Method and Apparatus for Corrosion Detection of Grounding Electrode of Transmission Tower Based on Ultrasonic Guided Waves

Abstract

The present invention discloses a method and device for detecting the corrosion of a grounding electrode of a power transmission tower based on ultrasonic guided waves, and relates to the technical field of corrosion detection. The method comprises the following steps: setting a plurality of ultrasonic guided wave receiving sensors at the grounding electrode of a power transmission tower to be detected, applying ultrasonic guided waves, and collecting ultrasonic signals reflected by the grounding electrode of the power transmission tower through the ultrasonic guided wave receiving sensors; performing noise filtering preprocessing on the collected ultrasonic signals, and extracting features from the preprocessed signal data to obtain feature parameters of the ultrasonic signals; obtaining environmental parameters around the grounding electrode of the power transmission tower to be detected, and compensating the extracted feature parameters based on the obtained environmental parameters to obtain accurate feature parameters; generating a corrosion degree coefficient based on the accurate feature parameters combined with the grounding resistance of the grounding electrode, comparing the calculated corrosion degree coefficient with a preset corrosion degree threshold, and judging the corrosion degree of the grounding electrode of the power transmission tower to be detected according to different comparison results.

Description

Technical Field

[0001] The present invention relates to the technical field of corrosion detection, and in particular to a method and device for detecting corrosion of a ground electrode of a power transmission tower based on ultrasonic guided waves. Background Art

[0002] In modern power systems, the safety and reliability of transmission towers directly affect the stability of power transmission. The grounding electrode of the transmission tower is an important component of it, mainly used to ensure the safety of equipment and personnel, and prevent electrical accidents caused by lightning strikes and faults. However, over time, the grounding electrode may be affected by environmental factors such as geology and climate, leading to corrosion. This corrosion will reduce the conductivity of the grounding electrode, thereby affecting the safety and stability of the entire power system. Therefore, timely and accurate detection of the corrosion of the grounding electrode of the transmission tower is the key to ensuring the safe operation of power facilities.

[0003] Traditional ground electrode corrosion detection methods mainly rely on regular inspections and manual measurements. This method is not only time-consuming and labor-intensive, but also easily affected by subjective factors, resulting in reduced accuracy and reliability of the detection results. In addition, traditional methods have limited capabilities in dynamic monitoring and cannot provide real-time feedback on changes in the state of the ground electrode, resulting in a lag between detection and the actual corrosion state. With the development of science and technology, ultrasonic technology has gradually been applied to detection in various fields due to its advantages such as high efficiency, non-contact and real-time monitoring. However, there is still a lack of mature application solutions for the detection of ground electrode corrosion on transmission towers, resulting in many potential safety hazards that have not been effectively identified and handled.

[0004] Therefore, there is an urgent need for a detection scheme that can accurately and quickly reflect the degree of corrosion of the grounding electrode of the transmission tower, and can effectively deal with the influencing factors under different environmental conditions, thereby providing reliable protection for the safe operation of the power system.

[0005] In the prior art, the publication number CN116026920A discloses a method for grounding flat steel corrosion classification and thinning quantification based on electromagnetic ultrasonic waveguide, which collects various grounding flat steel corrosion reference sample detection data in advance, generates a corrosion reference sample database, and actually collects grounding flat steel detection data; according to various grounding flat steel corrosion reference sample detection data, selects corresponding signal feature quantities that can accurately reflect and describe various types of corrosion thinning information, and classifies each corresponding signal feature quantity. This method identifies and evaluates the types of corrosion defects of grounding grid grounding electrodes based on the characteristic values ​​of echo data, and quantifies the thinning degree of flat steel, timely understands the state of grounding electrodes, and ensures the safety and integrity of grounding electrodes. However, in this scheme, the construction of the reference sample database depends on a sufficient variety of corrosion samples. If the number of samples is insufficient or not diverse enough, the accuracy and reliability of the model may be reduced; at the same time, environmental factors are not considered. Environmental factors such as different soil types, humidity, and temperature may affect the propagation characteristics of ultrasonic signals, resulting in samples with the same degree of corrosion producing different echo characteristics under different environments. Therefore, the accuracy and effectiveness of the system are reduced during implementation.

