A method and system for detecting partial discharge of high voltage cables

Abstract

The invention discloses a method and system for detecting partial discharge of a high-voltage cable. The method comprises the following steps: simulating coupling of a cable and a radio frequency antenna in a target area to obtain an output result of a coupled model, wherein the output result reflects the spatial radiation characteristics between the radio frequency antenna and the cable; extracting the simulation operation result based on the spatial radiation characteristics to obtain a coupling gap parameter and a set of radio frequency receiving coupling points between the radio frequency antenna and the cable; screening the set of radio frequency receiving coupling points according to a standard corresponding to the coupling gap parameter to obtain a target radio frequency receiving coupling point to receive an original partial discharge signal; performing feature analysis on the original partial discharge signal using a signal-to-noise stripping technique, and analyzing a constructed phase-resolved partial discharge spectrum to obtain a signal to be decomposed; analyzing the signal to be decomposed using an empirical mode decomposition method, inputting a trained partial discharge analysis model to obtain a partial discharge detection result, so as to improve the accuracy of monitoring power equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of power system monitoring, and in particular to a method and system for detecting partial discharge of a high-voltage cable. Background Art

[0002] Traditional partial discharge detection methods, such as ultrasonic detection methods, have problems such as limited sensitivity and susceptibility to external interference, resulting in low accuracy of detection results, making it difficult to meet the needs of partial discharge detection of high-voltage cables.

[0003] It can be seen that how to optimize the detection method of partial discharge of high-voltage cables and improve the accuracy of monitoring and maintenance of power equipment has become a technical problem that technical personnel in this field need to solve urgently. Summary of the invention

[0004] The present invention provides a high-voltage cable partial discharge detection method and system, so as to solve the problem of how to improve the detection means of the high-voltage cable partial discharge and realize accurate monitoring of the high-voltage cable partial discharge phenomenon.

[0005] In order to solve the above technical problems, an embodiment of the present invention provides a high-voltage cable partial discharge detection method and system, including:

[0006] Couple a simulation operation model established by the cable set and the radio frequency antenna array in the target area to obtain a simulation operation result output by the coupled model, wherein the simulation operation result reflects the spatial radiation characteristics between the radio frequency antenna array and the cable set;

[0007] Extracting the simulation operation result based on the change of spatial radiation, and obtaining the coupling gap parameter and the RF receiving coupling point set between the RF antenna array and the cable set;

[0008] According to the threshold standard corresponding to the coupling gap parameter, the set of radio frequency receiving coupling points is screened by using an optimization algorithm to obtain a target radio frequency receiving coupling point;

[0009] Receiving a local discharge original signal in the target area based on the target radio frequency receiving coupling point;

[0010] Performing feature analysis on the original partial discharge signal using a signal-to-noise stripping technique, and processing a phase-resolved partial discharge spectrum constructed from the feature analysis result to obtain signal data to be decomposed;

[0011] The signal data to be decomposed is subjected to time-frequency analysis by using an empirical mode decomposition method, and the time-frequency analysis result is input into a trained partial discharge analysis model to obtain a partial discharge detection result of the target area.

[0012] Furthermore, the extracting of the simulation running results based on the change of spatial radiation to obtain the coupling gap parameters and the RF receiving coupling point set between the RF antenna array and the cable set includes:

[0013] Determine a signal-to-noise ratio of a signal received by the radio frequency antenna array in the target area by analyzing the change of the spatial radiation, and optimize the parameters of the radio frequency antenna array according to the signal-to-noise ratio under preset conditions;

[0014] The Maxwell equations algorithm is used to dynamically adjust the electromagnetic field distribution between the optimized radio frequency antenna array and the cable set to obtain the coupling gap parameters and the radio frequency receiving coupling point set.

[0015] Further, the filtering of the RF reception coupling point set by using an optimization algorithm according to a threshold standard corresponding to the coupling gap parameter to obtain a target RF reception coupling point includes:

[0016] Real-time monitoring of the ambient temperature and humidity information of the target area, and analyzing changes in the coupling gap parameters under different temperatures and humidities;

[0017] Determining a threshold value standard corresponding to the coupling gap parameter according to the analysis result;

[0018] According to the threshold standard and the ambient temperature and humidity information, a coupling point screening model is constructed, and the coupling point screening model is iteratively solved by using an optimization algorithm to obtain a screening result;

[0019] The target radio frequency receiving coupling point is determined according to the screening result.

