Radio frequency array detection method and system for internal defects of post porcelain insulator flange

Abstract

The invention belongs to the technical field of insulator detection, and particularly relates to a radio frequency array detection method and system for internal defects of a pillar porcelain insulator flange. N rectangular excitation ports are annularly arranged on the surface of a porcelain piece above a post insulator flange at equal intervals to form a radio frequency antenna array; extracting a rectangular excitation port and applying broadband excitation; taking the rectangular excitation port which is not extracted as a sampling port, and collecting scattering parameters from the sampling port; scattering parameter data are gathered, accumulative evaluation loss is calculated, and the severity degree of the gap defect of the porcelain flange of the post insulator is judged according to the accumulative evaluation loss. According to the method, scattering parameters are introduced into internal defect detection of the post insulator, the sensitivity to early microdefects is improved by calculating accumulative evaluation loss, the porcelain flange gap defect of the post insulator can be effectively detected, hidden dangers are eliminated for the post insulator in operation of an electric power system in time, and safe and stable operation of the electric power system is guaranteed.

Description

Technical Field

[0001] This invention belongs to the field of insulator testing technology, specifically relating to a radio frequency array detection method and system for internal defects in post porcelain insulator flanges. Background Technology

[0002] Post insulators are important electrical components widely used in power transmission and distribution networks. Post insulators are a common type of post insulator, primarily composed of porcelain insulators providing main insulation and flanges nested at both ends. During the manufacturing, assembly, and long-term use of post insulators, minute gap defects can easily occur between the porcelain insulators and the flanges. These defects may be caused by manufacturing processes, assembly processes, and long-term exposure to electromechanical loads, atmospheric pollution, and temperature changes. These minute defects may take the form of holes, seams, or cracks. Under long-term operating conditions, these defects may gradually expand, leading to a decline in the insulation and mechanical properties of the post insulator, ultimately causing power grid accidents. While easily detectable defects such as scratches, notches, and sharp points on the surface of the porcelain insulator and flange, defects at the gap between the porcelain insulator and the flange are located inside the post insulator and are difficult to detect. Currently, the mainstream method for detecting the gap between the porcelain insulator and the flange is ultrasonic testing. This method requires the application of a coupling agent, has low testing efficiency, is easily interfered with by defects in the flange porcelain itself, and has insufficient accuracy. In recent years, although some studies have attempted to apply radio frequency (RF) detection technology to this field, such as CN119915843A which uses RF waveform analysis to qualitatively determine defects, this method has significant limitations: the acquired RF waveforms are easily affected by electromagnetic interference in the field, resulting in poor stability; moreover, its ability to quantitatively assess defects is insufficient, relying heavily on complex signal mapping transformations, and its sensitivity to early micro-defects is limited, making it difficult to achieve accurate and reliable defect severity classification. Therefore, developing an RF detection method with strong anti-interference capabilities, accurate quantification, and applicability to field engineering remains a pressing technical challenge in this field, and the disclosure of this invention aims to solve this problem. Summary of the Invention

[0003] The purpose of this invention is to provide a radio frequency array detection method and system for internal defects in post porcelain insulator flanges. This invention introduces scattering parameters from microwave engineering into the insulator defect detection system and proposes a cumulative evaluation loss model based on the differential error analysis of scattering parameters, which improves the sensitivity to early micro-defects and has better stability and strong anti-interference ability.

[0004] This invention is achieved through the following technical solution. A method for detecting internal defects in a post-support porcelain insulator flange using a radio frequency array, comprising the following steps: S1: Install rectangular excitation ports circumferentially at equal intervals on the surface of the ceramic part above the flange of the post insulator to form a radio frequency antenna array; S2: Iterate through all possible excitation-sampling port combination patterns in sequence. For each pattern, extract one or more rectangular excitation ports and apply wideband excitation. S3: Use the rectangular excitation ports that are not sampled under each excitation mode as sampling ports, collect scattering parameters from the sampling ports, and construct a test scattering parameter matrix. S4: Compare the test scattering parameter matrix with the preset same-mode reference scattering parameter matrix. Calculate the sum of the squares of the differences between the first and second derivatives of the two matrices in the frequency domain, and fuse them based on predetermined weights and characteristic frequency shift step size to obtain the total scattering parameter loss. Finally, sum the total scattering parameter losses of all port combinations to obtain the cumulative evaluation loss. S5: Determine the severity of flange gap defects in post insulators based on cumulative evaluation losses.

