Monitoring device and method for tower sweeping of blades of wind generating set

Abstract

The invention discloses a monitoring device and method for tower sweeping of blades of a wind generating set. The device comprises a fan master controller, a variable-pitch driver and a metal coating net arranged on the blades. Reference resistors are arranged at two ends of a measuring port of the variable-pitch driver; the fan master controller is connected with the variable pitch driver; the wire resistor and the metal coating net are connected in series and then are 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 embedded binding posts in the cavity in the blade respectively. Binding posts are embedded in the blade body and used for connecting the metal coating net into a variable-pitch driver through wires in the fan hoisting and debugging stage. And the wire resistor is a resistor of a wire between the blade pre-embedded binding post and the variable pitch driver. According to the method, the dangerous working condition of tower sweeping can be accurately recognized, the unit is controlled to complete safe propeller collection, and the accuracy of fault recognition and the safety of the unit are improved.

Description

Technical Field

[0001] The present invention relates to the field of monitoring technology, and in particular to a monitoring device and method for blade sweeping tower of a wind turbine generator set. Background Art

[0002] As the power level of wind turbines increases, wind turbine blades become longer and longer. Under certain special conditions, the blades will deform significantly and the distance between them and the tower will be less than the safety threshold, resulting in a dangerous situation where the blades hit the tower and sweep the tower, endangering the safety of the wind turbine. Therefore, the unit must be stopped immediately after a blade sweeps the tower, provided that accurate and stable monitoring of the tower sweep condition can be achieved.

[0003] Regarding the monitoring of blade tower sweep mentioned in the background technology, the current tower sweep monitoring method mainly relies on lidar or other complex sensors to monitor clearance, that is, to detect the distance between the blade and the tower, and to warn of possible tower sweep. These control strategies are all implemented through indirect measurement, which is greatly affected by internal and external factors such as sensor accuracy, installation, weather, and control strategy. In actual applications, there is a situation where blade tower sweep cannot be monitored, and false triggering is prone to occur, which leads to misjudgment of the tower sweep status, causing unnecessary shutdown of the wind turbine and resulting in loss of wind turbine power generation. The existing monitoring solutions are costly and cannot accurately and economically protect the safety of the unit. Summary of the invention

[0004] In view of this, the present invention provides a monitoring device and method for blade sweeping of a wind turbine generator set, which realizes accurate identification of dangerous working conditions of tower sweeping.

[0005] The invention discloses a monitoring device for blade tower sweeping of a wind turbine generator set, which comprises a wind turbine main control, a pitch drive and a metal coating net arranged on the blade; reference resistors are arranged at both ends of a measuring port of the pitch drive; the wind turbine main control is connected to the pitch drive; a 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 sequentially arranged metal coating strips, both ends of the metal coating net are respectively electrically connected to pre-buried terminals in a cavity inside the blade, and each metal coating strip is electrically connected in parallel through pre-buried wires; the pre-buried terminals of the blade body are used to connect the metal coating net to the pitch drive through wires during the wind turbine hoisting and debugging stage; the line resistance is the resistance of the wire between the pre-buried terminals of the blade and the pitch drive.

[0006] Furthermore, a group of metal coating meshes are sprayed radially and parallelly between the leading edge of the blade body and the external protective coating; the resistance of each metal coating strip is R1, each metal coating strip is electrically connected in parallel by a pre-buried wire, and the resistance of the complete metal coating mesh is R ref , n is the total number of metal coating strips in the metal coating mesh; when the wind turbine is hoisted and the pitch system is debugged, the resistance of the metal coating mesh is identified by the pitch drive, and the resistance reference value of the metal coating mesh after the unit is debugged is R ref .

[0007] Furthermore, R2 is the real-time resistance of the metal coating 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, and its resistance value is much larger than the sum of R2 and R3.

[0008] Furthermore, when the special working condition of tower sweeping occurs, the part of the blade tip with metal coating collides with the tower. The impact and friction generated by the collision destroy the coating of the contact part between the blade and the tower, thereby changing the real-time resistance R2 of the metal coating network. The pitch drive recognizes the tower sweeping condition by detecting the change in the resistance value of resistor R2.

