Contact impedance evaluation method and device of electric contact structure and electronic equipment

Abstract

The invention provides a contact impedance evaluation method and device of an electric contact structure and electronic equipment, and relates to the technical field of power equipment monitoring and diagnosis. The method comprises the following steps: acquiring a first reflection coefficient curve of a to-be-tested phase cable in a test frequency band; performing windowing processing on the first reflection coefficient curve based on a window function to obtain a windowed reflection coefficient curve; performing inverse fast Fourier transform on the windowed reflection coefficient curve to obtain a time domain reflection coefficient curve of the to-be-measured phase cable; based on the time domain reflection coefficient curve, determining spatial distance distribution corresponding to the impedance of the to-be-measured phase cable; and according to the spatial distance distribution, evaluating the contact impedance of the electric contact structures at different positions. The impedance of different positions of the to-be-measured phase cable can be clearly and intuitively reflected through the spatial distance distribution, the contact impedance of the electric contact structure at each position on the to-be-measured phase cable can be accurately evaluated, higher spatial resolution is realized, and the evaluation precision of the contact impedance of the electric contact structure is further improved.

Description

Technical Field

[0001] The present application relates to the technical field of power equipment monitoring and diagnosis, and in particular to a contact impedance evaluation method, device, and electronic equipment for an electrical contact structure. Background Art

[0002] Switchgear is a critical switchgear device in power systems, and its operational reliability impacts the safety and stability of the entire power system. Multiple electrical contact structures are located in various locations within the switchgear. Over long-term operation, these structures are affected by environmental and mechanical factors, gradually increasing contact impedance and leading to localized degradation of contact performance. Especially when the switchgear operates at full load for extended periods, high currents flowing through abnormal electrical contact structures can cause serious equipment failures and potential safety hazards. Therefore, to ensure the long-term safe and stable operation of the switchgear, accurate assessment of the contact impedance of these structures is crucial.

[0003] In the related art, the impedance of the entire circuit of the switch cabinet is measured offline or online, and the contact impedance of the electrical contact structure in the switch cabinet is evaluated based on the measured impedance. However, it is impossible to accurately obtain the local impedance value of the electrical contact structure arranged at different positions. In particular, in power equipment such as switch cabinets that contain complex electrical contact networks, there is a problem of low evaluation accuracy, which makes it difficult to meet the needs of power engineering. Summary of the Invention

[0004] The present application provides a contact impedance evaluation method, device and electronic equipment for an electrical contact structure, which are used to solve the problem in related technologies of low evaluation accuracy and difficulty in meeting the needs of power engineering.

[0005] In a first aspect, the present application provides a contact impedance evaluation method for an electrical contact structure, wherein a plurality of electrical contact structures are arranged on a phase cable to be tested of an electrical device, and the contact impedance evaluation method comprises:

[0006] Obtaining a first reflection coefficient curve of the phase cable to be tested within a test frequency band;

[0007] Performing windowing processing on the first reflection coefficient curve based on the window function to obtain a windowed reflection coefficient curve;

[0008] Perform inverse fast Fourier transform on the windowed reflection coefficient curve to obtain the time domain reflection coefficient curve of the phase cable to be tested;

[0009] Based on the time domain reflection coefficient curve, determine the spatial distance distribution corresponding to the impedance of the phase cable to be tested;

[0010] The contact impedance of the electrical contact structure at different positions is evaluated based on the spatial distance distribution.

[0011] In one possible implementation, determining the spatial distance distribution corresponding to the impedance of the phase cable to be measured based on the time domain reflection coefficient curve includes:

[0012] Determine the impedance time domain distribution of the phase cable to be tested based on the time domain reflection coefficient curve;

[0013] Based on the propagation speed of the electrical signal in the phase cable to be tested and the impedance time domain distribution, the spatial distance distribution corresponding to the impedance of the phase cable to be tested is determined.

[0014] In one possible implementation, obtaining a first reflection coefficient curve of a phase cable to be tested within a test frequency band includes:

[0015] Obtaining a second reflection coefficient curve corresponding to the phase cable to be tested, where the second reflection coefficient curve does not include a reflection coefficient corresponding to zero frequency, and the reflection coefficient in the second reflection coefficient curve is measured by a vector network analyzer;

[0016] determining a Smith chart corresponding to the second reflection coefficient curve;

[0017] According to the set frequency sampling point and Smith chart, the target reflection coefficient corresponding to zero frequency is obtained;

[0018] The target reflection coefficient is added to the second reflection coefficient curve to obtain a first reflection coefficient curve of the phase cable to be tested.

[0019] In one possible implementation, evaluating the contact impedance of electrical contact structures at different locations based on spatial distance distribution includes:

[0020] Based on the target position of the electrical contact structure on the phase cable to be tested, the target impedance corresponding to the target position is extracted from the spatial distance distribution;

[0021] The target impedance is determined as the contact impedance corresponding to the electrical contact structure.

[0022] In a possible implementation, performing windowing processing on the first reflection coefficient curve based on a window function to obtain a windowed reflection coefficient includes:

[0023] Based on the Kaiser window, the first reflection coefficient curve is subjected to windowing processing to obtain a windowed reflection coefficient.

[0024] In a possible implementation, the contact impedance evaluation method further includes:

[0025] Monitor the contact impedance of electrical contact structures at different locations;

[0026] If the contact impedance is greater than the impedance threshold, an early warning message is output to indicate that an abnormality exists in the electrical contact structure.

[0027] In a second aspect, the present application provides a contact impedance evaluation device for an electrical contact structure, wherein a plurality of electrical contact structures are arranged on a phase cable to be tested of an electric power device, and the contact impedance evaluation device comprises:

[0028] An acquisition module, configured to acquire a first reflection coefficient curve of the phase cable to be tested within a test frequency band;

[0029] A first processing module is configured to perform windowing processing on the first reflection coefficient curve based on a window function to obtain a windowed reflection coefficient curve;

[0030] The second processing module is used to perform an inverse fast Fourier transform on the windowed reflection coefficient curve to obtain a time domain reflection coefficient curve of the phase cable to be tested;

[0031] A determination module, configured to determine a spatial distance distribution corresponding to the impedance of the phase cable to be measured based on a time domain reflection coefficient curve;

[0032] The evaluation module is used to evaluate the contact impedance of the electrical contact structure at different positions based on the spatial distance distribution.

[0033] In one possible implementation, the determination module is specifically used to: determine the impedance time domain distribution of the phase cable to be measured based on the time domain reflection coefficient curve; and determine the spatial distance distribution corresponding to the impedance of the phase cable to be measured based on the impedance time domain distribution based on the propagation speed of the electrical signal in the phase cable to be measured.

