Insulation surface charge state detection method and device

Abstract

The invention discloses an insulation surface charge state detection method and device, and the method comprises the steps: building a wind tunnel simulation test platform for simulating the charge state of an insulation surface when a blade rotates at a high speed; based on the established wind tunnel simulation test platform, setting different test times, wind speeds and angles between the insulation surface and the head-on airflow for testing to obtain insulation surface charge states formed under different test times, wind speeds and angles between the insulation surface and the airflow; building an insulation surface charge distribution measurement system, and respectively carrying out potential distribution measurement on insulation surface charge states formed at different test times, wind speeds and angles between the insulation surface and airflow to obtain different measurement results; and performing comparative analysis based on different measurement results to obtain an influence rule of the time, the wind speed and the angle between the insulation surface and the airflow on the friction charge of the insulation surface.

Description

Technical Field

[0001] The invention relates to a method and a device for detecting the charging state of an insulating surface, and in particular to a method and a device for detecting the charging state of an insulating surface of a blade under the action of a 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 parts to lightning strikes. Blade damage will affect the aerodynamic performance of the wind turbine. In severe cases, it will force the wind turbine to shut down or even cause blade disintegration accidents. At present, the lightning protection system of wind turbine blades usually consists of a lightning rod embedded in the surface of the blade and an internal grounding down conductor. Under normal circumstances, when it successfully receives lightning, the lightning will be discharged through the lightning rod and the down conductor, avoiding the burning of the blade insulation material. However, on-site operation and maintenance often find signs of burning or breakdown on the blade surface, which indicates that the lightning protection system of the blade still has 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 adopting 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 when the blade rotates at high speed, the charge state of the insulation surface of the blade when it rotates at high speed 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 charge state of an insulating surface is provided, comprising: 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, different test times, wind speeds, and angles between the insulating surface and the oncoming airflow were set to conduct tests, and the charge state of the insulating surface formed under different test times, wind speeds, and angles between the insulating 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, and different measurement results were obtained; Based on a comparative analysis of different measurement results, the effects of time, wind speed and the angle between the insulation surface and the airflow on the frictional charging of the insulation surface were obtained.

[0005] 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 produce 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.

[0006] 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.

[0007] 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.

[0008] 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: The insulating surface to be measured is equally divided into N square grids. Assuming that the charge distribution in a single grid is uniform, the initial value of the 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.

[0009] 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.

[0010] 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 of the model as air in all calculation domains, setting the insulating surface material in the middle of the calculation domain, and setting the corresponding relative dielectric constant, and setting other boundaries as zero charge boundary conditions; meshing the set model through physical field control, dividing the insulating surface into N squares; assigning the inverted charge density in the squares, and calculating the spatial electric field in the steady state.

[0011] According to one aspect of the present invention, there is provided a device for detecting a charge state of an insulating surface, comprising: The wind tunnel simulation test platform is used to simulate the charge state of the insulating surface of the blade when it rotates at high speed. Based on the built 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, and the charge state of the insulating surface formed under different test times, wind speeds, and angles between the insulating surface and the airflow is obtained; 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.

[0012] 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 with 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 with 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.

[0013] 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.

[0014] Compared with the prior art, the present invention has the following beneficial effects: 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, and provides help for further research on lightning protection of wind turbines.

[0015] 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.

[0016] The present invention can change the experimental parameters of the simulation experiment according to the influencing factors that need to be explored, so as to explore the influence of different parameters on the charge state of the insulation surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, a brief introduction is 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.

[0018] Figure 1 It is a flow chart of a method for detecting the charge state of an insulation surface provided by an embodiment of the present invention.

[0019] Figure 2 It is a structural diagram of a wind tunnel simulation test platform built according to an embodiment of the present invention.

[0020] Figure 3 It is a structural diagram of an insulating surface charge distribution measurement system constructed according to an embodiment of the present invention.

[0021] Figure 4 This is a diagram of partial insulating surface charge distribution results obtained under different experimental parameters provided by an embodiment of the present invention.

[0022] In the 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. Position to be measured. DETAILED DESCRIPTION

[0023] 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 to deposit electrostatic charges, thereby affecting the state of the metal lightning arrester. However, there is currently only qualitative analysis and speculation on the friction charging process, and there is a lack of quantitative characterization of the friction charging state of the insulation surface of rotating fan blades. It is urgent to carry out research on the charge state of the blade surface under the action of high-speed airflow.

