Lightning protection circuit of wind power blade deicing control system and test method

Abstract

The invention provides a wind power blade deicing control system lightning protection circuit and a test method, the circuit comprises 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 arranged on a wind power blade, a first signal end, a second signal end and a shielding shell of the temperature sensor are connected with the lightning protection module, and the optocoupler signal isolator is connected with the PLC. The lightning protection module is connected with the optocoupler signal isolator, the optocoupler signal isolator is connected with the PLC, the PLC is connected with the main CPU, a power supply from a wind power host is connected with the power supply assembly, and the power supply assembly is connected with the PLC, the main CPU and the optocoupler signal isolator and is used for supplying power. According to the invention, the PLC, the switching power supply, the CAN bus and other modules in the control system can be protected from common ground, so that the lightning current cannot enter equipment to cause damage during lightning stroke, the lightning protection method in the control system is protected to be distributed according to the lightning protection level, and the position of a lightning triggering point during lightning stroke of the wind power blade deicing control system is protected.

Description

Technical Field

[0001] The present invention relates to the technical field of wind turbine blade deicing, and in particular to a lightning protection circuit and a test method for a wind turbine blade deicing control system. Background Art

[0002] Ice on wind turbine blades in winter can easily cause the wind turbine to stop operating or even be damaged. To address the above problems, both domestic and foreign countries have adopted the method of installing deicing devices and deicing control systems on the original wind turbine generator sets. During on-site operation, the deicing device control system has repeatedly experienced lightning damage to the switching power supply, PLC, sensor, etc., causing the deicing device to operate abnormally and affecting the deicing effect of the blades. Therefore, it is very necessary to design a lightning protection circuit and test method for the wind turbine blade deicing control system. Summary of the invention

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

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] 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 component. The temperature sensor is arranged on a wind turbine blade, a first signal end, a second signal end and a 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, a power source from a wind turbine host is connected to the power supply component, and the power supply component is connected to the PLC, the main CPU and the optocoupler signal isolator for power supply.

[0006] Preferably, the power supply component includes a first 230V power surge SPD, a second 230V power surge SPD, a communication surge protection SPD, a first power module, a second power module, a third power module, a 24V repeater and a photoelectric isolation power supply. The power supply from the wind power host is connected to the power supply component, connected to the first 230V power surge SPD and the second 230V power surge SPD. The first 230V power surge SPD is connected to the first power module and the second power module. The second 230V power surge 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 through the communication surge protection 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 photoelectric isolation power supply. The photoelectric isolation 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 for lightning current to flow through.

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

[0008] The present invention also provides a method for testing a lightning protection circuit of a wind turbine blade deicing control system, comprising:

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

[0010] Conduct overvoltage and overcurrent tests on the first lightning protection zone entry point;

[0011] Carry out overvoltage and overcurrent tests on the second lightning protection zone entry point and the third lightning protection zone entry point.

[0012] Preferably, an overvoltage and overcurrent test is performed on the first lightning protection belt entry point, specifically:

[0013] Carry out overvoltage and overcurrent tests on the first lightning protection zone entry point. The test waveform adopts positive and negative polarity and repeats the test 5 times. The interval between each impact is not less than 3 minutes. The impact current waveform is 8 / 20μs, and the impact voltage waveform is 1.2 / 50μs.

[0014] Preferably, the second lightning protection zone entry point and the third lightning protection zone entry point are subjected to overvoltage and overcurrent tests, specifically:

[0015] Overvoltage and overcurrent tests are carried out on the second lightning protection zone entry point and the third lightning protection zone entry point. The test waveform uses positive and negative polarity and repeats the test 5 times each. The interval between each impact is not less than 3 minutes. The impact current waveform is 8 / 20μs, and the impact voltage waveform is 1.2 / 50μs.

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

[0017] The present invention provides a lightning protection circuit and test method for a wind turbine blade deicing 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 component, the method includes taking the 230 input point of the power supply from the wind turbine host as the first lightning protection input point, taking the first signal end as the second lightning protection input point, taking the shielding shell as the third lightning protection input point, performing overvoltage and overcurrent tests on the first lightning protection input point, and performing overvoltage and overcurrent tests on the second lightning protection input point and the third lightning protection input point. The present invention can protect the PLC controller, switching power supply, CAN bus and other modules in the control system from sharing the same ground, so that the lightning current does not enter the equipment to cause damage when it is struck by lightning, protect the lightning protection method in the control system to be distributed according to the lightning protection level, and protect the position of the lightning induction point when the wind turbine blade deicing control system is struck by lightning. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0019] Figure 1 A schematic diagram of the structure of a lightning protection circuit for a wind turbine blade deicing control system provided by an embodiment of the present invention;

