Insulator surface algae grading measurement method based on photothermal radiation

Abstract

The invention provides a grading measurement method for algae on the surface of an insulator based on photothermal radiation. The efficiency and safety of operation and maintenance of a power system are effectively improved. The method comprises the following steps: irradiating the surface of the insulator by using a light source to excite algae to generate heat radiation; capturing thermal radiation change by using a thermal imager; analyzing thermal radiation and thermal image data through a processing unit, determining algae distribution and density, and calculating an algae coverage rate; and determining an algae coverage degree grade according to a pre-calibrated empirical function relationship between the algae coverage rate and the insulator flashover voltage drop rate. The method is non-contact and efficient, the detection accuracy of the algae on the surface of the insulator is improved, the detection risk is reduced, and the method is suitable for maintenance and monitoring of the insulator in a power system.

Description

Technical Field

[0001] The invention relates to an insulator detection technology, and in particular to an insulator surface algae classification measurement method based on photothermal radiation. Background Art

[0002] In recent years, power grid companies have discovered that a large number of algae have attached to insulators of transmission lines in mountainous areas in the southwest. Algae attachment poses a huge risk to the safe operation and maintenance of the lines. On the one hand, algae make it easier for dirt to attach to insulators, which accelerates the rate of dirt accumulation on insulators, and the problem of excessive dirtiness is prone to occur, resulting in an increase in the number of power outages for cleaning. On the other hand, algae on the surface of insulators are easily damaged by external forces, which increases the risk of slipping hands or feet of operation and maintenance personnel, greatly affecting the safety and efficiency of maintenance work. Traditional algae detection methods such as manual inspection and chemical analysis have problems of low efficiency and insufficient accuracy. At present, there is no grading measurement method for algae on the surface of insulators that can be directly applied to engineering practice. Existing studies mainly include starting from biomass, using coverage area and algae cell density as parameters for grading strategies or based on the visual observation and experience of operation and maintenance personnel for manual power outage cleaning. However, from the perspective of power system observation, it is unreliable to evaluate the probability of flashover accidents on the surface of insulators based solely on the algae coverage area or density or manual observation. Therefore, developing an efficient and accurate hierarchical measurement method is of great significance to help the power sector promptly detect potential risks and carry out operation and maintenance.

[0003] It should be noted that the information disclosed in the above background technology section is only used for understanding the background of the present application, and therefore may include information that does not constitute prior art known to ordinary technicians in the field. Summary of the invention

[0004] The main purpose of the present invention is to overcome the defects existing in the above-mentioned background technology and provide a method for measuring algae classification on the surface of an insulator based on photothermal radiation.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for measuring algae classification on an insulator surface based on photothermal radiation, comprising:

[0007] S1. Irradiate the surface of the insulator to be tested with light to stimulate the algae to generate thermal radiation;

[0008] S2, capturing the changes in thermal radiation on the insulator surface caused by light irradiation;

[0009] S3, inputting the thermal radiation change data into the processing unit for analysis to determine the distribution and density of algae on the surface of the insulator, thereby obtaining the algae coverage rate;

[0010] S4. Based on the obtained algae coverage rate and the empirical functional relationship between the algae coverage rate and the insulator flashover voltage drop rate, calculate the drop value of the insulator flashover voltage, and determine the level of algae coverage according to the drop value of the insulator flashover voltage; wherein the empirical functional relationship between the algae coverage rate and the insulator flashover voltage drop rate is established through prior experimental calibration.

[0011] Furthermore, the method further includes a step of calibrating parameters for algae detection and classification on the insulator surface in a specific area, the step comprising:

[0012] Select region-specific algae-covered insulators as test samples;

[0013] Under the simulated regional environmental conditions, the samples were treated with constant temperature and humidity;

[0014] The insulator flashover voltage under different algae coverage was measured by the up-down method.

[0015] Calculate the average value and standard deviation of the flashover voltage based on multiple test data;

[0016] Using the obtained average flashover voltage and standard deviation, the proportionality coefficient of the flashover voltage drop rate associated with the algae coverage was determined.

[0017] Furthermore, it also includes monitoring the real-time ambient temperature through an ambient temperature sensor before measurement or calibration, and performing temperature compensation in the data analysis during measurement to reduce the impact of ambient temperature changes on the detection results.

