A lightning protection circuit of a wind power blade deicing control system and a test method

Abstract

The application provides a lightning protection circuit and a test method for a wind power blade deicing control system. The circuit comprises a temperature sensor, a lightning protection module, an optical coupling signal isolator, a PLC, a main CPU and a power supply assembly. The temperature sensor is arranged on the wind power blade. The first signal end, the second signal end and the shielded shell of the temperature sensor are connected to the lightning protection module. The lightning protection module is connected to the optical coupling signal isolator. The optical coupling signal isolator is connected to the PLC. The PLC is connected to the main CPU. The power supply from the wind power host is connected to the power supply assembly. The power supply assembly is connected to the PLC, the main CPU and the optical coupling signal isolator for power supply. The application can protect the PLC controller, the switching power supply and the CAN bus module in the control system from being grounded, so that the lightning current does not enter the equipment to cause damage when lightning strikes. The lightning protection method in the control system is distributed according to the lightning protection level, and the position of the lightning attraction point of the wind power blade deicing control system when lightning strikes is protected.

Description

Technical Field

[0001] This invention relates to the field of wind turbine blade de-icing technology, and in particular to a lightning protection circuit and test method for a wind turbine blade de-icing control system. Background Technology

[0002] Winter icing on wind turbine blades can easily cause turbine shutdowns or even damage. To address this issue, both domestic and international solutions involve installing de-icing devices and control systems on existing wind turbine units. However, during field operation, the de-icing device control system has repeatedly experienced lightning strike damage to its power supply, PLC, and sensors, leading to malfunctions and affecting the de-icing effect. Therefore, designing a lightning protection circuit and testing method for a wind turbine blade de-icing control system is essential. Summary of the Invention

[0003] In order to overcome the shortcomings of the prior art, the purpose of this invention is to provide a lightning protection circuit and test method for a wind turbine blade de-icing control system.

[0004] To achieve the above objectives, the present invention provides the following solution:

[0005] This invention provides a lightning protection circuit for a wind turbine blade de-icing control system, comprising: a temperature sensor, a lightning protection module, an optocoupler signal isolator, a PLC, a main CPU, and a power supply assembly. The temperature sensor is installed on the wind turbine blade. The first signal terminal, the second signal terminal, and the shielding shell of the temperature sensor are connected to the lightning protection module. The lightning protection module is connected to the optocoupler signal isolator. The optocoupler signal isolator is connected to the PLC. The PLC is connected to the main CPU. Power from the wind turbine is connected to the power supply assembly. The power supply assembly is connected to the PLC, the main CPU, and the optocoupler signal isolator for power supply.

[0006] Preferably, the power supply assembly includes a first 230V power surge protection device (SPD), a second 230V power surge protection device (SPD), a communication surge protection device (SPD), a first power module, a second power module, a third power module, a 24V repeater, and an opto-isolated power supply. Power from the wind turbine is connected to the power supply assembly and then to the first and second 230V power surge protection devices (SPDs). The first 230V power surge protection device (SPD) is connected to the first and second power modules. The second 230V power surge protection device (SPD) is connected to the third power module. The first power module is connected to the main CPU. The main CPU is connected to the PLC via the communication surge protection device (SPD). The second power module is connected to the PLC. The third power module is connected to the 24V repeater. The 24V repeater is connected to the opto-isolated power supply. The opto-isolated power supply and the PLC are connected to the optocoupler signal isolator. The lightning protection module is connected to the optocoupler signal isolator and grounded to allow lightning current to flow.

[0007] Preferably, the lightning protection circuit further includes an internal temperature controller and a box temperature sensor, with the power supply from the wind turbine connected to the internal temperature controller and the internal temperature controller connected to the box temperature sensor.

[0008] This invention also provides a test method for the lightning protection circuit of a wind turbine blade de-icing control system, comprising:

[0009] The 230 input point of the power supply from the wind turbine is used as the first lightning protection input point, the first signal terminal is used as the second lightning protection input point, and the shielding shell is used as the third lightning protection input point.

[0010] Overvoltage and overcurrent tests were conducted on the first lightning protection entry point;

[0011] Overvoltage and overcurrent tests were conducted on the second and third lightning protection entry points.