[0020] Furthermore, the signal-to-noise stripping technology is used to perform feature analysis on the original partial discharge signal, and the phase-resolved partial discharge spectrum constructed by the feature analysis result is processed to obtain the signal data to be decomposed, including:

[0021] Preprocessing the partial discharge original signal by filtering to remove high-frequency noise and low-frequency interference;

[0022] Performing signal-to-noise stripping on the preprocessed original partial discharge signal to extract a target partial discharge signal;

[0023] Extracting the phase information of the power frequency voltage from the target partial discharge signal by using a phase detection algorithm, and constructing the phase-resolved partial discharge spectrum by combining the phase information and the amplitude of the target partial discharge signal;

[0024] The image grayscale processing technology is introduced to perform image spectrum feature mapping to obtain the signal data to be decomposed.

[0025] Furthermore, the introduction of the image grayscale processing technology to perform image spectrum feature mapping to obtain the signal data to be decomposed includes:

[0026] Extracting and quantifying the phase-resolved partial discharge spectrum to obtain feature information to be mapped; the feature information to be mapped reflects the number and amplitude of partial discharge;

[0027] Mapping the feature information to be mapped to a grayscale image, and determining parameters of the grayscale image according to the value size and distribution of the feature information to be mapped;

[0028] By adjusting the parameters, the discharge characteristic changes reflected in the grayscale image are analyzed to obtain the signal data to be decomposed.

[0029] Furthermore, after the characteristic analysis of the original partial discharge signal using the signal-to-noise stripping technology is performed, the method further includes:

[0030] Extracting key features of the target partial discharge signal and inputting them into a preset chaotic mapping function for iterative calculation;

[0031] According to the output result, nonlinear analysis is performed on the target partial discharge signal to obtain high-level characteristic information.

[0032] Furthermore, the chaos mapping function is expressed by the following formula:

[0033]

[0034] in, is the value of the nth iteration, corresponding to a certain feature in the partial discharge signal; is the value of the next iteration, that is, the nonlinear transformation result of the chaotic mapping function on the eigenvalue; is a constant representing the control parameter of the system.

[0035] Furthermore, after obtaining the partial discharge detection result of the target area, the method further includes:

[0036] Compare and analyze the local discharge characteristic information in the local discharge detection result with the discharge mode database to determine the corresponding cable fault level;

[0037] Formulate and execute a diagnostic strategy according to the cable fault level, generate a diagnostic report and store the diagnostic information in the discharge mode database;

[0038] The diagnostic report is analyzed to adjust the diagnostic strategy.

[0039] Furthermore, it also includes:

[0040] According to the discharge position information in the partial discharge detection result, cross-correlation analysis is performed on the partial discharge signal at each position to obtain the path difference information and time difference information of the radio frequency antenna array in the process of receiving the signal;

[0041] Processing the path difference information and the time difference information using an arrival time difference positioning algorithm to obtain initial positioning coordinates of the partial discharge point;

[0042] Under a preset positioning accuracy, weighted calculation is performed on the initial positioning coordinates obtained through multiple positioning processes to determine the target positioning coordinates.

[0043] Another embodiment of the present invention provides a high-voltage cable partial discharge detection system, comprising:

[0044] A coupling simulation module is used to couple the simulation operation model established by the cable set and the radio frequency antenna array in the target area to obtain the simulation operation result output by the coupled model, wherein the simulation operation result reflects the spatial radiation characteristics between the radio frequency antenna array and the cable set;

[0045] A coupling analysis module, used to extract the simulation operation results based on the change of spatial radiation, and obtain the coupling gap parameters and the RF receiving coupling point set between the RF antenna array and the cable set;

[0046] A coupling point screening module, configured to screen the set of RF receiving coupling points using an optimization algorithm according to a threshold standard corresponding to the coupling gap parameter to obtain a target RF receiving coupling point;

[0047] A signal receiving module, configured to receive an original partial discharge signal in the target area based on the target radio frequency receiving coupling point;

[0048] A signal feature analysis module, used to perform feature analysis on the original partial discharge signal using a signal-to-noise stripping technique, and process a phase-resolved partial discharge spectrum constructed from the feature analysis result to obtain signal data to be decomposed;

[0049] The partial discharge analysis module is used to perform time-frequency analysis on the signal data to be decomposed by using the empirical mode decomposition method, input the time-frequency analysis results into the trained partial discharge analysis model, and obtain the partial discharge detection results of the target area.