[0020] Figure 2 A detailed schematic diagram of a lightning protection circuit for a wind turbine blade deicing control system provided by an embodiment of the present invention;

[0021] Figure 3 Design the rear schematic diagram for a general lightning protection circuit;

[0022] Figure 4 Design the front side schematic diagram for a general lightning protection circuit;

[0023] Figure 5 A schematic flow chart of a lightning protection circuit test method for a wind turbine blade de-icing control system provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] Figure 1 A schematic diagram of the lightning protection circuit structure of a wind turbine blade deicing control system provided by an embodiment of the present invention. Figure 2 A detailed schematic diagram of a lightning protection circuit for a wind turbine blade deicing control system provided by an embodiment of the present invention is shown in FIG. 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 arranged on the wind turbine blade, the first signal end, the second signal end 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, the power supply from the wind turbine host 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 component includes a first 230V power surge SPD, a second 230V power surge SPD, a communication surge protection SPD, a first power module, a second power module, a third power module, a 24V repeater and a photoelectric isolation power supply. The power supply from the wind power host is connected to the power supply component connected to the first 230V power surge SPD and the second 230V power surge SPD. The first 230V power surge SPD is connected to the first power module and the second power module. The second 230V power surge 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 through the communication surge protection 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 photoelectric isolation power supply. The photoelectric isolation 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 for lightning current to flow through. The photoelectric isolation power supply is a module that is only matched with the optocoupler to prevent power supply interference from affecting the operation of the optocoupler isolator.

[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, and the ground wires pe of the PLC and the main CPU are suspended.

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

[0030] A temperature sensor is set on the wind turbine blade to collect the blade temperature. After the measurement signal is input by the sensor, it enters the PLC through the lightning protection module and the optocoupler signal isolator. The lightning protection module is used to solve the problem that the temperature sensor brings the high voltage signal of lightning into the main CPU to damage the components. The temperature signal is input from the PLC to the main CPU through the CAN bus for calculation and judgment. After the main CPU calculates, it transmits the judgment result to the PLC and controls the 24V repeater and circuit breaker at the same time. The power supply comes from the power supply of the wind turbine host, and the main CPU and PLC are powered by the first power module, the second power module, and the third power module respectively. The optocoupler signal isolator (the optocoupler signal isolator is used to isolate external signals through photoelectric isolation methods to prevent high voltage and high current signals from entering the CPU) has an isolation transformer inside to achieve isolation between the primary voltage and the secondary voltage. The reference ground GNDx of the front and rear ends of the isolation and the front and rear ends of the CAN bus are not shared. PE is the casing protection ground, which is isolated from the reference ground of each channel.

[0031] The present application is provided with a first 230V power surge SPD, a second 230V power surge SPD, and a communication surge protection SPD to realize low-voltage SPD configuration, transient overvoltage protection caused by surges, and gradually absorbs surge energy from the entrance of the power supply system. The transient overvoltage is suppressed in stages by adopting a hierarchical protection method. The first stage is set at the power distribution box, and a voltage-limiting SPD should be used. The power protection level is <3kV, and the current capacity is 20~40kA (8 / 20μs). The high-voltage lightning pulse is limited to a lower voltage level, that is, the protection level of general electrical equipment is achieved. The second stage is a voltage-limiting or composite SPD with a current capacity of 10~20kA (8 / 20μs), which further limits the lightning current to a lower level. Its voltage protection level has different values ​​according to different types of SPDs, generally between 1~1.8kV. The third stage is installed in series at the front end of the UPS power supply and the front end of the equipment that requires special protection. It is a fine-grade protection SPD with a current capacity of 10 to 20kA (8 / 20μs). Its output residual voltage is ultra-low, generally below 1kV, which can meet the fine protection requirements of the equipment.

[0032] This application adopts a general lightning protection circuit design, such as Figure 3 and Figure 4As shown, the lightning impulse injection point is selected as Figure 4 When the lightning injection point is located at the middle, the general circuit design Figure 3 The lightning discharge circuit is a lightning current circuit. When the lightning current is 0.1kA, the control system works normally. According to the lightning protection requirements, the lightning current is further increased. When the lightning current amplitude reaches 0.2-0.4kA, the test causes a trip. After powering on again, it is found that the PLC is damaged. The reason is that the PE port of the lightning arrester is electrically connected to the ground port of the PLC. Figure 3 After inspection, it was found that the GND (reference zero potential) of the PLC was connected to the PE, causing lightning current to enter the PLC port and damage the PLC components. To prove the above results, the reference ground (GND) of the PLC communication CAN bus was separated from the chassis ground (PE), and the PLC housing was suspended and isolated from the ground rail. No problems were found in the test according to the lightning protection requirements.

