A monitoring device and method for wind turbine blade sweep tower

Abstract

The application discloses a kind of wind turbine blade sweeps tower monitoring device and method, the device includes fan master control, variable pitch driver and metal coating net arranged on blade;The measuring port of variable pitch driver is provided with reference resistance at both ends;Fan master control is connected with variable pitch driver;Line resistance and metal coating net are connected in series and then are connected in parallel with reference resistance;Metal coating net is composed of metal coating strip arranged in sequence, and both ends of metal coating net are electrically connected with pre-buried terminal stud in the internal cavity of blade;The blade body pre-buried terminal stud is used to connect metal coating net into variable pitch driver by wire during fan hoisting and debugging stage;Line resistance is the resistance of wire between blade pre-buried terminal stud and variable pitch driver.The application can realize accurate identification of sweep tower dangerous working condition and control unit to complete safe pitch, improve the accuracy of fault identification and unit safety.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of monitoring, in particular to a wind turbine blade tower-sweeping monitoring device and method. BACKGROUND

[0002] With the increase of wind turbine power level, wind turbine blades are getting longer. In some special working conditions, the blades will deform greatly, and the distance between the blades and the tower will be less than the safety threshold, which will lead to the tower-sweeping danger of the blades hitting the tower, endangering the safety of the wind turbine. Therefore, the wind turbine must be stopped immediately after the tower-sweeping event of the blades occurs, provided that the accurate and stable monitoring of the tower-sweeping condition is realized.

[0003] For the monitoring of the blade tower-sweeping mentioned in the background, the current tower-sweeping monitoring method mainly relies on laser radar or other complex sensors to monitor the clearance, that is, to detect the distance between the blades and the tower and to warn of the possible tower-sweeping situation. These control strategies are realized by indirect measurement and are greatly affected by internal and external factors such as sensor accuracy, installation, weather, and control strategy. In actual application, there are cases where the tower-sweeping of the blades cannot be monitored, and false triggering and misjudgment of the tower-sweeping state are prone to occur, which leads to unnecessary shutdown of the wind turbine and loss of wind turbine power generation. The existing monitoring scheme is high in cost and cannot accurately and economically protect the safety of the wind turbine. SUMMARY

[0004] In view of this, the present application provides a wind turbine blade tower-sweeping monitoring device and method, which realizes accurate identification of the tower-sweeping dangerous working condition.

[0005] The present application discloses a wind turbine blade tower-sweeping monitoring device, which comprises a wind turbine main control, a variable pitch drive and a metal coating net arranged on the blade. A reference resistance is arranged at the measuring port of the variable pitch drive. The wind turbine main control is connected with the variable pitch drive. The line resistance and the metal coating net are connected in series and then connected in parallel with the reference resistance. The metal coating net is composed of metal coating strips arranged in sequence, and the two ends of the metal coating net are electrically connected with the pre-buried terminal stud in the internal cavity of the blade, respectively. Each metal coating strip is electrically connected in parallel through the pre-buried wire. The pre-buried terminal stud of the blade body is used to connect the metal coating net to the variable pitch drive through the wire during the wind turbine hoisting and debugging stage. The line resistance is the resistance of the wire between the pre-buried terminal stud of the blade and the variable pitch drive.

[0006] Further, a group of metal coating nets are radially and parallelly sprayed between the leading edge of the blade body and the external protective coating. The resistance of each metal coating strip is R1, and each metal coating strip is electrically connected in parallel through the pre-buried wire. The resistance of the complete metal coating net is R ref , n is the total number of metal coating strips in the metal coating net; when the fan is hoisted and the variable pitch system is debugged, the resistance of the metal coating net is identified by the variable pitch driver, and the resistance reference value of the metal coating net after the unit debugging is completed is R ref .

[0007] Further, R2 is the real-time resistance of the metal coating net embedded in the blade calculated by the resistance conversion module in the variable pitch driver; R3 is the line resistance of the wire between the blade embedded terminal and the variable pitch driver; and R4 is a reference resistance, the resistance of which is much greater than the sum of R2 and R3.

