Insulator surface dirt humidity dynamic monitoring method and system

Abstract

The invention discloses a method and a system for dynamically monitoring the humidity of dirt on the surface of an insulator, and the method is characterized in that the method comprises the following steps: placing an insulator sample to be tested on an insulation test bench, collecting the flashover characteristics of the insulator sample, and deploying a test voltage and a sampling interval according to the flashover characteristics; collecting a multi-channel flashover spectral image of the to-be-tested insulator sample at a sampling interval by using the test voltage, and calculating a humidity value of the multi-channel flashover spectral image; and constructing a continuous time sequence of a humidity graph by utilizing the humidity values of the multi-channel flashover spectral image so as to monitor the humidity change of the insulator sample to be detected in the insulator flashover state.

Description

Technical Field

[0001] The present invention relates to the field of power systems, and more specifically, to a method and system for dynamically monitoring insulator contamination humidity. Background Art

[0002] Line insulators or power equipment bushings bear the mechanical support and electrical insulation between transmission lines and transmission towers, and between power equipment and processing lines. However, since insulators or bushings work in outdoor atmospheric environments for a long time, dirt will inevitably accumulate on the surface of the insulator to form a dirt layer, which greatly increases the risk of surface flashover of the insulator. In the development process of insulator dirt flashover (referred to as dirt flashover), the dirt layer will first be dampened in severe weather conditions such as high humidity, rain and fog. Part of the dirt will dissolve, and the leakage current on the surface of the insulator will increase. Then, the ohmic heat effect will form a local high-resistance dry zone, which will trigger a local arc, or even bridge to form a comprehensive flashover. The distribution form and moisture degree of the dirt layer play a key role in the formation of insulator dirt flashover. However, due to the limitations of measurement technology, it is difficult to effectively and directly observe the above-mentioned dynamic change process of wet dirt in experiments.

[0003] The existing methods and measurement technologies for pollution humidity mainly focus on the detection of pollution degree and overall wetness, but there are no reports on the in-situ visual measurement method of pollution wetness distribution, nor are there any special experimental devices. At present, there are three methods for detecting the overall wetness of the pollution layer in the industry: 1) Leakage current method, by applying voltage to the insulator and measuring the leakage current flowing through the polluted insulator at the ground terminal, the change trend of the total current and fundamental component is obtained to conduct a qualitative analysis of the wetness of the pollution layer. However, it is difficult to form a quantitative relationship between the unsaturated wetness and the pollution distribution and the leakage current value; 2) Conductivity method or local conductivity method, when the pollution layer is damp, accompanied by the dissolution of soluble pollutants, the conductivity of the pollution layer will increase significantly. By applying a DC voltage to the entire or local insulation, the DC leakage current is obtained, and the conductivity of the entire or local pollution layer is calculated. Since this method requires a higher applied voltage to ensure the signal-to-noise ratio of the microcurrent signal, the moisture state will change with the voltage application time, and it is difficult to obtain the initial distribution of the pollution wetness; 3) Mass difference determination method, by measuring the mass of the insulator under different wetness to achieve indirect measurement of wetness, this method only needs to obtain the initial weight under dry pollution conditions, and has high requirements for the test environment and instrument accuracy.

[0004] Generally speaking, the effect of humidity on the flashover voltage (or lightning withstand level) of insulators needs to be considered in the design of insulators. However, most of the existing experimental verifications use the flashover voltage under dirty and wet conditions for verification (called wet flashover voltage), while ignoring the dynamic process of the dirty humidity on the insulator surface under voltage (the dynamic process of humidity change will directly affect the electric field distribution on the insulator surface, thereby affecting the flashover voltage). The dynamic process is related to the insulator surface material, device type and atmospheric conditions. If the humidity dynamic process can be visualized for analysis, it can provide a more direct experimental analysis method for insulator surface optimization and insulator structure design.

[0005] In view of the above problems, there is an urgent need for a method and system for dynamically monitoring the contamination and humidity on the surface of insulators. Summary of the invention

[0006] In order to solve the deficiencies in the prior art, the present invention provides a method and system for dynamically monitoring the contamination and humidity on the surface of an insulator, providing new experimental equipment and technology for observing the dynamic characteristics of insulator flashover, preventing and controlling insulator flashover, optimizing the surface of insulating materials and designing the structure of insulators.

