Fan blade lightning arrester downlead conductivity monitoring system

Abstract

The invention discloses a conduction monitoring system for a downlead of a lightning arrester of a fan blade, and relates to the field of power equipment. The monitoring system comprises a light self-taking energy source, a discharge control circuit, a current sensor, a wireless collector and a terminal. The light energy self-taking and discharging control circuit is installed in a blade tip of a wind driven generator blade, and the current sensor and the wireless collector are placed in a fan hub. The light self-taking energy is used for generating electric energy; the discharge control circuit periodically discharges to the lightning arrester down lead; the current sensor monitors a current signal of the lightning arrester downlead; the wireless collector converts the current signal into a digital signal and sends the digital signal to a terminal; and the terminal judges the conduction condition of the downlead of the lightning arrester based on the received digital signal. According to the invention, the current signal of the down lead of the lightning arrester is collected through the current sensor and the wireless collector, the terminal judges the conductivity of the down lead of the lightning arrester based on the current, and the conductivity of the down lead of the lightning arrester can be monitored in real time.

Description

Technical Field

[0001] The present invention relates to the technical field of power equipment, and more specifically, to a monitoring system for the electrical conductivity of the downlead of a lightning arrester for a wind turbine blade. Background Art

[0002] With the continuous increase in the installed capacity and the number of units of wind turbines, the problem of lightning strike accidents on wind turbines has become increasingly prominent, seriously threatening the safe operation of wind farms. At present, the lightning protection system for wind turbine blades mainly adopts the IEC61400-24 technical standard. Lightning arresters are installed at the blade tip and the blade body, and then grounded through downleads. However, the observed data shows that there is a risk of lightning flashover failure in the lightning protection system for wind turbine blades. Therefore, in order to ensure the normal operation of the lightning arrester of the wind turbine and reduce the impact of lightning on the wind turbine system, it is necessary to regularly detect the electrical conductivity of the downlead of the lightning arrester of the wind turbine.

[0003] At present, the commonly used method for detecting the electrical conductivity of the downlead is the ohmmeter method. The resistance is measured with a multimeter at both ends of the downlead manually. Its principle is: if the downlead is intact without breaks, the resistance value shows extremely small; if there is a break, the resistance value shows infinity. However, although the principle of the ohmmeter method is simple, the detection efficiency is low. In addition, currently, a drone can also be equipped with a video camera, an electro-mechanical clamp and carry a test wire. On the ground, a remote controller is used to remotely control the drone to fly to the blade tip through the video image and the infrared ranging sensor, hover near the blade tip and remotely control the mechanical arm clamp to clamp the lightning arrester at the blade tip to achieve the conductivity measurement. This method avoids manual tower climbing operations and improves the detection efficiency to a certain extent. However, this method still requires manual operation, and due to the shaking of the blade, it is difficult to operate the mechanical arm clamp to clamp the lightning arrester, resulting in a still low detection efficiency. Summary of the Invention

[0004] In view of this, the present invention provides a monitoring system for the electrical conductivity of the downlead of a lightning arrester for a wind turbine blade, which is used to solve the problems of complex operation and low detection efficiency of the existing methods for detecting the electrical conductivity of the downlead.

[0005] To achieve the above object, the following solution is proposed: A monitoring system for the electrical conductivity of the downlead of a lightning arrester for a wind turbine blade, the monitoring system includes: a lightweight self-power supply, a discharge control circuit, a current sensor, a wireless collector and a terminal; The lightweight self-power supply and the discharge control circuit are installed inside the blade tip of the wind turbine, and the current sensor and the wireless collector are placed inside the wind turbine hub; The lightweight self-power supply generates electrical energy; The discharge control circuit discharges periodically to the downlead of the lightning arrester; The current sensor monitors the current signal of the downlead of the lightning arrester; The wireless collector converts the current signal obtained by the current sensor into a digital signal and sends it to the terminal; The terminal judges the conduction condition of the downlead of the lightning arrester based on the received digital signal.

[0006] Preferably, the structure of the light self-powered energy source includes: N power generation units, a housing and a housing cover, where N is a positive integer; After the power generation units are connected in series, they are output through the wire holes on the housing; The housing cover is used for encapsulation.

[0007] Preferably, the structure of the power generation unit includes: a power generation unit housing, an aluminum film and a rolling body; There are at least two grooves for installing the aluminum film in the power generation unit housing; The aluminum film is installed in the grooves of the power generation unit housing, and there is a gap between the aluminum films; The surface of the rolling body serves as a friction layer and rolls in the power generation unit housing.