[0006] The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not constitute the prior art that is already known to one of ordinary skill in the art. Summary of the invention

[0007] The object of the present invention is to provide a method and device for detecting corrosion of grounding electrodes of power transmission towers based on ultrasonic guided waves, so as to solve the problems raised in the above-mentioned background technology.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A method for detecting corrosion of grounding electrodes of transmission towers based on ultrasonic guided waves, the specific steps comprising:

[0010] Determine the location of the grounding electrode of the transmission tower to be detected, set up a number of ultrasonic guided wave receiving sensors at the location of the grounding electrode of the transmission tower to be detected, apply ultrasonic guided waves to the grounding electrode of the transmission tower to be detected, and collect ultrasonic signals reflected by the grounding electrode of the transmission tower through the ultrasonic guided wave receiving sensors;

[0011] Performing noise filtering preprocessing on the collected ultrasonic signal, performing Fourier transform on the ultrasonic signal based on the preprocessed ultrasonic signal, performing feature extraction on the transformed signal data, and obtaining characteristic parameters of the ultrasonic signal, wherein the characteristic parameters include peak amplitude, reflection time and average value of frequency components;

[0012] Acquire environmental parameters around the grounding electrode of the transmission tower to be detected, and compensate the extracted characteristic parameters of the ultrasonic signal based on the acquired environmental parameters to obtain accurate characteristic parameters, wherein the environmental parameters include surface temperature and average soil humidity;

[0013] Based on the compensated precise characteristic parameters and the grounding resistance of the grounding electrode of the transmission tower to be detected, a corrosion degree coefficient is generated. The calculated corrosion degree coefficient is compared with a preset corrosion degree threshold, and the corrosion degree of the grounding electrode of the transmission tower to be detected is judged according to different comparison results.

[0014] Furthermore, a plurality of ultrasonic guided wave receiving sensors are arranged at the grounding electrode of the transmission tower to be detected, wherein the method for setting the ultrasonic guided wave receiving sensors is: selecting a sensor with an operating frequency between 10kHz and 100kHz for penetrating soil and concrete, arranging a plurality of sensors at a certain radius around the grounding electrode to form a sensor matrix to capture reflected signals in different directions, wherein the spacing between adjacent sensors is kept consistent, wherein the formula for calculating the spacing between adjacent sensors is:

[0015] ;

[0016] In the formula, is the distance between adjacent sensors, is the empirical coefficient, is the minimum propagation distance of ultrasonic guided waves, is the signal attenuation coefficient, is the ultrasonic guided wave frequency, is the propagation velocity of ultrasonic guided waves in soil.

[0017] Furthermore, based on the bandpass filter, a low-frequency cutoff frequency and a high-frequency cutoff frequency are set, wherein the specific expression of the transfer function of the filter is:

[0018] ;

[0019] In the formula, is the transfer function of the bandpass filter, is the frequency of the collected ultrasonic signal, represents the low frequency cutoff frequency, is the high frequency cutoff frequency; the transfer function is converted to The ultrasonic signal with a value of 1 is retained, and the transfer function Ultrasonic signals with a value of 0 are discarded.

[0020] Further, based on the preprocessed ultrasonic signal, the ultrasonic signal is subjected to Fourier transform, and feature extraction is performed on the transformed signal data to obtain feature parameters of the ultrasonic signal, wherein the formula for Fourier transform is:

[0021] The formula for Fourier transform of ultrasonic signal data is:

[0022] ;

[0023] In the formula, is the preprocessed ultrasonic signal time domain data, for The frequency domain signal obtained after Fourier transform is is the frequency of the collected ultrasonic signal, is an imaginary unit used to represent phase information;

[0024] Based on the frequency domain signal after Fourier transformation, feature extraction is performed to obtain the characteristic parameters of the ultrasonic signal. The specific formulas for obtaining the characteristic parameters are:

[0025] ;

[0026] ;

[0027] ;

[0028] In the formula, is the peak amplitude, is the reflection time, is the time when the reflected signal is received, is the moment of launching the ultrasonic guided wave, is the average value of the frequency components, For the frequency components, The number of sample points processed for the Fourier transform, Indicates The amplitude spectrum of the frequency components, is the index of the frequency component, .

