Partial discharge detection device, method and equipment for subway cable

Abstract

The invention discloses a partial discharge detection device, method and equipment for a subway cable, and belongs to the technical field of electric power facilities. The device comprises a current signal acquisition module used for acquiring a current signal through a high-frequency current transformer arranged on a cable grounding wire; the pulse current identification module is used for identifying whether a pulse current signal exists in the current signals or not; the feature extraction module is used for carrying out feature extraction on the pulse current signal under the condition that the pulse current signal exists in the current signal, so as to obtain a pulse current feature; and the partial discharge detection module is used for analyzing the pulse current characteristics to obtain a partial discharge detection result. According to the technical scheme, by identifying whether the pulse current signal exists in the current signal of the cable grounding wire and determining the partial discharge detection result according to the pulse current signal, efficient and accurate detection of the partial discharge condition of the subway cable can be realized, so that safe operation of the subway cable is guaranteed.

Description

Technical Field

[0001] The present application belongs to the technical field of electric power facilities, and specifically relates to a partial discharge detection device, method and equipment for subway cables. Background Art

[0002] As the core carrier of urban public transportation, the reliability and safety of subway operation are related to the travel efficiency and life safety of the public. As the key hub of subway power transmission, cables are responsible for providing stable power supply for train traction systems and various auxiliary equipment.

[0003] When partial discharge occurs in subway cables, the high-energy particles generated will destroy the molecular structure of the insulating material, causing electrical and water dendrites in the cable insulation layer, which may eventually cause the cable insulation layer to break down and lose its insulation function. Partial discharge abnormalities may even cause subway cables to short-circuit. The huge short-circuit current will cause the subway cables to overheat and burn, causing a fire. Moreover, the electromagnetic interference generated by partial discharge abnormalities will interfere with signal transmission, causing signal distortion and increased bit error rate, thereby interfering with the communication and control signals of subway trains and endangering driving safety.

[0004] Therefore, how to efficiently and accurately detect partial discharge anomalies in subway cables is an issue that people in this field need to solve urgently. Summary of the invention

[0005] The embodiments of the present application provide a partial discharge detection device, method and equipment for subway cables, aiming to achieve efficient and accurate detection of partial discharge conditions of subway cables, thereby ensuring the safe operation of subway cables.

[0006] In a first aspect, an embodiment of the present application provides a partial discharge detection device for a subway cable, the device comprising:

[0007] A current signal acquisition module is used to acquire a current signal through a high-frequency current transformer arranged on the cable grounding wire;

[0008] A pulse current identification module, used to identify whether there is a pulse current signal in the current signal;

[0009] A feature extraction module, for extracting features of the pulse current signal to obtain pulse current features when a pulse current signal is identified as existing in the current signal; wherein the pulse current features include at least one of pulse amplitude, pulse width, pulse rise time and pulse fall time;

[0010] The partial discharge detection module is used to analyze the pulse current characteristics to obtain partial discharge detection results.

[0011] In a second aspect, an embodiment of the present application provides a method for detecting partial discharge of a subway cable, the method comprising:

[0012] The current signal is obtained by a current signal acquisition module through a high-frequency current transformer arranged on the cable grounding wire;

[0013] Identify whether there is a pulse current signal in the current signal by a pulse current identification module;

[0014] When a pulse current signal is identified as existing in the current signal, the feature extraction module extracts features of the pulse current signal to obtain a pulse current feature; wherein the pulse current feature includes at least one of a pulse amplitude, a pulse width, a pulse rise time, and a pulse fall time;

[0015] The pulse current characteristics are analyzed by a partial discharge detection module to obtain a partial discharge detection result.

[0016] In a third aspect, an embodiment of the present application provides an electronic device, which includes a processor, a memory, and a program or instruction stored in the memory and executable on the processor, wherein the program or instruction, when executed by the processor, implements the steps of the method described in the first aspect.