[0024] The terms "including" and "having" and any variations thereof in the specification 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 comprising 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.

[0025] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities may be implemented in software, or 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 exemplary and do not necessarily include all the contents and operations / steps, nor do they necessarily have to be executed in the order described. For example, some operations / steps may be further decomposed, while some operations / steps may be combined or partially combined, so the actual execution order may change according to the actual situation.

[0026] 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 in 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. 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 the structural composition mode, but must be based on the ability of ordinary technicians in this field to achieve. When the combination of technical solutions is contradictory or cannot be achieved, it should be considered that this combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0027] The embodiment of the present invention provides a method for using a wind tunnel test box to create a high-speed airflow method to simulate the relative movement of the blade tip with the surrounding air when the blade tip rotates at high speed, thereby accurately simulating the charge state of the insulation surface of the blade when the blade rotates at high speed, and can provide assistance for further research on lightning protection of wind turbines. A method for detecting the charge state of the insulation surface is provided. 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, overcomes the disadvantages of difficulty in measuring charge density, and can be widely used in charge distribution measurement of various electrical equipment.

[0028] like Figure 1As shown, a method for detecting the charge state of an insulating surface provided by an embodiment of the present invention includes the following steps: 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 wind turbine blade. The purpose of the wind tunnel test box is to create high-speed airflow to simulate the relative movement of the blade tip with the surrounding air when it rotates at high speed. The function of the anemometer is to measure the speed of the airflow in the wind tunnel test box. 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 with different flow rates under the drive of the wind tunnel motor. Such as Figure 2 As shown, the insulating surface test sample is placed in a wind tunnel test box, and air inlets and air outlets are respectively arranged on opposite sides of the wind tunnel test box to cooperate with the anemometer to form an air duct in the box. An upper plate electrode is arranged on the top of the box to simulate a thundercloud, and a lower plate electrode is arranged on the bottom to simulate the earth.

[0029] Step 2, conduct the test on the wind tunnel simulation test platform built in step 1, and set different parameters for simulation experiments. In order to explore the influence of multiple factors on triboelectric charging, three test times of 60, 120 and 180 minutes are designed for testing, three wind speeds of 20m / s, 40m / s and 60m / s are set for testing, and three angles of 0°, 15° and 30° between the insulating surface specimen and the oncoming airflow are designed for testing, 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.

[0030] 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, and the others remain unchanged, so as to form different test parameters for testing, thereby obtaining different test results.

[0031] Step 3: Build an insulation surface charge distribution measurement system to calculate the insulation surface charge density obtained in step 2. Figure 3 As shown, 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 is moved according to the preset program to complete the measurement of the insulation surface potential distribution.

[0032] Step 4, analyze and compare the results: compare and analyze the results obtained 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 obtain its rules.

[0033] Figure 4 The charge density distribution of the insulating surface at different positions and different airflow speeds at different times is given. As can be seen from the figure, the charge density increases with time, and this increase continues as the test time increases. As the airflow speed increases, the charge accumulation on the insulating surface increases significantly. The charge density is negatively correlated with the airflow angle. The smaller the airflow angle, the greater the charge accumulation caused by friction. The surface charge accumulation is characterized by more accumulation in the middle of the insulating surface and in the direction of airflow.

[0034] In the above-mentioned charge distribution measurement method, after the charging test in step 3 is completed, the measurement of the insulation surface potential distribution is completed by moving the measurement probe plane according to the preset program. The insulation surface charge inversion algorithm based on the Lanczos-Tikhonvo algorithm is used to calculate the insulation surface charge density distribution.

[0035] The specific operation method to obtain the actual charge distribution is as follows: Step 4.1, divide the insulating surface to be measured into N square grids, assume that the charge distribution in a single grid is uniform, preset the initial value of the charge density of the N grids according to the surface charge distribution measured by the electrostatic probe method, and calculate the spatial electric field distribution; Step 4.2, considering the distortion effect of space charge on the electric field, establish a simulation model of the space charge transport process of corona discharge under high-speed airflow, and calculate the space charge distribution and electric field distribution; Step 4.3, superimpose the above electric field calculation results and compare them with the electric field distribution measured based on EFISH. If they are consistent, the inversion is completed and the charge density distribution of the insulating surface is output; if they are inconsistent, correct the charge density values ​​of the N grids in the first step and repeat steps 4.1 and 4.2.