[0029] Furthermore, Frequency components The calculation is based on the formula:

[0030] ;

[0031] In the formula, is the sampling frequency of the reflected signal receiving sensor;

[0032] No. The formula for calculating the amplitude spectrum of a frequency component is:

[0033] ;

[0034] in, yes The real part of yes The imaginary part of .

[0035] Furthermore, the environmental parameters around the grounding electrode of the transmission tower to be detected are obtained, and the extracted characteristic parameters of the ultrasonic signal are compensated based on the obtained environmental parameters to obtain accurate characteristic parameters, wherein the two characteristic parameters of the peak amplitude and the average value of the frequency component are compensated by the surface temperature and the average soil humidity, wherein the formulas for obtaining the accurate characteristic parameters are respectively:

[0036] ;

[0037] ;

[0038] In the formula, Indicates the exact amplitude of the peak. is the exact average value of the frequency components, is the propagation distance of ultrasonic guided waves, To detect the average soil moisture in the area, is the surface temperature and average soil moisture The decay function under is the reference humidity value, is the influence coefficient of humidity on the frequency component; the distance of ultrasonic guided wave propagation The calculation is based on the formula:

[0039] ;

[0040] Surface temperature and average soil moisture The decay function under The specific expression is:

[0041] ;

[0042] In the formula is the attenuation coefficient, and are the influence coefficients of humidity and temperature on attenuation, respectively. is the reference temperature value, To detect the regional surface temperature, ,and and Both are greater than 0.

[0043] Furthermore, based on the compensated accurate characteristic parameters and the grounding resistance of the grounding electrode of the transmission tower to be detected, a corrosion degree coefficient is generated, wherein the formula for calculating the corrosion degree coefficient is:

[0044] ;

[0045] In the formula, is the corrosion severity coefficient, , , and They are the precise amplitude of the wave peak, the reflection time, the precise average value of the frequency component and the weight coefficient of the grounding resistance of the grounding electrode. is the grounding resistance of the grounding electrode, where and , , and Both are greater than 0.

[0046] Furthermore, the corrosion degree coefficient calculated is compared with the preset corrosion degree threshold, and the logic for judging the corrosion degree of the grounding electrode of the transmission tower is as follows: the preset corrosion degree threshold is calibrated as ;

[0047] when When the grounding pole of the transmission tower is judged to be at the first level of corrosion, no maintenance or replacement is required;

[0048] when When the grounding pole of the transmission tower is judged to be at the second level of corrosion, the staff is reminded to carry out maintenance;

[0049] when When the grounding electrode of the transmission tower is judged to be at the third level of corrosion, work should be stopped and the grounding electrode of the transmission tower should be replaced.

[0050] The present invention also provides a transmission tower ground electrode corrosion detection device based on ultrasonic guided waves, the transmission tower ground electrode corrosion detection device based on ultrasonic guided waves is used to perform the above-mentioned transmission tower ground electrode corrosion detection method based on ultrasonic guided waves, comprising:

[0051] The ultrasonic signal acquisition module is used to determine the location of the grounding electrode of the transmission tower to be detected, set a number of ultrasonic guided wave receiving sensors at the location of the grounding electrode of the transmission tower to be detected, apply ultrasonic guided waves to the grounding electrode of the transmission tower to be detected, and collect the ultrasonic signal reflected by the grounding electrode of the transmission tower through the ultrasonic guided wave receiving sensors;

[0052] A signal feature extraction module is used to perform noise filtering preprocessing on the collected ultrasonic signal, perform Fourier transform on the ultrasonic signal based on the preprocessed ultrasonic signal, perform feature extraction on the transformed signal data, and obtain feature parameters of the ultrasonic signal, wherein the feature parameters include peak amplitude, reflection time and average value of frequency components;

[0053] A signal characteristic correction module is used to obtain environmental parameters around the grounding electrode of the transmission tower to be detected, and to compensate the extracted ultrasonic signal characteristic parameters based on the obtained environmental parameters to obtain accurate characteristic parameters, wherein the environmental parameters include surface temperature and average soil humidity;

[0054] The corrosion degree judgment module is used to generate a corrosion degree coefficient based on the compensated precise characteristic parameters combined with the grounding resistance of the grounding electrode of the transmission tower to be detected, compare the calculated corrosion degree coefficient with a preset corrosion degree threshold, and judge the corrosion degree of the grounding electrode of the transmission tower to be detected according to different comparison results.