[0017] In the embodiment of the present application, the current signal acquisition module is used to acquire the current signal through the high-frequency current transformer arranged on the cable grounding wire; the pulse current identification module is used to identify whether there is a pulse current signal in the current signal; the feature extraction module is used to extract the features of the pulse current signal to obtain the pulse current features when it is identified that there is a pulse current signal in the current signal; wherein the pulse current features include at least one of the pulse amplitude, pulse width, pulse rise time and pulse fall time; the partial discharge detection module is used to analyze the pulse current features to obtain the partial discharge detection result. The above-mentioned partial discharge detection device for subway cables can realize efficient and accurate detection of partial discharge of subway cables by identifying whether there is a pulse current signal in the current signal of the cable grounding wire and determining the partial discharge detection result according to the pulse current signal, thereby ensuring the safe operation of subway cables. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of a partial discharge detection device for a subway cable provided in Example 1 of the present application;

[0019] Figure 2 It is a structural schematic diagram of a partial discharge detection device for a subway cable provided in Example 2 of the present application;

[0020] Figure 3It is a structural schematic diagram of a partial discharge detection device for a subway cable provided in Example 3 of the present application;

[0021] Figure 4 It is a flow chart of a method for detecting partial discharge of a subway cable provided in Embodiment 4 of the present application;

[0022] Figure 5 It is a schematic diagram of the structure of an electronic device provided in Example 5 of the present application. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical scheme and advantages of the present application clearer, the specific embodiments of the present application are further described in detail below in conjunction with the accompanying drawings. It is understood that the specific embodiments described herein are only used to explain the present application, rather than to limit the present application. It should also be noted that, for the convenience of description, only the part related to the present application but not all of the content is shown in the accompanying drawings. Before discussing the exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processes or methods depicted as flow charts. Although the flow chart describes each operation (or step) as a sequential process, many of the operations therein can be implemented in parallel, concurrently or simultaneously. In addition, the order of each operation can be rearranged. The process can be terminated when its operation is completed, but it can also have additional steps not included in the accompanying drawings. The process can correspond to a method, a function, a procedure, a subroutine, a subprogram, etc.

[0024] The following will be combined with the drawings in the embodiments of the present application to clearly describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments in the present application belong to the scope of protection of this application.

[0025] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0026] The following is a detailed description of the partial discharge detection device, method and equipment for subway cables provided in the embodiments of the present application through specific embodiments and their application scenarios in conjunction with the accompanying drawings.

[0027] Embodiment 1

[0028] Figure 1 Schematic diagram of the structure of the partial discharge detection device for subway cables provided in Example 1 of the present application. Figure 1 As shown, the device comprises:

[0029] A current signal acquisition module 110 is used to acquire a current signal through a high-frequency current transformer arranged on the cable grounding wire;

[0030] A pulse current identification module 120, used to identify whether there is a pulse current signal in the current signal;

[0031] A feature extraction module 130 is used to extract features of the pulse current signal to obtain pulse current features when it is identified that there is a pulse current signal in the current signal; wherein the pulse current feature includes at least one of a pulse amplitude, a pulse width, a pulse rise time, and a pulse fall time;

[0032] The partial discharge detection module 140 is used to analyze the pulse current characteristics to obtain a partial discharge detection result.

[0033] This application is applicable to scenarios where subways are equipped with cables. Specifically, the recognition of pulse current signals, the extraction of pulse current characteristics, and the determination of partial discharge detection results can be performed by intelligent terminal devices. Based on the partial discharge detection results obtained, the staff can take corresponding maintenance measures for subway cables with partial discharge to ensure the normal and safe operation of the subway.

[0034] Based on the above usage scenarios, it can be understood that the executor of the present application can be a smart terminal device, such as a desktop computer, a laptop computer, a mobile phone, a tablet computer, and interactive multimedia, etc., and no excessive limitations are made here.

[0035] The current signal acquisition module 110 is used to acquire the current signal through a high-frequency current transformer arranged on the cable grounding wire.

[0036] A cable is a device used to transmit power or signals. A cable ground wire is a conductor used to make an electrical connection between a cable and the earth.

[0037] The current signal may refer to the amount of charge passing through the conductor cross section of the subway cable per unit time.

