Method and device for detecting charging state of insulation surface

Abstract

The present invention discloses a method and device for detecting the charge state of an insulating surface. The method comprises: establishing a wind tunnel simulation test platform for simulating the charge state of an insulating surface of a blade when rotating at high speed; based on the established wind tunnel simulation test platform, setting different test times, wind speeds, and angles between the insulating surface and the oncoming airflow for testing, and obtaining the charge states of the insulating surface formed under different test times, wind speeds, and angles between the insulating surface and the airflow; establishing an insulating surface charge distribution measurement system, and measuring the potential distribution of the charge states of the insulating surface formed under different test times, wind speeds, and angles between the insulating surface and the airflow, and obtaining different measurement results; and performing comparative analysis based on the different measurement results to obtain the influence of time, wind speed, and the angle between the insulating surface and the airflow on the frictional charging of the insulating surface.

Description

Technical Field

[0001] The present invention relates to a method and device for detecting the charging state of an insulating surface, and in particular to a method and device for detecting the charging state of an insulating surface of a blade under the action of high-speed airflow. Background Art

[0002] As the capacity of wind turbines continues to increase and their structures become taller, the risk of lightning strikes also increases. Blades are the most vulnerable part to lightning strikes. Blade damage can affect the aerodynamic performance of the wind turbine, forcing it to shut down in severe cases or even causing blade disintegration. Currently, the lightning protection system for wind turbine blades typically consists of a lightning rod embedded in the blade surface and an internal grounding down conductor. Under normal circumstances, when lightning is successfully received, the lightning is discharged through the lightning rod and the down conductor, preventing erosion of the blade insulation material. However, on-site maintenance often reveals signs of erosion or breakdown on the blade surface, indicating that the blade lightning protection system is still experiencing lightning failure. Summary of the Invention

[0003] In order to overcome the shortcomings of the above-mentioned prior art, the present invention provides a method and device for detecting the charge state of the insulation surface. By using a wind tunnel test box to create a high-speed airflow method to simulate the relative movement of the blade tip and the surrounding air during high-speed rotation, the charge state of the insulation surface of the blade during high-speed rotation can be accurately simulated, which can provide assistance for further research on lightning protection of wind turbines.

[0004] According to one aspect of the present invention, a method for detecting a state of charge on an insulating surface is provided, comprising:

[0005] Establish a wind tunnel simulation test platform to simulate the charging state of the insulating surface of the blade when it rotates at high speed;

[0006] Based on the wind tunnel simulation test platform, the test was conducted with different test times, wind speeds, and angles between the insulation surface and the oncoming airflow. The charge state of the insulation surface formed under different test times, wind speeds, and angles between the insulation surface and the airflow was obtained.

[0007] An insulation surface charge distribution measurement system was built to measure the potential distribution of the insulation surface charge state formed under different test times, wind speeds, and angles between the insulation surface and the airflow, obtaining different measurement results.

[0008] Based on a comparative analysis of different measurement results, the influence of time, wind speed and the angle between the insulation surface and the airflow on the friction charging of the insulation surface was obtained.

[0009] As a further technical solution, a wind tunnel simulation test platform is established, including: a wind tunnel test box, a wind tunnel motor, a cooling fan and an anemometer; wherein, the wind tunnel test box is used to generate high-speed airflow to simulate the relative movement of the blade tip and the surrounding air when it rotates at high speed, the wind tunnel motor is used to drive the wind tunnel fan in the wind tunnel test box to generate airflows of different flow rates, the anemometer is used to measure the speed of the airflow in the wind tunnel test box, and the cooling fan is used to cool the wind tunnel motor.

[0010] As a further technical solution, different test times, wind speeds and angles between the insulating surface and the oncoming airflow are set for testing, including: constructing a time data group, a wind speed data group and an angle data group for the test respectively; based on the constructed data groups, different test parameters are formed, and the formed test parameters are used to conduct the test to obtain the charging state of the insulating surface corresponding to the current test parameters.

[0011] As a further technical solution, the insulation surface charge distribution measurement system is built in a shielded room, including a Trek electrostatic potentiometer, an electrostatic probe, an oscilloscope, a transmission motor and a transmission arm. The Trek electrostatic potentiometer is used to measure the potential of the insulation surface through the electrostatic probe, the electrostatic probe is used to move in a plane on the insulation surface, the oscilloscope is used to display the measurement results, and the transmission motor is connected to the transmission arm to drive the transmission arm to drive the electrostatic probe to move in a plane.