[0036] 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, and if the difference is not obvious, it can be considered to be consistent.

[0037] In step 4.2, the simulation charge method is used based on the COMSOL platform to build a spatial electric field distribution model. In the material setting of the model, all calculation domains are first set to air, and its relative dielectric constant is set to 1. Then set the insulating surface material in the middle of the calculation domain and set the corresponding relative dielectric constant. Other boundaries are set to zero charge boundary conditions, that is, n·D=0. Then the model is meshed by physical field control, and the insulating surface is divided into N squares. Finally, the inverted charge density is assigned to the squares to calculate and process the spatial electric field problem in the steady state.

[0038] Based on the same technical concept as the aforementioned method embodiment, the embodiment of the present invention further provides an insulating surface charge state detection device, comprising: The wind tunnel simulation test platform is used to simulate the charge state of the insulating surface of the blade when it rotates at high speed. Based on the built 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, and the charge state of the insulating surface formed under different test times, wind speeds, and angles between the insulating surface and the airflow is obtained; 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.

[0039] An insulating surface charge state detection device provided in an embodiment of the present invention aims at the current situation that there is only qualitative analysis and speculation on the friction charging process, and there is a lack of quantitative characterization of the friction charging state of the insulating surface of a rotating fan blade. The charge state of the insulating surface of the blade when rotating at high speed is simulated through a wind tunnel simulation test platform, and the charge density distribution on the insulating surface is measured and calculated 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 realizing the quantitative characterization of the friction charging state of the insulating surface of the rotating fan blade.

[0040] 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 also 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 with 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 with 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.

[0041] Based on the contents of the above device embodiments, as a preferred embodiment, an insulating surface charge state detection device provided in the embodiments of the present invention, the insulating surface charge distribution measurement system further includes: 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 perform planar movement 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 perform planar movement.

[0042] 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 an insulation surface charge inversion algorithm based on the Lanczos-Tikhonvo algorithm to calculate the insulation surface charge density distribution.

[0043] The system embodiments described above are merely illustrative, wherein the units described as separate components are or are not physically separated, and the components shown as units are or are not physical units, located in one place, or distributed on multiple network units. Some or all of the modules are selected according to actual conditions to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art can understand and implement without creative effort.

[0044] 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 preventing discharge and breakdown caused by electric field distortion and ensuring the normal operation of the wind turbine generator set.

[0045] 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, different test times, wind speeds, and angles between the insulating surface and the oncoming airflow were set to conduct tests, and the charge state of the insulating surface formed under different test times, wind speeds, and angles between the insulating 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, and different measurement results were obtained; Based on a comparative analysis of different measurement results, the effects of time, wind speed and the angle between the insulation surface and the airflow on the frictional charging of the insulation surface were 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 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 with 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. A method for detecting the charge state of an insulating surface according to claim 1, characterized in that: 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. A method for detecting the charge state of an insulating surface according to claim 1, 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 perform planar movement 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 perform planar movement.

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 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: The insulating surface to be measured is equally divided into N square grids. Assuming that the charge distribution in a single grid is uniform, the initial value of the 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, the charge density values ​​of N grids are corrected and the inversion process is repeated.

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, setting the material in all calculation domains as air, setting the insulating surface material in the middle of the calculation domain, and setting the corresponding relative dielectric constant, and setting other boundaries as zero charge boundary conditions; meshing the set model through physical field control, dividing the insulating surface into N squares; assigning the inverted charge density in the squares, and calculating the spatial electric field under steady state.

8. An insulating surface charge state detection device, characterized in that: include: The wind tunnel simulation test platform is used to simulate the charge state of the insulating surface of the blade when it rotates at high speed. Based on the built 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, and the charge state of the insulating surface formed under different test times, wind speeds, and angles between the insulating surface and the airflow is obtained; 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 with 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 with 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 perform planar movement 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 perform planar movement.

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