[0055] Compared with the prior art, the present invention has the following beneficial effects:

[0056] First, by accurately determining the detection location and arranging multiple ultrasonic guided wave receiving sensors in the area, comprehensive signal collection and high data quality are ensured. This multi-angle data acquisition method can effectively improve the signal-to-noise ratio, thereby enhancing the reliability of the signal and making subsequent analysis more accurate. Secondly, the collected ultrasonic signals are subjected to noise filtering preprocessing and Fourier transform, which can effectively clarify the signal characteristics and extract key parameters such as peak amplitude, reflection time and frequency components. These characteristic parameters are compensated in combination with the temperature and humidity of the environment to be detected, which helps to eliminate the influence of the external environment on the signal and ensure the accuracy of the test results. Finally, the corrosion degree coefficient generated based on the compensated characteristic parameters and the grounding resistance provides a scientific basis for judging the corrosion degree of the grounding electrode, thereby providing reliable data support for maintenance decisions and ensuring the safety and stability of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 It is a schematic diagram of the overall method flow of the present invention;

[0058] Figure 2 It is a schematic diagram of the overall system structure of the present invention. DETAILED DESCRIPTION

[0059] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments.

[0060] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0061] Example:

[0062] See also Figure 1 , the present invention provides a technical solution:

[0063] A method for detecting corrosion of grounding electrodes of transmission towers based on ultrasonic guided waves, the specific steps comprising:

[0064] Step 1: Determine the location of the grounding electrode of the transmission tower to be detected, set up a number of ultrasonic guided wave receiving sensors at the location of the grounding electrode of the transmission tower to be detected, apply ultrasonic guided waves to the grounding electrode of the transmission tower to be detected, and collect the ultrasonic signal reflected by the grounding electrode of the transmission tower through the ultrasonic guided wave receiving sensors;

[0065] A number of ultrasonic guided wave receiving sensors are set at the grounding electrode of the transmission tower to be detected. The method of setting the ultrasonic guided wave receiving sensors is: select a sensor with an operating frequency between 10kHz and 100kHz to penetrate soil and concrete, and arrange multiple sensors around the grounding electrode with a certain radius to form a sensor matrix to capture reflected signals in different directions, wherein the spacing between adjacent sensors remains consistent, and the formula for calculating the spacing between adjacent sensors is:

[0066] ;

[0067] In the formula, is the distance between adjacent sensors, is the empirical coefficient, is the minimum propagation distance of ultrasonic guided waves, is the signal attenuation coefficient, is the ultrasonic guided wave frequency, is the propagation velocity of ultrasonic guided waves in soil.

[0068] Use a special bracket to fix the sensor on the ground to ensure that the bottom of the sensor is in good contact with the ground. At the same time, a coupling agent (such as coupling glue) can be used at the bottom of the sensor to improve the transmission efficiency of sound waves. Use a shielded cable to connect the sensor to the data acquisition system to reduce electromagnetic interference.

[0069] Step 2: Perform noise filtering preprocessing on the collected ultrasonic signal, perform Fourier transform on the ultrasonic signal based on the preprocessed ultrasonic signal, perform feature extraction on the transformed signal data, and obtain characteristic parameters of the ultrasonic signal, wherein the characteristic parameters include peak amplitude, reflection time and average value of frequency components;

[0070] The logic for noise filtering preprocessing of the collected ultrasonic signal is: based on a bandpass filter, a low-frequency cutoff frequency and a high-frequency cutoff frequency are set, wherein the specific expression of the transfer function of the filter is:

[0071] ;

[0072] In the formula, is the transfer function of the bandpass filter, is the frequency of the collected ultrasonic signal, represents the low frequency cutoff frequency, is the high frequency cutoff frequency; the transfer function is converted to The ultrasonic signal with a value of 1 is retained, and the transfer function Ultrasonic signals with a value of 0 are discarded.