[0005] Specifically, the radio frequency antenna array includes: The antenna substrate of the rectangular excitation port is rectangular, and the number of the rectangular excitation ports is [number missing]. ; The shape and size of the antenna radiating elements at each rectangular excitation port are strictly uniform; The tilt angle of the antenna radiation main lobe direction along the insulator axis of each rectangular excitation port is configured between 30° and 60°.

[0006] Specifically, step S2 involves sequentially traversing all possible excitation-sampling port combination patterns as follows: N rectangular excitation ports are numbered sequentially. By changing the selection step size s and the starting offset p of the excitation ports, a variety of excitation-sampling combinations are systematically constructed, where s and p are integers and satisfy 1 ≤ s ≤ N, 0 ≤ p < s, to ensure that scattering parameter data reflecting the different path structure states of the insulator are collected.

[0007] Specifically, the self-sampling port acquires scattering parameters and constructs a test scattering parameter matrix, including: The sampling port is responsible for acquiring the radio frequency signal emitted from the rectangular excitation port where broadband excitation is applied, deriving the scattering parameters, and filling them into the scattering parameter matrix in the order of extraction and sampling. Its matrix elements For port For port The test scattering parameters, where i and j are the indices of the rectangular excitation port.

[0008] Specifically, the calculation process for the cumulative evaluation loss is as follows: ; ; ; ; in, The sample size of the sampled data. For the excitation source frequency, As the lower limit of the excitation source frequency, This is the upper limit of the excitation source frequency. For port For port The test scattering parameters, For ports in the same mode For port The reference scattering parameters, For port For port The first-order loss of the scattering parameters, For port For port The second-order loss of the scattering parameters, and These are the weighting coefficients for the first-order and second-order losses of the scattering parameters, respectively. The characteristic frequency shift step size, For port For port The total loss of scattering parameters, To evaluate the cumulative losses.

[0009] Specifically, in step S5, the rule for judging the severity of defects based on cumulative evaluation loss is as follows: a threshold range is determined in advance through experiments, and the cumulative evaluation loss is compared with the threshold range to divide the severity of defects into multiple levels.

[0010] This invention also provides a radio frequency array detection system for internal defects in post porcelain insulator flanges, characterized in that it includes: The antenna array module consists of N rectangular excitation ports that are circumferentially and equally spaced on the surface of the ceramic part above the flange of the post insulator; The excitation signal source module is used to apply a wideband excitation signal to the selected rectangular excitation port according to the set excitation-sampling combination mode; The signal acquisition and processing module is used to acquire scattering parameters from the rectangular excitation port, which serves as the sampling port, and transmit them to the data processing module. The data processing and analysis module is configured to: receive scattering parameter data and construct a test scattering parameter matrix, call a preset benchmark scattering parameter matrix, and output the judgment result of the severity of defects based on the cumulative evaluation loss.

[0011] The present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, it implements the steps of the radio frequency array detection method for internal defects of the post porcelain insulator flange.

[0012] The present invention also provides a non-volatile computer-readable storage medium storing a computer program thereon, characterized in that, when the computer program is executed by a processor, it implements the steps of the radio frequency array detection method for internal defects of the post porcelain insulator flange.

