High-voltage cable intermediate joint partial discharge detection method and system, storage medium and electronic terminal

Abstract

The invention discloses a high-voltage cable intermediate joint partial discharge detection method and system, a storage medium and an electronic terminal.Partial discharge signals are collected through multi-sensor fusion, and adaptive filtering anti-interference processing, characteristic parameter extraction and a time difference positioning algorithm are combined; high-sensitivity detection, accurate positioning and severity evaluation of partial discharge of the intermediate joint of the high-voltage cable are realized, so that the problems of low sensitivity, weak anti-interference capability and insufficient positioning accuracy of an existing detection method are solved, the detection sensitivity is remarkably improved, weak partial discharge signals can be effectively captured, and the detection accuracy is improved. And reliable technical support is provided for safe operation and maintenance of the high-voltage cable intermediate joint.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of detection of high-voltage equipment in power systems, and in particular to a high-voltage cable intermediate joint partial discharge detection method and system, a storage medium, and an electronic terminal. BACKGROUND

[0002] In a power system, high-voltage cables are the core equipment for power transmission, and their operational safety is directly related to the stable operation of the power system. High-voltage cable intermediate joints, as key connecting components of cable lines, have complex structures and high installation process requirements, as they need to achieve electrical conduction and insulation restoration between cables, and thus become a weak link in cable lines.

[0003] In actual operation, the internal part of the high-voltage cable intermediate joint is prone to partial discharge due to factors such as manufacturing process defects, substandard installation quality, or harsh operating environment. Partial discharge continuously erodes the insulation material, causing the insulation to age faster. If not detected and addressed in a timely manner, it may eventually lead to insulation breakdown, causing serious power outages, affecting industrial production and residents' lives, and possibly causing significant economic losses and safety hazards. Therefore, accurately detecting partial discharge in high-voltage cable intermediate joints is an important means to ensure the safe and stable operation of the power system, and has important practical significance.

[0004] Currently, the detection methods for partial discharge in high-voltage cable intermediate joints mainly include ultrasonic detection, ultra-high frequency detection, and pulse current method, but these methods have obvious limitations in practical application:

[0005] The ultrasonic detection method detects by capturing ultrasonic signals generated by partial discharge, but this method is easily disturbed by environmental noise (such as equipment vibration and air flow-generated sound waves), resulting in low detection sensitivity and difficulty in effectively capturing weak partial discharge signals;

[0006] The ultra-high frequency detection method can capture ultra-high frequency electromagnetic signals generated by partial discharge, but the signals attenuate quickly during transmission, making it difficult to detect weak or distant partial discharge signals, and the anti-electromagnetic interference capability is weak, limiting the detection accuracy in complex power environments;

[0007] The pulse current method needs to be directly electrically connected to the cable to obtain the pulse current signal generated by partial discharge, which may affect the normal operation of the cable, and has poor positioning accuracy, making it difficult to accurately determine the specific location of partial discharge in the intermediate joint, which is not conducive to subsequent fault diagnosis and maintenance.

[0008] In summary, the existing high-voltage cable intermediate joint partial discharge detection method has the defects of insufficient sensitivity, weak anti-interference ability, low positioning accuracy, and influence on normal operation of the cable, and it is difficult to meet the demand of the power system for accurate detection of the partial discharge of the high-voltage cable intermediate joint. Therefore, it is urgent to develop a high-voltage cable intermediate joint partial discharge detection method with high sensitivity, strong anti-interference ability and precise positioning function to overcome the shortcomings of the prior art. SUMMARY

[0009] The purpose of the present application is to provide a high-voltage cable intermediate joint partial discharge detection method and system, a storage medium, and an electronic terminal. By fusing multiple sensors to collect partial discharge signals, combining adaptive filtering anti-interference processing, feature parameter extraction, and time difference positioning algorithm, high-sensitivity detection, precise positioning, and severity assessment of the partial discharge of the high-voltage cable intermediate joint are realized, thereby solving the problems of low sensitivity, weak anti-interference ability, and insufficient positioning accuracy of the existing detection method, and providing reliable technical support for the safe operation and maintenance of the high-voltage cable intermediate joint.