[0012] As a further technical solution, the insulating surface charge distribution measurement system is equipped with an insulating surface charge inversion algorithm based on the Lanczos-Tikhonvo algorithm, which is used to calculate the insulating surface charge density distribution, including:

[0013] The insulating surface to be measured is divided into N equal square grids. Assuming that the charge distribution in a single grid is uniform, the initial charge density of the N grids is preset according to the surface charge distribution measured by the electrostatic probe method, and the spatial electric field distribution is calculated.

[0014] Considering the distortion effect of space charge on the electric field, a simulation model of the space charge transport process of corona discharge under high-speed airflow is established to calculate the space charge distribution and electric field distribution;

[0015] The above electric field calculation results are superimposed and compared with the electric field distribution measured based on electric field induced second harmonic EFISH. If they are consistent, the inversion is completed and the insulating surface charge density distribution is output.

[0016] As a further technical solution, the insulating surface charge inversion based on the Lanczos-Tikhonvo algorithm further includes: if there is inconsistency, correcting the charge density values ​​of N grids and repeating the inversion process.

[0017] As a further technical solution, a simulation model of the spatial charge transport process of corona discharge under high-speed airflow is established to calculate the spatial charge distribution and electric field distribution, including: building a spatial electric field distribution model based on the COMSOL platform using the simulated charge method, setting the material settings in all calculation domains to air, setting the insulating surface material in the middle of the calculation domain, and setting the corresponding relative dielectric constant, and setting other boundaries to zero charge boundary conditions; meshing the set model through physical field control, dividing the insulating surface into N squares; assigning the upper inverted charge density in the squares, and calculating the spatial electric field under steady state.

[0018] According to one aspect of the present invention, there is provided a device for detecting the state of charge of an insulating surface, comprising:

[0019] A wind tunnel simulation test platform is used to simulate the charge state of the insulating surface of a blade during high-speed rotation. Based on the constructed wind tunnel simulation test platform, different test times, wind speeds, and angles between the insulating surface and the oncoming airflow are set to conduct tests to obtain the charge state of the insulating surface formed under different test times, wind speeds, and angles between the insulating surface and the airflow;

[0020] The insulation surface charge distribution measurement system is used to measure the potential distribution of the insulation surface charge state formed under different test times, wind speeds, and angles between the insulation surface and the airflow, and obtain different measurement results;

[0021] The processing module is used to perform comparative analysis based on different measurement results to obtain the influence of time, wind speed and the angle between the insulation surface and the airflow on the friction charging of the insulation surface.

[0022] As a further technical solution, the wind tunnel simulation test platform includes: a wind tunnel test box, a wind tunnel motor, a cooling fan and an anemometer; wherein, the wind tunnel test box is used to generate high-speed airflow to simulate the relative movement of the blade tip and the surrounding air when it rotates at high speed, the wind tunnel motor is used to drive the wind tunnel fan in the wind tunnel test box to generate airflows of different flow rates, the anemometer is used to measure the speed of the airflow in the wind tunnel test box, and the cooling fan is used to cool the wind tunnel motor.

[0023] As a further technical solution, the insulation surface charge distribution measurement system is built in a shielded room, including a Trek electrostatic potentiometer, an electrostatic probe, an oscilloscope, a transmission motor and a transmission arm. The Trek electrostatic potentiometer is used to measure the potential of the insulation surface through the electrostatic probe, the electrostatic probe is used to move in a plane on the insulation surface, the oscilloscope is used to display the measurement results, and the transmission motor is connected to the transmission arm to drive the transmission arm to drive the electrostatic probe to move in a plane.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention establishes a wind tunnel simulation test platform, which can accurately simulate the relative movement of the blade tip and the surrounding air when the blade tip rotates at high speed, providing assistance for further research on lightning protection of wind turbines.

[0026] The present invention builds an insulation surface charge distribution measurement system, which can accurately calculate the insulation surface charge density distribution and can be widely used in charge distribution measurement of various electrical equipment.

[0027] The present invention can change the experimental parameters of the simulation experiment according to the influencing factors to be explored, thereby exploring the influence of different parameters on the charge state of the insulating surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief introduction will be given below to the drawings used in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0029] Figure 1 This is a flow chart of a method for detecting the charge state of an insulating surface provided by an embodiment of the present invention.

[0030] Figure 2 It is a structural diagram of a wind tunnel simulation test platform built according to an embodiment of the present invention.

[0031] Figure 3 It is a structural diagram of the insulating surface charge distribution measurement system constructed in an embodiment of the present invention.