[0007] The present invention adopts the following technical solution.

[0008] The first aspect of the present invention relates to a method for dynamically monitoring the contamination humidity of an insulator surface, the method comprising the following steps: placing an insulator sample to be tested on an insulation test bench, collecting the flashover characteristics of the insulator sample and deploying a test voltage and a sampling interval accordingly; collecting a multi-channel flashover spectrum image of the insulator sample to be tested using the test voltage and the sampling interval, and calculating the humidity value of the multi-channel flashover spectrum image; constructing a continuous time series of a humidity map using the humidity value of the multi-channel flashover spectrum image to monitor the humidity change of the insulator sample to be tested under the insulator flashover state.

[0009] Preferably, the insulator sample to be tested is placed on an insulation test bench, the flashover characteristics of the insulator sample are collected and the test voltage and sampling interval are deployed accordingly, including: deploying the insulation test bench in a simulated environment to ensure that the errors of ambient temperature, ambient humidity, and ambient light source are controllable in a single test; connecting a high-voltage AC power frequency power supply to two electrodes on the insulation test bench connected to the insulator sample to be tested, and applying the test voltage to the insulator sample to be tested by a step-by-step pressurization method.

[0010] Preferably, a test voltage is applied to the insulator sample to be tested in a step-by-step pressurization manner, including: applying the test voltage to the insulator sample to be tested in a step-by-step pressurization manner until the surface flashover of the insulator sample to be tested is tested, and recording the voltage at the moment of surface flashover as the power frequency flashover voltage of the insulator sample to be tested; taking the power frequency flashover voltage as the highest voltage, setting a plurality of step voltages lower than or equal to the highest voltage and corresponding pressurization times, thereby obtaining the test voltage.

[0011] Preferably, collecting the flashover characteristics of the insulator sample and deploying the test voltage and sampling interval accordingly includes: the sampling interval at time t is set to:

[0012]

[0013] Where P int is the initial active power output by the high-voltage AC power frequency power supply when the test voltage is applied to the insulator sample to be tested,

[0014] U bd is the power frequency flashover voltage;

[0015] The above formula solves for the sampling interval in seconds based on the power in watts and the voltage in volts.

[0016] Preferably, a multi-channel flashover spectrum image of the insulator sample to be tested is collected using a test voltage and a sampling interval, and the humidity value of the multi-channel flashover spectrum image is calculated, including: setting non-coaxial spectrum channels, each spectrum channel has a different passing band, and collecting a multi-channel flashover spectrum image based on this; aligning the multi-channel flashover spectrum image collected at time t to obtain a multi-channel target image; using preset coefficients to solve the static humidity value of the corresponding pixel point in the multi-channel spectrum image, and using the static humidity value to solve the dynamic humidity value, so as to obtain the static humidity value and dynamic humidity value of each pixel point in the aligned multi-channel target image.

[0017] Preferably, the static humidity value of the corresponding pixel point in the multi-channel spectral image is solved by using the preset coefficient, and the dynamic humidity value is solved by using the static humidity value, including: the static humidity value is:

[0018]

[0019] Where k is the spectral channel number, Ω is the number set of visible light spectral channels,

[0020] m s (t) = [m s-mn ] MN , m s-mn is the pixel value of the mth row and nth column in the multi-channel target image at time t, M×N is the number of image pixels,

[0021] is the spectral reflectance matrix of the target image under the kth spectral channel at time t,

[0022] a k , b are preset coefficients.

[0023] Preferably, the spectral reflectance matrix R of the target image under different spectral channels isλk The way to obtain is:

[0024]

[0025] Where W λk is the channel white calibration grayscale value under the acquisition band of the kth spectral channel,

[0026] B λk Calibrates the grayscale value for the channel black at the acquisition band of the kth spectral channel.

[0027] Preferably, the static humidity value of the corresponding pixel point in the multi-channel spectral image is solved by using the preset coefficient, and the dynamic humidity value is solved by using the static humidity value, including: the dynamic humidity value is:

[0028] m d (t) = m s (t) · [exp(t / H) - r · exp(t / T)]

[0029] Where H is the pixel grayscale matrix of the image collected by the mid-infrared spectral channel,

[0030] T is the temperature of the simulated environment, and r is the relative humidity of the simulated environment.