[0013] Technical effects of the present invention: Existing radio frequency (RF) detection methods largely rely on complex mathematical transformations and mappings of acquired RF waveforms to extract qualitative or semi-quantitative evaluation indices. This method lacks sufficient quantification capability for defects and is easily affected by algorithm parameters, leading to less objective results. This invention introduces scattering parameters from microwave network theory as the core detection quantity, establishing a method for evaluating the severity of flange gap defects in post insulator ceramic components based on cumulative evaluation losses. This achieves accurate, objective, and repeatable numerical assessment of defect severity.

[0014] Traditional waveform analysis methods respond well to obvious defects, but have limited sensitivity to early-stage, micro-cracks or gap changes (i.e., "micro-defects") that originate inside insulators, making early warning difficult. This invention utilizes the first and second derivative properties of scattering parameters in the frequency domain. The difference in the first derivative is used to capture macroscopic defect characteristics, while the difference in the second derivative is extremely sensitive to local curvature changes in the signal, effectively amplifying the weak signal distortion caused by micro-defects, thereby significantly improving the detection capability of early-stage defects.

[0015] Detection methods based on radio frequency waveforms are highly susceptible to interference from complex electromagnetic environments, and the computationally intensive mapping algorithms are not conducive to rapid and stable implementation in the field. The scattering parameters used in this invention are inherent parameters characterizing network properties and possess better stability. Furthermore, the cumulative evaluation loss proposed in this invention, through differential operations and weighted fusion, can effectively suppress the influence of random noise and common-mode interference, making the detection results more robust. Attached Figure Description

[0016] Figure 1 This is a flowchart of the method of the present invention; Figure 2 Schematic diagram of rectangular excitation port installation; Figure 3 These are the test scattering parameters used in Example 1; Figure 4 These are the reference scattering parameters used in Example 1; Figure 5 The first-order loss expansion of the scattering parameter matrix obtained in Example 1; Figure 6 The second-order loss expansion of the scattering parameter matrix obtained in Example 1; Figure 7 This is the distribution of the total loss across the ports obtained in Example 1. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Reference Figure 1 A method for detecting internal defects in a post-support porcelain insulator flange using a radio frequency array, comprising the following steps: S1: The rectangular excitation ports are installed circumferentially at equal intervals on the surface of the ceramic part above the flange of the post insulator to form a radio frequency antenna array.

[0019] like Figure 2 As shown, each rectangular excitation port has the same length and width, and the number of rectangular excitation ports is [number missing]. .

[0020] S2: Iterate through all possible excitation-sampling port combination patterns in sequence. For each pattern, extract one or more rectangular excitation ports and apply wideband excitation. Will Each rectangular excitation port is arranged according to The natural numbers are numbered in counter-clockwise order, starting from... One rectangular excitation port is selected sequentially from the rectangular excitation ports to apply broadband excitation.

[0021] S3: Use the rectangular excitation ports that are not sampled under each excitation mode as sampling ports, collect scattering parameters from the sampling ports, and construct a test scattering parameter matrix. The sampling port is responsible for acquiring the radio frequency signal emitted from the rectangular excitation port where broadband excitation is applied, and deriving the scattering parameters. These parameters are then sequentially filled into the test scattering parameter matrix according to the order of extraction and sampling. Specifically, the matrix elements For port For port The test scattering parameters. Figure 3 This embodiment demonstrates some of the test scattering parameters collected on an insulator under test. The curve example reflects the signal transmission characteristics between ports under actual testing conditions.

[0022] S4: Summarize the scattering parameter data and calculate the cumulative evaluation loss: The cumulative evaluation loss is calculated using the method provided by this invention as follows:

[0023] ;

[0024] ;

[0025] ;

[0026] ; in, The sample size of the sampled data. For the excitation source frequency, As the lower limit of the excitation source frequency, This is the upper limit of the excitation source frequency. For port For port The test scattering parameters, For ports in the same mode For port The reference scattering parameters, For port For port The first-order loss of the scattering parameters, For port For port The second-order loss of the scattering parameters, and These are the weighting coefficients for the first-order and second-order losses of the scattering parameters, respectively, in this embodiment. , , In this embodiment, the characteristic frequency shift step size is... E stands for exponentiation, meaning "multiplied by the power of 10". For port For port The total loss of scattering parameters, To evaluate the cumulative losses.