[0012] Preferably, overvoltage and overcurrent tests are performed on the first lightning protection entry point, specifically as follows:

[0013] Overvoltage and overcurrent tests were conducted on the first lightning protection entry point. The test waveforms were repeated 5 times each with positive and negative polarities, with an interval of not less than 3 minutes between each impact. The impact current waveform was 8 / 20μs and the impact voltage waveform was 1.2 / 50μs.

[0014] Preferably, overvoltage and overcurrent tests are performed on the second and third lightning protection entry points, specifically as follows:

[0015] Overvoltage and overcurrent tests were conducted on the second and third lightning protection entry points. The test waveforms were repeated 5 times each with positive and negative polarities, with an interval of not less than 3 minutes between each impact. The impact current waveform was 8 / 20μs and the impact voltage waveform was 1.2 / 50μs.

[0016] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0017] This invention provides a lightning protection circuit and testing method for a wind turbine blade de-icing control system. The circuit includes a temperature sensor, a lightning protection module, an optocoupler signal isolator, a PLC, a main CPU, and a power supply assembly. The method involves using the 230V input point from the wind turbine's power supply as the first lightning protection input point, the first signal terminal as the second lightning protection input point, and the shielding shell as the third lightning protection input point. Overvoltage and overcurrent tests are performed on the first lightning protection input point, and overvoltage and overcurrent tests are also performed on the second and third lightning protection input points. This invention can protect the PLC controller, switching power supply, CAN bus, and other modules in the control system from common grounding, preventing lightning current from entering the equipment and causing damage during lightning strikes. It also protects the lightning protection methods in the control system according to the lightning protection level and protects the location of the lightning strike point in the wind turbine blade de-icing control system. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the lightning protection circuit structure of the wind turbine blade de-icing control system provided in an embodiment of the present invention;

[0020] Figure 2 This is a detailed schematic diagram of the lightning protection circuit of the wind turbine blade de-icing control system provided in an embodiment of the present invention;

[0021] Figure 3 A schematic diagram of the rear side of a general-purpose surge protection circuit design;

[0022] Figure 4 Front view diagram of a general-purpose surge protection circuit design;

[0023] Figure 5 A schematic diagram of the test method for the lightning protection circuit of the wind turbine blade de-icing control system provided in an embodiment of the present invention. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] Figure 1 This is a schematic diagram of the lightning protection circuit structure of the wind turbine blade de-icing control system provided in an embodiment of the present invention. Figure 2 This is a detailed schematic diagram of the lightning protection circuit for the wind turbine blade de-icing control system provided in an embodiment of the present invention, as shown below. Figure 1 and Figure 2 As shown, the present invention provides a lightning protection circuit for a wind turbine blade de-icing control system, comprising: a temperature sensor, a lightning protection module, an optocoupler signal isolator, a PLC, a main CPU, and a power supply assembly. The temperature sensor is installed on the wind turbine blade. The first signal terminal, the second signal terminal, and the shielding shell of the temperature sensor are connected to the lightning protection module. The lightning protection module is connected to the optocoupler signal isolator. The optocoupler signal isolator is connected to the PLC. The PLC is connected to the main CPU. Power from the wind turbine is connected to the power supply assembly. The power supply assembly is connected to the PLC, the main CPU, and the optocoupler signal isolator for power supply.

[0027] The power supply assembly includes a first 230V power surge protection device (SPD), a second 230V power surge protection device (SPD), a communication surge protection device (SPD), a first power module, a second power module, a third power module, a 24V repeater, and an opto-isolated power supply. Power from the wind turbine is connected to the power supply assembly and then to the first and second 230V power surge protection devices (SPDs). The first 230V power surge protection device (SPD) is connected to the first and second power modules. The second 230V power surge protection device (SPD) is connected to the third power module. The first power module is connected to the main CPU. The main CPU is connected to the PLC via the communication surge protection device (SPD). The second power module is connected to the PLC. The third power module is connected to the 24V repeater. The 24V repeater is connected to the opto-isolated power supply. The opto-isolated power supply and the PLC are connected to the optocoupler signal isolator. The lightning protection module is connected to the optocoupler signal isolator and grounded to allow lightning current to flow. The opto-isolated power supply is a module specifically designed for the optocoupler to prevent power interference from affecting its operation.