[0034] In one possible embodiment, the acquisition module is specifically used to: obtain a second reflection coefficient curve corresponding to the phase cable to be tested, the second reflection coefficient curve does not include the reflection coefficient corresponding to zero frequency, and the reflection coefficient in the second reflection coefficient curve is measured by a vector network analyzer; determine the Smith chart corresponding to the second reflection coefficient curve; obtain the target reflection coefficient corresponding to zero frequency based on the set frequency sampling point and the Smith chart; add the target reflection coefficient to the second reflection coefficient curve to obtain the first reflection coefficient curve of the phase cable to be tested.

[0035] In a possible implementation, the evaluation module is specifically configured to: extract a target impedance corresponding to the target position from a spatial distance distribution based on the target position of the electrical contact structure on the phase cable to be tested; and determine the target impedance as the contact impedance corresponding to the electrical contact structure.

[0036] In a possible implementation, the first processing module is specifically configured to: perform windowing processing on the first reflection coefficient curve based on a Kaiser window to obtain a windowed reflection coefficient curve.

[0037] In a possible implementation, the evaluation module is further configured to: monitor the contact impedance of the electrical contact structure at different positions; and output warning information indicating an abnormality in the electrical contact structure if the contact impedance is greater than an impedance threshold.

[0038] In a third aspect, the present application provides an electronic device, comprising: a memory, a processor;

[0039] Memory stores computer-executable instructions;

[0040] The processor executes the computer-executable instructions stored in the memory, so that the processor executes the above first aspect and / or various possible implementations of the first aspect.

[0041] In a fourth aspect, the present application provides a computer-readable storage medium, which stores computer-executable instructions. When the computer-executable instructions are executed by a processor, they are used to implement the above first aspect and / or various possible implementation methods of the first aspect.

[0042] In a fifth aspect, the present application provides a computer program product, comprising a computer program, which, when executed by a processor, implements the above first aspect and / or various possible implementations of the first aspect.

[0043] The contact impedance evaluation method, device, and electronic device for an electrical contact structure provided in the present application obtain a first reflection coefficient curve of a phase cable to be tested within a test frequency band; based on a window function, the first reflection coefficient curve is windowed to obtain a windowed reflection coefficient curve; the windowed reflection coefficient curve is inversely fast Fourier transformed to obtain a time domain reflection coefficient curve of the phase cable to be tested; based on the time domain reflection coefficient curve, the spatial distance distribution corresponding to the impedance of the phase cable to be tested is determined; and according to the spatial distance distribution, the contact impedance of the electrical contact structure at different positions is evaluated. The present application obtains the first reflection coefficient curve of the phase cable to be tested within a test frequency band and performs windowing and inverse fast Fourier transform, thereby being able to accurately obtain a time domain reflection coefficient curve, wherein the windowing process can effectively reduce spectrum leakage and sidelobe interference, improve the signal-to-noise ratio of the windowed reflection coefficient curve, and make subsequent contact impedance evaluation results more accurate and reliable. Furthermore, the spatial distance distribution of impedance, derived from the time-domain reflection coefficient curve, can be used to clearly and intuitively reflect the impedance at different locations on the phase cable under test. This helps accurately assess the contact impedance of the electrical contact structure at various locations on the phase cable under test, achieving higher spatial resolution and improving assessment accuracy. This in turn provides more accurate data support for analyzing the performance and aging of the electrical contact structure. This is particularly applicable to power equipment with complex electrical contact networks, such as switchgear. Furthermore, by accurately assessing the contact impedance of the electrical contact structure at various locations on the phase cable under test, the efficiency and accuracy of locating faulty electrical contact structures are improved, facilitating more targeted maintenance and repairs, reducing unnecessary inspections and replacements, improving maintenance efficiency, and effectively ensuring the safety and reliability of the operating status of power equipment such as switchgear. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0045] Figure 1 A schematic diagram of a scenario of a contact impedance evaluation method for an electrical contact structure provided in an embodiment of the present application;

[0046] Figure 2 Schematic diagram of the process of the contact impedance evaluation method of the electrical contact structure provided in the embodiment of the present application Figure 1 ;

[0047] Figure 3 A schematic diagram of the structure of the simulation verification model provided in the embodiment of the present application;

[0048] Figure 4 The simulation verification results provided for the embodiments of this application;

[0049] Figure 5 Schematic diagram of the process of the contact impedance evaluation method of the electrical contact structure provided in the embodiment of the present application Figure 2 ;

[0050] Figure 6 A schematic structural diagram of a contact impedance evaluation device for an electrical contact structure provided in an embodiment of the present application;

[0051] Figure 7 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application.

[0052] The above drawings illustrate specific embodiments of the present application, which will be described in more detail below. These drawings and the textual description are not intended to limit the scope of the present application in any way, but rather to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0053] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments consistent with the present application. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the present application, as detailed in the appended claims.

[0054] The terms "first", "second" etc. in the specification and claims of the present application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchangeable in appropriate circumstances, so that the embodiments of the present application described herein can, for example, be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, the process, system, product or equipment comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or that are inherent to these processes, products or equipment.

[0055] As power transmission and distribution systems evolve toward higher voltages and larger capacities, the operating environment of switchgear becomes increasingly complex, with equipment operating under high or heavy loads for extended periods. This poses even more severe reliability challenges for electrical contact structures. An abnormal increase in the contact impedance of an electrical contact structure can not only lead to localized overheating but can also cause localized arcing, accelerating the aging and damage of the contact surface and further deteriorating the equipment's operating condition. Furthermore, the high temperatures generated by localized overheating and arcing can ignite internal insulation materials, leading to more serious fires or electrical accidents. Therefore, accurate monitoring and assessment of the contact impedance of electrical contact structures is not only crucial for preventing switchgear failures but also a crucial measure for ensuring the safe operation of the entire transmission and distribution system.

[0056] In related technologies, impedance measurement of the entire switch cabinet circuit obtains the average impedance value of the entire circuit, which cannot accurately determine the local impedance values ​​at different positions in the circuit. The spatial resolution is low, resulting in low accuracy in contact impedance assessment of electrical contact structures at different positions.

[0057] In order to solve the above technical problems, the contact impedance evaluation method of the electrical contact structure provided in the present application obtains the reflection coefficient curve of the phase cable to be tested in the time domain based on the reflection coefficient curve of the phase cable to be tested, and further obtains the spatial distance distribution of the impedance of the phase cable to be tested based on the time domain reflection coefficient curve conversion, thereby realizing the extraction of the contact impedance of the electrical contact structure at different positions in the loop, improving the spatial resolution, and thereby improving the evaluation accuracy of the contact impedance of the electrical contact structure.