[0008] Preferably, the process of generating electric energy by the light self-powered energy source includes: When the wind turbine works, the rolling body rolls back and forth in the power generation unit housing and contacts the aluminum film; When the rolling body rolls out of the current aluminum film, the electrons of the adjacent aluminum film are introduced into the current aluminum film, causing the light self-powered energy source to generate alternating current.

[0009] Preferably, the structure of the discharge control circuit includes: a rectifier bridge, an energy storage capacitor and a switch; The rectifier bridge converts the alternating current output by the light self-powered energy source into direct current and stores the direct current in the energy storage capacitor; The switch is used to control the energy storage capacitor to discharge to the downlead of the lightning arrester.

[0010] Preferably, the switch includes: a zener diode, a thyristor and a current limiting resistor; The process of the switch controlling the energy storage capacitor to discharge to the downlead of the lightning arrester includes: When the voltage of the energy storage capacitor reaches the reverse breakdown voltage of the zener diode, the zener diode conducts reversely and the thyristor conducts; The energy storage capacitor discharges to the downlead of the lightning arrester through the thyristor until the anode current and cathode current of the thyristor are less than the holding current, and then the discharge stops; The current limiting resistor is used to prevent the gate current of the thyristor from being too large.

[0011] Preferably, the process of the terminal judging the conduction condition of the downlead of the lightning arrester based on the received digital signal includes: If no current flows through the downlead of the lightning arrester, the downlead of the lightning arrester is faulty; If there is current flowing through the down-conductor of the lightning arrester, the resistance value is calculated based on the measured maximum current value. If the resistance value is greater than the detection standard, the down-conductor of the lightning arrester is faulty. If the resistance value is less than or equal to the detection standard, the down-conductor of the lightning arrester is conducting normally.

[0012] According to the specific embodiments provided by the present invention, the following technical effects are disclosed by the present invention: The lightning arrester down-conductor conductivity monitoring system provided by the present invention includes a lightweight self-power generation source, a discharge control circuit, a current sensor, a wireless collector, and a terminal. Among them, the lightweight self-power generation source and the discharge control circuit are installed inside the tip of the wind turbine blade, and the current sensor and the wireless collector are placed inside the wind turbine hub. The lightweight self-power generation source generates electrical energy; the discharge control circuit discharges periodically to the down-conductor of the lightning arrester; the current sensor monitors the current signal of the down-conductor of the lightning arrester; the wireless collector converts the current signal obtained by the current sensor into a digital signal and sends it to the terminal; the terminal judges the conductivity of the down-conductor of the lightning arrester based on the received digital signal. The present invention collects the current signal of the down-conductor of the lightning arrester through the current sensor and the wireless collector, and the terminal judges the conductivity of the down-conductor of the lightning arrester based on the current, so that the conductivity of the down-conductor of the lightning arrester can be monitored in real time, improving the detection efficiency of conductivity.

[0013] The lightning arrester down-conductor conductivity monitoring system of the present invention is powered internally by a lightweight self-power generation source, without external power supply, and can be maintained without maintenance for a long time.

[0014] The present invention directly installs the monitoring system inside the wind turbine blade, does not require installation during monitoring, and does not require manual operation, further improving the detection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the provided drawings.

[0016] Figure 1 It is a schematic installation diagram of a lightning arrester down-conductor conductivity monitoring system provided by an embodiment of the present invention; Figure 2 It is a schematic structural diagram of a lightweight self-power generation source provided by an embodiment of the present invention; Figure 3 It is a schematic internal structure diagram of a power generation unit provided by an embodiment of the present invention; Figure 4 Schematic diagram of the installation of a lightweight self - generating energy provided by an embodiment of the present invention; Figure 5 Schematic diagram of the power generation working principle of the power generation unit provided by an embodiment of the present invention.

[0017] Figure 6 Circuit diagram of a discharge control circuit provided by an embodiment of the present invention; Figure 7 An equivalent discharge circuit provided by an embodiment of the present invention. Specific embodiments

[0018] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0019] First, in combination with Figure 1 A lightning arrester down - conductor conductivity monitoring system for a wind turbine blade provided by an embodiment of the present invention will be introduced. As Figure 1 shown, the monitoring system includes: a lightweight self - generating energy 1, a discharge control circuit 2, a current sensor 3, a wireless collector 4, and a terminal 5; As Figure 1 shown, the lightweight self - generating energy 1 and the discharge control circuit 2 are installed inside the tip of the wind turbine blade 7. The current sensor 3 and the wireless collector 4 are placed inside the wind turbine hub 8, and a current sensor 3 is installed at the root of the lightning arrester down - conductor 6. The terminal 5 is located on the ground, and the grounding lead 9 of the monitoring system is led out from the wind turbine tower 10.