[0031] Preferably, a continuous time series of a humidity map is constructed using the humidity values ​​of the multi-channel flashover spectrum image to monitor the humidity change of the insulator sample to be tested under the insulator flashover state, including: the continuous humidity map generated at the continuous sampling time [t0, t1, ...] is:

[0032] F(t)=[m d (t0),m d (t1),…].

[0033] The second aspect of the present invention relates to a system for dynamically monitoring the contamination and humidity of an insulator surface, which is implemented by a method for dynamically monitoring the contamination and humidity of an insulator surface in the first aspect of the present invention; the system includes a deployment module, a calculation module and a monitoring module; wherein the deployment module is used to place the insulator sample to be tested on an insulation test bench, collect the flashover characteristics of the insulator sample and deploy the test voltage and sampling interval accordingly; the calculation module is used to collect the multi-channel flashover spectrum image of the insulator sample to be tested using the test voltage and sampling interval, and calculate the humidity value of the multi-channel flashover spectrum image; the monitoring module is used to construct a continuous time series of humidity diagrams using the humidity values ​​of the multi-channel flashover spectrum image, so as to monitor the humidity changes of the insulator sample to be tested in the insulator flashover state. The beneficial effect of the present invention is that, compared with the prior art, the method and system for dynamically monitoring the contamination and humidity of an insulator surface in the present invention provide new experimental devices and technologies for observing the dynamic characteristics of insulator flashover, preventing and controlling insulator flashover, optimizing the surface of insulating materials and designing insulator structures. The device and method for dynamic monitoring of contamination and humidity on the insulator surface proposed in the present invention are based on the principle of jointly measuring reflection spectrum imaging and infrared imaging under artificial light source and realizing visualization of contamination and humidity on the insulator surface through algorithm inversion. It has good gradient characteristics and can obtain two-dimensional image characteristics of humidity distribution.

[0034] The beneficial effects of the present invention also include:

[0035] 1. Compared with the existing insulator surface humidity measurement method, the present invention can not only obtain the overall humidity state of the contamination layer, but also analyze the distribution of the surface humidity of the contamination layer. The distribution characteristics of the contamination humidity are the key factors affecting the voltage withstand performance of the insulator.

[0036] 2. Compared with the existing insulator surface humidity measurement device, the present invention adopts a completely non-contact, sampling-free imaging technology to achieve significant improvement in measurement efficiency and target coverage. It can be used for insulator performance research and verification, as well as for live inspection of actual insulators.

[0037] 3. Compared with the single-band image analysis method, the present invention can more accurately invert and analyze the interaction process between the dynamic changes of pollution humidity and current-induced heating, and is more suitable for insulator researchers or manufacturing companies to conduct mechanism research and performance optimization. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of a simulated environment in a method for dynamically monitoring the contamination humidity on the surface of an insulator according to the present invention;

[0039] Figure 2 It is a flow chart of a method for dynamically monitoring the contamination humidity on the surface of an insulator according to the present invention;

[0040] Figure 3 It is an insulator contamination humidity diagram in a method for dynamically monitoring contamination humidity on the surface of an insulator according to the present invention;

[0041] Reference numerals:

[0042] Figure 1 (a) -1 small environmental simulation chamber, -2 non-Tongzhou 6-spectral channel imaging acquisition device, -3 uniform halogen light source group, -4 high voltage power supply, -5 cavity sleeve, -6 host computer image analysis system;

[0043] Figure 1 (b) -1 to -3 visible and near-infrared spectral channels, -6 mid-infrared spectral channel. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical scheme and advantages of the present invention clearer, the technical scheme of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. The embodiments described in the present invention are only embodiments of a part of the present invention, not all embodiments. Based on the spirit of the present invention, all other embodiments not recorded in the present invention obtained by ordinary technicians in this field according to the embodiments recorded in the present invention without making creative work should belong to the protection scope of the present invention.