[0073] Based on the preprocessed ultrasonic signal, the ultrasonic signal is Fourier transformed, and the feature extraction is performed on the transformed signal data to obtain the characteristic parameters of the ultrasonic signal. The formula for Fourier transform is:

[0074] The formula for Fourier transform of ultrasonic signal data is:

[0075] ;

[0076] In the formula, is the preprocessed ultrasonic signal time domain data, for The frequency domain signal obtained after Fourier transform is is the frequency of the collected ultrasonic signal, is an imaginary unit used to represent phase information;

[0077] Based on the frequency domain signal after Fourier transformation, feature extraction is performed to obtain the characteristic parameters of the ultrasonic signal. The specific formulas for obtaining the characteristic parameters are:

[0078] ;

[0079] ;

[0080] ;

[0081] In the formula, is the peak amplitude, is the reflection time, is the time when the reflected signal is received, is the moment of launching the ultrasonic guided wave, is the average value of the frequency components, For the frequency components, The number of sample points processed for the Fourier transform, Indicates The amplitude spectrum of the frequency components, is the index of the frequency component, .

[0082] Corrosion causes changes in the acoustic properties of materials. Especially when cracks or defects appear on the surface of the material, ultrasonic waves will be scattered and attenuated during propagation, thereby reducing the amplitude of the reflected signal.

[0083] Corrosion may cause changes in the internal structure of the material, slowing down the propagation speed of ultrasound when passing through the corroded area, which in turn prolongs the arrival time of the reflected wave. In addition, deformation and defects caused by corrosion may also increase the path for wave propagation, thereby prolonging the reflection time.

[0084] As the corrosion level increases, the material may become non-uniform and have multiple defects, which will cause the ultrasonic signal spectrum to disperse, manifested as a decrease in frequency components and a broadening of the spectrum. When the material structure becomes more complex, the propagation characteristics of the ultrasonic wave also become more complex, affecting the distribution of its frequency components.

[0085] Among them Frequency components The calculation is based on the formula:

[0086] ;

[0087] In the formula, is the sampling frequency of the reflected signal receiving sensor;

[0088] No. The formula for calculating the amplitude spectrum of a frequency component is:

[0089] ;

[0090] in, yes The real part of yes The imaginary part of .

[0091] Step 3: Acquire environmental parameters around the grounding electrode of the transmission tower to be detected, and compensate the extracted characteristic parameters of the ultrasonic signal based on the acquired environmental parameters to obtain accurate characteristic parameters, wherein the environmental parameters include surface temperature and average soil humidity;

[0092] The environmental parameters around the grounding electrode of the transmission tower to be detected are obtained, and the extracted characteristic parameters of the ultrasonic signal are compensated based on the obtained environmental parameters to obtain accurate characteristic parameters, wherein the two characteristic parameters of the peak amplitude and the average value of the frequency component are compensated by the surface temperature and the average soil humidity. The formulas for obtaining the accurate characteristic parameters are:

[0093] ;

[0094] ;

[0095] In the formula, Indicates the exact amplitude of the peak. is the exact average value of the frequency components, is the propagation distance of ultrasonic guided waves, To detect the average soil moisture in the area, is the surface temperature and average soil moisture The decay function under is the reference humidity value, is the influence coefficient of humidity on frequency components, which can be set by combining the public data with the expert experience; the distance of ultrasonic guided wave propagation The calculation is based on the formula:

[0096] ;

[0097] Surface temperature and average soil moisture The decay function under The specific expression is:

[0098] ;

[0099] In the formula is the attenuation coefficient, and are the influence coefficients of humidity and temperature on attenuation, respectively. is the reference temperature value, To detect the regional surface temperature, , and because the influence of humidity on the detection signal is greater than that of temperature, it is set ,and and If both are greater than 0, select a suitable reference humidity value. Usually, this reference humidity can be selected as a common or ideal environmental condition, such as indoor standard humidity (for example, 40% or 50% relative humidity). The same is true for temperature. Generally, the reference temperature value is , attenuation coefficient It can be measured through systematic experiments. The specific steps include: conducting a series of ultrasonic propagation experiments under the selected reference humidity, setting up ultrasonic transmitters and receivers and ensuring that they are under the same environmental conditions, recording the ultrasonic signal strength at different distances, and calculating the attenuation of signal strength based on the ultrasonic signal strength at different distances.

[0100] In high temperature and high humidity environments, the presence of water may affect the propagation of ultrasonic guided waves, especially increasing the attenuation of guided waves through scattering and absorption. Therefore, the two characteristic parameters of peak amplitude and average value of frequency components are compensated, while the reflection time is usually not directly affected by the scattering and absorption caused by water molecules.