[0050] Compared with the prior art, the embodiments of the present invention have the following advantages:

[0051] (1) The embodiment of the present invention can accurately simulate the spatial radiation characteristics between the RF antenna and the cable through the simulation model of the coupling cable and the RF antenna. It helps to accurately determine the coupling gap parameters and the RF receiving coupling point, thereby ensuring that the received original partial discharge signal has high fidelity. Combined with the signal-to-noise stripping technology, phase-resolved partial discharge spectrum and image grayscale processing technology for partial discharge signals, accurate detection and analysis of high-voltage cable partial discharge signals can be achieved, providing strong guarantee for the safe and stable operation of the power system.

[0052] (2) By using the empirical mode decomposition method to perform time-frequency analysis on the decomposed signal data and combining it with the discharge analysis model, the time-frequency characteristics of the signal can be deeply revealed to formulate an accurate fault diagnosis strategy, significantly improving the detection efficiency of partial discharge of high-voltage cables. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a schematic flow chart of a method for detecting partial discharge of a high-voltage cable in one embodiment of the present invention;

[0054] Figure 2 It is a structural schematic diagram of a high-voltage cable partial discharge detection system in one embodiment of the present invention. DETAILED DESCRIPTION

[0055] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The purpose of providing these embodiments is to make the disclosure of the present invention more thorough and comprehensive. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0056] In the description of this application, the terms "first", "second", "third", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first", "second", "third", etc. may explicitly or implicitly include one or more of the feature. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0057] In the description of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be a connection between the two elements. The terms "vertical", "horizontal", "left", "right", "upper", "lower" and similar expressions used herein are only for illustrative purposes, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0058] In the description of this application, it should be noted that, unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood by specific circumstances.

[0059] In order to accurately monitor the partial discharge phenomenon of high-voltage cables and provide early warning and accurate positioning of potential faults in power systems, an embodiment of the present invention provides a method for detecting partial discharge of high-voltage cables. For details, see Figure 1 , Figure 1 The figure shows a schematic flow chart of a method for detecting partial discharge of a high-voltage cable in one embodiment of the present invention, which comprises the following steps:

[0060] S1. Couple a simulation operation model established by a cable assembly and a radio frequency antenna array in a target area to obtain a simulation operation result output by the coupled model, wherein the simulation operation result reflects the spatial radiation characteristics between the radio frequency antenna array and the cable assembly.

[0061] It can be understood that by utilizing the transmission characteristics of RF signals, coupling with cables can be achieved in a non-contact or micro-contact manner. A certain distance is maintained between the antenna and the cable (the optimal distance is determined by precise calculation). At this distance, sufficient RF signal strength can be received by the antenna while avoiding interference with the operation of the cable.

[0062] Based on this, the embodiment of the present invention inputs the acquired electrical parameters between the cable and the RF antenna into the simulation model by means of coupling simulation model, so as to simulate the electromagnetic field distribution and energy exchange process between the cable and the RF antenna. These electrical parameters include but are not limited to the characteristic impedance, attenuation constant, voltage standing wave ratio (return loss) and capacitance of the cable, as well as the key parameters such as the radiation pattern, gain, polarization mode of the RF antenna.

[0063] In some embodiments of the present invention, professional electromagnetic simulation software (such as CST, HFSS, etc.) is selected to establish a three-dimensional model corresponding to the cable assembly and the RF antenna array in the target area, and the simulation software is run to perform electromagnetic coupling calculations on the cable assembly and the RF antenna array to obtain simulation operation results output by the coupled model. These results usually include electric field distribution, magnetic field distribution, S parameters (scattering parameters), etc. in space, reflecting the spatial radiation characteristics between the RF antenna array and the cable assembly.

[0064] S2. Extract the simulation operation result based on the change of spatial radiation, and obtain the coupling gap parameter and the RF receiving coupling point set between the RF antenna array and the cable set.