[0010] To achieve the purpose of the present application, the technical solution provided by the present application is as follows:

[0011] First aspect

[0012] The present application provides a high-voltage cable intermediate joint partial discharge detection method, comprising the following steps:

[0013] Step S1: Collecting multi-dimensional partial discharge signals, including partial discharge ultra-high frequency signals, partial discharge ultrasonic signals, and partial discharge very high frequency signals, the partial discharge ultra-high frequency signals, the partial discharge ultrasonic signals, and the partial discharge very high frequency signals are obtained by three groups of detection units respectively;

[0014] Step S2: Preprocessing the multi-dimensional partial discharge signals to obtain the effective partial discharge signals after preprocessing;

[0015] Step S3: Extracting feature parameters from the effective partial discharge signals to obtain a partial discharge feature vector;

[0016] Step S4: Based on the position coordinates of the three groups of detection units and the effective partial discharge signals, calculating the time difference of the effective partial discharge signals reaching the three groups of detection units, establishing a time difference equation set, and obtaining the partial discharge source position by solving the time difference equation set;

[0017] Step S5: According to the partial discharge feature vector and the partial discharge source position, combining the preset evaluation standard to evaluate the severity of the partial discharge.

[0018] Second aspect

[0019] The application provides a partial discharge detection system for a high-voltage cable intermediate joint, which comprises a multi-dimensional partial discharge signal acquisition unit, a signal preprocessing unit, a partial discharge feature vector extraction unit, a partial discharge source position acquisition unit and a partial discharge severity evaluation unit.

[0020] The multi-dimensional partial discharge signal acquisition unit is used for acquiring multi-dimensional partial discharge signals, including partial discharge ultrahigh frequency signals, partial discharge ultrasonic signals and partial discharge very high frequency signals, wherein the partial discharge ultrahigh frequency signals, the partial discharge ultrasonic signals and the partial discharge very high frequency signals are obtained through three groups of detection units respectively.

[0021] The signal preprocessing unit is used for preprocessing the multi-dimensional partial discharge signals to obtain effective partial discharge signals after preprocessing.

[0022] The partial discharge feature vector extraction unit is used for extracting feature parameters of the effective partial discharge signals to obtain a partial discharge feature vector.

[0023] The partial discharge source position acquisition unit is used for calculating time differences of the effective partial discharge signals reaching the three groups of detection units based on the position coordinates of the three groups of detection units and the effective partial discharge signals, establishing a time difference equation set and obtaining the partial discharge source position by solving the time difference equation set.

[0024] The partial discharge severity evaluation unit is used for evaluating the partial discharge severity according to the partial discharge feature vector and the partial discharge source position in combination with a preset evaluation standard.

[0025] The third aspect

[0026] The application provides a storage medium, wherein at least one instruction, at least one program, a code set or an instruction set is stored in the storage medium, and the at least one instruction, the at least one program, the code set or the instruction set is loaded and executed by a processor to realize the partial discharge detection method for the high-voltage cable intermediate joint.

[0027] The fourth aspect

[0028] The application provides an electronic terminal, which comprises a processor and a memory, wherein at least one instruction, at least one program, a code set or an instruction set is stored in the memory, and the at least one instruction, the at least one program, the code set or the instruction set is loaded and executed by the processor to realize the partial discharge detection method for the high-voltage cable intermediate joint.

[0029] Compared with the prior art, the application has the following beneficial effects:

[0030] (1) In the application, multi-sensor fusion is adopted to acquire multi-dimensional partial discharge signals, and feature parameter extraction is combined, so that the limitation of single sensor detection is avoided, the detection sensitivity is significantly improved, and weak partial discharge signals can be effectively captured.