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

[0034] Step 100: using the 230 input point of the power supply from the wind turbine host as the first lightning protection input point, using the first signal end as the second lightning protection input point, and using the shielding shell as the third lightning protection input point;

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

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

[0037] In step 200, the first lightning protection belt is subjected to overvoltage and overcurrent tests, specifically:

[0038] The first lightning protection zone entry point is subjected to overvoltage and overcurrent tests. The test waveform adopts positive and negative polarities and the test is repeated 5 times. The interval between each impact is not less than 3 minutes. The impact current waveform is 8 / 20μs, and the impact voltage waveform is 1.2 / 50μs. The amplitude is determined according to the different lightning protection levels shown in Table 1 and Table 2. The impact current amplitude is 10kA, and the impact voltage amplitude is 4kV. After the lightning protection impact test, the power supply of the control system meets the requirements normally.

[0039] Table 1 AC power port lightning current test intensity level

[0040]

[0041] Table 2 AC power port impulse voltage amplitude

[0042]

[0043] In step 300, an overvoltage and overcurrent test is performed on the second lightning protection zone entry point and the third lightning protection zone entry point, specifically:

[0044] Overvoltage and overcurrent tests are carried out on the second lightning protection zone entry point and the third lightning protection zone entry point. The test waveform uses positive and negative polarity and repeats the test 5 times. The interval between each impact is not less than 3 minutes. The impact current waveform is 8 / 20μs, and the impact voltage waveform is 1.2 / 50μs. The amplitude is determined according to the different lightning protection levels shown in Table 3 and Table 4. The impact current amplitude is 5kA, and the impact voltage amplitude is 4kV. After the impact test, the equipment is powered on and the system equipment can work normally.

[0045] Table 3 Signal port lightning current test intensity level

[0046]

[0047] Table 4 Classification of lightning protection levels for power supply and communication ports

[0048]

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

[0050] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A lightning protection circuit for a wind turbine blade deicing control system, characterized in that: include: A temperature sensor, a lightning protection module, an optocoupler signal isolator, a PLC, a main CPU and a power supply component. The temperature sensor is arranged on a wind turbine blade. The first signal end, the second signal end 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. The power supply from the wind turbine host is connected to the power supply component. The power supply component is connected to the PLC, the main CPU and the optocoupler signal isolator for power supply.

2. The lightning protection circuit according to claim 1, characterized in that: The power supply component includes a first 230V power surge SPD, a second 230V power surge SPD, a communication surge protection SPD, a first power module, a second power module, a third power module, a 24V repeater and a photoelectric isolation power supply. The power supply from the wind power host is connected to the power supply component connected to the first 230V power surge SPD and the second 230V power surge SPD. The first 230V power surge SPD is connected to the first power module and the second power module. The second 230V power surge 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 through the communication surge protection 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 photoelectric isolation power supply. The photoelectric isolation 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 for lightning current to flow through.

3. The lightning protection circuit according to claim 1, characterized in that: The lightning protection circuit also includes an in-box temperature controller and a box temperature sensor. The power supply from the wind power host is connected to the in-box temperature controller, and the in-box temperature controller is connected to the box temperature sensor.

4. A wind turbine blade deicing control system lightning protection circuit test method, characterized in that: include: The 230 input point of the power supply from the wind turbine host is used as the first lightning protection input point, the first signal end is used as the second lightning protection input point, and the shielding shell is used as the third lightning protection input point; Conduct overvoltage and overcurrent tests on the first lightning protection zone entry point; Carry out overvoltage and overcurrent tests on the second lightning protection zone entry point and the third lightning protection zone entry point.

5. The method according to claim 4, characterized in that Conduct overvoltage and overcurrent tests on the first lightning protection zone entry point, specifically: Carry out overvoltage and overcurrent tests on the first lightning protection zone entry point. The test waveform adopts positive and negative polarity and repeats the test 5 times. The interval between each impact is not less than 3 minutes. The impact current waveform is 8 / 20μs, and the impact voltage waveform is 1.2 / 50μs.

6. The method according to claim 5, characterized in that Conduct overvoltage and overcurrent tests on the second and third lightning protection zone entry points, specifically: Overvoltage and overcurrent tests are carried out on the second lightning protection zone entry point and the third lightning protection zone entry point. The test waveform uses positive and negative polarity and repeats the test 5 times each. The interval between each impact is not less than 3 minutes. The impact current waveform is 8 / 20μs, and the impact voltage waveform is 1.2 / 50μs.

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