[0009] Furthermore, the pitch drive determines the severity of the tower sweeping accident by detecting the change in the resistance value of R2; when sweeping the tower, m metal coating strips are damaged. If m=n, that is, all the metal coating strips are damaged, then the resistance measured by the pitch drive is a fixed value R4. If 0<m<n, the metal coating strips are partially damaged, and the current real-time resistance of the metal coating network is

[0010] The present invention also discloses a method for monitoring the blade sweeping tower of a wind turbine generator set, which is applicable to any of the above-mentioned monitoring devices for the blade sweeping tower of a wind turbine generator set, and comprises:

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

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

[0013] Step 3: Determine whether the total resistance R is equal to the reference resistance value R4. If not, proceed to step 4. Otherwise, it means that the detection circuit is open, corresponding to a dangerous working condition. Dangerous working conditions include disconnection of the measurement line or complete damage of the blade tip, and proceed to step 6.

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

[0015] Step 5: Compare the measured resistance value of resistor R2 with the initial resistance R of the metal coating mesh. ref The difference between the two is then compared with the allowable resistance variation range ΔR ref Compare;

[0016] Step 6: The pitch system triggers a tower sweep fault, the system state machine enters the emergency pitch retraction mode and safely shuts down, disconnects the pitch safety chain, and feeds back to the wind turbine master control system and SCADA through the hardware DO signal and communication module;

[0017] Step 7: The pitch system triggers a blade sweep tower monitoring signal failure, and the operation and maintenance personnel board the aircraft to check whether the detection circuit of the pitch drive port is normal;

[0018] Step 8: The operation and maintenance personnel go on board to check whether the blades are abnormal and perform repairs.

[0019] Furthermore, the step 1 comprises:

[0020] If the measured temperature value T is the first temperature value, it means that the port is short-circuited, and the process goes to step 7;

[0021] If the measured temperature value T is the second temperature value, it means that the port is open circuit, and the process goes to step 7;

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

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

[0024] R=R0(1+αT)

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

[0026] Furthermore, the step 5 comprises:

[0027] If |R2-R ref |≤ΔR ref , then we think that R2=R ref , indicating 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, and jumps back to step 1;

[0028] If R2-R ref >ΔR ref , then R2>R ref , which means that the metal coating mesh is damaged and the blade has a tower sweep accident. R1 is the resistance value of each metal coating strip, m is the number of damaged metal coating strips in the metal coating mesh, n is the total number of metal coating strips in the metal coating mesh, and the process goes to step 6.

[0029] Further, the step 8 comprises:

[0030] The blades are normal, the fan is reset, the unit continues to run, and returns to step 1;

[0031] The blades are abnormal, a tower sweep accident occurs, the metal coating mesh is damaged, and the blades need to be repaired and re-sprayed with the metal coating mesh for subsequent monitoring.

[0032] Due to the adoption of the above technical solution, the present invention has the following advantages:

[0033] The present application can monitor the metal coating mesh on the leading edge of the blade in real time through the detection circuit, without adding additional measurement modules. It can accurately identify and control the unit to complete safe retraction of the blades when the unit encounters a dangerous condition of blade sweeping the tower, avoiding accidents such as blade breakage or even overturning, thereby improving the accuracy of fault identification and the safety of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the embodiments of the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0035] Figure 1 It is the flow chart of blade sweeping tower monitoring by the pitch drive;

[0036] Figure 2 This is a schematic diagram of the position of the blade tip and the tower during tower sweeping;

[0037] Figure 3 It is a schematic diagram of the location of the metal coating mesh of the blade;

[0038] Figure 4 It is a normal metal coated mesh;

[0039] Figure 5 It is the metal-coated mesh behind the sweep tower;

[0040] Figure 6 This is a diagram of the measurement structure of a metal coated mesh. DETAILED DESCRIPTION

[0041] The present invention is further described in conjunction with the accompanying drawings and embodiments, and the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by ordinary technicians in this field should fall within the scope of protection of the embodiments of the present invention.

[0042] See also Figure 1The present invention provides an embodiment of a monitoring device for blade sweeping tower of a wind turbine generator set, which includes a wind turbine main control, a pitch drive and a metal coating net arranged on the blade; reference resistors are arranged at both ends of the measuring port of the pitch drive; the wind turbine main control is connected to the pitch drive; the wire group 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 respectively electrically connected to the embedded terminals in the internal cavity of the blade; each metal coating strip is electrically connected in parallel through the embedded wires; the embedded terminals of the blade body are used to connect the metal coating net to the pitch drive through the wires during the wind turbine hoisting and debugging stage; the wire resistance is the resistance of the wire between the embedded terminals of the blade and the pitch drive.