[0038] A high-frequency current transformer is a special current transformer dedicated to measuring high-frequency current signals. Similar to ordinary current transformers, high-frequency current transformers also operate based on the law of electromagnetic induction. However, ordinary current transformers are suitable for measuring current signals with frequencies of 50 Hz or 60 Hz, while high-frequency current transformers can be used to measure current signals with frequencies in the range of dozens of kilohertz or even higher.

[0039] A pulse current identification module 120 is configured to identify whether there is a pulse current signal in the current signal.

[0040] A pulse current signal can be a current signal that exhibits short and intermittent characteristics in time. To identify whether there is a pulse current signal in the current signal, the method can include determining the probability density function of the current signal, determining the first similarity between the probability density function and a preset normal current function, and determining the second similarity between the probability density function and a preset pulse current function. If the second similarity exceeds the first similarity, it is identified that there is a pulse current signal in the current signal.

[0041] In this technical solution, optionally, the pulse current identification module is specifically configured to:

[0042] Determine the probability density function of the current signal;

[0043] Determine the first similarity between the probability density function and a preset normal current function, and determine the second similarity between the probability density function and a preset pulse current function;

[0044] If the second similarity exceeds the first similarity, it is identified that there is a pulse current signal in the current signal.

[0045] The probability density function can be used to describe the probability distribution of a continuous random variable near a certain value point. The definition of the probability density function is as follows: For a continuous random variable X, if there exists a non-negative integrable function f(x) such that for any real numbers a and b (a < b), the probability that the random variable X falls within the interval (a, b] can be expressed as Then the function f(x) is called the probability density function of the random variable X. The probability density function of the current signal can be determined by the kernel density estimation method. The basic idea of the kernel density estimation method is to place a "kernel" at each observed data point, and construct an estimate of the probability density function by weighted summation of these kernel functions.

[0046] The preset normal current function may refer to a pre-constructed probability density function of a normal current signal that does not include a pulse current signal; the preset pulse current function may refer to a pre-constructed probability density function of a pulse current signal. The first similarity may be a numerical value used to measure the similarity between the probability density function and the preset normal current function; the second similarity may be a numerical value used to measure the similarity between the probability density function and the preset pulse current function. The method for determining the first similarity between the probability density function and the preset normal current function may be to calculate the Euclidean distance, cosine similarity or Kullback-Leibler divergence between the probability density function and the preset normal current function as the first similarity; the method for determining the second similarity between the probability density function and the preset pulse current function may be to calculate the Euclidean distance, cosine similarity or Kullback-Leibler divergence between the probability density function and the preset pulse current function as the second similarity.

[0047] The second similarity exceeds the first similarity, indicating that the probability distribution characteristics of the current current signal are more consistent with the probability distribution characteristics of the pre-constructed pulse current signal, and therefore it can be identified that there is a pulse current signal in the current signal.

[0048] The advantage of such a setting of the present scheme is that by identifying the presence of a pulse current signal in the current signal when the second similarity between the probability density function of the current signal and the preset pulse current function exceeds the first similarity between the probability density function of the current signal and the preset normal current function, the pulse current signal can be more accurately and objectively distinguished from the complex current signal, reducing misjudgment caused by subjective judgment or single feature recognition, and improving the sensitivity and reliability of pulse current signal recognition.

[0049] The feature extraction module 130 is used to extract features from the pulse current signal to obtain pulse current features when it is identified that there is a pulse current signal in the current signal.

[0050] Pulse current characteristics can be parameters or information that can describe the unique properties of pulse current signals. Pulse current characteristics can include pulse amplitude, pulse width, pulse rise time, and pulse fall time. Specifically, pulse amplitude can refer to the amplitude of the pulse current signal at the peak point; pulse width can refer to the time interval between the start of the rise and the end of the fall of the pulse current signal; pulse rise time refers to the time interval between the start of the rise and the peak of the pulse current signal; pulse fall time refers to the time interval between the peak point and the end of the fall of the pulse current signal.

[0051] The method of extracting features of the pulse current signal to obtain the pulse current features can be to determine the pulse amplitude of the pulse current signal according to the current signal, and to determine other pulse current features of the pulse current signal according to the current signal and the pulse amplitude.