[0101] Step 4: Generate a corrosion degree coefficient based on the compensated precise characteristic parameters combined with the grounding resistance of the grounding electrode of the transmission tower to be detected. Compare the calculated corrosion degree coefficient with the preset corrosion degree threshold, and judge the corrosion degree of the grounding electrode of the transmission tower to be detected based on different comparison results.

[0102] Based on the compensated accurate characteristic parameters and the grounding resistance of the grounding electrode of the transmission tower to be tested, the corrosion degree coefficient is generated. The formula for calculating the corrosion degree coefficient is:

[0103] ;

[0104] In the formula, is the corrosion severity coefficient, , , and They are the precise amplitude of the wave peak, the reflection time, the precise average value of the frequency component and the weight coefficient of the grounding resistance of the grounding electrode. is the grounding resistance of the grounding electrode. Among them, the precise amplitude of the wave peak has the most obvious characterization of the corrosion degree among the parameters reflecting the corrosion degree, and the grounding resistance of the grounding electrode has the second best reflection ability. The precise average value of the frequency component and the reflection time have relatively little influence on the grounding resistance of the grounding electrode. and , , and Both are greater than 0.

[0105] Grounding resistance of grounding electrode It can be calculated based on the contact area between the grounding electrode and the soil and the electrical conductivity characteristics of the soil. The specific calculation formula is:

[0106] ;

[0107] In the formula, is the contact area between the grounding electrode and the soil, is the electrical conductivity of the soil, where It can be approximately expressed as:

[0108] ;

[0109] In the formula, is the specific coefficient of the soil material (related to soil type and conditions), is the reflection coefficient, which can be expressed by the square of the ratio of the reflected amplitude to the incident amplitude.

[0110] The logic for judging the corrosion degree of the transmission tower grounding electrode is as follows: the pre-set corrosion degree threshold is calibrated as ;

[0111] when When the grounding pole of the transmission tower is judged to be at the first level of corrosion, no maintenance or replacement is required;

[0112] when When the grounding pole of the transmission tower is judged to be at the second level of corrosion, the staff is reminded to carry out maintenance;

[0113] when When the grounding electrode of the transmission tower is judged to be at the third level of corrosion, work should be stopped and the grounding electrode of the transmission tower should be replaced.

[0114] See also Figure 2 The present invention also provides a transmission tower ground electrode corrosion detection device based on ultrasonic guided waves, the transmission tower ground electrode corrosion detection device based on ultrasonic guided waves is used to perform the above-mentioned transmission tower ground electrode corrosion detection method based on ultrasonic guided waves, comprising:

[0115] The ultrasonic signal acquisition module is used to determine the location of the grounding electrode of the transmission tower to be detected, set a number of ultrasonic guided wave receiving sensors at the location of the grounding electrode of the transmission tower to be detected, apply ultrasonic guided waves to the grounding electrode of the transmission tower to be detected, and collect the ultrasonic signal reflected by the grounding electrode of the transmission tower through the ultrasonic guided wave receiving sensors;

[0116] A signal feature extraction module is used to perform noise filtering preprocessing on the collected ultrasonic signal, perform Fourier transform on the ultrasonic signal based on the preprocessed ultrasonic signal, perform feature extraction on the transformed signal data, and obtain feature parameters of the ultrasonic signal, wherein the feature parameters include peak amplitude, reflection time and average value of frequency components;

[0117] A signal characteristic correction module is used to obtain environmental parameters around the grounding electrode of the transmission tower to be detected, and to compensate the extracted ultrasonic signal characteristic parameters based on the obtained environmental parameters to obtain accurate characteristic parameters, wherein the environmental parameters include surface temperature and average soil humidity;

[0118] The corrosion degree judgment module is used to generate a corrosion degree coefficient based on the compensated precise characteristic parameters combined with the grounding resistance of the grounding electrode of the transmission tower to be detected, compare the calculated corrosion degree coefficient with a preset corrosion degree threshold, and judge the corrosion degree of the grounding electrode of the transmission tower to be detected according to different comparison results.

[0119] The above formulas are all dimensionless and numerical calculations. The formula is a formula for the most recent real situation obtained by collecting a large amount of data and performing software simulation. The preset parameters in the formula are set by technicians in this field according to actual conditions.