[0045] The three main pollution wetness test methods described in the background technology are unable to quickly and effectively obtain the spatial distribution of pollution wetness, and are even more unable to obtain in situ the spatial dynamic changes of pollution wetness with applied voltage or leakage current. This makes it difficult to effectively observe the effect of humidity on leakage current and flashover path under voltage under specific conditions such as insulator type or insulator surface state, and there is a lack of experimental basis for insulator type design and material selection.

[0046] Figure 1 The figure is a schematic diagram of the simulated environment in a method for dynamically monitoring the contamination and humidity of an insulator surface according to the present invention. Figure 2 As shown, the first aspect of the present invention relates to a method for dynamically monitoring the contamination and humidity on the surface of an insulator, and the method includes steps 1 to 3.

[0047] Step 1: Place the insulator sample to be tested on the insulation test bench, collect the flashover characteristics of the insulator sample and deploy the test voltage and sampling interval accordingly.

[0048] Preferably, the insulator sample to be tested is placed on an insulation test bench, the flashover characteristics of the insulator sample are collected and the test voltage and sampling interval are deployed accordingly, including: deploying the insulation test bench in a simulated environment to ensure that the errors of ambient temperature, ambient humidity, and ambient light source are controllable in a single test; connecting a high-voltage AC power frequency power supply to two electrodes on the insulation test bench connected to the insulator sample to be tested, and applying the test voltage to the insulator sample to be tested by a step-by-step pressurization method.

[0049] The inner wall of the small environment simulation chamber is made of light-absorbing material with an absorbance of more than 90%, which can simulate an environmental relative humidity range of 20% to 85%, and the humidity change rate within 5 minutes is not higher than 5%. The spectral response range requirements of each spectral channel of the non-coaxial 6-spectral channel imaging acquisition device are as follows: visible spectral channel 1 (406±25nm); visible spectral channel 2 (533±25nm); visible spectral channel 3 (681±25nm); near-infrared spectral channel 4 (912±25nm); near-infrared spectral channel 5 (983±25nm); mid-infrared spectral channel 6 (8-12μm).

[0050] The pixel resolution of each spectral channel of the non-coaxial 6-spectral channel imaging acquisition device shall not be less than 640×480px, the image registration rate of the 6 channels above the shooting distance of 50cm shall not be less than 90%, and the maximum shutter speed shall not be less than 1 / 250s. The high-voltage power supply can generate a high-voltage AC voltage of 40 to 60Hz, and the maximum output current under each voltage shall not be less than 5A.

[0051] Collect the flashover characteristics of the insulator samples and deploy the test voltage and sampling interval accordingly, including: the sampling interval at time t is set to:

[0052]

[0053] Where P int is the initial active power output by the high-voltage AC power frequency power supply when the test voltage is applied to the insulator sample to be tested, U bd is the power frequency flashover voltage; the above formula is solved for the sampling interval in seconds based on the power in watts and the voltage in volts.

[0054] The sampling interval can be set flexibly, and the interval time is related to the power of the power supply and the surface flashover voltage of the insulator, ensuring that the continuous humidity changes of the insulator during the test can be collected.

[0055] In the above formula, P int U is the active power output by the power supply. bd Take the flashover voltage value under power frequency AC voltage when the surface of the tested insulator or insulation sample is clean and the atmospheric humidity is less than 30%.

[0056] Step 2: collect a multi-channel flashover spectrum image of the insulator sample to be tested using a test voltage and a sampling interval, and calculate a humidity value of the multi-channel flashover spectrum image.

[0057] The method of the present invention is realized by relying on the above monitoring device. In the necessary preparation and debugging process before the test, the contaminated insulator or contaminated sample is placed flat on the Figure 1 The halogen lamp is turned on and the illumination power is adjusted to the upper limit that does not cause saturation of the spectral channel acquisition device.

[0058] A test voltage is applied to the insulator sample to be tested in a step-by-step pressurization manner, including: applying the test voltage to the insulator sample to be tested in a step-by-step pressurization manner until the surface flashover of the insulator sample to be tested is tested, and recording the voltage at the moment of surface flashover as the power frequency flashover voltage of the insulator sample to be tested; taking the power frequency flashover voltage as the highest voltage, setting a plurality of step voltages lower than or equal to the highest voltage and corresponding pressurization times, thereby obtaining the test voltage.