[0008] Further, in the special working condition of tower scanning, the part of the blade tip with the metal coating collides with the tower barrel, the impact and friction generated by the collision will damage the coating of the contact part of the blade and the tower barrel, thereby changing the real-time resistance R2 of the metal coating net, and the variable pitch driver realizes the identification of the tower scanning condition by detecting the resistance value change of R2.

[0009] Further, the variable pitch driver judges the severity of the tower scanning accident by detecting the change of R2; when m metal coating strips are damaged in the tower scanning, if m=n, that is, all the metal coating strips are damaged, the resistance measured by the variable pitch driver is a constant value R4, if 0

[0010] The application further discloses a monitoring method for tower scanning of a wind turbine generator unit blade, which is suitable for the monitoring device of any one of the above.

[0011] Step 1: The measurement port of the variable pitch driver monitors the temperature value T of the detection circuit in real time;

[0012] Step 2: Convert the measured temperature value T into the total resistance R of the detection circuit; the detection circuit comprises a metal coating net and a reference resistance connected in series;

[0013] Step 3: Determine whether the total resistance R is equal to the reference resistance value R4, if not, go to step 4, otherwise, it represents that the detection circuit is open circuit, corresponding to a dangerous working condition; the dangerous working condition includes that the measurement line is disconnected or the blade tip is completely damaged, and go to step 6;

[0014] Step 4: Calculate the resistance value of the resistance R2 of the metal coating net;

[0015] Step 5: Compare the resistance value of the measured resistance R2 with the resistance value of the initial resistance R ref of the metal coating net, and compare the difference between the two with the allowed resistance change range AR ref .

[0016] Step 6: The pitch system triggers a tower-sweeping fault, the system state machine enters an emergency pitch-in mode safe shutdown, disconnects the pitch safety chain, and feeds back to the wind turbine main control system and SCADA through a hardware DO signal and a communication module;

[0017] Step 7: The pitch system triggers a blade tower-sweeping monitoring signal fault, and the operation and maintenance personnel board to check whether the detection circuit at the pitch driver port is normal;

[0018] Step 8: The operation and maintenance personnel board to check whether the blade is abnormal and perform maintenance.

[0019] Further, the step 1 comprises:

[0020] If the measured temperature value T is a first temperature value, it represents a port short circuit, and step 7 is entered;

[0021] If the measured temperature value T is a second temperature value, it represents a port open circuit, and step 7 is entered;

[0022] If the measured temperature value T is between the first temperature value and the second temperature value, step 2 is entered.

[0023] Further, in the step 2, the pitch controller internal control module calculates the corresponding total resistance R by using the following formula:

[0024] R = R0(1 + αT)

[0025] Wherein, R0 is the resistance value at 0 degrees Celsius, and α is the temperature coefficient of the metal material.

[0026] Further, the step 5 comprises:

[0027] If |R2-R ref |≤ΔR ref , it is considered that R2=R ref , representing that the blade is normal, R2 is the real-time resistance of the metal coating net embedded in the blade calculated by the control algorithm in the pitch driver, and step 1 is returned to;

[0028] If R2-R ref >ΔR ref , R2>R ref , representing that the metal coating net is damaged, and the blade has a tower-sweeping accident, at this time R1 is the resistance value of each metal coating strip, m is the number of damaged metal coating strips in the metal coating net, and n is the total number of metal coating strips in the metal coating net, and step 6 is entered.

[0029] Further, the step 8 comprises:

[0030] The blade is normal, the wind turbine is reset, the unit continues to operate, and step 1 is returned to;

[0031] Blade anomaly, tower scanning accident occurs, metal coating net is damaged, blade needs to be repaired and metal coating net is resprayed for subsequent monitoring.