[0065] This step determines the coupling gap parameters between the RF antenna array and the cable assembly, such as coupling coefficient, coupling loss, and coupling capacitance gap, by analyzing the changes in spatial radiation characteristics. And based on the distribution of spatial radiation characteristics, all possible RF receiving coupling points are identified, that is, the locations where the best coupling between the antenna and the cable may occur.

[0066] Specifically, by analyzing the change of the spatial radiation, the signal-to-noise ratio of the signal received by the RF antenna array in the target area is determined, and under preset conditions, the parameters of the RF antenna array are optimized according to the signal-to-noise ratio. In this embodiment, the spatial radiation characteristics when the interval between the antenna and the cable is 50 cm can be analyzed, and a preset signal-to-noise ratio threshold, such as 20 dB, can be set. Under this condition, the internal geometric parameters of the RF antenna are optimized. This step is to meet the accuracy requirements of the subsequent received signals.

[0067] Next, the Maxwell equations algorithm is used to dynamically adjust and analyze the electromagnetic field distribution between the optimized RF antenna array and the cable collection to obtain the coupling gap parameters and the RF receiving coupling point set, so that the RF antenna can receive the RF signal from the discharge point inside the cable to the greatest extent while reducing external interference.

[0068] S3-S4, according to the threshold standard corresponding to the coupling gap parameter, the set of RF receiving coupling points is screened by using an optimization algorithm to obtain a target RF receiving coupling point; and the original partial discharge signal in the target area is received based on the target RF receiving coupling point.

[0069] In this embodiment, by traversing the set of RF reception coupling points, the coupling gap parameter of each point is screened, and the point that meets the screening criteria is determined as the target RF reception coupling point, and the point that does not meet the criteria is eliminated.

[0070] In the screening process, the influence of environmental factors on the coupling gap parameters is fully considered, such as temperature, humidity, electromagnetic interference, etc. Specifically, the environmental temperature and humidity information of the target area is monitored in real time, and the changes of the coupling gap parameters under different temperatures and humidities are analyzed, that is, the collected coupling gap parameter data are statistically analyzed to understand the change law of the parameters with temperature and humidity.

[0071] According to the statistical analysis results, the threshold standard corresponding to the coupling gap parameter is determined. It can be understood that this standard can reflect the stability and reliability of the performance of the RF receiving coupling point under different temperature and humidity conditions.

[0072] According to the threshold standard and the ambient temperature and humidity information, a coupling point screening model is constructed, and the coupling point screening model is iteratively solved using an optimization algorithm to obtain a screening result. In some embodiments of the present invention, a genetic algorithm or a particle swarm algorithm may be selected to optimize and solve the screening model. During the optimization process, considering the influence of temperature and humidity factors on the coupling gap parameters, the temperature and humidity conditions may be incorporated into the algorithm as constraints.

[0073] Through iterative solution, the optimal solution is gradually approached. In each iteration, the algorithm parameters or search direction are adjusted according to the performance evaluation results of the current solution. When the algorithm converges or reaches a preset number of iterations, the iteration is stopped and the screening results are output to determine the target RF receiving coupling point. In some embodiments of the present invention, the iterative screening process also needs to add a verification link later to ensure that the target RF receiving coupling point can stably and accurately receive the partial discharge signal in actual application.

[0074] It is worth noting that, considering the influence of environmental factors, some embodiments of the present invention establish an environmental compensation model to deal with the interference of environmental factors on the screening results. After the environmental compensation model is established, it is integrated into the coupling point screening model. In addition to the coupling gap parameter and temperature and humidity conditions, the input variables of the coupling point screening model may also include the compensation value calculated by the environmental compensation model. In the iterative process, the coupling gap parameter is corrected using the environmental compensation model to reduce the interference of temperature and humidity factors on the screening results.

[0075] S5. Performing feature analysis on the original partial discharge signal using a signal-to-noise stripping technique, and processing a phase-resolved partial discharge spectrum constructed based on the feature analysis result to obtain signal data to be decomposed.

[0076] It can be understood that signal-to-noise stripping technology refers to the technology of separating pure signals from noisy signals in the field of signal processing. Since the received original partial discharge signal is often mixed with various noises and interferences, these noises may come from the background noise of the equipment itself, environmental noise or interference during the transmission process. Through signal-to-noise stripping technology, these noises can be effectively removed, the quality of partial discharge signals can be improved, and it can be easier to analyze and identify. The phase-resolved partial discharge spectrum (PRPD diagram) is a diagram that can correspond the amplitude of the partial discharge signal to the phase angle of the power frequency voltage, and display the discharge activity in a complete voltage cycle from 0° to 360°.