[0020] When the wind turbine is operating normally, the lightweight self - generating energy 1 generates electric energy. The electric energy generated by the lightweight self - generating energy 1 is periodically discharged to the lightning arrester down - conductor 6 through the discharge control circuit 2. When the lightning arrester down - conductor 6 is conducting normally, when the discharge control circuit 2 discharges to the lightning arrester down - conductor 6, the current sensor 3 can monitor the current signal of the lightning arrester down - conductor 6. The wireless collector 4 can collect the information collected by the current sensor 3, convert the current signal obtained by the current sensor 3 from an analog signal to a digital signal, and send it to the terminal 5. The current sensor 3 can monitor whether there is current flowing through the lightning arrester down - conductor 6 and can also monitor the magnitude of the flowing current. The wireless collector 4 includes an analog - to - digital converter and a wireless transmission module, etc.

[0021] The terminal 5 judges the conductivity of the lightning arrester down - conductor 6 based on the received digital signal.

[0022] Specifically, if no current flows through the down-conductor 6 of the lightning arrester, it is considered that the down-conductor 6 of the lightning arrester fails; if current flows through the down-conductor 6 of the lightning arrester, the resistance value is calculated based on the measured maximum current value; if the resistance value is greater than the detection standard, the down-conductor 6 of the lightning arrester fails; if the resistance value is less than or equal to the detection standard, the down-conductor 6 of the lightning arrester conducts normally.

[0023] The lightning arrester down-conductor conductivity monitoring system provided by the embodiment of the present invention includes a lightweight self-power supply, a discharge control circuit, a current sensor, a wireless collector, and a terminal. Among them, the lightweight self-power supply and the discharge control circuit are installed inside the tip of the wind turbine blade, and the current sensor and the wireless collector are placed inside the wind turbine hub. The lightweight self-power supply generates electric energy; the discharge control circuit discharges to the down-conductor of the lightning arrester periodically; the current sensor monitors the current signal of the down-conductor of the lightning arrester; the wireless collector converts the current signal obtained by the current sensor into a digital signal and sends it to the terminal; the terminal judges the conductivity of the down-conductor of the lightning arrester based on the received digital signal. By collecting the current signal of the down-conductor of the lightning arrester through the current sensor and the wireless collector, and judging the conductivity of the down-conductor of the lightning arrester based on the current by the terminal, the present invention can monitor the conductivity of the down-conductor of the lightning arrester in real time and improve the detection efficiency of the conductivity.

[0024] In the embodiment of the present invention, the monitoring system is directly installed inside the wind turbine blade, without the need for installation during monitoring and without manual operation, further improving the detection efficiency.

[0025] Next, the structure and working principle of the lightweight self-power supply 1 in the embodiment of the present invention will be introduced, as Figure 2 shown, the structure of the lightweight self-power supply 1 includes: N power generation units 13, a housing 11, and a housing cover 12. Among them, the lightweight self-power supply 1 includes at least one power generation unit 13, so N is a positive integer. The power generation unit 13 is provided with a wire hole as an output end. After the power generation units 13 are connected in series through wires, they are output through the wire hole on the housing 11, and the housing cover 12 is used for encapsulation to improve the durability of the lightweight self-power supply.

[0026] The internal structure of the power generation unit is as Figure 3As shown in the figure, the power generation unit includes a power generation unit housing 131, an aluminum film 133, and a rolling body 132. The material of the power generation unit housing 131 is polylactic acid, which serves as a support part. Inside the power generation unit housing 131, there are at least two grooves for installing the aluminum film 133, and wire holes are provided at the grooves as output terminals. The aluminum film 133 is installed in the groove of the power generation unit housing 131, and there is a certain interval between adjacent aluminum films 133. The non-adjacent aluminum films 133 are connected by wires. The aluminum film 133 simultaneously serves as a friction layer and an electrode. The surface of the rolling body 132 serves as a friction layer and rolls inside the power generation unit housing 131. The rolling body 132 is made of a material with different electronegativity from aluminum, such as polytetrafluoroethylene, polydimethylsiloxane (PDMS), polyvinyl chloride, or polyimide. In addition, the used aluminum film 132 can also be replaced with a copper film material. The length of the rolling body 132 is the same as the width of the aluminum film 133, and the diameter is slightly smaller than the inner diameter of the power generation unit housing 131. As Figure 4 shown in the figure, the lightweight self-powered power supply 1 is installed at the tip of the wind turbine blade 7. The power generation unit 13 is perpendicular to the blade in the radial direction, and the output terminal is connected to the discharge control circuit 2. The shape of the rolling body 132 can be cylindrical or spherical.