[0032] With the above technical solutions, the application has the following advantages:

[0033] The application can monitor the metal coating net of the blade leading edge in real time through the detection circuit, without adding an additional measurement module, so that the unit can be accurately identified and controlled to complete safe pitch when the unit is in a blade tower scanning dangerous working condition, to avoid accidents such as blade fracture and even machine reversal, and to improve the accuracy of fault identification and the safety of the unit. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments described in the embodiments of the application, and other drawings can also be obtained by those skilled in the art according to these drawings.

[0035] Figure 1 is a flow chart of tower scanning monitoring of the pitch drive;

[0036] Figure 2 is a schematic view of the position of the blade tip and the tower drum when scanning;

[0037] Figure 3 is a schematic view of the position of the blade metal coating net;

[0038] Figure 4 is a normal metal coating net;

[0039] Figure 5 is a metal coating net after scanning;

[0040] Figure 6 is a metal coating net measurement structure. DETAILED DESCRIPTION

[0041] The application will be further described in combination with the drawings and embodiments, and the described embodiments are only some of the embodiments of the application, not all the embodiments. All other embodiments obtained by those skilled in the art should belong to the scope of protection of the embodiments of the application.

[0042] See Figure 1The embodiment of the wind turbine blade tower-sweeping monitoring device provided by the application comprises a fan master control, a variable pitch driver and a metal coating net arranged on the blade; a reference resistor is arranged at the measuring port of the variable pitch driver; the fan master control is connected with the variable pitch driver; the wire set and the metal coating net are connected in series and then connected in parallel with the reference resistor; the metal coating net is composed of metal coating strips arranged in sequence, and the two ends of the metal coating net are electrically connected with the pre-buried terminal stud in the internal cavity of the blade; each metal coating strip is electrically connected in parallel through the pre-buried wire; the blade body pre-buried terminal stud is used for connecting the metal coating net into the variable pitch driver through the wire during the hoisting and debugging stage of the fan; and the wire resistance is the resistance of the wire between the blade pre-buried terminal stud and the variable pitch driver.

[0043] The blade tower-sweeping is a working state between normal working and blade damage and fracture, which is mostly caused by that the deformation of the blade is too large to exceed the design range, and the contact with the fan tower is caused, and then the safety of the fan is affected. Since the current wind power blade is relatively more slender, the contact between the blade tip and the tower is relatively slight at the initial tower-sweeping, the influence on the fan is small, the fan cannot be stopped by triggering the vibration protection measure, and irreversible damage will be caused to the blade and the fan after multiple tower-sweeping.

[0044] Since the wind power blade is slender, the cavity at the blade tip is small, and the relative deformation is small, therefore, the strain gauge cannot completely and accurately detect the occurrence of the tower-sweeping event. Figure 2 As shown in the figure, when the blade tower-sweeping occurs, the leading edge of the blade tip first contacts the tower and changes the structure of the blade tip.

[0045] The application provides a blade tower-sweeping monitoring method and a measuring circuit structure, and the specific blade structure is shown in the figure. Figure 3 After the production of the blade body is completed, a group of metal coating nets are sprayed in the radial direction between the leading edge of the blade body and the external protective coating, the metal coating net is electrically connected with the pre-buried terminal stud in the internal cavity of the blade, the blade body pre-buried terminal stud is used for connecting the metal coating net into the variable pitch driver through the wire during the hoisting and debugging stage of the fan, and the detection circuit connection diagram is shown in the figure. Figure 6 The CANopen (CAN bus) communication between the master control system and the variable pitch driver needs to be realized through a communication module, the control module is used for some calculations in the variable pitch driver, and the resistance conversion module is used for converting the temperature T into the resistance R2.

[0046] The complete metal coating net is composed of n slender metal coating strips, as shown in the figure. Figure 4 The resistance of each independent metal coating strip is R1, the metal coating strips are electrically connected in parallel through the pre-buried wire, and the reference resistance of the metal coating net is R ref , R refThe resistance tolerance is ±0.06%. When the fan is hoisted and the variable pitch system is debugged, the resistance of the metal coating net is identified by the variable pitch driver, and the R ref is measured after the unit debugging is completed, and is stored in the variable pitch driver parameter table.

