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A wind turbine blade vibration monitoring system based on fiber optic Ethernet, characterized in that, This includes various measuring points on the wind turbine, local control cabinets, wind turbine MCC cabinets, fiber optic cables, network gateways, Ethernet, servers, clients, fiber optic network switches, and SIS servers; Each measuring point on the wind turbine is used to collect physical signals and transmit them to the local control cabinet. The wind turbine MCC cabinet provides power to the local control cabinet through a cable. The local control cabinet transmits the data to the network gateway through optical fiber. The network gateway transmits the data to the fiber optic network switch through Ethernet. The fiber optic network switch then connects the server, client and SIS server together through Ethernet. The vibration acquisition components at each measuring point on the wind turbine include a rotor vibration monitoring system and a blade vibration monitoring system. The acquisition components of the rotor vibration monitoring system and the blade vibration monitoring system include a key phase sensor system, a shaft vibration acquisition system, and a blade tip timing acquisition system. The key phase sensor system includes key phase measuring points and key phase sensors. The shaft vibration acquisition system includes a casing vibration sensor. The blade tip timing acquisition system includes four blade tip sensors arranged along the circumferential side of the blade tip and one blade tip sensor arranged at the blade tip. 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 dynamic voltage signals output by the four blade tip sensors are connected in parallel to the acquisition system. A key phase measuring point is set on the wind turbine shaft and equipped with one key phase sensor as the reference point for sampling the blade circumferential angle and the whole cycle. The whole-cycle acquisition mode is adopted, that is, one rotation of the rotor is one sampling cycle. Within a single cycle, the rotor vibration monitoring system and the blade vibration monitoring system collect 256 sampling points at equal phase intervals, and 17 acquisition cycles are extracted as the analysis data segment. The rotation cycle signal of the rotor is provided by the switch signal of the key phase sensor. The first key phase signal is the starting point and the next key phase signal is the ending point. The time interval of sampling points in the next cycle is determined by the time length of the previous cycle.

2. The wind turbine blade vibration monitoring system based on fiber optic 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 fiber optic Ethernet according to claim 1, characterized in that, The vibration of the rotor blades is monitored using the blade tip timing method. The blade tip sensor is an eddy current sensor, and the blade tip sensor is arranged with equal arc on the casing.

4. The wind turbine blade vibration monitoring system based on fiber optic Ethernet according to claim 1, characterized in that, When the blade vibrates, the signals transmitted through the blade tip are discretely distributed. The torsion of the blade can be estimated by taking the average of the multi-cycle phases of four blade tip sensors arranged along the circumferential side of the blade tip and the average of the multi-cycle phases of one blade tip sensor arranged at the blade tip. Fault diagnosis can be performed based on the post-processing analysis.

5. The wind turbine blade vibration monitoring system based on fiber optic Ethernet according to claim 1, 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 tip and one blade tip sensor arranged at the blade tip. The blade torsion angle is analyzed by analyzing the phase difference between the two phase signals. By comparing the torsion consistency of 19 blades in this cycle, and combining the characteristic frequency and vibration amplitude of the blade tip vibration, abnormal blades are screened out for blade crack fault diagnosis.

6. A method for monitoring wind turbine blade vibration based on fiber optic Ethernet, characterized in that, This method is based on the fiber optic Ethernet-based wind turbine blade vibration monitoring system described in claim 1, comprising: By arranging four blade tip sensors along the circumferential side of the blade tip on the wind turbine, and one blade tip sensor, along with a key phase sensor, key phase measuring point, and casing vibration sensor at the rear end of the blade, the physical quantities collected by these measuring points on the wind turbine are transmitted to the local control cabinet via 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 gateway via optical fiber. The network gateway transmits the data to the fiber optic network switch via Ethernet. The server is connected to the fiber optic network switch via Ethernet to store the data transmitted from the network gateway. The SIS server is connected to the fiber optic network switch via Ethernet. Clients are connected to the fiber optic network switch via Ethernet to access the server and the SIS server. The local control cabinet combines the characteristic frequency and vibration amplitude of the blade tip vibration to filter out data of abnormal blades, thereby realizing real-time monitoring of the wind turbine blade operating status, visualization of the induced draft fan operating point, and online real-time monitoring, analysis, and diagnosis of mechanical faults.

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