[0077] Based on this, this embodiment first pre-processes the partial discharge original signal through a filter, such as removing high-frequency noise and low-frequency interference. Then, wavelet transform or other denoising algorithms are applied to the pre-processed partial discharge original signal to perform signal-noise stripping to extract a useful partial discharge signal, i.e., a target partial discharge signal.

[0078] It is worth noting that in signal processing, chaos mapping can be used for chaotic modulation and demodulation of signals to improve the safety and reliability of signal transmission. At the same time, it can also be used to analyze nonlinear characteristics in complex signals. Based on this, in some embodiments of the present invention, after the feature analysis of the original partial discharge signal, the key features of the target partial discharge signal, such as discharge waveform, discharge frequency, etc., can be further extracted and input into a preset chaos mapping function for iterative calculation. Preferably, this embodiment selects the Logistic chaos mapping function.

[0079] Then the chaos mapping function is expressed by the following formula:

[0080]

[0081] in, is the value of the nth iteration, corresponding to a certain feature in the partial discharge signal; is the value of the next iteration, that is, the nonlinear transformation result of the chaotic mapping function on the eigenvalue; is a constant representing the control parameter of the system.

[0082] Through iterative calculation, the behavioral characteristics of the chaotic mapping function, such as chaotic attractors, Lyapunov exponents, etc., are observed, and nonlinear analysis of the target partial discharge signal is performed based on the output results to obtain high-level feature information, making the detection process more reliable.

[0083] In some embodiments of the present invention, a phase detection algorithm, such as a phase locked loop (PLL), is used to extract the phase information of the power frequency voltage from the target partial discharge signal, and the phase resolved partial discharge spectrum is constructed by combining the phase information and the amplitude of the target partial discharge signal.

[0084] This embodiment introduces the image grayscale processing technology to perform image feature mapping on the constructed phase-resolved partial discharge spectrum to obtain the signal data to be decomposed. Specifically,

[0085] The phase-resolved partial discharge spectrum is subjected to feature extraction and quantization processing to obtain feature information to be mapped, and the feature information to be mapped reflects the number and amplitude of partial discharge.

[0086] The feature information to be mapped is mapped to a grayscale image, and the parameters of the grayscale image are determined according to the numerical value and distribution of the feature information to be mapped, the changes of the grayscale image are observed, and the parameters are adjusted according to actual needs to highlight the key features in the spectrum, and finally the discharge feature changes reflected in the grayscale image are analyzed to obtain the signal data to be decomposed. Exemplarily, the parameters of the grayscale image include grayscale and contrast.

[0087] S6. Performing time-frequency analysis on the signal data to be decomposed by empirical mode decomposition method, inputting the time-frequency analysis result into a trained partial discharge analysis model, and obtaining the partial discharge detection result of the target area.

[0088] Specifically, this embodiment decomposes the signal data to be decomposed into several intrinsic mode function components (IMF) by the empirical mode decomposition (EMD) method, performs time-frequency analysis on each IMF, and extracts its time domain and frequency domain features. It can be understood that the time domain features may include discharge amplitude and discharge times, while the frequency domain features may include spectrum distribution and frequency components.

[0089] The extracted features are input into a pre-trained partial discharge analysis model. In some embodiments of the present invention, the model can be constructed based on machine learning, deep learning and other algorithms, and can automatically identify and analyze the characteristics of partial discharge signals.

[0090] The model outputs partial discharge detection results, including characteristic information such as the discharge type, discharge intensity, and discharge location of partial discharge generated by the cable. For example, the model can distinguish between types such as corona discharge, suspended discharge, and surface discharge, as well as confirm discharge locations such as cable joints and cable segments. This information will be used for fault diagnosis of electrical equipment.

[0091] It is worth noting that in some embodiments of the present invention, during the EMD decomposition process, an ensemble empirical mode decomposition (EEMD) algorithm can be introduced in parallel, which can reduce the modal aliasing phenomenon that may occur during the decomposition process by adding white noise to the signal.