[0027] Figure 4 The test scattering parameter matrix is ​​shown. The corresponding reference scattering parameter matrix Example of a curve, reference scattering parameter matrix The samples were derived from defect-free standard samples, providing a benchmark for subsequent calculation of differential errors. Figures 3-7 The numbers on the middle horizontal axis represent port numbers, such as 41 representing ports 4 through 1. Figure 5 and Figure 6 They respectively showed the works of Figure 3 and Figure 4 First-order loss of scattering parameter matrix obtained from data calculation and second-order loss The unfolded surface plot visually presents the difference distribution between the test sample and the reference sample in the first and second order differential characteristics in the frequency domain. Figure 7 This shows the total loss of the scattering parameters obtained from the final calculation. The distribution of each port pair is shown in this diagram. This diagram is used to visually observe the differences in the impact of defects on signals along different circumferential paths of the insulator. The cumulative evaluation loss λ is the sum of the total losses of all port pairs.

[0028] S5: Determine the severity of flange gap defects in the porcelain components of the post insulator based on the cumulative assessed loss. Specifically, the cumulative assessed loss... The larger the value, the more severe the flange gap defect in the ceramic insulator. The rule for judging the severity of defects based on cumulative evaluation loss is as follows: a threshold range is determined in advance through experiments, and the cumulative evaluation loss is compared with the threshold range to classify the severity of defects into multiple levels.

[0029] This embodiment uses As a criterion for judging severe defects, in practical applications, the appropriate value can be selected based on detection experience and different reference scattering parameter matrices.

[0030] The following are some scattering parameter data collected in the embodiments of the present invention:

[0031] The cumulative evaluation loss calculated in this embodiment Generally, when If the flange gap of the porcelain component of the post insulator is found to be significantly defective, the insulator under test should be replaced in a timely manner in accordance with the relevant maintenance specifications of the power system, according to the method provided in this invention. Example 2

[0032] To implement the method of Embodiment 1, this embodiment provides a radio frequency array detection system for internal defects in a post porcelain insulator flange, comprising: The antenna array module consists of N rectangular excitation ports that are circumferentially and equally spaced on the surface of the ceramic part above the flange of the post insulator; The excitation signal source module is used to apply a wideband excitation signal to the selected rectangular excitation port according to the set excitation-sampling combination mode; The signal acquisition and processing module is used to acquire scattering parameters from the rectangular excitation port, which serves as the sampling port, and transmit them to the data processing module. The data processing and analysis module is configured to: receive scattering parameter data and construct a test scattering parameter matrix, call a preset benchmark scattering parameter matrix, and output the judgment result of the severity of defects based on the cumulative evaluation loss. Example 3

[0033] This embodiment provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the steps of the radio frequency array detection method for internal defects of the support porcelain insulator flange described in Embodiment 1. Example 4

[0034] This embodiment provides a non-volatile computer-readable storage medium storing a computer program thereon. The computer program, when executed by a processor, implements the steps of the radio frequency array detection method for internal defects in a post porcelain insulator flange as described in Embodiment 1.

[0035] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for detecting internal defects in a post-support porcelain insulator flange using a radio frequency array, characterized in that, The steps are as follows: S1: Install rectangular excitation ports circumferentially at equal intervals on the surface of the ceramic part above the flange of the post insulator to form a radio frequency antenna array; S2: Iterate through all possible excitation-sampling port combination patterns in sequence. For each pattern, extract one or more rectangular excitation ports and apply wideband excitation. S3: Use the rectangular excitation ports that are not sampled under each excitation mode as sampling ports, collect scattering parameters from the sampling ports, and construct a test scattering parameter matrix. S4: Compare the test scattering parameter matrix with the preset same-mode reference scattering parameter matrix. Calculate the sum of the squares of the differences between the first and second derivatives of the two matrices in the frequency domain, and fuse them based on predetermined weights and characteristic frequency shift step size to obtain the total scattering parameter loss. Finally, sum the total scattering parameter losses of all port combinations to obtain the cumulative evaluation loss. S5: Determine the severity of flange gap defects in post insulators based on cumulative evaluation losses.