[0058] The following specific embodiments describe in detail the technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0059] Figure 1Schematic diagram of the contact impedance evaluation method of the electrical contact structure provided in the embodiment of the present application. Figure 1 As shown, the scenario includes a vector network analyzer 11, a fixture adapter plate 12, a switch cabinet 13, a switch cabinet 14, and a host computer 15. The vector network analyzer 11 has two ports (Port 1 and Port 2), and the switch cabinet 13 includes three phases: A, B, and C. In this scenario, Port 1 of the vector network analyzer 11 is connected to the connector of the phase cable to be tested (one of phases A, B, and C) of the switch cabinet 13 via the fixture adapter plate 12. The host computer 15 is connected to the vector network analyzer 11 via a general purpose interface bus (GPIB). The host computer 15, which can be a Windows system, sends measurement instructions to the vector network analyzer 11 to measure the reflection coefficient of the phase cable to be tested in the switch cabinet 13. The vector network analyzer 11 then sends the measurement results to the host computer 15 via the GPIB bus. The host computer 15 then executes the contact impedance evaluation method for electrical contact structures provided in this application.

[0060] It should be noted that switch cabinet 14 is directly connected to switch cabinet 13. When testing the phase cable to be tested of switch cabinet 13, it is necessary to ensure that the phase cable to be tested of switch cabinet 14 is in an open-circuit offline state. The fixture adapter plate 12 is, for example, a Sub-Miniature A (SMA) connector. The SMA connector shell is grounded, and the pins are connected to the connector wires of the phase cable to be tested of switch cabinet 13. The other end of the SMA connector is connected to port Port 1 of the vector network analyzer 11. The host computer 15, as the core terminal product for executing the evaluation method, must have data processing, analysis, storage, and user interaction capabilities. The host computer 15 can be an industrial computer, an embedded industrial computer, a desktop computer, a portable computer (such as a notebook, a PDA, an IPAD, etc.), a server, a dedicated evaluation terminal, etc.

[0061] It should also be noted that if there is wiring in the cables of power equipment, an electrical contact structure will be generated. Therefore, the contact impedance evaluation method of the electrical contact structure provided in this application can be applied to any power equipment that contains an electrical contact structure. The power equipment is not limited to switch cabinets, but can also be high-voltage circuit breakers, disconnectors, plug-in cable connectors, etc.

[0062] The following combination Figure 1 For application scenarios, refer to Figure 2 The contact impedance evaluation method of the electrical contact structure provided by the embodiment of the present application is described. It should be noted that the above application scenarios are only shown to facilitate understanding of the spirit and principles of the present application, and the implementation of the present application is not affected by Figure 1 Limitations of the application scenario shown.

[0063] Figure 2Schematic diagram of the process of the contact impedance evaluation method of the electrical contact structure provided in the embodiment of the present application Figure 1 The contact impedance evaluation method of the electrical contact structure provided in the embodiment of the present application is as follows: Figure 1 The host computer 15 in the process is executed. Figure 2 As shown, the contact impedance evaluation method includes:

[0064] S201: Obtain a first reflection coefficient curve of a phase cable to be tested within a test frequency band.

[0065] The phase cable under test of power equipment (such as switchgear) is equipped with multiple electrical contact structures. The reflection coefficient is a parameter that describes the relationship between the reflected wave and the incident wave when an electromagnetic wave encounters a discontinuity (such as an impedance change) in the phase cable under test. This parameter typically includes amplitude and phase information. The first reflection coefficient curve contains the reflection coefficient for each frequency point within the test frequency band, plotting the amplitude and phase of the reflection coefficient as a function of frequency. The horizontal axis of the first reflection coefficient curve represents frequency, and the vertical axis represents the amplitude of the reflection coefficient.

[0066] For example, the test frequency band is a frequency range of 0 to 10 GHz, and the host computer 15 obtains the first reflection coefficient curve of the phase cable to be tested within the test frequency band from a vector network analyzer 11 that supports the frequency range of 0 to 10 GHz or other servers. Other servers can be regarded as storage nodes, which can store the first reflection coefficient curves of multiple switch cabinets or multi-phase cables of a certain switch cabinet within the test frequency band.

[0067] S202: Perform windowing processing on the first reflection coefficient curve based on the window function to obtain a windowed reflection coefficient curve.

[0068] In applications, in order to reduce spectral leakage, improve spectral resolution, and optimize the time-frequency characteristics of the signal, windowing can help smooth the first reflection coefficient curve, suppress noise interference, and better highlight the main features of the curve, such as impedance discontinuities, to facilitate subsequent feature extraction and analysis.

[0069] For example, the window function can be a Hanning window, a Hamming window, a Blackman window, a Kaiser window, etc. After selecting a suitable window function, the windowing process of the first reflection coefficient curve includes: determining the window function length N, such as according to the length of the first reflection coefficient curve; generating a window function sequence of corresponding length according to the selected window function type; , ; The generated window function sequence and the first reflection coefficient curve Perform point-by-point multiplication to obtain the windowed reflection coefficient curve (i.e., the windowed reflection coefficient curve ).

[0070] Optionally, before performing the windowing process, the first reflection coefficient curve may be pre-processed, such as denoising, normalization, etc., to improve the effect of the windowing process.

[0071] It should be noted that a suitable window function can be selected based on a comprehensive evaluation of specific measurement requirements, the characteristics of the first reflection coefficient curve, and the characteristics of the window function. The embodiments of the present application do not impose any specific restrictions on this.

[0072] S203 , performing inverse fast Fourier transform on the windowed reflection coefficient curve to obtain a time domain reflection coefficient curve of the phase cable to be tested.

[0073] It can be understood that the windowed reflection coefficient curve is a frequency domain signal. The inverse fast Fourier transform is the inverse process of the Fourier transform, which is used to convert the frequency domain signal into a time domain signal to obtain the reflection coefficient curve of the phase cable to be tested in the time domain, that is, the time domain reflection coefficient curve. For example, the windowed reflection coefficient curve is expressed as ), then the time domain reflection coefficient curve of the phase cable to be tested is ,in is the frequency, is the inverse fast Fourier transform.

[0074] S204 : Determine the spatial distance distribution corresponding to the impedance of the phase cable to be measured based on the time domain reflection coefficient curve.

[0075] For example, time domain reflectometry (TDR) analysis software (including but not limited to Keysight N1911A and Tektronix DSA8300) is used to automatically extract impedance-distance distribution from the time domain reflectometry curve to obtain the spatial distance distribution corresponding to the impedance of the phase cable to be tested.

[0076] In another example, the reflection coefficient and instantaneous impedance calculation formula is used to calculate the impedance distribution of the phase cable under test in the time domain (i.e., the impedance time-domain distribution) based on the time-domain reflection coefficient curve. This impedance time-domain distribution is then converted into the impedance distribution over spatial distance. The specific process is described in the following embodiment.