[0018] Furthermore, the light source used in step S1 is a pulsed xenon flash lamp with a wavelength range of 400nm to 700nm, a pulse duration of 1ms to 10ms, and an energy density of 1J / cm 2 .

[0019] Furthermore, the wavelength range of the thermal imager used in step S2 is 8 μm to 14 μm, and the thermal sensitivity reaches ≤0.05°C.

[0020] Furthermore, in the empirical function relationship in step S4, for every 10% increase in algae coverage, the flashover voltage decreases by about 8% to 9%.

[0021] Furthermore, in step S4, the formula for calculating the insulator flashover voltage drop value is ΔV=V0×k×10C, where k is the proportionality coefficient and C is the algae coverage rate.

[0022] Furthermore, in step S4, according to the calculation result of the flashover voltage drop rate, the algae coverage degree is divided into three levels: light: coverage rate 0%-20%, medium: coverage rate 20%-40%, and heavy: coverage rate>40%.

[0023] The present invention has the following beneficial effects:

[0024] The present invention comprehensively applies photothermal radiation technology and image processing technology to propose an efficient, accurate, safe and reliable method for measuring the algae classification on the surface of an insulator. The method uses a light source to illuminate the surface of the insulator to stimulate the algae to generate thermal radiation, and then uses a high-precision infrared camera or thermal imager to capture the thermal radiation changes caused by light irradiation. The distribution and density of the algae are determined by the processing unit analysis, thereby obtaining the algae coverage rate. Based on the empirical function relationship calibrated in advance, the drop value of the insulator flashover voltage is calculated according to the algae coverage rate, and the level of algae coverage is determined according to the drop value of the insulator flashover voltage. This detection method of the present invention not only avoids direct contact with the surface of the insulator, reduces the risk of damage, but also improves the efficiency and accuracy of the detection. By clarifying the wavelength range, energy density and performance parameters of the light source and the thermal imager, the present invention is an efficient, safe and reliable detection scheme suitable for insulator maintenance and monitoring in the power system, which significantly improves the efficiency and accuracy of algae detection, helps the power department to timely discover and deal with potential risks, and ensure the safe operation and maintenance of the power grid.

[0025] Other beneficial effects of the embodiments of the present invention will be further described below. DETAILED DESCRIPTION

[0026] The following is a detailed description of the embodiments of the present invention. It should be emphasized that the following description is only exemplary and is not intended to limit the scope and application of the present invention.

[0027] The present invention proposes a method for measuring the grading of algae on the surface of an insulator based on photothermal radiation, realizing a non-destructive testing method mainly based on photothermal radiation. By irradiating a laser beam or pulsed light onto the surface of the insulator, the light energy is absorbed by the surface of the insulator and converted into heat energy, resulting in an increase in the local temperature of the surface of the insulator. Due to the different thermal conductivity and thermal expansion characteristics caused by different amounts of algae attachment, the difference in algae attachment on the surface of the insulator will cause abnormal changes in the surface temperature. These temperature changes are recorded by a high-precision infrared camera or thermal imager, and then the relationship between the abnormal temperature distribution and the growth of algae on the surface of the insulator is analyzed by a processing unit, so that the growth of algae on the surface of the insulator can be obtained, and then the insulator flashover voltage drop rate is obtained according to the empirical function, and finally the algae coverage level on the surface of the insulator is determined.

[0028] The embodiment of the present invention provides a method for measuring algae classification on an insulator surface based on photothermal radiation, comprising:

[0029] Step S1, irradiating the surface of the insulator to be tested with light to stimulate the algae to generate thermal radiation.

[0030] Preferably, a pulsed xenon flash lamp is used as the light source, with a wavelength range of 400nm to 700nm, a pulse duration of 1ms to 10ms, and an energy density of 1J / cm 2 .

[0031] Step S2: capturing the change of thermal radiation on the surface of the insulator caused by light irradiation.

[0032] Preferably, the wavelength range of the thermal imager used is 8 μm to 14 μm, and the thermal sensitivity reaches ≤0.05°C.