[0047] R2 is the real-time resistance of the blade embedded metal coating net calculated by the resistance conversion module in the variable pitch driver; R3 is the line resistance between the blade embedded terminal post and the variable pitch driver in the variable pitch system, since the current fan blade is as long as hundreds of meters, the line resistance of hundreds of meters cannot be ignored; R4 is a reference resistance, whose resistance is much larger than R2+R3, R4 in the circuit has two functions, one is that since R4 and R2+R3 are connected in parallel, when R2 changes, the total resistance measured by the variable pitch driver changes more obviously, improving the sensitivity of the measurement circuit, the second is that when the detection circuit is disconnected, the data measured by the variable pitch driver is a specific value, i.e. the resistance of R4, which meets the input range requirement of the variable pitch driver measurement port and can represent special working conditions such as line disconnection or blade fracture.

[0048] The metal coating material includes but is not limited to copper and aluminum, and further other materials can be added to the metal coating material, which does not reduce the conductivity of the material, changes the temperature coefficient of the material, adjusts R1, and further adjusts the resistance of R2; to ensure that the position where the tip may contact the tower is coated with metal, n≥20 is set, so that the metal coating has a certain area; the size of each independent metal coating strip can be an elongated rectangle of 200 cm×2 cm, and the thickness is d, so that the metal coating strip is more likely to change or be damaged in structure when the tip contacts the tower.

[0049] In the special working condition of tower collision, the part of the tip with metal coating collides with the tower, which does not damage the blade body when the collision is slight, but due to the thin and long structure of each independent metal coating strip in the metal coating net, the impact and friction generated by the collision can easily damage the coating of the contact part, change the real-time resistance R2 of the metal coating net, and the variable pitch driver detects the change of the resistance to realize the recognition of the tower collision condition. The structure of the metal coating net after the tower collision is shown as Figure 5 .

[0050] The variable pitch driver judges the severity of the tower collision accident by detecting the change of R2; when m(m≤n) metal coating strips are damaged during the tower collision, if m=n, i.e. all the metal coating strips are damaged, the resistance measured by the variable pitch driver is a constant value R4, if 0

[0051] The measurement circuit is connected by using a temperature (PT100) measurement port of the pitch drive, and a control algorithm is designed, the measurement port of the pitch drive and related parameters can be designed according to a platinum resistance, therefore, the measured temperature value needs to be inversely converted into the resistance value of the metal coating net R2, the change of R2 is detected in real time, different control strategies are switched to protect the unit. Specifically, the application provides a wind turbine blade tower scanning monitoring method, which is suitable for the wind turbine blade tower scanning monitoring device described in the above embodiment, and comprises the following steps:

[0052] Step 1: The temperature value T of the temperature measurement port of the pitch drive is monitored in real time.

[0053] In step 1, A is-55℃ and B is 175℃.

[0054] Step 1.1: If the measured temperature value T is A, it represents that the port is short-circuited, and step 7 is entered.

[0055] Step 1.2: If the measured temperature value T is B, it represents that the port is open-circuited, and step 7 is entered.

[0056] Step 1.3: If the measured temperature value T is between A and B, step 2 is entered.

[0057] Step 2: The measured temperature value T is converted into the total resistance R of the detection circuit.

[0058] In step 2, a specific conversion method and several characteristic values are involved; the internal control module of the pitch controller calculates the corresponding total resistance R by using the following formula:

[0059] R=R0(1+αT)

[0060] Wherein, R0 is the resistance value at 0℃, which is set to 100; α is the temperature coefficient of the metal material, which is set to 0.00385, and different temperature coefficient values can be set according to the actual metal coating material.

[0061] Step 3: Whether R is equal to the reference resistance R4 is judged, if not, step 4 is entered, otherwise, it represents that the detection circuit is open-circuited, corresponding to the disconnection of the measurement circuit or the complete damage of the blade tip, and step 6 is entered.