2. The radio frequency array detection method for internal defects in a support porcelain insulator flange according to claim 1, characterized in that, The radio frequency antenna array includes: The antenna substrate of the rectangular excitation port is rectangular, and the number of the rectangular excitation ports is [number missing]. ; The shape and size of the antenna radiating elements at each rectangular excitation port are strictly uniform; The tilt angle of the antenna radiation main lobe direction along the insulator axis of each rectangular excitation port is configured between 30° and 60°.

3. The radio frequency array detection method for internal defects in a support porcelain insulator flange according to claim 1, characterized in that, Step S2 involves iterating through all possible excitation-sampling port combinations in sequence as follows: N rectangular excitation ports are numbered sequentially. By changing the selection step size *s* and the initial offset *p* of the excitation ports, various excitation-sampling combinations are systematically constructed, where *s* and *p* are integers and satisfy 1 ≤ *s* ≤ *N*, 0 ≤ *p* < *s*, to ensure that scattering parameter data reflecting different path structural states of the insulator are acquired.

4. The radio frequency array detection method for internal defects of a support porcelain insulator flange according to claim 1, characterized in that, The self-sampling port acquires scattering parameters and constructs a test scattering parameter matrix, including: The sampling port is responsible for acquiring the radio frequency signal emitted from the rectangular excitation port where broadband excitation is applied, deriving the scattering parameters, and filling them into the scattering parameter matrix in the order of extraction and sampling. Its matrix elements For port For port The test scattering parameters, where i and j are the indices of the rectangular excitation port.

5. The radio frequency array detection method for internal defects in a post porcelain insulator flange according to claim 1, characterized in that, The calculation process for the cumulative evaluation loss is as follows: ； ； ； ； in, The sample size of the sampled data. For the excitation source frequency, As the lower limit of the excitation source frequency, This is the upper limit of the excitation source frequency. For port For port The test scattering parameters, For ports in the same mode For port The reference scattering parameters, For port For port The first-order loss of the scattering parameters, For port For port The second-order loss of the scattering parameters, and These are the weighting coefficients for the first-order and second-order losses of the scattering parameters, respectively. The characteristic frequency shift step size, For port For port The total loss of scattering parameters, To evaluate the cumulative losses.

6. The radio frequency array detection method for internal defects in a post porcelain insulator flange according to claim 1, characterized in that, In step S5, the rule for judging the severity of defects based on cumulative evaluation loss is as follows: a threshold range is determined in advance through experiments, and the cumulative evaluation loss is compared with the threshold range to divide the severity of defects into multiple levels.

7. A radio frequency array detection system for internal defects in a post-support porcelain insulator flange for implementing the method of any one of claims 1 to 6, characterized in that, include: The antenna array module consists of N rectangular excitation ports that are circumferentially and equally spaced on the surface of the ceramic part above the flange of the post insulator; The excitation signal source module is used to apply a wideband excitation signal to the selected rectangular excitation port according to the set excitation-sampling combination mode; The signal acquisition and processing module is used to acquire scattering parameters from the rectangular excitation port, which serves as the sampling port, and transmit them to the data processing module. The data processing and analysis module is configured to: receive scattering parameter data and construct a test scattering parameter matrix, call a preset benchmark scattering parameter matrix, and output the judgment result of the severity of defects based on the cumulative evaluation loss.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the radio frequency array detection method for internal defects of a post porcelain insulator flange as described in any one of claims 1 to 6.

9. A non-volatile computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the radio frequency array detection method for internal defects of the post porcelain insulator flange as described in any one of claims 1 to 6.

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