[0120] The above embodiments may be implemented in whole or in part by software, hardware, firmware or any other combination thereof. When implemented by software, the above embodiments may be implemented in whole or in part in the form of a computer program product. Those skilled in the art may appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein may be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed by hardware or software methods depends on the specific application and design constraints of the technical solution.

[0121] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, and may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0122] The above description is only a specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application.

Claims

1. A method for detecting ground electrode corrosion of a transmission tower based on ultrasonic guided waves, characterized in that: The specific steps include: Determine the location of the grounding electrode of the transmission tower to be detected. Set several ultrasonic guided wave receiving sensors at the location of the grounding electrode of the transmission tower to be detected. Apply ultrasonic guided waves to the grounding electrode of the transmission tower to be detected, and collect the ultrasonic signals reflected by the grounding electrode of the transmission tower through the ultrasonic guided wave receiving sensors; Set several ultrasonic guided wave receiving sensors at the location of the grounding electrode of the transmission tower to be detected. The method for setting the ultrasonic guided wave receiving sensors is as follows: Select sensors with a working frequency between 10 kHz and 100 kHz for penetrating soil and concrete. Arrange multiple sensors around the grounding electrode at a certain radius to form a sensor matrix to capture reflected signals in different directions. The distance between adjacent sensors remains consistent. The formula for calculating the distance between adjacent sensors is: In the formula, d is the distance between adjacent sensors, k is an empirical coefficient, R is the minimum propagation distance of ultrasonic guided waves, τ is the signal attenuation coefficient, f is the frequency of ultrasonic guided waves, and v is the propagation speed of ultrasonic guided waves in soil; Perform noise filtering preprocessing on the collected ultrasonic signals. Based on the preprocessed ultrasonic signals, perform Fourier transform on the ultrasonic signals, extract features from the transformed signal data, and obtain the characteristic parameters of the ultrasonic signals. The characteristic parameters include the peak amplitude, reflection time, and average value of frequency components; The formula for performing Fourier transform is: The formula for performing Fourier transform on ultrasonic signal data is: Where α(t) is the preprocessed ultrasonic signal time domain data, α(f s ) is the frequency domain signal obtained after Fourier transform of α(t), f s is the frequency of the collected ultrasonic signal, j is an imaginary unit used to represent the phase information; Based on the frequency domain signal after Fourier transform, perform feature extraction to obtain the characteristic parameters of the ultrasonic signals. The specific formulas for obtaining the characteristic parameters are: A=max(|α(f s )|) T r =t ref -t emi Where A is the peak amplitude, T r is the reflection time, t ref is the time when the reflected signal is received, t emi is the moment of launching the ultrasonic guided wave, is the average value of the frequency component, f k is the kth frequency component, N is the number of sample points processed by Fourier transform, |α(f k )| represents the amplitude spectrum of the kth frequency component, k is the index of the frequency component, k = 0, 1, ..., N-1; Obtain the environmental parameters around the grounding electrode of the transmission tower to be detected. Compensate the extracted characteristic parameters of the ultrasonic signals based on the obtained environmental parameters to obtain accurate characteristic parameters. The environmental parameters include the surface temperature and the average soil humidity; The formulas for obtaining the accurate characteristic parameters are: A′=A*e -α(H,T)*L Where A′ represents the exact amplitude of the peak, is the precise average value of the frequency component, L is the propagation distance of the ultrasonic guided wave, H is the average soil moisture in the detection area, α(H,T) is the attenuation function under the surface temperature T and the average soil moisture H, H ref is the reference humidity value, β f is the influence coefficient of humidity on the frequency component; the formula for calculating the distance L of ultrasonic guided wave propagation is: L=v*T r The specific expression of the attenuation function α(H,T) at the surface temperature T and the average soil humidity H is: α(H,T)=α0+β H *(|HH ref |)+b T *(|TT ref |) Where α0 is the attenuation coefficient, β H and β T are the influence coefficients of humidity and temperature on attenuation, T ref is the reference temperature value, T is the surface temperature of the detection area, where β H >β T , and β H and β T All are greater than 0; Based on the compensated accurate characteristic parameters combined with the grounding resistance of the grounding electrode of the transmission tower to be detected, generate a corrosion degree coefficient. Compare the calculated corrosion degree coefficient with the pre-set corrosion degree threshold, and judge the corrosion degree of the grounding electrode of the transmission tower to be detected according to different comparison results; The formula for calculating the corrosion degree coefficient is: In the formula, FS is the corrosion degree coefficient, ω1, ω2, ω3, and ω4 are the weight coefficients of the peak accurate amplitude, reflection time, accurate average value of frequency components, and the grounding resistance of the grounding electrode respectively. R is the grounding resistance of the grounding electrode. Among them, ω1>ω4>ω3>ω2 and ω1, ω2, ω3, and ω4 are all greater than 0; Compare the calculated corrosion degree coefficient with the pre-set corrosion degree threshold. The logic for judging the corrosion degree of the grounding electrode of the transmission tower is: Calibrate the pre-set corrosion degree threshold as yz; When 0≤FS<yz*0.3, it is judged that the grounding electrode of the transmission tower is in the first-level corrosion degree and no maintenance and replacement are required; When yz * 0.3 ≤ FS < yz * 0.6, it is judged that the grounding electrode of the transmission tower is in the second - level corrosion degree, and the staff is reminded to carry out maintenance; When yz * 0.6 ≤ FS < yz * 1.0, it is judged that the grounding electrode of the transmission tower is in the third - level corrosion degree, and the work should be stopped to replace the grounding electrode of the transmission tower.