[0043] Blade sweeping is a working state between normal operation and blade damage and fracture. It is mostly caused by the blade deformation being too large beyond the design range, and coming into contact with the wind turbine tower, thus affecting the safety of the wind turbine. As current wind turbine blades are relatively slender, the contact between the blade tip and the tower is relatively slight at the initial stage of sweeping, which has little impact on the wind turbine and cannot be shut down by triggering protection measures such as wind turbine vibration. After multiple sweeps, irreversible damage will be caused to the blades and wind turbine.

[0044] Due to the slender structure of wind turbine blades, there are fewer cavities at the blade tip and the relative deformation is very small. Therefore, the method of using strain gauges to measure blade deformation cannot completely and accurately detect the occurrence of tower sweep events. Figure 2 As shown in FIG. 1 , when a blade sweeps the tower, the leading edge of the blade tip first contacts the tower and changes the structure of the blade tip.

[0045] This application proposes a blade sweeping tower monitoring method and a measurement circuit structure. The specific blade structure is as follows: Figure 3 After the blade body is produced, a group of metal coating meshes are sprayed radially and parallelly between the leading edge of the blade body and the external protective coating. The metal coating meshes are electrically connected to the embedded terminals in the internal cavity of the blade. The embedded terminals of the blade body are used to connect the metal coating meshes to the pitch drive through wires during the hoisting and debugging stage of the wind turbine. The detection circuit connection diagram is shown in Figure 6 The CANopen (CAN bus) communication between the main control system and the pitch drive needs to be realized through the communication module. The control module is required for some calculations inside the pitch drive. The resistance conversion module converts the temperature T into resistance R2.

[0046] The complete metal coating network consists of n slender metal coating strips, such as Figure 4 As shown. The resistance of each independent metal coating strip is R1, and each metal coating strip is electrically connected in parallel by a pre-buried wire. The reference resistance of the metal coating network is R ref , R refThe resistance tolerance is ±0.06%. When the wind turbine is installed and the pitch system is debugged, the resistance of the metal coating mesh is identified by the pitch drive, and the R ref , and stored in the pitch drive parameter table.

[0047] R2 is the real-time resistance of the metal coating mesh embedded in the blades calculated by the resistance conversion module in the pitch drive; R3 is the line resistance of the wire between the pre-embedded terminal of the blades and the pitch drive in the pitch system. Since the current wind turbine blades are hundreds of meters long, the line resistance of hundreds of meters cannot be ignored; R4 is the reference resistor, and its resistance is much larger than R2+R3. R4 in the circuit has two functions. First, since R4 and R2+R3 are connected in parallel, the total resistance measured by the pitch drive changes more obviously when R2 changes, thereby improving the sensitivity of the measurement circuit. Second, when the detection circuit is disconnected, the data measured by the pitch drive is a specific value, namely the resistance value of R4, which meets the input range requirements of the pitch drive measurement port and can characterize special working conditions such as line disconnection or blade breakage.

[0048] The metal coating material includes but is not limited to copper and aluminum. Further, other materials may be added to the metal coating material to change the temperature coefficient of the material without reducing the conductivity of the material, thereby adjusting R1 and then adjusting the resistance value of R2. In order to ensure that the positions where the blade tip and the tower may contact are all 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 a slender rectangle of 200 cm × 2 cm with a thickness of d, so that the structure of the metal coating strip is more easily changed or damaged when the blade tip contacts the tower.

[0049] When the special working condition of tower sweeping occurs, the part with metal coating on the blade tip collides with the tower. When the collision is minor, it will not damage the blade body. However, due to the thin and slender structure of each independent metal coating strip in the metal coating net, the impact and friction generated by the collision can easily destroy the coating of the contact part, changing the real-time resistance R2 of the metal coating net. The pitch drive recognizes the tower sweeping working condition by detecting the change of resistance. The structure of the metal coating net after tower sweeping is shown as follows Figure 5 shown.