[0027] The working mode of the power generation unit 13 is the independent layer mode of the triboelectric nanogenerator. The working principle of the lightweight self-powered power supply 1 is as Figure 5 shown in the figure. When the wind turbine is working, under the action of gravity, the rolling body 132 rolls back and forth inside the power generation unit housing 131 and contacts the aluminum film. As Figure 5 shown in a of the figure, when the surface of the rolling body 132 contacts the aluminum film 133, since the material of the rolling body 132 has a stronger electronegativity than aluminum of the aluminum film 133, the surface of the rolling body 132 is negatively charged and the surface of the aluminum film 133 is positively charged. As Figure 5 shown in b of the figure, during the process of the rolling body 132 gradually rolling out of the current aluminum film 133, the contact area between the rolling body 132 and the current aluminum film 133 gradually decreases. Under the action of electrostatic induction, electrons from the next adjacent aluminum film 133 flow into the current aluminum film 133 through the wire. As Figure 5 shown in c of the figure, the rolling body 132 is in full contact with the next adjacent aluminum film 133, and at this time, the adjacent aluminum film 133 becomes the new current aluminum film 133. As Figure 5 shown in d of the figure, when the rolling body 132 continues to roll, the surface of the rolling body 132 gradually rolls out of the current aluminum film 133 again. Under the action of electrostatic induction, electrons in the next adjacent aluminum film 133 flow into the current aluminum film 133. Until as Figure 5 shown in e of the figure, the rolling body 132 is in full contact with the next aluminum film 133. Repeating this cycle will generate alternating current at both ends of the wire.

[0028] The internal power supply of the lightning conductor downlead conductivity monitoring system according to the embodiment of the present invention is powered by a lightweight self - power generation energy source, without external power supply, and can be maintained without maintenance for a long time. The lightweight self - power generation energy source of the embodiment of the present invention is light in weight, less than 50 g, and has little impact on the operating state of the fan.

[0029] Next, the embodiment of the present invention introduces the discharge control circuit structure, as Figure 6 shown. The discharge control circuit includes a rectifier bridge 21, an energy storage capacitor 22, and a switch 23. Among them, the switch includes a zener diode 231, a thyristor 232, and a current - limiting resistor 233. In addition, the switch 23 composed of the thyristor 232, the zener diode 231, and the current - limiting resistor 233 can also be replaced by a switching device such as a gas discharge tube.

[0030] The output end of the lightweight self - power generation energy source 1 is connected to the discharge control circuit 2, and the lightweight self - power generation energy source 1 outputs alternating current. First, the rectifier bridge 21 converts the alternating current output by the lightweight self - power generation energy source 1 into direct current, and stores the direct current in the energy storage capacitor 22. The switch 23 is used to control the energy storage capacitor 22 to discharge to the lightning conductor downlead 6.

[0031] The lightweight self - power generation energy source 1 continuously injects charges into the energy storage capacitor 22, causing the voltage in the energy storage capacitor 22 to continuously increase. When the voltage across the energy storage capacitor 22 reaches the reverse breakdown voltage of the zener diode 231, the zener diode 231 conducts in the reverse direction. At this time, the gate voltage of the thyristor 232 reaches the trigger threshold, and the thyristor 232 conducts. The energy storage capacitor 22 discharges to the lightning conductor downlead 6 through the thyristor 232. The function of the current - limiting resistor 233 is to prevent the gate current of the thyristor 232 from being too large and burning out the thyristor 232. During the discharge process of the energy storage capacitor 22 to the lightning conductor downlead 6, the anode current and cathode current of the thyristor 232 gradually decrease until they are less than the holding current of the thyristor 232, and then the thyristor turns off. Therefore, during the operation of the fan, the discharge control circuit 2 can discharge to the lightning conductor downlead 6 periodically.