[0031] (2) In this application, the anti-interference processing combining wavelet threshold denoising and adaptive filtering greatly enhances the anti-environment interference capability, and can accurately extract effective partial discharge signals even in complex electromagnetic environments.

[0032] (3) Based on the multi-detection unit time difference positioning algorithm and combined with the intermediate connector structure parameters, this application realizes the accurate positioning of the partial discharge source, and the positioning error can be controlled within 5mm.

[0033] (4) In this application, the severity of partial discharge can be intuitively judged through the comprehensive evaluation of characteristic parameters and positioning results, providing a reliable basis for the operation and maintenance decision of high voltage cable intermediate joints. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the partial discharge detection method for high-voltage cable intermediate joints provided in the embodiments of this application. Detailed Implementation

[0035] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0036] like Figure 1 As shown in the figure, this example provides a method for detecting partial discharge at a high-voltage cable intermediate joint, including the following steps:

[0037] Step S1: Collect multi-dimensional partial discharge signals, including partial discharge ultra-high frequency signals, partial discharge ultrasonic signals, and partial discharge ultra-high frequency signals. The partial discharge ultra-high frequency signals, partial discharge ultrasonic signals, and partial discharge ultra-high frequency signals are obtained through three sets of detection units, respectively.

[0038] Preferably, in step S1, the three sets of detection units are evenly arranged circumferentially around the intermediate joint of the high-voltage cable, and each set of detection units includes an ultra-high frequency sensor, an ultrasonic sensor, and a super high frequency sensor; the ultra-high frequency sensor is close to the outer sheath of the intermediate joint and is used to collect partial discharge ultra-high frequency signals of 300-1500MHz; the ultrasonic sensor maintains a distance of 5-10mm from the outer surface of the intermediate joint and is used to collect partial discharge ultrasonic signals of 40-100kHz; the super high frequency sensor is arranged 30-50cm directly above the intermediate joint and is used to collect partial discharge super high frequency signals of 300-3000MHz; the sampling frequency is set to 5MHz, the sampling time is 10s, and the multi-dimensional partial discharge signals of the three sets of detection units are collected simultaneously.

[0039] Step S2: Preprocess the multi-dimensional partial discharge signal to obtain the preprocessed effective partial discharge signal;

[0040] Preferably, the step S2 specifically comprises the following:

[0041] Firstly, the multi-dimensional partial discharge signal is preliminarily denoised by a wavelet threshold denoising algorithm, a db4 wavelet base is selected, the number of decomposition layers is 5, and a soft threshold function is used as a threshold function;

[0042] Then, an adaptive filtering algorithm is used to remove environmental interference, the collected environmental noise signal is used as a reference input, the multi-dimensional partial discharge signal is used as a main input, the filter coefficient is updated through an LMS adaptive algorithm until the output error is minimum, and the effective partial discharge signal after denoising is obtained, wherein the environmental noise signal is obtained by arranging a sensor of the same type at a position 10 m away from the intermediate joint.

[0043] Step S3: extracting feature parameters from the effective partial discharge signal to obtain a partial discharge feature vector;

[0044] Preferably, the step S3 specifically comprises the following: extracting feature parameters from the effective partial discharge signal: extracting feature parameters of the ultrahigh frequency signal, including: discharge amplitude, pulse width, rising edge time; extracting feature parameters of the ultrasonic signal, including: sound pressure amplitude, duration; extracting feature parameters of the very high frequency signal, including: discharge frequency, phase distribution characteristics;

[0045] All the extracted feature parameters are integrated into a partial discharge feature vector.