[0059] Aim the field of view of the device at the test sample, and apply voltage to the test sample in a step-by-step manner. The applied voltage level should be consistent with the working voltage of the insulator. If the test sample is a non-type insulator or an insulating sample, the flashover voltage should be the upper limit.

[0060] The multi-channel flashover spectrum image of the insulator sample to be tested is collected by using a test voltage and a sampling interval, and the humidity value of the multi-channel flashover spectrum image is calculated, including: setting non-coaxial spectrum channels, each spectrum channel has a different passing band, and collecting multi-channel flashover spectrum images accordingly; aligning the multi-channel flashover spectrum images collected at time t to obtain a multi-channel target image; using preset coefficients to solve the static humidity value of the corresponding pixel point in the multi-channel spectrum image, and using the static humidity value to solve the dynamic humidity value, so as to obtain the static humidity value and dynamic humidity value of each pixel point in the aligned multi-channel target image.

[0061] The static humidity value of the corresponding pixel point in the multi-channel spectral image is solved by using the preset coefficient, and the dynamic humidity value is solved by using the static humidity value, including: the static humidity value is:

[0062]

[0063] Where k is the spectral channel number, Ω is the number set of visible light spectral channels, and m s (t) = [m s-ij ] MN , m s-mnis the pixel value of the mth row and nth column in the multi-channel target image at time t, M×N is the number of image pixels, is the spectral reflectance matrix of the target image under the kth spectral channel at time t, a k , b are preset coefficients.

[0064] In one embodiment, the pixel grayscale data collected from spectral channels 1 to 5 are calculated according to the following formula to obtain the static humidity value m: s :

[0065]

[0066] Wherein, a1 and a2 are positive correlation coefficients given in the present invention, -a3, -a4 and -a5 are negative correlation coefficients given in the present invention, and b is a compensation coefficient given in the present invention.

[0067] The preferred typical parameters are as follows:

[0068] a1 a2 a3 a4 a5 b 1.45 4.78 4.60 7.18 1.05 1.70

[0069] Among them, R 406 , R 533 , R 681 , R 912 and R 983 They are the spectral reflectances corresponding to wavelengths of 406nm, 533nm, 681nm, 912nm and 983nm, respectively, which need to be measured by standard black and white boards before each experiment.

[0070] The correlation coefficients a1 to a5 and the compensation coefficient b are recommended values ​​obtained by measuring and fitting different dirt label samples and different humidity conditions in the laboratory, and are also the preferred parameters of the present invention. Adjusting these parameters may affect the implementation effect of the invention.

[0071] Spectral reflectance matrix R of target image under different spectral channels λk The way to obtain is:

[0072]

[0073] Where W λk is the channel white calibration grayscale value under the acquisition band of the kth spectral channel, B λk Calibrates the grayscale value for the channel black at the acquisition band of the kth spectral channel.

[0074] The black calibration grayscale value is the average grayscale value of the pixels on the screen obtained by uniformly irradiating a black diffuse reflector with good Lambertian scattering characteristics and a reflectivity of less than 5% with a characteristic wavelength light source. The white calibration grayscale value is the average grayscale value of the pixels on the screen obtained by uniformly irradiating a white diffuse reflector with good Lambertian scattering characteristics and a reflectivity of more than 90% with a characteristic wavelength light source. Each channel is calibrated by itself, and the grayscale value of the black and white board calibration is determined by measuring the black and white board before shooting the actual object. Use a wide spectrum light source to cover the bands of all channels.

[0075] The static humidity value of the corresponding pixel point in the multi-channel spectral image is solved by using the preset coefficient, and the dynamic humidity value is solved by using the static humidity value, including: the dynamic humidity value is:

[0076] m d (t) = m s (t) · [exp(t / H) - r · exp(t / T)]

[0077] Wherein, H is the pixel grayscale matrix of the image collected by the mid-infrared spectral channel, which is channel 6 in the present invention. T is the temperature of the simulated environment, and r is the relative humidity of the simulated environment.

[0078] The pixel grayscale data collected by infrared spectrum channel No. 6 is calculated according to the above formula to obtain the dynamic humidity value.

[0079] Step 3, using the humidity values ​​of the multi-channel flashover spectrum image to construct a continuous time series of humidity diagrams, so as to monitor the humidity changes of the insulator sample to be tested under the insulator flashover state.