[0032] Figure 4 This is a diagram of the charge distribution results of a portion of the insulating surface obtained under different experimental parameters provided by an embodiment of the present invention.

[0033] Figure: 1. Anemometer; 2. Upper plate electrode; 3. Air inlet; 4. Insulation surface test piece; 5. Air outlet; 6. Oscilloscope; 7. Trek electrostatic potentiometer; 8. Transmission arm; 9. Electrostatic probe; 10. Location to be measured. DETAILED DESCRIPTION

[0034] At present, studies have shown that the reason for the failure of lightning protection systems on blades is related to the charge state of the blade insulation surface. The linear speed of the blade tip of a large wind turbine exceeds 60m / s. When rotating at high speed, the blade surface will rub and collide with the air and the suspended particles in it, depositing electrostatic charges, which in turn affect the state of the metal lightning receptor. However, there is currently only qualitative analysis and speculation on the triboelectric charging process, and there is a lack of quantitative characterization of the triboelectric charge state of the insulating surface of rotating wind turbine blades. There is an urgent need to study the charge state of the blade surface under the action of high-speed airflow.

[0035] The terms "including" and "having" and any variations thereof in the description and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions, for example, a process, method, system, product or apparatus that includes a series of steps or units is not necessarily limited to the steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products or apparatuses.

[0036] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically separate entities. That is, these functional entities may be implemented in software, in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices. The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily need to be executed in the order described. For example, some operations / steps may be further decomposed, while others may be combined or partially combined, so the actual execution order may vary depending on the actual situation.

[0037] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are 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 making creative work are within the scope of protection of the present invention. In addition, the technical features in the various embodiments or single embodiments provided by the present invention are arbitrarily combined with each other to form a new technical solution. This combination is not restricted by the sequence of steps and / or structural composition mode, but must be based on the ability of ordinary technicians in this field to implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that this combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0038] An embodiment of the present invention provides a method for detecting the charge state of an insulation surface by using a wind tunnel test chamber to create a high-speed airflow method to simulate the relative motion of a blade tip with the surrounding air during high-speed rotation, thereby accurately simulating the charge state of the insulation surface of the blade during high-speed rotation. This method can provide assistance for further research on lightning protection of wind turbines. The method also uses an insulation surface charge inversion algorithm based on the Lanczos-Tikhonvo algorithm to accurately calculate the charge density distribution on the insulation surface, overcoming shortcomings such as the difficulty in measuring charge density. The method can be widely used in charge distribution measurement of various electrical equipment.

[0039] like Figure 1As shown, an embodiment of the present invention provides a method for detecting the charge state of an insulating surface, comprising the following steps:

[0040] Step 1, establish a wind tunnel simulation test platform. This platform is an insulating surface friction charged wind tunnel simulation test platform, which is used to simulate the charging state of the insulating surface of the blade when it rotates at high speed. The insulating surface friction charged wind tunnel simulation test platform consists of a wind tunnel test box, a wind tunnel motor, a cooling fan, an anemometer and an insulating surface specimen. Among them, the insulating surface specimen simulates the actual fan blade, the purpose of the wind tunnel test box is to create a high-speed airflow to simulate the relative movement of the blade tip with the surrounding air when it rotates at high speed, the role of the anemometer is to measure the speed of the airflow in the wind tunnel test box, and the cooling fan is used to cool the wind tunnel motor to ensure the long-term and stable operation of the motor. There is a wind tunnel fan in the wind tunnel test box, and its function is to generate airflows of different flow rates under the drive of the wind tunnel motor. Such as Figure 2 As shown, the insulating surface specimen is placed in a wind tunnel test chamber. Air inlets and outlets are provided on opposite sides of the wind tunnel test chamber to cooperate with the anemometer to form an air duct in the chamber. An upper plate electrode is provided above the chamber to simulate a thundercloud, and a lower plate electrode is provided below the chamber to simulate the earth.

[0041] Step 2: Conduct the test on the wind tunnel simulation test platform built in Step 1, setting different parameters for the simulation experiment. To explore the influence of multiple factors on triboelectric charging, three test durations of 60, 120, and 180 minutes were designed for the test, three wind speeds of 20m / s, 40m / s, and 60m / s were set for the test, and three angles between the insulating surface specimen and the oncoming airflow of 0°, 15°, and 30° were designed for the test. The test was conducted to explore the influence of time, wind speed, and the angle between the insulating surface and the airflow on the triboelectric charging of the insulating surface.