[0062] Step 4: The real-time resistance value R2 of the metal coating net is calculated, and step 5 is entered.

[0063]

[0064] Step 5: The measured R2 is compared with the initial value R ref of the metal coating net, and the difference is compared with ΔR ref .

[0065] Considering the measurement error and resistance tolerance, set the allowable resistance variation range ΔR ref , ΔR ref ≤ 0.06% R ref ; for example, ΔR ref is not greater than 0.5Ω for platinum resistance.

[0066] Step 5.1: If |R2-R ref |≤ ΔR ref , then R2=R ref , indicating that the blade is normal, and jumping back to step 1.

[0067] Step 5.2: If R2-R ref > ΔR ref , then R2>R ref , indicating that the metal coating net is damaged, and the blade has a tower-scanning accident, at which time Step 6 is entered.

[0068] Step 6: The pitch system triggers a tower-scanning fault, the system state machine enters an emergency pitch collection mode for safe shutdown, disconnects the pitch safety chain, and feeds back to the wind turbine main control system and SCADA (supervisory control and data acquisition system) through a hardware 24V DO (24V direct current digital output) signal and a communication module.

[0069] The communication mode between the pitch system and the main control system includes but is not limited to CANopen, RS485 (serial communication standard), EtherCAT (Ethernet for control automation technology), Modbus (serial communication protocol), etc.

[0070] Step 7: The pitch system triggers a blade tower-scanning monitoring signal fault, and the operation and maintenance personnel board to check whether the detection circuit at the pitch drive port is normal.

[0071] Step 8: The operation and maintenance personnel board to check whether the blade is abnormal and perform maintenance;

[0072] Step 8.1: The blade is normal, the wind turbine is reset, the unit continues to operate, and returns to step 1.

[0073] Step 8.2: The blade is abnormal, a tower-scanning accident occurs, and the metal coating net is damaged, so the blade needs to be repaired and resprayed with a metal coating net for subsequent monitoring.

[0074] It should be pointed out finally that the above embodiments are only used to illustrate the technical solutions of the present application but not to limit it. Although the present application has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that the specific embodiments of the present application can be modified or replaced equivalently without departing from the spirit and scope of the present application, and any modification or equivalent replacement without departing from the spirit and scope of the present application should be covered in the protection scope of the claims of the present application.

Claims

1. A monitoring device for wind turbine blade sweeping, characterized in that, It includes the main control unit of the wind turbine, the pitch driver, and a metal-coated mesh installed on the blades; a reference resistor is installed at both ends of the measurement port of the pitch driver; the main control unit of the wind turbine is connected to the pitch driver; the line resistor and the metal-coated mesh are connected in series and then connected in parallel with the reference resistor; the metal-coated mesh is composed of metal coating strips arranged in sequence, and both ends of the metal-coated mesh are electrically connected to the pre-embedded terminals in the internal cavity of the blade; the pre-embedded terminals on the blade body are used to connect the metal-coated mesh to the pitch driver through wires during the wind turbine hoisting and commissioning stage; Line resistance is the resistance of the wire between the blade's embedded terminal and the pitch drive. R2 is the real-time resistance of the metal-coated mesh embedded in the blade, calculated by the resistance conversion module in the pitch drive; R3 is the line resistance of the wire between the blade embedded terminal and the pitch drive; R4 is the reference resistor, whose resistance is much greater than the sum of R2 and R3. When the special working condition of tower sweeping occurs, the part with metal coating on the blade tip collides with the tower. The impact and friction generated by the collision will damage the coating of the part of the blade in contact with the tower, thereby changing the real-time resistance R2 of the metal coating mesh. The pitch drive identifies the tower sweeping working condition by detecting the change in the resistance value of R2. The pitch actuator determines the severity of the tower sweeping accident by detecting changes in the resistance of R2. During tower sweeping, if m metal coating strips are damaged, and m = n (all metal coating strips are damaged), the pitch actuator measures a constant value R4. If 0 < m < n, some metal coating strips are damaged, and the current real-time resistance of the metal coating mesh is [value missing].