[0052] The partial discharge detection module 140 is used to analyze the pulse current characteristics to obtain a partial discharge detection result.

[0053] The partial discharge detection result may be the detection and analysis information of the partial discharge anomaly of the subway cable, which may include whether there is a partial discharge anomaly, the partial discharge type, the partial discharge intensity, and the partial discharge location.

[0054] The pulse current characteristics are analyzed to obtain the partial discharge detection results. The method can be to identify whether the pulse current signal meets the local discharge anomaly based on the generation time of the pulse current signal and the spacing distance between the cable grounding wires; compare the pulse current characteristics with the pre-constructed local discharge current characteristics to obtain the local discharge type and local discharge intensity; obtain the specification parameters of the cable insulation layer, and determine the propagation speed of the pulse current signal based on the specification parameters, and determine the local discharge location based on the generation time and propagation speed of the pulse current signal and the spacing distance between the cable grounding wires.

[0055] In the example of the present application, the current signal acquisition module is used to acquire the current signal through the high-frequency current transformer arranged on the cable grounding wire; the pulse current identification module is used to identify whether there is a pulse current signal in the current signal; the feature extraction module is used to extract the features of the pulse current signal when it is identified that there is a pulse current signal in the current signal, and obtain the pulse current feature; wherein the pulse current feature includes at least one of the pulse amplitude, pulse width, pulse rise time and pulse fall time; the partial discharge detection module is used to analyze the pulse current feature and obtain the partial discharge detection result. This technical solution can realize efficient and accurate detection of the partial discharge of the subway cable by identifying whether there is a pulse current signal in the current signal of the cable grounding wire and determining the partial discharge detection result according to the pulse current signal, thereby ensuring the safe operation of the subway cable.

[0056] Embodiment 2

[0057] Figure 2It is a structural schematic diagram of the partial discharge detection device for subway cables provided in Example 2 of the present application. This solution has made better improvements on the basis of the above-mentioned embodiments, and the specific improvements are as follows: the feature extraction module is specifically used for: a pulse amplitude determination unit, which is used to determine the pulse amplitude of the pulse current signal according to the current signal; other feature extraction units, which are used to determine other pulse current features of the pulse current signal according to the current signal and the pulse amplitude; wherein the other pulse current features include at least one of pulse width, pulse rise time and pulse fall time.

[0058] like Figure 2 As shown, the device comprises:

[0059] A current signal acquisition module 210 is used to acquire a current signal through a high-frequency current transformer arranged on the cable grounding wire;

[0060] A pulse current identification module 220, used to identify whether there is a pulse current signal in the current signal;

[0061] A feature extraction module 230 is used to extract features of the pulse current signal to obtain pulse current features when it is identified that there is a pulse current signal in the current signal; wherein the pulse current feature includes at least one of a pulse amplitude, a pulse width, a pulse rise time, and a pulse fall time;

[0062] The partial discharge detection module 240 is used to analyze the pulse current characteristics to obtain a partial discharge detection result.

[0063] The feature extraction module 230 is specifically used for:

[0064] A pulse amplitude determination unit 2301, configured to determine the pulse amplitude of the pulse current signal according to the current signal;

[0065] The other feature extraction unit 2302 is used to determine other pulse current features of the pulse current signal according to the current signal and the pulse amplitude; wherein the other pulse current features include at least one of pulse width, pulse rise time and pulse fall time.

[0066] The method of determining the pulse amplitude of the pulse current signal according to the current signal can be to obtain a current fluctuation curve by interpolation fitting of the current signal, determine at least one current peak position according to the current fluctuation curve, and when the amplitude of the current peak position exceeds a preset amplitude threshold, determine the amplitude as the pulse amplitude of the pulse current signal.

[0067] In the technical solution, optionally, the pulse amplitude determination unit is specifically used to:

[0068] Performing interpolation fitting on the current signal to obtain a current fluctuation curve;

[0069] Determine at least one current peak position according to the current fluctuation curve;

[0070] When the amplitude at the current peak position exceeds a preset amplitude threshold, the amplitude is determined as the pulse amplitude of the pulse current signal.