[0033] Step S3, inputting the thermal radiation change data into the processing unit for analysis to determine the distribution and density of algae on the surface of the insulator, thereby obtaining the algae coverage rate;

[0034] Step S4: Calculate the drop value of the insulator flashover voltage based on the obtained algae coverage rate and the empirical functional relationship between the algae coverage rate and the insulator flashover voltage drop rate, and The drop in flashover voltage determines the algae The coverage level of algae is The empirical functional relationship between the voltage drop rate of the insulator flashover is established through preliminary experimental calibration.

[0035] In some embodiments, the formula for calculating the insulator flashover voltage drop value is ΔV=V0×k×10C, where k is the proportionality coefficient and C is the algae coverage. In one embodiment, according to the empirical function relationship, for every 10% increase in algae coverage, the flashover voltage drops by about 8% to 9%.

[0036] In some embodiments, according to the calculation result of the flashover voltage drop rate, the algae coverage degree is divided into three levels: light: coverage rate 0%-20%, medium: coverage rate 20%-40%, and heavy: coverage rate >40%.

[0037] In a preferred embodiment, the method further includes the step of calibrating parameters for the detection and classification of algae on the surface of insulators in a specific area, which specifically includes: selecting algae-covered insulators in a specific area as test samples; subjecting the samples to constant temperature and humidity treatment under simulated regional environmental conditions; using the lifting and lowering method to measure the flashover voltage of insulators under different algae coverage; calculating the average value and standard deviation of the flashover voltage based on multiple test data; using the obtained average flashover voltage and standard deviation to determine the proportional coefficient of the flashover voltage drop rate related to the algae coverage. Preferably, before measurement or calibration, the real-time ambient temperature is first monitored by an ambient temperature sensor, and temperature compensation is performed in the data analysis during measurement to reduce the impact of ambient temperature changes on the detection results.

[0038] The present invention proposes a new method for measuring the graded algae on the surface of insulators in an efficient, accurate, safe and reliable manner by innovatively integrating photothermal radiation technology and image processing technology. The method irradiates the surface of the insulator with a light source of appropriate wavelength to stimulate the attached algae to produce a measurable thermal radiation signal, combines the thermal radiation changes captured by the thermal imager, and uses image processing methods to analyze the distribution and density of the algae, and accurately calculates the algae coverage rate. Based on this coverage rate and the empirical function relationship obtained in advance through experimental calibration, the present invention can accurately calculate the drop value of the insulator flashover voltage, and determine the level of algae coverage accordingly. The method of the present invention improves the efficiency and accuracy of detection through precise photothermal and thermal image data analysis, and at the same time, the non-contact nature reduces the risk of physical damage to the insulator. The present invention is an efficient and reliable detection scheme suitable for the maintenance and monitoring of insulators in power systems, which significantly improves the efficiency and accuracy of algae detection, helps the power sector to promptly discover and deal with potential risks, and ensures the safe operation and maintenance of the power grid.

[0039] The specific embodiments of the present invention are further described below.

[0040] A method for measuring algae classification on the surface of an insulator based on photothermal radiation, the specific measurement process includes the following steps:

[0041] 1. Sample processing and placement:

[0042] Place the algae-covered insulator to be tested between the light source and the thermal sensor of the detection system to ensure that its surface is completely exposed in the detection area. In order to adapt to the complex outdoor ambient light intensity and temperature conditions, a flash lamp (pulse light source) that can instantly release high-energy pulses is selected to quickly heat the insulator surface.

[0043] 2. Light source selection and excitation:

[0044] Start the light source and irradiate the surface of the insulator. A pulsed xenon lamp is selected as the light source. The wavelength range of the emitted light is 400nm to 700nm, which corresponds to the visible spectrum range. In this band, the algae have a higher absorption rate of light energy. The pulse duration is set to 1ms to 10ms, and the energy density is 1J / cm 2 to ensure that the algae can fully absorb light energy without causing damage to the insulator surface.

[0045] 3. Thermal radiation capture:

[0046] Algae absorb light energy and convert it into heat energy, causing local temperature rise. High-resolution thermal imagers can be used to capture changes in thermal radiation on the surface of insulators. Thermal imagers have a wavelength range of 8μm to 14μm (long-wave infrared) and a thermal sensitivity of ≤0.05℃, which can detect tiny temperature differences and obtain accurate thermal images even when the ambient temperature fluctuates.