[0028] The ground wires PE of the first 230V power surge SPD, the second 230V power surge SPD, the first power module, the second power module, the third power module, the 24V repeater, the optocoupler signal isolator and the lightning protection module are grounded, while the ground wires PE of the PLC and the main CPU are left floating.

[0029] The lightning protection circuit also includes an internal temperature controller and a box temperature sensor. The power supply from the wind turbine is connected to the internal temperature controller, and the internal temperature controller is connected to the box temperature sensor.

[0030] Temperature sensors are installed on the wind turbine blades to collect blade temperature data. The measured signal, input from the sensor, passes through a surge protection module and an optocoupler signal isolator before entering the PLC. The surge protection module prevents high-voltage lightning strike signals from the temperature sensor from damaging components in the main CPU. The temperature signal from the PLC is input to the main CPU via the CAN bus for calculation and judgment. The main CPU then transmits the judgment result back to the PLC, simultaneously controlling the 24V repeater and circuit breaker. Power is supplied from the wind turbine's main power supply, which is provided to the main CPU and PLC via a first, second, and third power supply module, respectively. The optocoupler signal isolator (used to isolate external signals through opto-isolation to prevent high-voltage, high-current signals from entering the CPU) contains an isolation transformer to isolate the primary and secondary voltages. The reference grounds GNDx at both ends of the isolation circuit and the CAN bus circuit are not common grounds; PE is the chassis protective ground, isolated from all reference grounds.

[0031] This application includes a first 230V power surge protection SPD, a second 230V power surge protection SPD, and a communication surge protection SPD, achieving low-voltage SPD configuration and transient overvoltage protection caused by surges. Surge energy absorption begins at the power supply system inlet, and a graded protection method is used to suppress transient overvoltages in stages. The first stage is located at the power distribution box and should use a voltage-limiting SPD with a power protection level <3kV and a current carrying capacity of 20-40kA (8 / 20μs), limiting the high-voltage lightning pulse to a low voltage level, achieving the protection level of general electrical equipment. The second stage is a voltage-limiting or composite SPD with a current carrying capacity of 10-20kA (8 / 20μs), further limiting the lightning current to a low level. Its voltage protection level varies depending on the type of SPD, generally between 1 and 1.8kV. The third stage is installed in series at the front end of the UPS power supply and at the front end of equipment requiring special protection. It is a fine-level protection SPD with a current capacity of 10-20kA (8 / 20μs) and an ultra-low output residual voltage, generally below 1kV, which can meet the fine protection requirements of the equipment.

[0032] This application adopts a general surge protection circuit design, such as Figure 3 and Figure 4As shown, the selected lightning impulse injection point is... Figure 4 General circuit design when the lightning injection point is in the middle. Figure 3 The lightning discharge circuit is a lightning current circuit. When the lightning current is 0.1kA, the control system operates normally. As the lightning current is increased according to lightning protection requirements, when the lightning current amplitude reaches 0.2-0.4kA, the test causes a trip. After power is restored, it is found that the PLC is damaged. The reason is that there is an electrical connection between the surge protector's PE port and the PLC's grounding port. Figure 3 Upon inspection, it was found that the PLC's GND (reference zero potential) was connected to the PE, causing lightning current to enter the PLC port and damage the PLC device. To verify the above results, the PLC communication CAN bus reference ground (GND) was separated from the chassis ground (PE), and the PLC casing was suspended and isolated from the grounding rail. Tests were conducted according to lightning protection requirements, and no problems were found.

[0033] like Figure 5 As shown, the present invention also provides a test method for the lightning protection circuit of a wind turbine blade de-icing control system, comprising:

[0034] Step 100: Take the 230 input point of the power supply from the wind turbine as the first lightning protection input point, the first signal terminal as the second lightning protection input point, and the shielding shell as the third lightning protection input point.

[0035] Step 200: Conduct overvoltage and overcurrent tests on the first lightning protection entry point;

[0036] Step 300: Conduct overvoltage and overcurrent tests on the second and third lightning protection entry points.