[0046] Step S4: based on the position coordinates of the three groups of detection units and the effective partial discharge signal, calculating the time difference of the effective partial discharge signal reaching the three groups of detection units, establishing a time difference equation set, and obtaining the partial discharge source position by solving the time difference equation set;

[0047] Preferably, the step S4 specifically comprises the following:

[0048] Based on the position coordinates of the three groups of detection units and the effective partial discharge signal, the time difference of the effective partial discharge signal reaching the three groups of detection units is calculated:

[0049] A three-dimensional coordinate system is established with the center of the intermediate joint as the origin, and the coordinates of each group of detection units are recorded as (x1, y1, z1), (x2, y2, z2), (x3, y3, z3);

[0050] The partial discharge source position is (x, y, z), the propagation speed of the effective partial discharge signal in the insulating medium of the intermediate joint is v, and according to the time t1, t2, t3 of the effective partial discharge signal reaching the three groups of detection units, a time difference equation set is established:

[0051] \sqrt{(x-x1)^2+(y-y1)^2+(z-z1)^2} / v=t1-t0;

[0052] \sqrt{(x-x2)^2+(y-y2)^2+(z-z2)^2} / v=t2-t0;

[0053] \sqrt{(x-x3)^2+(y-y3)^2+(z-z3)^2} / v=t3-t0;

[0054] Wherein, t0 is the time when the partial discharge occurs, for the propagation speed v, the hyper frequency signal propagation speed takes 0.8c, c is the speed of light; the ultrasonic signal propagation speed takes 340m / s;

[0055] The partial discharge source position (x, y, z) is obtained by solving the equation set.

[0056] Step S5: According to the partial discharge feature vector and the partial discharge source position, the preset evaluation standard is combined to evaluate the partial discharge severity.

[0057] Preferably, the step S5 specifically comprises the following:

[0058] According to the partial discharge feature vector and the partial discharge source position, the preset evaluation standard is combined to evaluate the partial discharge severity: if the discharge amplitude <500mV, the discharge frequency <10 times / s, and the partial discharge source is located in the middle joint edge area, it is determined as slight partial discharge; if the discharge amplitude is 500-1000mV, the discharge frequency is 10-50 times / s, and the partial discharge source is located in the middle joint insulating layer, it is determined as moderate partial discharge; if the discharge amplitude >1000mV, the discharge frequency >50 times / s, and the partial discharge source is located near the middle joint conductor, it is determined as severe partial discharge.

[0059] Application example:

[0060] (I) Detection preparation

[0061] The 110kV high-voltage cable middle joint is selected as the detection object, the middle joint is a prefabricated structure, and the outer sheath is made of cross-linked polyethylene. Three groups of detection units are uniformly arranged around the middle joint, each group of detection units includes: a hyper frequency sensor (model: UHF-100, bandwidth 300-1500MHz), an ultrasonic sensor (model: US-200, bandwidth 40-100kHz), and a very high frequency sensor (model: THF-300, bandwidth 300-3000MHz).

[0062] The hyper frequency sensor is tightly attached to the outer sheath of the middle joint through magnetic attraction, the ultrasonic sensor is fixed through a support and maintains a 8mm spacing with the outer surface, and the very high frequency sensor is arranged 40cm above the middle joint through an insulating support. At the same time, the same type of sensor is arranged 10m away from the middle joint as an environmental noise acquisition end.

[0063] (II) Signal acquisition and processing

[0064] Turn on the data acquisition device, set the sampling frequency to 5 MHz, the sampling time to 10 s, and synchronously collect the signals of the three detection units and the noise collection end. The collected raw signals are preprocessed: wavelet threshold denoising is performed using db4 wavelet basis and 5 layers of decomposition, and then the noise signal is taken as a reference to remove interference through LMS adaptive filtering (convergence factor is 0.01) to obtain effective partial discharge signals.

[0065] (III) Feature extraction and positioning

[0066] Characteristic parameters such as ultra-high frequency discharge amplitude (200-800 mV), ultrasonic sound pressure amplitude (50-200 Pa), and ultra-high frequency discharge frequency (5-30 times / s) are extracted from the effective signals. According to the coordinates of the three detection units ((50, 0, 0) mm, (-25, 43.3, 0) mm, (-25, -43.3, 0) mm) and the signal arrival times (t1 = 1.2 μs, t2 = 1.5 μs, t3 = 1.3 μs), the time difference equation is calculated to obtain the partial discharge source position as (10, 5, 0) mm.