[0050] The pitch drive determines the severity of the tower sweeping accident by detecting the change in the resistance value of R2; when sweeping the tower, m (m≤n) metal coating strips are damaged. If m=n, that is, all the metal coating strips are damaged, the resistance measured by the pitch drive is a fixed value R4. If 0<m<n, the metal coating strips are partially damaged, and the current real-time resistance of the metal coating network is

[0051] In the variable pitch drive, the temperature (PT100) measurement port provided by the variable pitch drive is used to connect the measurement circuit, and the control algorithm is designed. The measurement port and related parameters of the variable pitch drive can be designed according to the platinum resistance. Therefore, the measured temperature value needs to be reversely converted to the resistance value of the metal coating mesh R2. By detecting the change of R2 in real time, different control strategies are switched to protect the unit. Specifically, the present invention provides a monitoring method for the blade sweeping tower of a wind turbine generator set, which is applicable to the monitoring device for the blade sweeping tower of a wind turbine generator set described in the above embodiment, and includes:

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

[0053] In step 1, A was set to -55°C and B was set to 175°C.

[0054] Step 1.1: If the measured temperature value T is A, it means that the port is short-circuited, and go to step 7;

[0055] Step 1.2: If the measured temperature value T is B, it means that the port is open circuit, and go to step 7;

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

[0057] Step 2: Convert the measured temperature value T to 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 using the following formula:

[0059] R=R0(1+αT)

[0060] Among them, R0 is the resistance value at 0 degrees Celsius, 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: Determine whether R is equal to the reference resistance R4. If not, proceed to step 4. Otherwise, it means that the detection circuit is open, corresponding to dangerous working conditions such as disconnection of the measurement line or complete damage of the blade tip, and proceed to step 6.

[0062] Step 4: Calculate the resistance value of the metal coating mesh's real-time resistance value R2, and proceed to step 5:

[0063]

[0064] Step 5: Compare the measured R2 with the initial value R of the metal coating mesh ref Compare the difference between the two and ΔR ref Compare.

[0065] Considering the measurement error and resistance tolerance, set the allowable resistance variation range ΔR ref , ΔR ref ≤0.06%R ref ; Taking platinum resistance as an example, ΔR ref Not more than 0.5Ω.

[0066] Step 5.1: If |R2-R ref |≤ΔR ref , then we think that R2=R ref , indicating that the blade is normal, jump back to step 1;

[0067] Step 5.2: If R2-R ref >ΔR ref , then R2>R ref , which means that the metal coating mesh is damaged and the blade has a tower sweep accident. Go to step 6;

[0068] Step 6: The pitch system triggers a tower sweep fault, the system state machine enters the emergency pitch retraction mode and shuts down safely, disconnects the pitch safety chain, and feeds back to the wind turbine main control system and SCADA (supervisory control and data acquisition system) through the hardware 24VDO (24V DC digital output) signal and the communication module.

[0069] The communication methods between the pitch control system and the main control system include but are not limited to CANopen, RS485 (serial communication standard), EtherCAT (Ethernet control automation technology), Modbus (serial communication protocol) and other protocols.

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

[0071] Step 8: The operation and maintenance personnel go on board to check whether the blades are abnormal and perform maintenance;

[0072] Step 8.1: The blades are normal, the fan is reset, the unit continues to run, and return to step 1.

[0073] Step 8.2: The blade is abnormal, a tower sweep accident occurs, the metal coating mesh is damaged, and the blade needs to be repaired and re-sprayed with the metal coating mesh for subsequent monitoring.

[0074] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A monitoring device for blade sweeping of a wind turbine generator set, characterized in that: It includes a wind turbine main control, a pitch drive and a metal coating net arranged on the blade; reference resistors are arranged at both ends of the measuring port of the pitch drive; the wind turbine main control is connected to the pitch drive; the line resistance 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 respectively electrically connected to the embedded terminals in the internal cavity of the blade; the embedded terminals of the blade body are used to connect the metal coating net to the pitch drive through wires during the hoisting and commissioning stage of the wind turbine; The line resistance is the resistance of the wire between the blade embedded terminal and the pitch drive.