[0071] The current fluctuation curve can be a continuous curve that reflects the changing trend of the current signal over time and intuitively shows the fluctuation of the current signal. Interpolation fitting is a mathematical method used to construct a continuous function based on known discrete data points. The function can well describe the distribution law of these discrete data points and can be used to predict or estimate the values ​​of unknown data points. Common interpolation methods include linear interpolation, polynomial interpolation, and spline interpolation, and common fitting methods include linear least squares fitting, polynomial least squares fitting, and nonlinear least squares fitting.

[0072] The current peak position may refer to the position on the current fluctuation curve where the current signal reaches a local maximum value. According to the method of determining at least one current peak position of the current fluctuation curve, the current fluctuation curve may be first derivated and second derivated, and the point where the first derivative function value is 0 and the second derivative function value is negative is determined as the current peak position.

[0073] The preset amplitude threshold may be a lower limit of the amplitude indicating a significant rise in the current signal. If the amplitude at the current peak exceeds the preset amplitude threshold, it indicates that the amplitude at the current peak has exceeded the amplitude range allowed by normal current fluctuations, and thus the amplitude may be determined as the pulse amplitude of the pulse current signal.

[0074] The advantages of this setting of the present scheme are that, on the one hand, the current fluctuation curve obtained by interpolation fitting can show the changing trend of the current signal more smoothly, which helps to find the current peak position more clearly and avoid misjudgment caused by the discontinuity of discrete data points; on the other hand, the setting of the preset amplitude threshold provides a clear judgment standard, which can avoid determining the peak amplitude of the normal fluctuation of the current signal as the pulse amplitude.

[0075] The method of determining other pulse current characteristics of the pulse current signal based on the current signal and the pulse amplitude can be adopted by determining the pulse start position and the pulse end position of the pulse current signal based on the pulse amplitude, determining the pulse width of the pulse current signal based on the pulse start position and the pulse end position, determining the pulse rise time of the pulse current signal based on the pulse start position and the pulse amplitude, and determining the pulse fall time of the pulse current signal based on the pulse end position and the pulse amplitude.

[0076] In this technical solution, optionally, the other feature extraction unit is specifically used to:

[0077] Determine the pulse start position and the pulse end position of the pulse current signal according to the pulse amplitude;

[0078] Determining the pulse width of the pulse current signal according to the pulse start position and the pulse end position;

[0079] The pulse rise time of the pulse current signal is determined according to the pulse start position and the pulse amplitude, and the pulse fall time of the pulse current signal is determined according to the pulse end position and the pulse amplitude.

[0080] The method of determining the pulse start position and the pulse end position of the pulse current signal according to the pulse amplitude can be adopted by calculating the difference between the average value of the current signal and the pulse amplitude, multiplying the difference with a preset coefficient (for example, 10%) and adding the difference to the average value to obtain the pulse limit amplitude, and determining the time point when the amplitude of the current signal begins to exceed the pulse limit amplitude as the pulse start position, and determining the time point when the amplitude of the current signal begins to be lower than the pulse limit amplitude as the pulse end position.

[0081] The pulse width of the pulse current signal is determined according to the pulse start position and the pulse end position. The time interval between the pulse start position and the pulse end position can be calculated as the pulse width.

[0082] The pulse rise time of the pulse current signal is determined according to the pulse start position and the pulse amplitude, and the pulse fall time of the pulse current signal is determined according to the pulse end position and the pulse amplitude. The time interval between the pulse start position and the current peak position corresponding to the pulse amplitude can be calculated as the pulse rise time, and the time interval between the current peak position corresponding to the pulse amplitude and the pulse end position can be calculated as the pulse fall time.