[0047] 4. Data input and processing:

[0048] The collected thermal signal data is input into the processing unit to obtain a thermal image, which can be analyzed and processed through common techniques such as image preprocessing, threshold segmentation, feature extraction, and pattern recognition. The distribution and density of algae on the surface of the insulator can be analyzed and determined through thermal image segmentation and pattern recognition technology.

[0049] 5. Calculation of flashover voltage drop rate:

[0050] After the sample is processed, the flashover voltage drop rate is calculated based on the empirical functional relationship between the algae coverage rate and the insulator flashover voltage drop rate established by the pre-test calibration. Assuming that the initial flashover voltage of the insulator is V0 and the algae coverage rate is C (expressed as a decimal, such as 10% coverage rate is 0.1), the flashover voltage drop value ΔV can be expressed as:

[0051] ΔV=V0×k×10C(1)

[0052] Wherein, k is the proportionality coefficient. Experiments show that for every 10% increase in algae coverage, the flashover voltage decreases by about 8%, that is, k = -0.08. Considering the influence of ash content in actual operation, the parameter k is calibrated to -0.09.

[0053] Through the above-mentioned test calibration, the corresponding relationship between the local radiation and image data and the local algae coverage on the insulator surface can be established. Preferably, since there are differences in the types of algae on the insulator surface and the equivalent salt ash density in various regions, the parameter k is first recalibrated for the detection and classification of algae on the insulator surface in a specific area. The specific method includes the following steps:

[0054] 1) Select the algae-covered insulators in the area to be tested as calibration test samples.

[0055] 2) Use the detection system to detect the algae coverage on the surface of the test sample.

[0056] 3) Calibration test: Before the test, place the sample in a constant temperature and humidity chamber for 10 minutes. The temperature and humidity chamber is calibrated at 25℃ and 75% humidity (in this case, the temperature and humidity conditions in the southwestern mountainous area are simulated). Then, the flashover voltage U of the algae-covered insulator under different coverage amounts is measured by the lifting and lowering method. F Before the test, the insulator flashover voltage U m Make an estimate. Use the estimated voltage as the starting voltage for the experiment. The insulator flashes over, reducing ΔU, ΔU is U m 3%, the insulator does not flash over, and ΔU is increased. To ensure the effectiveness of the test, it is better to conduct at least 6 tests, and the standard deviation of each test should be less than 5%. F The calculation formula for its standard deviation σ is shown below.

[0057]

[0058] Where: U i is the i-th flashover voltage, kV; n is the total number of discharge tests.

[0059] The parameter k is calculated using formula (1):

[0060] To reduce the impact of sunlight, try to choose a time period with weaker light, such as morning or evening, to avoid the impact of strong sunlight at noon on the testing process. To avoid the impact of ambient temperature changes on the test results, try to test in weather with stable ambient temperature.

[0061] Preferably, before measurement or calibration, the real-time ambient temperature can be monitored by an ambient temperature sensor, and temperature compensation can be performed in data analysis to reduce the impact of ambient temperature changes on the detection results.

[0062] 7. Algae classification and report generation:

[0063] According to the calculation results of the flashover voltage drop rate, the algae coverage is divided into three levels: light (0%-20%), moderate (20%-40%) and severe (>40%). The processing unit generates a detailed inspection report, including algae distribution map, coverage rate, flashover voltage drop rate and maintenance recommendations.

[0064] Example of application of empirical function:

[0065] Assuming that the initial flashover voltage of the insulator is 100 kV and the algae coverage rate detected is 30% (C = 0.3), the drop in flashover voltage is:

[0066] ΔV=100kV×(-0.09)×0.3×10=-27kV

[0067] Therefore, algae coverage causes the insulator flashover voltage to drop by 27 kV, and its safety needs to be evaluated based on actual application scenarios.

[0068] The embodiment realizes accurate detection and evaluation of algae growth on the surface of insulators by clarifying the wavelength range and energy density of the light source, the performance parameters of the thermal imager, and the quantitative relationship between the algae coverage and the flashover voltage drop rate.