[0077] In another example, based on an established mapping model between reflection coefficient and impedance distribution, the mapping model is obtained, for example, based on a machine learning algorithm (such as a support vector machine, a neural network, etc.) and a large amount of labeled data training. The time domain reflection coefficient curve is input into the mapping model. After processing by the mapping model, the impedance value and its spatial position (i.e., the spatial distance distribution corresponding to the impedance) are output.

[0078] S205. Evaluate the contact impedance of the electrical contact structure at different positions according to the spatial distance distribution.

[0079] The electrical contact structure is usually located at a specific position of the phase cable to be tested, such as a branch point, a connection point, or a joint. The electrical contact structure usually causes a local mutation in the impedance of the phase cable to be tested (for example, the impedance at the connection point is significantly higher than that of the cable body).

[0080] In one case, the specific location of the electrical contact structure on the phase cable under test is unknown. Accordingly, the electrical contact structure is identified and the contact impedance is extracted by detecting the impedance discontinuity points in the spatial distance distribution corresponding to the impedance of the phase cable under test. For example, the impedance difference between adjacent points in the spatial distance distribution is calculated. If the difference exceeds a threshold, it is determined to be a discontinuity point, indicating that an electrical contact structure exists at that location. The impedance value at the discontinuity point or the statistical value (such as the peak value) of the discontinuity region is used as the contact impedance of the electrical contact structure.

[0081] In another scenario, the specific location of the electrical contact structure on the phase cable to be tested is predetermined based on the cable design drawing. Alternatively, for an already installed cable, the specific location of the electrical contact structure can be located using technologies such as laser ranging and visual recognition. Accordingly, the impedance value corresponding to the location of the electrical contact structure can be found from the spatial distance distribution corresponding to the impedance of the phase cable to be tested. If the electrical contact structure at a certain location spans multiple impedance measurement points (such as a wide joint), the average or maximum impedance value can be taken as the contact resistance of the electrical contact structure at that location. For example, if a connection point (electrical contact structure) is located 3m into the phase cable to be tested, and the impedance distribution shows an impedance of 0.5mΩ at that location, then the contact impedance is 0.5mΩ.

[0082] In an embodiment of the present application, by obtaining the first reflection coefficient curve of the phase cable to be tested within the test frequency band and performing windowing processing and inverse fast Fourier transform, a time domain reflection coefficient curve can be accurately obtained. Windowing processing can effectively reduce spectrum leakage and sidelobe interference, improve the signal-to-noise ratio of the windowed reflection coefficient curve, and make subsequent contact impedance evaluation results more accurate and reliable. Furthermore, the spatial distance distribution of impedance is obtained based on the time domain reflection coefficient curve conversion. The spatial distance distribution can clearly and intuitively reflect the impedance at different positions of the phase cable to be tested, which helps to accurately evaluate the contact impedance of the electrical contact structure at various positions on the phase cable to be tested, achieve higher spatial resolution, improve evaluation accuracy, and provide more accurate data support for analyzing the performance and aging degree of the electrical contact structure. This is particularly suitable for power equipment containing complex electrical contact networks, such as switchgear.

[0083] In addition, compared with the related art in which the impedance of the entire circuit is measured, when a fault occurs in an electrical contact structure in the circuit (such as poor contact), it is difficult to accurately determine the specific location of the fault. The embodiment of the present application improves the efficiency and accuracy of locating the faulty electrical contact structure by accurately evaluating the contact impedance of the electrical contact structure at various positions on the phase cable to be tested, which is conducive to more targeted maintenance and repairs, reduces unnecessary inspections and replacements, improves maintenance efficiency, and effectively ensures the safety and reliability of the operating status of power equipment such as switchgear.

[0084] In some embodiments, the spatial distance distribution corresponding to the impedance of the phase cable to be measured is determined based on the time domain reflection coefficient curve, including: determining the time domain distribution of the impedance of the phase cable to be measured according to the time domain reflection coefficient curve; and determining the spatial distance distribution corresponding to the impedance of the phase cable to be measured according to the impedance time domain distribution based on the propagation speed of the electrical signal in the phase cable to be measured.

[0085] For example, the time domain reflection coefficient curve is , using the calculation formula of reflection coefficient and instantaneous impedance, the time domain reflection coefficient curve is converted into instantaneous impedance value through the formula to obtain the impedance time domain distribution , the formula is expressed as

[0086]

[0087] in, is the characteristic internal resistance of the vector network analyzer, for example, 50Ω.

[0088] Furthermore, the impedance time-domain distribution is converted to its distribution over spatial distance. This process can be thought of as converting the time axis to a spatial distance axis. Specifically, based on the time delay and the propagation speed of the electrical signal in the phase cable under test, the spatial distance corresponding to the impedance is calculated. The resulting spatial distance distribution is represented by the horizontal axis as spatial distance and the vertical axis as impedance. The relationship between spatial distance, time delay, and propagation speed is expressed as follows:

[0089]

[0090] in, For delay, is the propagation speed of the electrical signal in the phase cable to be tested, Depends on the cable type (e.g. coaxial cable about 0.66c, twisted pair about 0.6c), c is the speed of light.

[0091] In this embodiment, the time-domain distribution of cable impedance is determined using a time-domain reflection coefficient curve and converted into a spatial distance distribution based on the signal propagation velocity, thereby improving the accuracy and reliability of the spatial distance distribution. Furthermore, the spatial distance distribution clearly and intuitively presents the impedance at different locations on the phase cable under test, accurately reflecting the impedance distribution pattern along the phase cable under test. This facilitates precise evaluation of the contact impedance of the electrical contact structure at various locations on the phase cable under test, achieving higher spatial resolution and improving assessment accuracy.

[0092] Considering that in practical applications, some vector network analyzers may not be able to directly start frequency sweeping from DC (i.e., zero frequency), zero padding of the reflection coefficient curve is required to improve the accuracy of the measurement results. Therefore, in some embodiments, obtaining a first reflection coefficient curve for the phase cable under test within a test frequency band includes: obtaining a second reflection coefficient curve corresponding to the phase cable under test, the second reflection coefficient curve excluding the reflection coefficient corresponding to zero frequency, the reflection coefficients in the second reflection coefficient curve being measured by a vector network analyzer; determining a Smith chart corresponding to the second reflection coefficient curve; obtaining a target reflection coefficient corresponding to zero frequency based on the set frequency sampling points and the Smith chart; and adding the target reflection coefficient to the second reflection coefficient curve to obtain a first reflection coefficient curve for the phase cable under test.