2. The monitoring device for wind turbine blade sweeping according to claim 1, characterized in that, A set of metallic coating mesh is sprayed radially parallel between the leading edge of the blade body and the external protective coating; the resistance of each metallic coating strip is R1, and each metallic coating strip is electrically connected in parallel by pre-embedded wires. The resistance of the complete metallic coating mesh is R. ref , n represents the total number of metal-coated strips in the metal-coated mesh; during the installation and commissioning of the pitch control system of the wind turbine, the resistance of the metal-coated mesh is identified through the pitch drive, and the reference value of the resistance of the metal-coated mesh after the unit commissioning is measured to be R. ref .

3. A method for monitoring the sweeping of wind turbine blades, applicable to the monitoring device for sweeping of wind turbine blades as described in claim 1 or 2, characterized in that, include: Step 1: The measurement port of the pitch drive monitors the temperature value T of the detection circuit in real time; Step 2: Convert the measured temperature value T into the total resistance R of the detection circuit; the detection circuit includes a metal-coated mesh and a reference resistor connected in series; Step 3: Determine if the total resistance R is equal to the reference resistance R4. If not, proceed to step 4. Otherwise, it indicates that the detection circuit is open, which corresponds to a dangerous condition. Dangerous conditions include a disconnected measurement circuit or complete damage to the blade tip. Proceed to step 6. Step 4: Calculate the resistance value of R2 of the metal-coated mesh; Step 5: Compare the measured resistance value of R2 with the reference resistance R of the metal-coated mesh. ref The resistance values ​​are compared, and the difference between the two is then compared with the allowable resistance variation range ΔR. ref Compare; Step 6: The pitch system triggers a tower sweeping fault, the system state machine enters emergency pitch recovery mode for safe shutdown, disconnects the pitch safety chain, and feeds back to the wind turbine main control system and SCADA through hardware DO signals and communication modules; Step 7: The pitch system triggers a fault in the blade sweep tower monitoring signal. Maintenance personnel board the aircraft to check whether the detection circuit at the pitch driver port is normal. Step 8: Maintenance personnel board the aircraft to check for any abnormalities in the blades and perform repairs.

4. The monitoring method for wind turbine blade sweeping according to claim 3, characterized in that, Step 1 includes: If the measured temperature value T is the first temperature value, it means that the port is short-circuited, and proceed to step 7; If the measured temperature value T is the second temperature value, it means that the port is open-circuited, and proceed to step 7; If the measured temperature value T is between the first temperature value and the second temperature value, proceed to step 2.

5. The monitoring method for wind turbine blade sweeping according to claim 3, characterized in that, In step 2, the internal control module of the pitch controller calculates the corresponding total resistance R using the following formula: R = R0(1 + αT) Where R0 is the resistance value at 0 degrees Celsius, and α is the temperature coefficient of the metallic material.

6. The monitoring method for wind turbine blade sweeping according to claim 3, characterized in that, Step 5 includes: If |R²-R ref |≤ΔR ref Then we consider R2 = R ref This indicates that the blade is normal. R2 is the real-time resistance of the metal coating mesh embedded in the blade, calculated by the control algorithm in the pitch drive. Jump back to step 1. If R2-R ref >ΔR ref Then R2 > R ref This indicates that the metal coating mesh has been damaged, and the blades have experienced a tower-sweeping accident. R1 is the resistance value of each metal-coated strip, m is the number of metal-coated strips in the metal-coated mesh that are damaged, and n is the total number of metal-coated strips in the metal-coated mesh. Proceed to step 6.

7. The monitoring method for wind turbine blade sweeping according to claim 3, characterized in that, Step 8 includes: If the blades are normal, the fan is reset, the unit continues to run, and the process returns to step 1. The blades malfunctioned, causing a tower sweeping accident. The metal coating mesh was damaged, and the blades need to be repaired and the metal coating mesh reapplied for subsequent monitoring.

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