[0032] During the discharge process, if the lightning conductor downlead 6 is conductive, there will be current flowing through the lightning conductor downlead 6, and the equivalent circuit during discharge is as Figure 7 shown. Assume that the reverse breakdown voltage of the zener diode 231 is U 0 , the resistance of the equivalent resistance 61 of the lightning conductor downlead is R, the capacitance of the energy storage capacitor 22 is C, and the time is t. When the energy storage capacitor 22 discharges, the equivalent circuit is equivalent to an RC discharge circuit, and the current flowing through both ends of R is I R , I R The expression is as follows: .

[0033] When t = 0, I RObtain the maximum value, and the maximum current is: .

[0034] Based on the relational expression of the equivalent circuit, the resistance of the downlead equivalent resistance 61 of the lightning arrester can be obtained.

[0035] The monitoring system of the embodiment of the present invention can measure the resistance value of the downlead of the lightning arrester while monitoring the conductivity.

[0036] Finally, it should also be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0037] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0038] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A wind turbine blade lightning arrester down conductor conductivity monitoring system, characterized in that: The monitoring system includes: lightweight self-collecting energy, discharge control circuit, current sensor, wireless collector and terminal; The lightweight self-powered energy and discharge control circuit are installed in the blade tip of the wind turbine blade, and the current sensor and wireless collector are placed in the wind turbine hub; Lightweight self-sourced energy to generate electricity; The discharge control circuit periodically discharges to the down conductor of the lightning arrester; The current sensor monitors the current signal of the lightning arrester down conductor; The wireless collector converts the current signal obtained by the current sensor into a digital signal and sends it to the terminal; The terminal determines the conduction status of the lightning device down conductor based on the received digital signal.

2. The wind turbine blade lightning arrester down conductor conductivity monitoring system according to claim 1, characterized in that: The structure of the lightweight self-energy source comprises: N power generation units, a shell and a shell cover, wherein N is a positive integer; After the power generation units are connected in series, the output is carried out through the wire holes on the shell; The housing cover is encapsulated.

3. The wind turbine blade lightning arrester down conductor continuity monitoring system according to claim 2 is characterized in that: The power generation unit structure comprises: a power generation unit shell, an aluminum film and a rolling body; There are at least two grooves in the power generation unit shell for installing aluminum films; The aluminum films are installed in the grooves of the power generation unit shell, and there are gaps between the aluminum films; The surface of the rolling element acts as a friction layer and rolls inside the power generation unit shell.

4. The wind turbine blade lightning arrester down conductor continuity monitoring system according to claim 3 is characterized in that: The process of generating electric energy from lightweight self-generated energy includes: When the wind turbine is working, the rolling element rolls back and forth in the power generation unit housing and contacts the aluminum film; When the rolling body rolls out of the current aluminum film, the electrons of the adjacent aluminum film are introduced into the current aluminum film, so that the lightweight self-energy generates alternating current.

5. The wind turbine blade lightning arrester down conductor continuity monitoring system according to claim 1, characterized in that: The discharge control circuit structure comprises: a rectifier bridge, an energy storage capacitor and a switch; The alternating current outputted by the lightweight self-sourced energy source is converted into direct current through a rectifier bridge, and the direct current is stored in an energy storage capacitor; The switch is used to control the energy storage capacitor to discharge the lightning device down conductor.

6. The wind turbine blade lightning arrester down conductor continuity monitoring system according to claim 5, characterized in that: The switch comprises: a voltage stabilizing diode, a thyristor and a current limiting resistor; The process of the switch controlling the energy storage capacitor to discharge the lightning device down conductor includes: When the voltage of the energy storage capacitor reaches the reverse breakdown voltage of the Zener diode, the Zener diode conducts in the reverse direction and the thyristor conducts; The energy storage capacitor discharges to the down conductor of the lightning arrester through the thyristor until the anode current and cathode current of the thyristor are less than the holding current, and then the discharge stops; Current limiting resistors are used to prevent excessive gate current in thyristors.

7. The wind turbine blade lightning arrester down conductor continuity monitoring system according to any one of claims 1 to 6, characterized in that: The process of the terminal judging the conduction status of the down conductor of the lightning arrester based on the received digital signal includes: If no current flows through the down conductor of the lightning arrester, the down conductor of the lightning arrester is faulty; If there is current flowing through the down conductor of the lightning arrester, the resistance value is calculated based on the maximum current value measured; If the resistance value is greater than the detection standard, the down conductor of the lightning arrester is faulty; If the resistance value is less than or equal to the detection standard, the lightning arrester down conductor is conducting normally.

Images