[0093] For example, a vector network analyzer scans a test frequency band excluding zero frequency (e.g., 5 Hz to 10 GHz) and records the reflection coefficient at each frequency point. After the measurement is complete, a curve is formed showing how the amplitude and phase of the reflection coefficient vary with frequency, known as the second reflection coefficient curve. The reflection coefficient corresponding to each frequency point is a complex number containing both amplitude and phase. The frequency sampling points are set to low-frequency sampling points, typically the first two sampling points (e.g., A and B) on the second reflection coefficient curve. A Smith chart is then drawn based on the second reflection coefficient curve. Points on the Smith chart represent complex reflection coefficients, with coordinates consisting of real and imaginary parts.

[0094] It should be noted that sampling points A and B are located on the Smith chart. Based on their coordinates on the Smith chart, the equation of the line connecting sampling points A and B can be determined. The abscissa of the intersection of this line and the real axis of the Smith chart is calculated. This value is the target reflection coefficient corresponding to zero frequency (a real number). The target reflection coefficient is added to the second reflection coefficient curve to supplement the second reflection coefficient curve with the reflection coefficient corresponding to zero frequency, thereby obtaining a first reflection coefficient curve with a frequency range of 0 to 10 GHz.

[0095] In an embodiment of the present application, the geometric characteristics of the Smith chart are utilized to make the first reflection coefficient curve change more smoothly in the low-frequency band through geometric interpolation, thereby avoiding the sudden change caused by direct zero padding and improving the accuracy of the low-frequency band measurement results; in addition, geometric interpolation is used to ensure that the target reflection coefficient is a real number with a reasonable amplitude, which conforms to the low-frequency characteristics, thereby improving the accuracy of zero padding of the first reflection coefficient curve.

[0096] In some embodiments, the contact impedance of the electrical contact structure at different positions is evaluated based on the spatial distance distribution, including: extracting the target impedance corresponding to the target position from the spatial distance distribution based on the target position of the electrical contact structure on the phase cable to be tested; and determining the target impedance as the contact impedance corresponding to the electrical contact structure.

[0097] The horizontal axis of the spatial distance distribution is the spatial distance, and the vertical axis is the impedance. The spatial distance represents the specific location on the phase cable to be tested. For example, the impedance is 55Ω at 1 meter from the head end of the phase cable to be tested, 58Ω at 2 meters, and 65Ω at 5 meters, and so on.

[0098] For example, when the electrical contact network is completed in power equipment such as a switchgear, the target locations of the various electrical contact structures on the phase cable to be tested are determined. For example, electrical contact structure a is located 2 meters from the beginning of the phase cable to be tested, electrical contact structure b is located 3 meters from the beginning of the phase cable to be tested, electrical contact structure c is located 5 meters from the beginning of the phase cable to be tested, and so on. Therefore, based on the target location of the electrical contact structure on the phase cable to be tested (e.g., 5 meters from the beginning of the phase cable to be tested), the target impedance corresponding to this target location can be determined as 65Ω in the spatial distance distribution. Furthermore, the target impedance at the target location is used as the contact impedance of the electrical contact structure at that target location.

[0099] In the embodiments of the present application, based on the target location of the electrical contact structure on the phase cable under test, the target impedance corresponding to the target location can be quickly extracted from the spatial distance distribution of the impedance, eliminating the need for complex electrical testing of the cable, thus saving testing time and cost. Furthermore, the spatial distance distribution accurately and intuitively reflects the distribution of impedance on the phase cable under test. When the target impedance at the target location is used as the contact impedance of the electrical contact structure at that target location, the contact impedance of the electrical contact structure can be accurately reflected, improving the accuracy of contact impedance assessments at different locations.

[0100] In some embodiments, performing windowing processing on the first reflection coefficient curve based on a window function to obtain a windowed reflection coefficient curve includes: performing windowing processing on the first reflection coefficient curve based on a Kaiser window to obtain a windowed reflection coefficient curve.

[0101] For example, the Kaiser window satisfies the following form:

[0102]

[0103] in, The window function is The value of the sampling point, is the zero-order Bessel function of the first kind, N is the window function length, , is the shape parameter of the window, which controls the balance between sidelobe attenuation and mainlobe width.

[0104] The first reflection coefficient curve , perform windowing on the first reflection coefficient curve, and generate the Kaiser window function sequence and the first reflection coefficient curve Perform point-by-point multiplication to obtain the windowed reflection coefficient curve (i.e., the windowed reflection coefficient curve ).

[0105] In an embodiment of the present application, a Kaiser window is used to perform windowing processing on the first reflection coefficient curve, thereby reducing spectral leakage, improving spectral resolution, and optimizing the time-frequency characteristics of the signal, thereby improving the accuracy of frequency domain analysis, and further improving the accuracy of the time domain reflection coefficient curve obtained by subsequent inverse fast Fourier transform, providing reliable and accurate data support for evaluating the contact impedance of electrical contact structures in different positions.

[0106] In some embodiments, the contact impedance evaluation method further includes: monitoring the contact impedance of the electrical contact structure at different positions; if the contact impedance is greater than an impedance threshold, outputting a warning message indicating that an abnormality exists in the electrical contact structure.

[0107] For example, the impedance threshold can be based on historical measurement data, calculating the range of contact impedance when the electrical contact structure is normal, thereby setting a reasonable impedance threshold. Alternatively, the impedance threshold can be set based on a combination of engineering experience and theory. The impedance thresholds corresponding to electrical contact structures at different locations may vary. During monitoring, the contact impedances of electrical contact structures at different locations are compared with their corresponding impedance thresholds. If the contact impedance is greater than the impedance threshold, for example, if the contact impedance is 52Ω and the impedance threshold is 50Ω, the electrical contact structure is determined to be abnormal and an early warning message is output. The early warning message is not limited to including the abnormal location, contact impedance, impedance threshold, timestamp, etc.

[0108] Optionally, the presentation of the warning information is not limited to notifying maintenance personnel through display screens, sound and light alarms, remote communications (such as text messages, emails), etc.

[0109] The embodiment of the present application monitors the contact impedance of the electrical contact structure and compares it with the impedance threshold to timely, efficiently and accurately detect potential abnormalities or faults, avoid accidents, and automatically outputs early warning information to indicate that there is an abnormality in the electrical contact structure when the contact impedance is greater than the impedance threshold, thereby improving the efficiency of troubleshooting abnormalities or faults and ensuring the reliability and safety of the operation of power equipment.