[0067] (IV) Evaluation results

[0068] Combined with the characteristic parameters (discharge amplitude 600 mV, frequency 20 times / s) and the positioning results (located in the middle joint insulating layer), it is determined that the middle joint has moderate partial discharge and needs to be further tracked and detected.

[0069] In addition, corresponding to the detection method, the application also provides an embodiment of a high-voltage cable middle joint partial discharge detection system, which comprises a multi-dimensional partial discharge signal acquisition unit, a signal preprocessing unit, a partial discharge feature vector extraction unit, a partial discharge source position acquisition unit, and a partial discharge severity evaluation unit.

[0070] The multi-dimensional partial discharge signal acquisition unit is used to acquire multi-dimensional partial discharge signals, including partial discharge ultra-high frequency signals, partial discharge ultrasonic signals, and partial discharge ultra-high frequency signals, which are obtained through three detection units respectively.

[0071] The signal preprocessing unit is used to preprocess the multi-dimensional partial discharge signals to obtain preprocessed effective partial discharge signals.

[0072] The partial discharge feature vector extraction unit is used to extract characteristic parameters from the effective partial discharge signals to obtain a partial discharge feature vector.

[0073] The partial discharge source position acquisition unit is used to calculate the time difference of the effective partial discharge signals arriving at the three detection units based on the position coordinates of the three detection units and the effective partial discharge signals, establish a time difference equation set, and obtain the partial discharge source position by solving the time difference equation set.

[0074] The partial discharge severity evaluation unit is configured to evaluate the partial discharge severity according to the partial discharge feature vector and the partial discharge source position in combination with a preset evaluation standard.

[0075] Preferably, the three groups of detection units are uniformly arranged in the circumferential direction of the high-voltage cable joint, and each group of detection units comprises an ultra-high frequency sensor, an ultrasonic sensor and a very-high frequency sensor; the ultra-high frequency sensor is in close contact with the outer sheath of the joint, and is configured to collect partial discharge ultra-high frequency signals of 300-1500 MHz; the ultrasonic sensor is arranged at a distance of 5-10 mm from the outer surface of the joint, and is configured to collect partial discharge ultrasonic signals of 40-100 kHz; the very-high frequency sensor is arranged 30-50 cm above the joint, and is configured to collect partial discharge very-high frequency signals of 300-3000 MHz; the sampling frequency is set to 5 MHz, and the sampling time is set to 10 s, and the multi-dimensional partial discharge signals of the three groups of detection units are synchronously collected.

[0076] In addition, the application further provides an embodiment of a storage medium, wherein at least one instruction, at least one program, a code set or an instruction set is stored in the storage medium, and the at least one instruction, the at least one program, the code set or the instruction set is loaded and executed by a processor to realize the partial discharge detection method for the high-voltage cable joint.

[0077] In addition, the application further provides an embodiment of an electronic terminal, wherein the electronic terminal comprises a processor and a memory, and at least one instruction, at least one program, a code set or an instruction set is stored in the memory, and the at least one instruction, the at least one program, the code set or the instruction set is loaded and executed by the processor to realize the partial discharge detection method for the high-voltage cable joint.

[0078] The above describes optional embodiments of the application embodiments in detail in combination with the drawings, but the application embodiments are not limited to the specific details in the above embodiments, and various simple modifications can be made to the technical solutions of the application embodiments within the technical concept of the application embodiments, and the simple modifications all belong to the protection scope of the application embodiments.