2. The monitoring device for blade sweeping tower of a wind turbine generator set according to claim 1, characterized in that: A group of metal coating meshes are sprayed radially and parallelly 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 by a pre-buried wire. The resistance of the complete metal coating mesh is R ref , n is the total number of metal coating strips in the metal coating mesh; when the wind turbine is hoisted and the pitch system is debugged, the resistance of the metal coating mesh is identified by the pitch drive, and the resistance reference value of the metal coating mesh after the unit is debugged is R ref .

3. The monitoring device for blade sweeping tower of a wind turbine generator set according to claim 1, characterized in that: R2 is the real-time resistance of the metal coating 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, and its resistance value is much larger than the sum of R2 and R3.

4. The monitoring device for blade sweeping tower of a wind turbine generator set according to claim 1, characterized in that: When the special working condition of tower sweeping occurs, the part of the blade tip with metal coating collides with the tower. The impact and friction generated by the collision destroy the coating of the contact part between the blade and the tower, thereby changing the real-time resistance R2 of the metal coating network. The pitch drive recognizes the tower sweeping condition by detecting the change in the resistance value of resistor R2.

5. The monitoring device for blade sweeping tower of wind turbine generator set according to claim 1, characterized in that: The pitch drive determines the severity of the tower sweeping accident by detecting the change in the resistance of R2. When sweeping the tower, m metal coating strips are damaged. If m=n, that is, all the metal coating strips are damaged, the resistance measured by the pitch drive is a fixed value R4. If 0<m<n, the metal coating strips are partially damaged. The current real-time resistance of the metal coating network is 6. A method for monitoring the blade sweeping tower of a wind turbine generator set, applicable to the monitoring device for the blade sweeping tower of a wind turbine generator set according to any one of claims 1 to 5, 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 a total resistance R of a detection circuit; the detection circuit includes a metal coating mesh and a reference resistor connected in series; Step 3: Determine whether the total resistance R is equal to the reference resistance R4. If not, proceed to step 4. Otherwise, it means that the detection circuit is open, corresponding to a dangerous working condition. Dangerous working conditions include disconnection of the measurement line or complete damage of the blade tip, and proceed to step 6. Step 4: Calculate the resistance value of the resistor R2 of the metal coating mesh; Step 5: Compare the measured resistance value of resistor R2 with the metal coating mesh reference resistance R ref The difference between the two is then compared with the allowable resistance variation range ΔR ref Make comparisons; Step 6: The pitch system triggers a tower sweep fault, the system state machine enters the emergency pitch retraction mode and safely shuts down, disconnects the pitch safety chain, and feeds back to the wind turbine master control system and SCADA through the hardware DO signal and communication module; Step 7: The pitch system triggers a blade sweep tower monitoring signal failure, and the operation and maintenance personnel board the aircraft to check whether the detection circuit of the pitch drive port is normal; Step 8: The operation and maintenance personnel go on board to check whether the blades are abnormal and perform repairs.

7. The method for monitoring the blade sweeping of a wind turbine generator set according to claim 6, characterized in that: The step 1 comprises: If the measured temperature value T is the first temperature value, it means that the port is short-circuited, and the process goes to step 7; If the measured temperature value T is the second temperature value, it means that the port is open circuit, and the process goes to step 7; If the measured temperature value T is between the first temperature value and the second temperature value, proceed to step 2.

8. The method for monitoring the blade sweeping of a wind turbine generator set according to claim 6, 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) Among them, R0 is the resistance value at 0 degrees Celsius, and α is the temperature coefficient of the metal material.

9. The method for monitoring the blade sweeping of a wind turbine generator set according to claim 6, characterized in that: The step 5 comprises: If R2-R ref |≤ΔR ref , then we think that R2=R ref , indicating 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, and jumps back to step 1; If R2-R ref >ΔR ref , then R2>R ref , which means that the metal coating mesh is damaged and the blade has a tower sweep accident. R1 is the resistance value of each metal coating strip, m is the number of damaged metal coating strips in the metal coating mesh, n is the total number of metal coating strips in the metal coating mesh, and the process goes to step 6.

10. The method for monitoring the blade sweeping of a wind turbine generator set according to claim 6, characterized in that: The step 8 comprises: The blades are normal, the fan is reset, the unit continues to run, and returns to step 1; The blades are abnormal, a tower sweep accident occurs, the metal coating mesh is damaged, and the blades need to be repaired and re-sprayed with the metal coating mesh for subsequent monitoring.

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