[0042] In the specific simulation test, one of the test time, wind speed and the angle between the insulating surface test piece and the oncoming airflow is changed, while the others remain unchanged, forming different test parameters for testing, thereby obtaining different test results.

[0043] Step 3: Build an insulation surface charge distribution measurement system and calculate the insulation surface charge density obtained in step 2. Figure 3 As shown in the figure, the insulation surface charge distribution measurement system is built in a shielded room and consists of a Trek electrostatic potentiometer, an electrostatic probe, an oscilloscope, a transmission motor, and a transmission arm. After the insulation surface friction charging test is completed, the measurement probe plane moves according to the preset program to complete the measurement of the insulation surface potential distribution.

[0044] Step 4, analyze and compare the results: Compare and analyze the results obtained from the measurement in step 3, conduct a quantitative characterization study on the frictional charging state of the insulating surface of the rotating fan blade, analyze and compare the effects of time, wind speed, and the angle between the insulating surface and the airflow on the frictional charging of the insulating surface, and thus obtain its rules.

[0045] Figure 4 The charge density distribution on the insulating surface at different locations and under different airflow velocities is shown at different times. The figure shows that the charge density increases over time, and this increase continues as the test duration increases. As the airflow velocity increases, the charge accumulation on the insulating surface significantly increases. The charge density is negatively correlated with the airflow angle; the smaller the airflow angle, the greater the charge accumulation caused by friction. Surface charge accumulation is characterized by a higher concentration in the center of the insulating surface and in the direction of the airflow.

[0046] In the above-mentioned charge distribution measurement method, after the charging test in step 3 is completed, the measurement probe plane is moved according to a pre-set program to complete the measurement of the insulation surface potential distribution. The insulation surface charge density distribution is calculated using an insulation surface charge inversion algorithm based on the Lanczos-Tikhonvo algorithm.

[0047] The specific operation method to obtain the actual charge distribution is as follows:

[0048] Step 4.1: Divide the insulating surface to be measured into N equal square grids. Assuming that the charge distribution within each grid is uniform, preset the initial charge density of the N grids based on the surface charge distribution measured by the electrostatic probe method, and calculate the spatial electric field distribution.

[0049] Step 4.2: Considering the distortion effect of space charge on the electric field, a simulation model of the space charge transport process of corona discharge under high-speed airflow is established to calculate the space charge distribution and electric field distribution;

[0050] In step 4.3, superimpose the above electric field calculation results and compare them with the electric field distribution measured using EFISH. If they are consistent, the inversion is complete and the charge density distribution on the insulating surface is output. If they are inconsistent, correct the charge density values ​​of the N grids in step 1 and repeat steps 4.1 and 4.2.

[0051] It should be noted that in step 4.3, when one of the parameters is controlled to change while the other parameters remain unchanged, the charge distribution is compared with each other. If the difference is not obvious, it can be considered to be consistent.

[0052] In step 4.2, the spatial electric field distribution model is constructed using the simulated charge method based on the COMSOL platform. In the model's material settings, all computational domains are first set to air, with a relative permittivity of 1. The insulating surface material is then set in the center of the computational domain, with the corresponding relative permittivity set. All other boundaries are set to zero charge boundary conditions, i.e., n·D=0. The model is then meshed using physical field control, dividing the insulating surface into N squares. Finally, the inverted charge density is assigned to the squares to calculate and process the steady-state spatial electric field problem.

[0053] Based on the same technical concept as the aforementioned method embodiment, an embodiment of the present invention further provides a device for detecting the charge state of an insulating surface, comprising:

[0054] A wind tunnel simulation test platform is used to simulate the charge state of the insulating surface of a blade during high-speed rotation. Based on the constructed wind tunnel simulation test platform, different test times, wind speeds, and angles between the insulating surface and the oncoming airflow are set to conduct tests to obtain the charge state of the insulating surface formed under different test times, wind speeds, and angles between the insulating surface and the airflow;

[0055] The insulation surface charge distribution measurement system is used to measure the potential distribution of the insulation surface charge state formed under different test times, wind speeds, and angles between the insulation surface and the airflow, and obtain different measurement results;

[0056] The processing module is used to perform comparative analysis based on different measurement results to obtain the influence of time, wind speed and the angle between the insulation surface and the airflow on the friction charging of the insulation surface.