2. The method for detecting corrosion of grounding electrodes of transmission towers based on ultrasonic guided waves according to claim 1 is characterized in that: The logic for pre - processing the collected ultrasonic signal by noise filtering is as follows: Based on a band - pass filter, the low - frequency cut - off frequency and the high - frequency cut - off frequency are set. The specific expression of the transfer function of the filter is: In the formula, H(f s ) is the transfer function of the bandpass filter, f s is the frequency of the collected ultrasonic signal, f low represents the low frequency cutoff frequency, f hig is the high frequency cut-off frequency; the transfer function H(f s ) is 1, and the transfer function H(f s ) is 0 and the ultrasonic signal is discarded.

3. The method for detecting corrosion of grounding electrodes of transmission towers based on ultrasonic guided waves according to claim 1 is characterized in that: The kth frequency component f k The calculation is based on the formula: In the formula, f z is the sampling frequency of the reflected signal receiving sensor; The formula for calculating the amplitude spectrum of the k - th frequency component is: Among them, Re{α(f k )} is α(f k ) is represented by the real part, Im{α(f k )} is α(f k ) is represented by the imaginary part of .

4. A transmission tower ground electrode corrosion detection device based on ultrasonic guided waves, characterized in that: The corrosion detection device for the grounding electrode of the transmission tower based on ultrasonic guided waves is used to execute the corrosion detection method for the grounding electrode of the transmission tower based on ultrasonic guided waves according to any one of claims 1 - 3, including: An ultrasonic signal acquisition module, which is used to determine the location of the grounding electrode of the transmission tower to be detected, set a number of ultrasonic guided wave receiving sensors at the location of the grounding electrode of the transmission tower to be detected, apply ultrasonic guided waves to the grounding electrode of the transmission tower to be detected, and collect the ultrasonic signals reflected by the grounding electrode of the transmission tower through the ultrasonic guided wave receiving sensors; A signal feature extraction module, which is used to pre - process the collected ultrasonic signal by noise filtering, perform Fourier transform on the ultrasonic signal based on the pre - processed ultrasonic signal, extract features from the transformed signal data, and obtain the feature parameters of the ultrasonic signal. The feature parameters include the peak amplitude, reflection time, and the average value of the frequency components; A signal feature correction module, which is used to obtain the environmental parameters around the grounding electrode of the transmission tower to be detected, compensate the extracted ultrasonic signal feature parameters based on the obtained environmental parameters, and obtain accurate feature parameters, where the environmental parameters include the surface temperature and the average soil humidity; A corrosion degree judgment module, which is used to generate a corrosion degree coefficient based on the compensated accurate feature parameters combined with the grounding resistance of the grounding electrode of the transmission tower to be detected, compare the calculated corrosion degree coefficient with the pre - set corrosion degree threshold, and judge the corrosion degree of the grounding electrode of the transmission tower to be detected according to different comparison results.

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