Claims

1. A method for detecting partial discharge at a high-voltage cable intermediate joint, characterized in that, Includes the following steps: Step S1: Collect multi-dimensional partial discharge signals, including partial discharge ultra-high frequency signals, partial discharge ultrasonic signals, and partial discharge ultra-high frequency signals. The partial discharge ultra-high frequency signals, partial discharge ultrasonic signals, and partial discharge ultra-high frequency signals are obtained through three sets of detection units, respectively. Step S2: Preprocess the multi-dimensional partial discharge signal to obtain the preprocessed effective partial discharge signal; Step S3: Extract feature parameters from the effective partial discharge signal to obtain the partial discharge feature vector; Step S4: Based on the position coordinates of the three sets of detection units and the effective partial discharge signal, calculate the time difference of the effective partial discharge signal arriving at the three sets of detection units, establish a set of time difference equations, and obtain the location of the partial discharge source by solving the set of time difference equations; Step S5: Assess the severity of partial discharge based on the partial discharge feature vector and the location of the partial discharge source, combined with preset evaluation criteria.

2. The method for detecting partial discharge at a high-voltage cable joint according to claim 1, characterized in that, In step S1, the three sets of detection units are evenly arranged circumferentially around the intermediate joint of the high-voltage cable, and each set of detection units includes an ultra-high frequency sensor, an ultrasonic sensor, and a super high frequency sensor. The ultra-high frequency sensor is close to the outer sheath of the intermediate joint and is used to collect partial discharge ultra-high frequency signals of 300-1500MHz. The ultrasonic sensor maintains a distance of 5-10mm from the outer surface of the intermediate joint and is used to collect partial discharge ultrasonic signals of 40-100kHz. The super high frequency sensor is arranged 30-50cm directly above the intermediate joint and is used to collect partial discharge super high frequency signals of 300-3000MHz. The sampling frequency is set to 5MHz and the sampling time is 10s, and the multi-dimensional partial discharge signals of the three sets of detection units are collected simultaneously.

3. The method for detecting partial discharge at a high-voltage cable joint according to claim 1, characterized in that, Step S2 specifically includes the following: First, the multi-dimensional partial discharge signal is initially denoised using a wavelet thresholding denoising algorithm. The db4 wavelet basis is selected, the decomposition layer is 5 layers, and the threshold function is a soft threshold. Then, an adaptive filtering algorithm is used to remove environmental interference. The collected environmental noise signal is used as the reference input, and the multi-dimensional partial discharge signal is used as the main input. The filter coefficients are updated by the LMS adaptive algorithm until the output error is minimized, and the denoised effective partial discharge signal is obtained.

4. The method for detecting partial discharge at a high-voltage cable intermediate joint according to claim 1, characterized in that, Step S3 specifically includes the following: extracting feature parameters from the effective partial discharge signal: extracting feature parameters of the ultra-high frequency signal, including: discharge amplitude, pulse width, and rise time; extracting feature parameters of the ultrasonic signal, including: sound pressure amplitude and duration; extracting feature parameters of the ultra-high frequency signal, including: discharge frequency and phase distribution characteristics; All extracted feature parameters are integrated into a partial discharge feature vector.

5. The method for detecting partial discharge at a high-voltage cable intermediate joint according to claim 1, characterized in that, Step S4 specifically includes the following: Based on the position coordinates of the three detection units and the effective partial discharge signal, the time difference of the effective partial discharge signal arriving at the three detection units is calculated: A three-dimensional coordinate system is established with the center of the intermediate joint as the origin, and the coordinates of each detection unit are recorded as (x1, y1, z1), (x2, y2, z2), and (x3, y3, z3). The partial discharge source is located at (x, y, z), and the propagation speed of the effective partial discharge signal in the insulating medium of the intermediate joint is v. Based on the time t1, t2, and t3 for the effective partial discharge signal to reach the three sets of detection units, a set of time difference equations is established: \sqrt{(x-x1)^2+(y-y1)^2+(z-z1)^2} / v=t1-t0; \sqrt{(x-x2)^2+(y-y2)^2+(z-z2)^2} / v=t2-t0; \sqrt{(x-x3)^2+(y-y3)^2+(z-z3)^2} / v=t3-t0; Where t0 is the time when partial discharge occurs, the location of the partial discharge source (x, y, z) is obtained by solving the system of equations.