[0069] The main technical parameters of the measurement system are shown in Table 1:

[0070] Table 1

[0071]

[0072] Compared with traditional detection technologies, the method proposed in the present invention can not only realize the rapid and efficient detection of algae on the surface of insulators, but also improve the accuracy of graded measurement by combining photothermal radiation and image processing technology. At the same time, the present invention avoids direct contact with the surface of the insulator. This non-contact detection method reduces the risk of insulator damage. In short, the graded measurement method of algae on the surface of insulators combined with photothermal radiation proposed in the present invention provides an efficient, safe and reliable innovative detection solution, which is suitable for insulator maintenance and monitoring in power systems and improves the efficiency and accuracy of algae detection.

[0073] The above content is a further detailed description of the present invention in combination with specific / preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, without departing from the concept of the present invention, it can also make several substitutions or modifications to these described embodiments, and these substitutions or modifications should be regarded as belonging to the protection scope of the present invention. In the description of this specification, the description of the reference terms "an embodiment", "some embodiments", "preferred embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily target the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In the absence of mutual contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions and modifications can be made herein without departing from the scope of protection of the patent application.

Claims

1. A method for measuring algae classification on the surface of an insulator based on photothermal radiation, characterized in that: include: S1. Irradiate the surface of the insulator to be tested with light to stimulate the algae to generate thermal radiation; S2, capturing the changes in thermal radiation on the insulator surface caused by light irradiation; S3, inputting the thermal radiation change data into the processing unit for analysis to determine the distribution and density of algae on the surface of the insulator, thereby obtaining the algae coverage rate; S4. Based on the obtained algae coverage rate and the empirical functional relationship between the algae coverage rate and the insulator flashover voltage drop rate, calculate the drop value of the insulator flashover voltage, and determine the level of algae coverage according to the drop value of the insulator flashover voltage; wherein the empirical functional relationship between the algae coverage rate and the insulator flashover voltage drop rate is established through prior experimental calibration.

2. The method for measuring algae classification on the surface of an insulator based on photothermal radiation according to claim 1, characterized in that: The method also includes the step of calibrating parameters for the detection and classification of algae on the surface of the insulator in a specific area, the step comprising: Select region-specific algae-covered insulators as test samples; Under the simulated regional environmental conditions, the samples were treated with constant temperature and humidity; The insulator flashover voltage under different algae coverage was measured by the up-down method. Calculate the average value and standard deviation of the flashover voltage based on multiple test data; Using the obtained average flashover voltage and standard deviation, the proportionality coefficient of the flashover voltage drop rate associated with the algae coverage was determined.

3. The method for measuring algae classification on the surface of an insulator based on photothermal radiation according to claim 1 or 2, characterized in that: It also includes monitoring the real-time ambient temperature through an ambient temperature sensor before measurement or calibration, and performing temperature compensation in the data analysis during measurement to reduce the impact of ambient temperature changes on the test results.

4. The method for measuring algae classification on the surface of an insulator based on photothermal radiation according to any one of claims 1 to 3, characterized in that: The light source used in step S1 is a pulsed xenon flash lamp with a wavelength range of 400nm to 700nm, a pulse duration of 1ms to 10ms, and an energy density of 1J / cm 2 .

5. The method for measuring algae classification on the surface of an insulator based on photothermal radiation according to any one of claims 1 to 4, characterized in that: The wavelength range of the thermal imager used in step S2 is 8 μm to 14 μm, and the thermal sensitivity reaches ≤0.05°C.

6. The method for measuring algae classification on the surface of an insulator based on photothermal radiation according to any one of claims 1 to 5, characterized in that: The empirical functional relationship in step S4 is that the flashover voltage decreases by about 8% to 9% for every 10% increase in algae coverage.

7. The method for measuring algae classification on the surface of an insulator based on photothermal radiation according to any one of claims 1 to 6, characterized in that: The formula for calculating the insulator flashover voltage drop value in step S4 is ΔV=V0×k×10C, where k is the proportionality coefficient and C is the algae coverage rate.

8. The method for measuring algae classification on the surface of an insulator based on photothermal radiation according to any one of claims 1 to 7, characterized in that: In step S4, according to the calculation result of the flashover voltage drop rate, the algae coverage degree is divided into three levels: light: coverage rate 0%-20%, medium: coverage rate 20%-40%, and heavy: coverage rate>40%.

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