[0110] In order to further verify the effectiveness of the contact impedance evaluation method provided in this application, a simulation model was established in the Advanced Design System (ADS). Figure 3 A schematic diagram of the structure of the simulation verification model provided in the embodiment of the present application is shown in FIG. Figure 3 As shown, in the simulation verification model, transmission line models with different impedance and time delay characteristics are used to simulate the contact impedance of different electrical contact structures. One end of the transmission line model is connected to a terminal with an internal resistance of 50Ω (corresponding to TermG1 in the figure), and the other end of the transmission line model is grounded. The reflection coefficient curve S11 of the port SP1 is extracted through the S parameter simulation module (corresponding to S-PARAMETERS in the figure), wherein the S parameter simulation module sets the starting frequency to 0MHz and the cutoff frequency to 20GHz. Multiple electrical contact structures are also set in the transmission line model, corresponding to TLD1 (contact impedance of 50Ω, time delay of 1ns), TLD2 (contact impedance of 75Ω, time delay of 2ns) and TLD3 (contact impedance of 50Ω, time delay of 1ns) in the figure. The contact impedance evaluation method provided in this application is used to calculate the extracted result S11 to obtain the impedance distribution in the time domain (impedance time domain distribution). Figure 4 The simulation verification results provided for the embodiment of the present application are shown in Figure 4. The horizontal axis represents time and the vertical axis represents impedance. It can be seen from the results that: at 1ns-3ns, the impedance is 50Ω; at 3ns-7ns, the impedance is 75Ω; and at 7ns-9ns, the impedance is 50Ω. This result is consistent with the properties of the electrical contact structure at different positions in the transmission line model, that is, the method can accurately identify the changes in different impedances at multiple positions. Therefore, the contact impedance evaluation method provided in the embodiment of the present application can be effectively applied to the measurement and status evaluation of the contact impedance of electrical contact structures at different positions in power equipment such as switchgear.

[0111] Figure 5 Schematic diagram of the process of the contact impedance evaluation method of the electrical contact structure provided in the embodiment of the present application Figure 2 .like Figure 5 As shown, this embodiment, based on the above embodiment, describes in detail a contact impedance evaluation method for an electrical contact structure, and the contact impedance evaluation method includes:

[0112] S501: Obtain a second reflection coefficient curve corresponding to the phase cable to be tested.

[0113] The second reflection coefficient curve does not include a reflection coefficient corresponding to zero frequency, and the reflection coefficient in the second reflection coefficient curve is measured by a vector network analyzer.

[0114] For example, before starting the measurement, set the key parameters of the vector network analyzer, such as the sweep bandwidth (start frequency, cutoff frequency) and the number of sampling points. To ensure the reliability of the measurement results, the start frequency should be selected from the minimum frequency value of the vector network analyzer, such as setting the sweep bandwidth to 5Hz to 10GHz. At the same time, calibrate the vector network analyzer to ensure measurement accuracy. Cutoff frequency With the starting frequency The following relationship should be satisfied:

[0115]

[0116] is the impedance rise time in the time domain, The smaller it is, the larger the sweep bandwidth is and the better the measurement effect is.

[0117] S502: Determine the Smith chart corresponding to the second reflection coefficient curve, and obtain the target reflection coefficient corresponding to the zero frequency according to the set frequency sampling point and the Smith chart.

[0118] A Smith chart is drawn according to the second reflection coefficient curve. The reflection coefficient corresponding to each frequency point in the second reflection coefficient curve is a complex number including amplitude and phase. The point on the Smith chart represents the reflection coefficient in complex form, and its coordinates consist of a real part and an imaginary part.

[0119] The frequency sampling points are set to low-frequency sampling points, usually the first two sampling points (such as A and B) on the second reflection coefficient curve. Sampling points A and B are located on the Smith circle. The equation of the straight line connecting sampling points A and B can be determined based on the coordinates of sampling points A and B on the Smith chart. The value of the abscissa of the intersection of the connecting line and the real axis of the Smith chart is calculated. This value is the target reflection coefficient corresponding to zero frequency (a real number).

[0120] S503: Add the target reflection coefficient to the second reflection coefficient curve to obtain a first reflection coefficient curve of the phase cable to be tested.

[0121] The target reflection coefficient is added to the second reflection coefficient curve to supplement the second reflection coefficient curve with the reflection coefficient corresponding to zero frequency, thereby obtaining a first reflection coefficient curve with a frequency range from 0 to 10 GHz.

[0122] S504: Perform windowing processing on the first reflection coefficient curve based on the Kaiser window to obtain a windowed reflection coefficient curve.

[0123] For example, the Kaiser window satisfies the following form:

[0124]

[0125] in, The window function is The value of the sampling point, is the zero-order Bessel function of the first kind, N is the window function length, , is the shape parameter of the window, which controls the balance between sidelobe attenuation and mainlobe width.

[0126] The first reflection coefficient curve , perform windowing on the first reflection coefficient curve, and generate the Kaiser window function sequence and the first reflection coefficient curve Perform point-by-point multiplication to obtain the windowed reflection coefficient curve (i.e., the windowed reflection coefficient curve ).

[0127] S505 , performing inverse fast Fourier transform on the windowed reflection coefficient curve to obtain a time domain reflection coefficient curve of the phase cable to be tested.

[0128] For example, the time domain reflection coefficient curve of the phase cable to be tested is ,in is the frequency, is the inverse fast Fourier transform.

[0129] S506 : Determine the impedance time domain distribution of the phase cable to be tested according to the time domain reflection coefficient curve.

[0130] For example, the time domain reflection coefficient curve is , using the calculation formula of reflection coefficient and instantaneous impedance, the time domain reflection coefficient curve is converted into instantaneous impedance value through the formula to obtain the impedance time domain distribution , the formula is expressed as

[0131]

[0132] in, is the characteristic internal resistance of the vector network analyzer, for example, 50Ω.

[0133] S507 : Determine the spatial distance distribution corresponding to the impedance of the phase cable to be measured based on the propagation speed of the electrical signal in the phase cable to be measured and according to the impedance time domain distribution.

[0134] The impedance time domain distribution is converted to the impedance distribution over spatial distance. This process can be thought of as converting the time axis to the spatial distance axis. Specifically, based on the time delay and the propagation speed of the electrical signal in the phase cable under test, the spatial distance corresponding to the impedance is calculated, resulting in a spatial distance distribution with spatial distance on the horizontal axis and impedance on the vertical axis. The relationship between spatial distance, time delay, and propagation speed is expressed as follows:

[0135]

[0136] in, For delay, is the propagation speed of the electrical signal in the phase cable to be tested, It depends on the cable type (e.g. coaxial cable about 0.66c, twisted pair about 0.6c), c is the speed of light.

[0137] S508 . Based on the target position of the electrical contact structure on the phase cable to be measured, extract the target impedance corresponding to the target position from the spatial distance distribution.

[0138] For example, the spatial distance distribution includes an impedance of 55Ω at 1 meter from the start end of the phase cable to be tested, 58Ω at 2 meters, 65Ω at 5 meters, and so on. Based on the target position of the electrical contact structure on the phase cable to be tested (e.g., 5 meters from the start end of the phase cable to be tested), the target impedance corresponding to this target position can be determined in the spatial distance distribution to be 65Ω.