6. The method for detecting partial discharge at a high-voltage cable intermediate joint according to claim 1, characterized in that, Step S5 specifically includes the following: Based on the partial discharge characteristic vector and the location of the partial discharge source, the severity of the partial discharge is assessed using preset evaluation criteria: if the discharge amplitude is <500mV, the discharge frequency is <10 times / s, and the partial discharge source is located in the edge area of ​​the intermediate joint, it is judged as slight partial discharge; if the discharge amplitude is 500-1000mV, the discharge frequency is 10-50 times / s, and the partial discharge source is located within the insulation layer of the intermediate joint, it is judged as moderate partial discharge; if the discharge amplitude is >1000mV, the discharge frequency is >50 times / s, and the partial discharge source is located near the conductor of the intermediate joint, it is judged as severe partial discharge.

7. A partial discharge detection system for high-voltage cable joints, characterized in that, It includes a multi-dimensional partial discharge signal acquisition unit, a signal preprocessing unit, a partial discharge feature vector extraction unit, a partial discharge source location acquisition unit, and a partial discharge severity assessment unit; The multi-dimensional partial discharge signal acquisition unit is used to acquire multi-dimensional partial discharge signals, including partial discharge ultra-high frequency signals, partial discharge ultrasonic signals, and partial discharge ultra-high frequency signals. The partial discharge ultra-high frequency signals, partial discharge ultrasonic signals, and partial discharge ultra-high frequency signals are obtained through three sets of detection units, respectively. The signal preprocessing unit is used to preprocess the multi-dimensional partial discharge signal to obtain the preprocessed effective partial discharge signal. The partial discharge feature vector extraction unit is used to extract feature parameters from the effective partial discharge signal to obtain a partial discharge feature vector. The partial discharge source location acquisition unit is used to calculate the time difference of the effective partial discharge signal arriving at the three sets of detection units based on the position coordinates of the three sets of detection units and the effective partial discharge signal, establish a set of time difference equations, and obtain the location of the partial discharge source by solving the set of time difference equations. The partial discharge severity assessment unit is used to assess the severity of partial discharge based on the partial discharge feature vector and the location of the partial discharge source, combined with a preset assessment standard.

8. The partial discharge detection system for a high-voltage cable intermediate joint according to claim 7, characterized in that, The three sets of detection units are evenly arranged circumferentially around the high-voltage cable intermediate joint, and each set of detection units includes an ultra-high frequency (UHF) sensor, an ultrasonic sensor, and an extra-high frequency (UHF) sensor. The UHF sensor is close to the outer sheath of the intermediate joint and is used to collect partial discharge UHF signals of 300-1500MHz. The ultrasonic sensor is kept 5-10mm away from the outer surface of the intermediate joint and is used to collect partial discharge ultrasonic signals of 40-100kHz. The UHF sensor is arranged 30-50cm directly above the intermediate joint and is used to collect partial discharge UHF signals of 300-3000MHz. The sampling frequency is set to 5MHz and the sampling time is 10s, and the multi-dimensional partial discharge signals of the three sets of detection units are collected simultaneously.

9. A storage medium, characterized in that, The storage medium stores at least one instruction, at least one program, code set, or instruction set, wherein the at least one instruction, the at least one program, the code set, or the instruction set is loaded and executed by a processor to implement the partial discharge detection method for high-voltage cable intermediate joints as described in any one of claims 1-6.

10. An electronic terminal, characterized in that, The electronic terminal includes a processor and a memory, wherein the memory stores at least one instruction, at least one program, code set, or instruction set, and the at least one instruction, the at least one program, the code set, or the instruction set is loaded and executed by the processor to implement the partial discharge detection method for high-voltage cable intermediate joints as described in any one of claims 1-6.

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