[0092] After obtaining the detection results, this embodiment formulates a corresponding cable diagnosis strategy based on the detection results. Specifically, the partial discharge characteristic information in the partial discharge detection results is compared and analyzed with the discharge pattern database to determine the corresponding cable fault level, which can be set to severe, medium, or general.

[0093] According to the cable fault level, a diagnostic strategy is formulated and executed, a diagnostic report is generated and the diagnostic information is stored in the discharge mode database, and the diagnostic report is analyzed to adjust the diagnostic strategy. The diagnostic strategy should include specific diagnostic steps, required tools and equipment, personnel division of labor and time arrangement. According to the diagnostic plan, the cable is diagnosed on site, and all data and information in the diagnostic process are recorded, including the waveform, spectrum, intensity, etc. of the discharge signal. The on-site diagnostic data is deeply analyzed, and the specific type of discharge and the cause of the fault are further determined by combining the characteristic information and the known discharge mode database.

[0094] This embodiment will achieve accurate positioning of the local discharge point by processing the discharge position information. Specifically, according to the discharge position information in the local discharge detection result, the local discharge signal at each position is cross-correlated and analyzed to obtain the path difference information and time difference information of the RF antenna array in the process of receiving the signal.

[0095] It can be understood that by performing cross-correlation analysis on local discharge signals at multiple locations, the time difference of receiving signals at different RF antennas can be obtained, and combined with the electromagnetic wave propagation speed (usually a known value in the cable), the path length difference from different RF antennas to the discharge point can be determined.

[0096] It can be understood that the Chan algorithm is a positioning algorithm based on the Time Difference of Arrival (TDOA) technology. Based on this, this embodiment uses the Chan algorithm to process the path difference information and the time difference information to obtain the initial positioning coordinates of the partial discharge point.

[0097] Under the preset positioning accuracy, the initial positioning coordinates obtained by multiple positioning processes are weighted to determine the target positioning coordinates. In some embodiments of the present invention, as an example, Monte Carlo simulation can be selected to process the initial positioning coordinates of the discharge point to obtain the theoretical positioning accuracy.

[0098] The reliability of the initial positioning coordinates is judged based on the theoretical positioning accuracy and the preset error threshold, and the weighted average processing of multiple positioning results is performed to finally determine the target positioning coordinates.

[0099] It is worth noting that during the operation of electricity, one of the factors that cannot be ignored is the insulation state of the cable. Based on this, in some embodiments of the present invention, according to the characteristic information such as discharge type, discharge position and discharge intensity obtained by local detection, the insulation test of the cable is performed, the insulation state of the cable is determined according to the test results, and the internal material properties of the cable are obtained in real time through the collected temperature and humidity information of the environment in which the cable is located.

[0100] The insulation state, the temperature and humidity information, and the internal material characteristics are used to train an aging model, and the characteristic information is input into the trained aging model to output the cable aging degree. According to the cable aging degree and insulation state, an early warning signal is generated and corresponding maintenance measures are formulated, thereby effectively warning of potential faults and improving the safety and efficiency of the power system.

[0101] In summary, the embodiment of the present invention realizes accurate reception of radio frequency signals by utilizing coupling gap parameters and optimal coupling points; realizes accurate analysis of local discharge signal characteristics by introducing signal-to-noise stripping, spectrum construction, and image grayscale processing, and realizes effective detection and diagnosis of local discharge of high-voltage cables by utilizing empirical mode decomposition and local discharge analysis models. This aspect can timely discover and handle potential defects and faults in cables through the above-mentioned scheme, thereby improving the safety and reliability of the power grid.

[0102] An embodiment of the present invention provides a high voltage cable partial discharge detection system. For details, see Figure 2 , Figure 2 The figure shows a schematic diagram of the structure of a high-voltage cable partial discharge detection system in one embodiment of the present invention, comprising:

[0103] A coupling simulation module M1 is used to couple a simulation operation model established by a cable assembly and a radio frequency antenna array in a target area to obtain a simulation operation result output by the coupled model, wherein the simulation operation result reflects the spatial radiation characteristics between the radio frequency antenna array and the cable assembly;

[0104] A coupling analysis module M2, used to extract the simulation operation results based on the change of spatial radiation, and obtain the coupling gap parameters and the RF receiving coupling point set between the RF antenna array and the cable set;