[0139] S509: Determine the target impedance as the contact impedance corresponding to the electrical contact structure.

[0140] In summary, this application has at least the following advantages:

[0141] 1. By obtaining the first reflection coefficient curve of the phase cable to be tested within the test frequency band and performing windowing processing and inverse fast Fourier transform, the time domain reflection coefficient curve can be accurately obtained. Among them, windowing processing can effectively reduce spectrum leakage and sidelobe interference, improve the signal-to-noise ratio of the windowed reflection coefficient curve, and make the subsequent contact impedance evaluation results more accurate and reliable.

[0142] Second, the spatial distance distribution of impedance is obtained based on the conversion of the time domain reflection coefficient curve. The spatial distance distribution can clearly and intuitively reflect the impedance at different positions of the phase cable to be tested, which helps to accurately evaluate the contact impedance of the electrical contact structure at various positions on the phase cable to be tested, achieve higher spatial resolution, and improve evaluation accuracy. It provides more accurate data support for analyzing the performance and aging degree of the electrical contact structure, which is especially suitable for power equipment containing complex electrical contact networks, such as switchgear.

[0143] 3. By accurately evaluating the contact impedance of the electrical contact structure at various locations on the phase cable to be tested, the efficiency and accuracy of locating the faulty electrical contact structure are improved, which is conducive to more targeted maintenance and repairs, reduces unnecessary inspections and replacements, improves maintenance efficiency, and effectively ensures the safety and reliability of the operating status of power equipment such as switchgear.

[0144] Fourth, by utilizing the geometric characteristics of the Smith chart, geometric interpolation is used to make the first reflection coefficient curve smoother in the low-frequency band, avoiding the sudden change caused by direct zero padding and improving the accuracy of the low-frequency measurement results. In addition, geometric interpolation is used to ensure that the target reflection coefficient is a real number with a reasonable amplitude, which conforms to the low-frequency characteristics, thereby improving the accuracy of zero padding of the first reflection coefficient curve.

[0145] Fifth, based on the target location of the electrical contact structure on the phase cable under test, the target impedance corresponding to the target location can be quickly extracted from the spatial distance distribution of the impedance, eliminating the need for complex electrical testing of the cable, saving testing time and cost. Furthermore, the spatial distance distribution accurately and intuitively reflects the impedance distribution pattern on the phase cable under test. When the target impedance at the target location is used as the contact impedance of the electrical contact structure at that target location, it accurately reflects the contact impedance of the electrical contact structure, improving the accuracy of contact impedance assessment at different locations.

[0146] 6. By monitoring the contact impedance of the electrical contact structure and comparing it with the impedance threshold, potential abnormalities or faults can be discovered in a timely, efficient and accurate manner to avoid accidents. When the contact impedance is greater than the impedance threshold, early warning information is automatically output to indicate that there is an abnormality in the electrical contact structure, thereby improving the efficiency of troubleshooting abnormalities or faults and ensuring the reliability and safety of power equipment operation.

[0147] Figure 6 This is a schematic diagram of a contact impedance evaluation device for an electrical contact structure provided in an embodiment of the present application. Multiple electrical contact structures are arranged on the phase cables to be tested of the power equipment, such as Figure 6 As shown, the contact impedance evaluation device 60 provided in this embodiment includes: an acquisition module 61, a first processing module 62, a second processing module 63, a determination module 64 and an evaluation module 65. Among them:

[0148] An acquisition module 61 is configured to acquire a first reflection coefficient curve of the phase cable to be tested within a test frequency band;

[0149] A first processing module 62 is configured to perform windowing processing on the first reflection coefficient curve based on a window function to obtain a windowed reflection coefficient curve;

[0150] The second processing module 63 is used to perform an inverse fast Fourier transform on the windowed reflection coefficient curve to obtain a time domain reflection coefficient curve of the phase cable to be tested;

[0151] A determination module 64 is configured to determine a spatial distance distribution corresponding to the impedance of the phase cable to be measured based on the time domain reflection coefficient curve;

[0152] The evaluation module 65 is configured to evaluate the contact impedances of the electrical contact structures at different positions according to the spatial distance distribution.

[0153] In one possible implementation, the determination module 64 is specifically configured to: determine the impedance time domain distribution of the phase cable to be measured based on the time domain reflection coefficient curve; and determine the spatial distance distribution corresponding to the impedance of the phase cable to be measured based on the impedance time domain distribution and the propagation speed of the electrical signal in the phase cable to be measured.

[0154] In one possible embodiment, the acquisition module 61 is specifically used to: obtain a second reflection coefficient curve corresponding to the phase cable to be tested, the second reflection coefficient curve does not include the reflection coefficient corresponding to zero frequency, and the reflection coefficient in the second reflection coefficient curve is measured by a vector network analyzer; determine the Smith chart corresponding to the second reflection coefficient curve; obtain the target reflection coefficient corresponding to zero frequency based on the set frequency sampling point and the Smith chart; add the target reflection coefficient to the second reflection coefficient curve to obtain the first reflection coefficient curve of the phase cable to be tested.

[0155] In a possible implementation, the evaluation module 65 is specifically configured to: extract a target impedance corresponding to the target position from the spatial distance distribution based on the target position of the electrical contact structure on the phase cable to be tested; and determine the target impedance as the contact impedance corresponding to the electrical contact structure.

[0156] In a possible implementation, the first processing module 62 is specifically configured to: perform windowing processing on the first reflection coefficient curve based on a Kaiser window to obtain a windowed reflection coefficient curve.

[0157] In a possible implementation, the evaluation module 65 is further configured to: monitor the contact impedance of the electrical contact structure at different positions; and output warning information indicating that an abnormality exists in the electrical contact structure if the contact impedance is greater than an impedance threshold.

[0158] The contact impedance evaluation device provided in this embodiment can execute the method provided in the above method embodiment. Its implementation principle and technical effects are similar and will not be described in detail in this embodiment.

[0159] Figure 7 This is a schematic diagram of the structure of the electronic device provided in the embodiment of the present application. Figure 7 As shown, the electronic device 70 provided in this embodiment includes: at least one processor 701 and a memory 702. Optionally, the electronic device 70 further includes a communication component 703. The processor 701, the memory 702 and the communication component 703 are connected via a bus 704.

[0160] During the specific implementation process, at least one processor 701 executes the computer-executable instructions stored in the memory 702, so that the at least one processor 701 performs the above method.

[0161] The specific implementation process of the processor 701 can be found in the above method embodiment. Its implementation principle and technical effects are similar and will not be repeated here in this embodiment.