[0057] An embodiment of the present invention provides an insulating surface charge state detection device, which addresses the current situation where there is only qualitative analysis and speculation on the friction charging process and a lack of quantitative characterization of the friction charging state of the insulating surface of a rotating fan blade. The device simulates the charge state of the insulating surface of the blade when it rotates at high speed through a wind tunnel simulation test platform, and measures and calculates the charge density distribution on the insulating surface through an insulating surface charge distribution measurement system. By comparing the measurement results under different test parameters, the influence of time, wind speed and the angle between the insulating surface and the oncoming airflow on the friction charging of the insulating surface is analyzed, thereby achieving quantitative characterization of the friction charging state of the insulating surface of a rotating fan blade.

[0058] Based on the content of the above device embodiment, as a preferred embodiment, an insulating surface charge state detection device provided in the embodiment of the present invention, the wind tunnel simulation test platform further includes:

[0059] A wind tunnel test box, a wind tunnel motor, a cooling fan and an anemometer; wherein the wind tunnel test box is used to generate high-speed airflow to simulate the relative movement of the blade tip and the surrounding air when the blade tip rotates at high speed; the wind tunnel motor is used to drive the wind tunnel fan in the wind tunnel test box to generate airflows of different flow rates; the anemometer is used to measure the speed of the airflow in the wind tunnel test box; and the cooling fan is used to cool the wind tunnel motor.

[0060] Based on the content of the above device embodiment, as a preferred embodiment, an insulating surface charge state detection device provided in the embodiment of the present invention, the insulating surface charge distribution measurement system further includes:

[0061] The insulation surface charge distribution measurement system is built in a shielded room and includes a Trek electrostatic potentiometer, an electrostatic probe, an oscilloscope, a transmission motor and a transmission arm. The Trek electrostatic potentiometer is used to measure the potential of the insulation surface through the electrostatic probe, the electrostatic probe is used to move in a plane on the insulation surface, the oscilloscope is used to display the measurement results, and the transmission motor is connected to the transmission arm to drive the transmission arm to drive the electrostatic probe to move in a plane.

[0062] After the charging test is completed, the embodiment of the present invention completes the measurement of the insulation surface potential distribution by moving the measurement probe plane according to a preset program, and further adopts the insulation surface charge inversion algorithm based on the Lanczos-Tikhonvo algorithm to calculate the insulation surface charge density distribution.

[0063] The system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, located in one place or distributed across multiple network units. Depending on practical needs, some or all of these modules may be selected to achieve the objectives of this embodiment. Persons of ordinary skill in the art will understand and implement these embodiments without inventive effort.

[0064] In summary, the present invention provides a method and device for detecting the charge state of the blade insulation surface under the action of high-speed airflow. By building a wind tunnel simulation experimental platform, conducting simulation experiments, changing influencing factors, and building a charge distribution measurement system, it is possible to accurately simulate and measure the charge state of the blade insulation surface under the action of high-speed airflow, thereby providing strong support for preventing discharge and breakdown caused by electric field distortion and ensuring the normal operation of wind turbines.

[0065] 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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the technical solutions of the embodiments of the present invention.

Claims

1. A method for detecting the charge state of an insulating surface, characterized in that: include: Establish a wind tunnel simulation test platform to simulate the charging state of the insulating surface of the blade when it rotates at high speed; Based on the wind tunnel simulation test platform, the test was conducted with different test times, wind speeds, and angles between the insulation surface and the oncoming airflow. The charge state of the insulation surface formed under different test times, wind speeds, and angles between the insulation surface and the airflow was obtained. An insulation surface charge distribution measurement system was built to measure the potential distribution of the insulation surface charge state formed under different test times, wind speeds, and angles between the insulation surface and the airflow, obtaining different measurement results. Based on a comparative analysis of different measurement results, the influence of time, wind speed and the angle between the insulation surface and the airflow on the friction charging of the insulation surface was obtained.

2. A method for detecting the charge state of an insulating surface according to claim 1, characterized in that: The established wind tunnel simulation test platform includes: a wind tunnel test box, a wind tunnel motor, a cooling fan and an anemometer; wherein, the wind tunnel test box is used to generate high-speed airflow to simulate the relative movement of the blade tip and the surrounding air when it rotates at high speed; the wind tunnel motor is used to drive the wind tunnel fan in the wind tunnel test box to generate airflows of different flow rates; the anemometer is used to measure the speed of the airflow in the wind tunnel test box; and the cooling fan is used to cool the wind tunnel motor.

3. The method for detecting the charge state of an insulating surface according to claim 1, wherein: The test is performed by setting different test times, wind speeds, and angles between the insulating surface and the oncoming airflow, including: constructing a time data group, a wind speed data group, and an angle data group for the test respectively; forming different test parameters based on the constructed data groups, and conducting the test using the formed test parameters to obtain the charge state of the insulating surface corresponding to the current test parameters.