[0080] Figure 2 FIG. 1 is a flow chart of a method for dynamically monitoring the contamination humidity on the surface of an insulator according to the present invention. Figure 2 As shown, a continuous time series of humidity graphs is constructed using humidity values ​​of multi-channel flashover spectrum images to monitor humidity changes of insulator samples to be tested under insulator flashover conditions, including: a continuous humidity graph generated at continuous sampling times [t0, t1, ...] is:

[0081] F(t)=[m d (t0),m d (t1),…].

[0082] Compared with the existing insulator surface humidity measurement method, the present invention can not only obtain the overall humidity state of the pollution layer, but also analyze the distribution of humidity on the surface of the pollution layer, and the distribution characteristics of pollution humidity are the key factors affecting the voltage tolerance performance of the insulator. The present invention adopts a completely non-contact, sampling-free imaging technology to achieve this, and the measurement efficiency and target coverage are significantly improved. It can be used for insulator performance research and verification, and can also be used for live inspection of actual insulators. Compared with the single-band image analysis method, the present invention can more accurately invert and analyze the interaction process between the dynamic change of pollution humidity and current-induced heating, and is more suitable for insulator pollution flashover research or verification of insulator device design.

[0083] Figure 3 This is an insulator contamination humidity diagram in a method for dynamically monitoring contamination humidity on the surface of an insulator according to the present invention. Figure 3 As shown, the present invention adopts silicone rubber material. After the grayscale image collected by the multi-channel spectral device is converted into a humidity image, the significant change process of the contamination humidity on the surface of the insulator can be obtained.

[0084] The second aspect of the present invention relates to a system for dynamically monitoring contamination and humidity on the surface of an insulator, characterized in that: the system is implemented using a method for dynamically monitoring contamination and humidity on the surface of an insulator in the first aspect of the present invention; the system includes a deployment module, a calculation module and a monitoring module; wherein the deployment module is used to place the insulator sample to be tested on an insulation test bench, collect the flashover characteristics of the insulator sample and deploy the test voltage and sampling interval accordingly; the calculation module is used to collect a multi-channel flashover spectrum image of the insulator sample to be tested using the test voltage and sampling interval, and calculate the humidity value of the multi-channel flashover spectrum image; the monitoring module is used to construct a continuous time series of humidity diagrams using the humidity values ​​of the multi-channel flashover spectrum images, so as to monitor the humidity changes of the insulator sample to be tested under the insulator flashover state.

[0085] 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 above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents, and any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for dynamically monitoring the contamination humidity on the surface of an insulator, characterized in that: The method comprises the following steps: Place the insulator sample to be tested on the insulation test bench, collect the flashover characteristics of the insulator sample and deploy the test voltage and sampling interval accordingly; Collecting a multi-channel flashover spectrum image of the insulator sample to be tested by using a test voltage and a sampling interval, and calculating a humidity value of the multi-channel flashover spectrum image; The humidity values ​​of the multi-channel flashover spectrum images are used to construct a continuous time series of humidity maps to monitor the humidity changes of the insulator samples under the insulator flashover state.

2. A method for dynamically monitoring the contamination humidity on the surface of an insulator according to claim 1, characterized in that: The method of placing the insulator sample to be tested on the insulation test bench, collecting the flashover characteristics of the insulator sample and deploying the test voltage and sampling interval accordingly includes: The insulation test bench is deployed in a simulated environment to ensure that the errors of ambient temperature, ambient humidity, and ambient light source are controllable in a single test; Connect a high-voltage AC power frequency power supply to two electrodes connected to the insulator sample to be tested on the insulation test bench, and apply a test voltage to the insulator sample to be tested in a step-by-step pressurization manner.

3. A method for dynamically monitoring the contamination humidity on the surface of an insulator according to claim 2, characterized in that: The step-by-step pressurization method is used to apply the test voltage to the insulator sample to be tested, including: Applying a test voltage to the insulator sample to be tested in a step-by-step pressurization manner until a surface flashover of the insulator sample to be tested is detected, and recording the voltage at the moment of surface flashover as the power frequency flashover voltage of the insulator sample to be tested; The power frequency flashover voltage is taken as the highest voltage, and a plurality of step voltages lower than or equal to the highest voltage and corresponding pressure application times are set to obtain the test voltage.