[0105] A coupling point screening module M3, configured to screen the set of RF receiving coupling points using an optimization algorithm according to a threshold standard corresponding to the coupling gap parameter to obtain a target RF receiving coupling point;

[0106] A signal receiving module M4, configured to receive the original partial discharge signal in the target area based on the target radio frequency receiving coupling point;

[0107] The signal feature analysis module M5 is used to perform feature analysis on the original partial discharge signal using a signal-to-noise stripping technique, and process a phase-resolved partial discharge spectrum constructed from the feature analysis result to obtain signal data to be decomposed;

[0108] The partial discharge analysis module M6 is used to perform time-frequency analysis on the signal data to be decomposed by using the empirical mode decomposition method, input the time-frequency analysis results into the trained partial discharge analysis model, and obtain the partial discharge detection results of the target area.

[0109] The technical features and technical effects of the high-voltage cable partial discharge detection system proposed in the embodiment of the present invention are the same as the technical features and technical effects of the high-voltage cable partial discharge detection method proposed in the embodiment of the present invention, and will not be elaborated here.

[0110] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A method for detecting partial discharge of a high voltage cable, characterized in that: include: Couple a simulation operation model established by the cable set and the radio frequency antenna array in the target area to obtain a simulation operation result output by the coupled model, wherein the simulation operation result reflects the spatial radiation characteristics between the radio frequency antenna array and the cable set; The simulation operation result is extracted based on the change of spatial radiation to obtain the coupling gap parameters and the set of RF receiving coupling points between the RF antenna array and the cable set; specifically including: determining the signal reception signal-to-noise ratio of the RF antenna array in the target area by analyzing the change of the spatial radiation, and optimizing the parameters of the RF antenna array according to the signal reception signal-to-noise ratio under preset conditions; using the Maxwell equations algorithm to dynamically adjust the electromagnetic field distribution between the optimized RF antenna array and the cable set to obtain the coupling gap parameters and the set of RF receiving coupling points, wherein the coupling gap parameters include coupling coefficient, coupling loss and coupling capacitance gap; According to the threshold standard corresponding to the coupling gap parameter, the set of RF receiving coupling points is screened by using an optimization algorithm to obtain a target RF receiving coupling point; specifically comprising: real-time monitoring of the ambient temperature and humidity information of the target area, and analyzing the change of the coupling gap parameter under different temperatures and humidities; according to the analysis result, determining the threshold standard corresponding to the coupling gap parameter; according to the threshold standard and the ambient temperature and humidity information, constructing a coupling point screening model, and iteratively solving the coupling point screening model by using an optimization algorithm to obtain a screening result; determining the target RF receiving coupling point according to the screening result; Receiving a local discharge original signal in the target area based on the target radio frequency receiving coupling point; Performing feature analysis on the original partial discharge signal using a signal-to-noise stripping technique, and processing a phase-resolved partial discharge spectrum constructed from the feature analysis result to obtain signal data to be decomposed; The signal data to be decomposed is subjected to time-frequency analysis by using an empirical mode decomposition method, and the time-frequency analysis result is input into a trained partial discharge analysis model to obtain a partial discharge detection result of the target area.

2. The high voltage cable partial discharge detection method according to claim 1, characterized in that: The method of using the signal-to-noise stripping technology to perform feature analysis on the original partial discharge signal, and processing the phase-resolved partial discharge spectrum constructed by the feature analysis result to obtain the signal data to be decomposed includes: Preprocessing the partial discharge original signal by filtering to remove high-frequency noise and low-frequency interference; Performing signal-to-noise stripping on the preprocessed original partial discharge signal to extract a target partial discharge signal; Extracting the phase information of the power frequency voltage from the target partial discharge signal by using a phase detection algorithm, and constructing the phase-resolved partial discharge spectrum by combining the phase information and the amplitude of the target partial discharge signal; The image grayscale processing technology is introduced to perform image spectrum feature mapping to obtain the signal data to be decomposed.

3. The high voltage cable partial discharge detection method according to claim 2, characterized in that: The method of introducing the image grayscale processing technology to perform image spectrum feature mapping to obtain the signal data to be decomposed includes: Extracting and quantifying the phase-resolved partial discharge spectrum to obtain feature information to be mapped; the feature information to be mapped reflects the number and amplitude of partial discharge; Mapping the feature information to be mapped to a grayscale image, and determining parameters of the grayscale image according to the value size and distribution of the feature information to be mapped; By adjusting the parameters, the discharge characteristic changes reflected in the grayscale image are analyzed to obtain the signal data to be decomposed.