4. The method for detecting the charge state of an insulating surface according to claim 1, wherein: The insulation surface charge distribution measurement system is built in a shielded room and includes a Trek electrostatic potentiometer, an electrostatic probe, an oscilloscope, a transmission motor and a transmission arm. The Trek electrostatic potentiometer is used to measure the potential of the insulation surface through the electrostatic probe, the electrostatic probe is used to move in a plane on the insulation surface, the oscilloscope is used to display the measurement results, and the transmission motor is connected to the transmission arm to drive the transmission arm to drive the electrostatic probe to move in a plane.

5. A method for detecting the charge state of an insulating surface according to claim 4, characterized in that: The insulating surface charge distribution measurement system has a built-in insulating surface charge inversion algorithm based on the Lanczos-Tikhonvo algorithm, which is used to calculate the insulating surface charge density distribution, including: The insulating surface to be measured is divided into N equal square grids. Assuming that the charge distribution in a single grid is uniform, the initial charge density of the N grids is preset according to the surface charge distribution measured by the electrostatic probe method, and the spatial electric field distribution is calculated. Considering the distortion effect of space charge on the electric field, a simulation model of the space charge transport process of corona discharge under high-speed airflow is established to calculate the space charge distribution and electric field distribution; The above electric field calculation results are superimposed and compared with the electric field distribution measured based on electric field induced second harmonic EFISH. If they are consistent, the inversion is completed and the insulating surface charge density distribution is output.

6. A method for detecting the charge state of an insulating surface according to claim 5, characterized in that: The inversion of insulating surface charge based on the Lanczos-Tikhonvo algorithm also includes: if there is inconsistency, correcting the charge density values ​​of N grids and repeating the inversion process.

7. A method for detecting the charge state of an insulating surface according to claim 5, characterized in that: A simulation model of the spatial charge transport process of corona discharge under high-speed airflow is established to calculate the spatial charge distribution and electric field distribution, including: building a spatial electric field distribution model based on the COMSOL platform using the simulated charge method. In the material setting of the model, all calculation domains are set to air, the insulating surface material is set in the middle of the calculation domain, and the corresponding relative dielectric constant is set, and other boundaries are set to zero charge boundary conditions; the set model is meshed through the physical field control method, and the insulating surface is divided into N squares; the inverted charge density is assigned to the squares, and the spatial electric field under steady state is calculated.

8. A device for detecting the charge state of an insulating surface, characterized in that: include: A wind tunnel simulation test platform is used to simulate the charge state of the insulating surface of a blade during high-speed rotation. Based on the constructed wind tunnel simulation test platform, different test times, wind speeds, and angles between the insulating surface and the oncoming airflow are set to conduct tests to obtain the charge state of the insulating surface formed under different test times, wind speeds, and angles between the insulating surface and the airflow; The insulation surface charge distribution measurement system is used to measure the potential distribution of the insulation surface charge state formed under different test times, wind speeds, and angles between the insulation surface and the airflow, and obtain different measurement results; The processing module is used to perform comparative analysis based on different measurement results to obtain the influence of time, wind speed and the angle between the insulation surface and the airflow on the friction charging of the insulation surface.

9. The device for detecting the charge state of an insulating surface according to claim 8, characterized in that: The wind tunnel simulation test platform includes: a wind tunnel test box, a wind tunnel motor, a cooling fan and an anemometer; wherein the wind tunnel test box is used to generate high-speed airflow to simulate the relative movement of the blade tip and the surrounding air when the blade tip rotates at high speed; the wind tunnel motor is used to drive the wind tunnel fan in the wind tunnel test box to generate airflows of different flow rates; the anemometer is used to measure the speed of the airflow in the wind tunnel test box; and the cooling fan is used to cool the wind tunnel motor.

10. The device for detecting the charge state of an insulating surface according to claim 8, characterized in that: The insulation surface charge distribution measurement system is built in a shielded room and includes a Trek electrostatic potentiometer, an electrostatic probe, an oscilloscope, a transmission motor and a transmission arm. The Trek electrostatic potentiometer is used to measure the potential of the insulation surface through the electrostatic probe, the electrostatic probe is used to move in a plane on the insulation surface, the oscilloscope is used to display the measurement results, and the transmission motor is connected to the transmission arm to drive the transmission arm to drive the electrostatic probe to move in a plane.

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