[0083] The following is an example code for determining other pulse current characteristics of a pulse current signal based on the current signal and the pulse amplitude:

[0084]

[0085]

[0086]

[0087] The advantage of this arrangement of the present scheme is that by determining the pulse start position and the pulse end position of the pulse current signal according to the pulse amplitude, determining the pulse width of the pulse current signal according to the pulse start position and the pulse end position, determining the pulse rise time of the pulse current signal according to the pulse start position and the pulse amplitude, and determining the pulse fall time of the pulse current signal according to the pulse end position and the pulse amplitude, the time domain characteristics of the pulse current signal can be comprehensively and meticulously quantitatively analyzed.

[0088] The advantage of this arrangement of the present scheme is that pulse current signals with different pulse amplitudes may exhibit different time characteristics and energy characteristics. By first determining the pulse amplitude of the pulse current signal based on the current signal, and then determining other pulse current characteristics of the pulse current signal based on the current signal and the pulse amplitude, the pulse current signal can be analyzed and processed in a more systematic and hierarchical manner.

[0089] Embodiment 3

[0090] Figure 3 It is a structural schematic diagram of the local discharge detection device for subway cables provided in Example 3 of the present application. This solution has made better improvements on the basis of the above embodiments, and the specific improvements are as follows: the local discharge detection module includes: a local discharge verification unit, which is used to identify whether the pulse current signal meets the local discharge anomaly based on the generation time of the pulse current signal and the spacing distance between the cable grounding wires; a local discharge analysis unit, which is used to compare the pulse current characteristics and the pre-constructed local discharge current characteristics to obtain the local discharge detection result when the pulse current signal is identified as meeting the local discharge anomaly; wherein the local discharge detection result includes the local discharge type and the local discharge intensity.

[0091] like Figure 3 As shown, the device comprises:

[0092] A current signal acquisition module 310 is used to acquire a current signal through a high-frequency current transformer arranged on the cable grounding wire;

[0093] A pulse current identification module 320, used to identify whether there is a pulse current signal in the current signal;

[0094] A feature extraction module 330 is used to extract features of the pulse current signal to obtain pulse current features when it is identified that there is a pulse current signal in the current signal; wherein the pulse current feature includes at least one of pulse amplitude, pulse width, pulse rise time and pulse fall time;

[0095] The partial discharge detection module 340 is used to analyze the pulse current characteristics to obtain a partial discharge detection result.

[0096] Wherein, the partial discharge detection module 340 includes:

[0097] A partial discharge verification unit 3401 is used to identify whether the pulse current signal meets the partial discharge anomaly according to the generation time of the pulse current signal and the spacing distance between the cable grounding wires;

[0098] The partial discharge analysis unit 3402 is used to compare the pulse current characteristics with the pre-constructed partial discharge current characteristics to obtain a partial discharge detection result when it is identified that the pulse current signal meets the partial discharge anomaly; wherein the partial discharge detection result includes the partial discharge type and the partial discharge intensity.

[0099] Local discharge anomaly may refer to a situation where the local electric field strength in the insulating material is too high, exceeding the breakdown field strength of the insulating medium, causing discharge in the local area but failing to form a conductive path throughout the entire insulation system.

[0100] The generation time of the pulse current signal may refer to the pulse start position of the pulse current signal on each cable grounding wire. The spacing distance between the cable grounding wires may refer to the distance between the cable grounding wires in space.

[0101] According to the generation time of the pulse current signal and the spacing distance between the cable grounding wires, the method of identifying whether the pulse current signal meets the local discharge anomaly can be adopted. The propagation speed of the pulse current signal can be determined according to the specification parameters of the cable insulation layer, and the estimated time of the pulse current signal reaching each cable grounding wire can be determined according to the propagation speed and the spacing distance. If the estimated time is consistent with the generation time, it is identified that the pulse current signal meets the local discharge anomaly.

[0102] The following is a sample code for identifying whether a pulse current signal meets the requirement of partial discharge anomaly based on the generation time of the pulse current signal and the spacing distance between the cable ground wires:

[0103]

[0104]

[0105]

[0106] The partial discharge type may be a type of partial discharge anomaly obtained by classifying the location and cause of the partial discharge anomaly in the cable structure; the partial discharge intensity may be an indicator used to describe the severity of the partial discharge anomaly.