[0037] In step 200, the first lightning protection entry point undergoes overvoltage and overcurrent tests, specifically as follows:

[0038] Overvoltage and overcurrent tests were conducted on the first lightning protection entry point. The test waveforms were repeated 5 times each with positive and negative polarities, with an interval of not less than 3 minutes between each impact. The impact current waveform was 8 / 20μs, and the impact voltage waveform was 1.2 / 50μs. The amplitudes were determined according to the different lightning protection levels shown in Tables 1 and 2. The impact current amplitude was taken as 10kA, and the impact voltage amplitude was taken as 4kV. After the lightning protection impact test, the power supply to the control system was normal and met the requirements.

[0039] Table 1 Lightning Current Test Intensity Levels for AC Power Ports

[0040]

[0041] Table 2. AC power port impulse voltage amplitude

[0042]

[0043] In step 300, overvoltage and overcurrent tests are performed on the second and third lightning protection entry points, specifically as follows:

[0044] Overvoltage and overcurrent tests were conducted on the second and third lightning protection entry points. The test waveforms were repeated 5 times each with positive and negative polarities, with an interval of not less than 3 minutes between each impact. The impact current waveform was 8 / 20μs, and the impact voltage waveform was 1.2 / 50μs. The amplitudes were determined according to the different lightning protection levels shown in Tables 3 and 4. The impact current amplitude was taken as 5kA, and the impact voltage amplitude was taken as 4kV. After the impact test, the equipment was powered on, and the system equipment could work normally.

[0045] Table 3 Lightning Current Test Intensity Levels for Signal Ports

[0046]

[0047] Table 4. Classification of Lightning Protection Levels for Power Communication Ports

[0048]

[0049] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0050] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A lightning protection circuit for a wind turbine blade de-icing control system, characterized in that, The application relates to a lightning protection circuit for a wind power generator, which comprises a temperature sensor, a lightning protection module, an optical coupling signal isolator, a PLC, a main CPU and a power supply component, wherein the temperature sensor is arranged on a wind power blade; the first signal end, the second signal end and the shielded shell of the temperature sensor are connected with the lightning protection module; the lightning protection module is connected with the optical coupling signal isolator; the optical coupling signal isolator is connected with the PLC; the PLC is connected with the main CPU; the power supply from a wind power host is connected with the power supply component; and the power supply component is connected with the PLC, the main CPU and the optical coupling signal isolator for power supply. The power supply component comprises a first 230V power supply surge SPD, a second 230V power supply surge SPD, a communication surge protection SPD, a first power supply module, a second power supply module, a third power supply module, a 24V repeater and an optical-electricity isolation power supply; the power supply from the wind power host is connected with the power supply component which is connected with the first 230V power supply surge SPD and the second 230V power supply surge SPD; the first 230V power supply surge SPD is connected with the first power supply module and the second power supply module; the second 230V power supply surge SPD is connected with the third power supply module; the first power supply module is connected with the main CPU; the main CPU is connected with the PLC through the communication surge protection SPD; the second power supply module is connected with the PLC; the third power supply module is connected with the 24V repeater; the 24V repeater is connected with the optical-electricity isolation power supply; the optical-electricity isolation power supply and the PLC are connected with the optical coupling signal isolator; the lightning protection module is connected with the optical coupling signal isolator and grounded for lightning current flow. The lightning protection circuit further comprises an in-box temperature controller and an in-box temperature sensor; the power supply from the wind power host is connected with the in-box temperature controller; and the in-box temperature controller is connected with the in-box temperature sensor. The test method comprises the following steps: The 230 input point of the power supply from the wind power host is taken as a first lightning protection input point; the first signal end is taken as a second lightning protection input point; and the shielded shell is taken as a third lightning protection input point. The overvoltage and overcurrent test is conducted on the first lightning protection input point, and the test waveforms are positive and negative polarities, each repeated for 5 times, the interval time of each impact is not less than 3 min, the impact current waveform is 8 / 20 mu s, and the impact voltage waveform is 1.2 / 50 mu s. The overvoltage and overcurrent test is conducted on the second lightning protection input point and the third lightning protection input point, and the test waveforms are positive and negative polarities, each repeated for 5 times, the interval time of each impact is not less than 3 min, the impact current waveform is 8 / 20 mu s, and the impact voltage waveform is 1.2 / 50 mu s. ​ ​ ​

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