4. The high voltage cable partial discharge detection method according to claim 2, characterized in that: After the signal-to-noise stripping technology is used to perform feature analysis on the original partial discharge signal, the method further includes: Extracting key features of the target partial discharge signal and inputting them into a preset chaotic mapping function for iterative calculation; According to the output result, nonlinear analysis is performed on the target partial discharge signal to obtain high-level characteristic information.

5. The high voltage cable partial discharge detection method according to claim 4, characterized in that: The chaos mapping function is expressed by the following formula: in, is the value of the nth iteration, corresponding to a certain feature in the partial discharge signal; is the value of the next iteration, that is, the nonlinear transformation result of the chaotic mapping function on the value of the feature; is a constant representing the control parameter of the system.

6. The high voltage cable partial discharge detection method according to claim 1, characterized in that: After obtaining the partial discharge detection result of the target area, the method further includes: Compare and analyze the local discharge characteristic information in the local discharge detection result with the discharge mode database to determine the corresponding cable fault level; Formulate and execute a diagnostic strategy according to the cable fault level, generate a diagnostic report and store the diagnostic information in the discharge mode database; The diagnostic report is analyzed to adjust the diagnostic strategy.

7. The high voltage cable partial discharge detection method according to claim 1, characterized in that: Also includes: According to the discharge position information in the partial discharge detection result, cross-correlation analysis is performed on the partial discharge signal at each position to obtain the path difference information and time difference information of the radio frequency antenna array in the process of receiving the signal; Processing the path difference information and the time difference information using an arrival time difference positioning algorithm to obtain initial positioning coordinates of the partial discharge point; Under a preset positioning accuracy, weighted calculation is performed on the initial positioning coordinates obtained through multiple positioning processes to determine the target positioning coordinates.

8. A high voltage cable partial discharge detection system, characterized in that: include: A coupling simulation module is used to couple the simulation operation model established by the cable set and the radio frequency antenna array in the target area to obtain the simulation operation result output by the coupled model, wherein the simulation operation result reflects the spatial radiation characteristics between the radio frequency antenna array and the cable set; A coupling analysis module, used to extract the simulation operation results based on the change of spatial radiation, and obtain the coupling gap parameters and the RF receiving coupling point set between the RF antenna array and the cable set; A coupling point screening module is used to screen the set of RF receiving coupling points using an optimization algorithm according to a threshold standard corresponding to the coupling gap parameter to obtain a target RF receiving coupling point; specifically comprising: determining the signal reception signal-to-noise ratio of the RF antenna array in the target area by analyzing the change of the spatial radiation, and optimizing the parameters of the RF antenna array according to the signal reception signal-to-noise ratio under preset conditions; using a Maxwell equations algorithm to dynamically adjust the electromagnetic field distribution between the optimized RF antenna array and the cable set to obtain the coupling gap parameter and the set of RF receiving coupling points, wherein the coupling gap parameter includes a coupling coefficient, a coupling loss, and a coupling capacitance gap; A signal receiving module, configured to receive an original partial discharge signal in the target area based on the target radio frequency receiving coupling point; The signal feature analysis module is used to perform feature analysis on the original partial discharge signal using the signal-to-noise stripping technology, and process the phase-resolved partial discharge spectrum constructed by the feature analysis results to obtain the signal data to be decomposed; specifically, it includes: real-time monitoring of the ambient temperature and humidity information of the target area, and analyzing the changes of the coupling gap parameters under different temperatures and humidity; according to the analysis results, determining the threshold standard corresponding to the coupling gap parameters; according to the threshold standard and the ambient temperature and humidity information, constructing a coupling point screening model, and using an optimization algorithm to iteratively solve the coupling point screening model to obtain a screening result; according to the screening result, determining the target RF receiving coupling point; The partial discharge analysis module is used to perform time-frequency analysis on the signal data to be decomposed by using the empirical mode decomposition method, input the time-frequency analysis results into the trained partial discharge analysis model, and obtain the partial discharge detection results of the target area.

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