[0107] The local discharge current feature may be a corresponding pulse current feature pre-constructed according to a historical pulse current signal. The local discharge current feature may be stored in association with a corresponding local discharge type and local discharge intensity. The current pulse current feature is compared with each pre-constructed local discharge current feature, and the local discharge type and local discharge intensity associated with the local discharge current feature with the highest similarity to the current pulse current feature are determined as the current local discharge type and local discharge intensity.

[0108] In this technical solution, optionally, the partial discharge verification unit is further used to:

[0109] When it is identified that the pulse current signal meets the local discharge anomaly, obtaining specification parameters of the cable insulation layer, and determining the propagation speed of the pulse current signal according to the specification parameters;

[0110] The local discharge position is determined according to the generation time of the pulse current signal, the propagation speed and the spacing distance between the cable grounding wires.

[0111] The cable insulation layer may refer to the insulating material layer wrapped around the cable conductor, which is mainly used to isolate the conductor, prevent current leakage, and ensure the safe operation of the cable. The specification parameters of the cable insulation layer may refer to various parameters that describe the characteristics of the cable insulation layer, which may include the type of insulation material, thickness of the insulation layer, relative dielectric constant, dielectric loss factor, and breakdown field strength. The specification parameters of the cable insulation layer can be obtained by referring to the production report of the subway cable and other explanatory documents.

[0112] The propagation speed of the pulse current signal may refer to the propagation distance of the pulse current signal in the cable insulation layer per unit time. The propagation speed of the pulse current signal is closely related to the specification parameters of the cable insulation layer. The method of determining the propagation speed of the pulse current signal according to the specification parameters may be to perform a square root operation on the relative dielectric constant in the specification parameters of the cable insulation layer, and divide the speed of light by the square root operation result to obtain the propagation speed of the pulse current signal.

[0113] The local discharge position may refer to the specific position where the local discharge anomaly actually occurs. According to the generation time and propagation speed of the pulse current signal and the spacing distance between the cable grounding wires, the local discharge position may be determined by finding two adjacent cable grounding wires whose generation time of the pulse current signal does not match the expected time and calculating the time difference between the two generation times, dividing the spacing distance between the cable grounding wires by the time difference and multiplying it by the propagation speed, and thus obtaining the distance between the local discharge position and one of the two adjacent cable grounding wires.

[0114] The benefit of this arrangement is that by determining the local discharge location based on the generation time and propagation speed of the pulse current signal and the spacing distance between the cable grounding wires, the specific location where the local discharge anomaly occurs in the subway cable can be quickly identified, helping maintenance personnel to quickly locate the maintenance location and improve maintenance efficiency.

[0115] The benefit of this arrangement of the present scheme is that by identifying whether the pulse current signal meets the local discharge anomaly based on the generation time of the pulse current signal and the spacing distance between the cable grounding wires, and by comparing the pulse current characteristics with the pre-constructed local discharge current characteristics to obtain the local discharge detection results, the local discharge anomaly of the subway cable can be identified and analyzed more comprehensively, accurately and efficiently.

[0116] Embodiment 4

[0117] Figure 4 1 is a flow chart of a method for detecting partial discharge of a subway cable provided in the fourth embodiment of the present application. Figure 4 As shown, the specific steps include:

[0118] S401, obtaining a current signal through a high-frequency current transformer disposed on a cable grounding wire by a current signal obtaining module;

[0119] S402, identifying whether there is a pulse current signal in the current signal by a pulse current identification module;

[0120] S403, when a feature extraction module is used to identify that there is a pulse current signal in the current signal, extract features of the pulse current signal to obtain a pulse current feature; wherein the pulse current feature includes at least one of a pulse amplitude, a pulse width, a pulse rise time, and a pulse fall time;

[0121] S404: Analyze the pulse current characteristics through a partial discharge detection module to obtain a partial discharge detection result.