[0162] In the above embodiments, it should be understood that the processor may be a central processing unit (CPU), other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASICs), etc. A general-purpose processor may be a microprocessor or any conventional processor. The steps of the method disclosed in the present invention may be directly executed by a hardware processor or by a combination of hardware and software modules within the processor.

[0163] The memory may include random access memory (RAM) and may also include non-volatile memory (NVM), such as at least one disk storage.

[0164] A bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus. Buses can be categorized as address buses, data buses, and control buses. For ease of illustration, the buses in the drawings of this application are not limited to just one bus or just one type of bus.

[0165] An embodiment of the present application also provides a computer program product, including a computer program, which implements the above method when executed by a processor.

[0166] An embodiment of the present application further provides a computer-readable storage medium, in which computer-executable instructions are stored. When a processor executes the computer-executable instructions, the above-mentioned method is implemented.

[0167] The readable storage medium may be implemented by any type of volatile or non-volatile memory device, or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. The readable storage medium may be any available medium that can be accessed by a general-purpose or special-purpose computer.

[0168] An exemplary readable storage medium is coupled to a processor so that the processor can read information from the readable storage medium and write information to the readable storage medium. Of course, the readable storage medium can also be an integral part of the processor. The processor and the readable storage medium can be located in an application specific integrated circuit (ASIC). Of course, the processor and the readable storage medium can also exist in the device as discrete components.

[0169] The division of units is merely a logical functional division; actual implementations may employ alternative divisions, such as combining or integrating multiple units or components into another system, or omitting or disabling certain features. Furthermore, any direct coupling or communication connection shown or discussed may be an indirect coupling or communication connection between devices or units, either through an interface, electrical, mechanical, or other means.

[0170] Units described as separate components may or may not be physically separate, and components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0171] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.

[0172] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the various embodiments of the method of the present invention. The aforementioned storage medium includes various media that can store program code, such as USB flash drives, mobile hard drives, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical disks.

[0173] Those skilled in the art will appreciate that all or part of the steps in the above-described method embodiments can be implemented using hardware associated with program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments. The aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0174] Finally, it should be noted that those skilled in the art will readily identify other embodiments of the present invention after considering the specification and practicing the invention disclosed herein. The present invention is intended to cover any variations, uses, or adaptations of the present invention that follow the general principles of the present invention and include common knowledge or customary techniques in the art not disclosed herein. The present invention is not limited to the precise structure described above and illustrated in the accompanying drawings, and various modifications and variations may be made without departing from the scope thereof. The scope of the present invention is limited solely by the appended claims.

Claims

1. A contact impedance evaluation method for an electrical contact structure, characterized in that: A plurality of electrical contact structures are arranged on a phase cable to be tested of an electric power device, and the contact impedance evaluation method includes: Obtaining a first reflection coefficient curve of the phase cable to be tested within a test frequency band; Performing windowing processing on the first reflection coefficient curve based on a window function to obtain a windowed reflection coefficient curve; Performing an inverse fast Fourier transform on the windowed reflection coefficient curve to obtain a time domain reflection coefficient curve of the phase cable to be tested; Determining a spatial distance distribution corresponding to the impedance of the phase cable to be measured based on the time domain reflection coefficient curve; The contact impedances of the electrical contact structures at different positions are evaluated according to the spatial distance distribution.

2. The contact impedance evaluation method according to claim 1, wherein: The determining, based on the time domain reflection coefficient curve, a spatial distance distribution corresponding to the impedance of the phase cable to be measured includes: Determining the impedance time domain distribution of the phase cable to be tested according to the time domain reflection coefficient curve; Based on the propagation speed of the electrical signal in the phase cable to be measured and according to the impedance time domain distribution, the spatial distance distribution corresponding to the impedance of the phase cable to be measured is determined.

3. The contact impedance evaluation method according to claim 1, wherein: The obtaining of a first reflection coefficient curve of the phase cable to be tested within a test frequency band includes: Obtaining a second reflection coefficient curve corresponding to the phase cable to be tested, where the second reflection coefficient curve does not include a reflection coefficient corresponding to zero frequency, and the reflection coefficient in the second reflection coefficient curve is measured by a vector network analyzer; determining a Smith chart corresponding to the second reflection coefficient curve; Obtaining a target reflection coefficient corresponding to zero frequency according to the set frequency sampling point and the Smith chart; The target reflection coefficient is added to the second reflection coefficient curve to obtain a first reflection coefficient curve of the phase cable to be tested.

4. The contact impedance evaluation method according to any one of claims 1 to 3, characterized in that: The step of evaluating the contact impedance of the electrical contact structures at different positions according to the spatial distance distribution includes: extracting a target impedance corresponding to the target position from the spatial distance distribution based on a target position of the electrical contact structure on the phase cable to be tested; The target impedance is determined as the contact impedance corresponding to the electrical contact structure.

5. The contact impedance evaluation method according to any one of claims 1 to 3, characterized in that: The step of performing windowing processing on the first reflection coefficient curve based on a window function to obtain a windowed reflection coefficient includes: Based on the Kaiser window, a windowing process is performed on the first reflection coefficient curve to obtain a windowed reflection coefficient.

6. The contact impedance evaluation method according to any one of claims 1 to 3, characterized in that: Also includes: Monitor the contact impedance of electrical contact structures at different locations; If the contact impedance is greater than the impedance threshold, a warning message is outputted to indicate that an abnormality exists in the electrical contact structure.

7. A contact impedance evaluation device for an electrical contact structure, characterized in that: A plurality of electrical contact structures are arranged on the phase cables to be tested of the power equipment, and the contact impedance evaluation device comprises: An acquisition module, configured to acquire a first reflection coefficient curve of the phase cable to be tested within a test frequency band; A first processing module is configured to perform windowing processing on the first reflection coefficient curve based on a window function to obtain a windowed reflection coefficient curve; A second processing module is configured to perform an inverse fast Fourier transform on the windowed reflection coefficient curve to obtain a time domain reflection coefficient curve of the phase cable to be tested; a determination module, configured to determine a spatial distance distribution corresponding to the impedance of the phase cable to be measured based on the time domain reflection coefficient curve; An evaluation module is used to evaluate the contact impedance of the electrical contact structure at different positions according to the spatial distance distribution.

8. An electronic device, characterized in that: include: Memory, processor; The memory stores computer-executable instructions; The processor executes the computer-executable instructions stored in the memory, so that the processor performs the method according to any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that The computer-readable storage medium stores computer-executable instructions, which are used to implement the method according to any one of claims 1 to 6 when executed.

10. A computer program product, characterized in that The invention comprises a computer program, which implements the method according to any one of claims 1 to 6 when the computer program is executed.

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