4. A method for dynamically monitoring the contamination humidity on the surface of an insulator according to claim 1, characterized in that: The method of collecting the flashover characteristics of the insulator samples and deploying the test voltage and sampling interval accordingly includes: The sampling interval at time t is set as: Where P int is the initial active power output by the high-voltage AC power frequency power supply when the test voltage is applied to the insulator sample to be tested, U bd is the power frequency flashover voltage; The above formula solves for the sampling interval in seconds based on the power in watts and the voltage in volts.

5. A method for dynamically monitoring the contamination humidity on the surface of an insulator according to claim 1, characterized in that: The method of collecting a multi-channel flashover spectrum image of the insulator sample to be tested by using a test voltage and a sampling interval, and calculating a humidity value of the multi-channel flashover spectrum image, comprises: Non-coaxial spectral channels are set, each of which has a different passing band, and multi-channel flash spectrum images are collected accordingly; The multi-channel flash spectrum image acquired at time t is registered to obtain a multi-channel target image; The static humidity value of the corresponding pixel point in the multi-channel spectral image is solved using the preset coefficient, and the dynamic humidity value is solved using the static humidity value, so as to obtain the static humidity value and dynamic humidity value of each pixel point in the registered multi-channel target image.

6. A method for dynamically monitoring the contamination humidity on the surface of an insulator according to claim 1, characterized in that: The method of solving the static humidity value of the corresponding pixel point in the multi-channel spectral image by using the preset coefficient and solving the dynamic humidity value by using the static humidity value includes: The static humidity value is: Where k is the spectral channel number, Ω is the number set of visible light spectral channels, m s (t) = [m s-mn ] MN , m s-mn is the pixel value of the mth row and nth column in the multi-channel target image at time t, M×N is the number of image pixels, is the spectral reflectance matrix of the target image under the kth spectral channel at time t, a k , b are preset coefficients.

7. A method for dynamically monitoring the contamination humidity on the surface of an insulator according to claim 6, characterized in that: The spectral reflectance matrix R of the target image under different spectral channels λk The way to obtain is: Where W λk is the channel white calibration grayscale value under the acquisition band of the kth spectral channel, B λk Calibrates the grayscale value for the channel black at the acquisition band of the kth spectral channel.

8. A method for dynamically monitoring the contamination humidity on the surface of an insulator according to claim 7, characterized in that: The method of solving the static humidity value of the corresponding pixel point in the multi-channel spectral image by using the preset coefficient and solving the dynamic humidity value by using the static humidity value includes: The dynamic humidity value is: m d (t)=m s (t)·[exp(t / H)-r·exp(t / T)] Where H is the pixel grayscale matrix of the image collected by the mid-infrared spectral channel, T is the temperature of the simulated environment, and r is the relative humidity of the simulated environment.

9. A method for dynamically monitoring the contamination humidity on the surface of an insulator according to claim 1, characterized in that: The method of constructing a continuous time series of humidity graphs using humidity values ​​of multi-channel flashover spectrum images to monitor humidity changes of the insulator sample to be tested in the insulator flashover state includes: The continuous humidity graph generated by the humidity graph at continuous sampling times [t0, t1, ...] is: F(t)=[m d (t0),m d (t1),…]。 10. A dynamic monitoring system for the contamination and humidity of an insulator surface, characterized in that: The system is implemented by using a method for dynamically monitoring the contamination and humidity of an insulator surface as described in any one of claims 1 to 9; The system includes a deployment module, a calculation module and a monitoring module; wherein, The deployment module is used to place the insulator sample to be tested on the insulation test bench, collect the flashover characteristics of the insulator sample and deploy the test voltage and sampling interval accordingly; The calculation module is used to collect the multi-channel flashover spectrum image of the insulator sample to be tested by using the test voltage and the sampling interval, and calculate the humidity value of the multi-channel flashover spectrum image; The monitoring module is used to construct a continuous time series of humidity diagrams using humidity values ​​of multi-channel flashover spectrum images, so as to monitor humidity changes of the insulator sample to be tested under the insulator flashover state.

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