[0122] In the embodiment of the present application, the current signal is acquired by the current signal acquisition module through the high-frequency current transformer arranged on the cable grounding wire; the pulse current identification module identifies whether there is a pulse current signal in the current signal; the feature extraction module extracts features of the pulse current signal when it is identified that there is a pulse current signal in the current signal, and obtains the pulse current feature; wherein the pulse current feature includes at least one of the pulse amplitude, pulse width, pulse rise time and pulse fall time; the pulse current feature is analyzed by the partial discharge detection module to obtain the partial discharge detection result. The above-mentioned partial discharge detection method of the subway cable can realize efficient and accurate detection of the partial discharge of the subway cable by identifying whether there is a pulse current signal in the current signal of the cable grounding wire and determining the partial discharge detection result according to the pulse current signal, thereby ensuring the safe operation of the subway cable.

[0123] The partial discharge detection method for subway cables provided in the embodiment of the present application corresponds to the partial discharge detection device for subway cables provided in the above embodiment, and has the same functional modules and beneficial effects. To avoid repetition, they will not be described here.

[0124] Embodiment 5

[0125] like Figure 5 As shown, the embodiment of the present application also provides an electronic device 500, including a processor 501, a memory 502, and a program or instruction stored in the memory 502 and executable on the processor 501. When the program or instruction is executed by the processor 501, each process of the above-mentioned subway cable partial discharge detection device embodiment is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0126] It should be noted that the electronic devices in the embodiments of the present application include the mobile electronic devices and non-mobile electronic devices mentioned above.

[0127] Embodiment 6

[0128] An embodiment of the present application also provides a readable storage medium, on which a program or instruction is stored. When the program or instruction is executed by a processor, each process of the above-mentioned subway cable partial discharge detection device embodiment is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be repeated here.

[0129] The processor is a processor in the electronic device described in the above embodiment. The readable storage medium includes a computer readable storage medium, such as a computer read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk.

[0130] Embodiment 7

[0131] An embodiment of the present application further provides a chip, which includes a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is used to run programs or instructions to implement the various processes of the above-mentioned embodiment of the partial discharge detection device for subway cables, and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0132] It should be understood that the chip mentioned in the embodiments of the present application can also be called a system-level chip, a system chip, a chip system or a system-on-chip chip, etc.

[0133] It should be noted that, in this article, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise one..." do not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0134] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a computer software product, which is stored in a storage medium (such as ROM / RAM, a disk, or an optical disk), and includes a number of instructions for a terminal (which can be a mobile phone, a computer, a server, or a network device, etc.) to execute the methods described in each embodiment of the present application.

[0135] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

[0136] The above are only preferred embodiments of the present application and the technical principles used. The present application is not limited to the specific embodiments described herein, and various obvious changes, readjustments and substitutions that can be made by those skilled in the art will not deviate from the scope of protection of the present application. Therefore, although the present application is described in more detail through the above embodiments, the present application is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present application, and the scope of the present application is determined by the scope of the claims.

Claims

1. A partial discharge detection device for subway cables, characterized in that: The device comprises: A current signal acquisition module is used to acquire a current signal through a high-frequency current transformer arranged on the cable grounding wire; A pulse current identification module, used to identify whether there is a pulse current signal in the current signal; A feature extraction module, configured to extract features of the pulse current signal to obtain pulse current features when a pulse current signal is identified as existing in the current signal; wherein the pulse current features include at least one of pulse amplitude, pulse width, pulse rise time and pulse fall time; The partial discharge detection module is used to analyze the pulse current characteristics to obtain partial discharge detection results.

2. The partial discharge detection device for subway cables according to claim 1, characterized in that: The pulse current identification module is specifically used for: determining a probability density function of the current signal; Determining a first similarity between the probability density function and a preset normal current function, and determining a second similarity between the probability density function and a preset pulse current function; When the second similarity exceeds the first similarity, it is recognized that a pulse current signal exists in the current signal.

3. The partial discharge detection device for subway cables according to claim 1, characterized in that: The feature extraction module is specifically used for: a pulse amplitude determination unit, configured to determine the pulse amplitude of the pulse current signal according to the current signal; The other feature extraction unit is used to determine other pulse current features of the pulse current signal according to the current signal and the pulse amplitude; wherein the other pulse current features include at least one of pulse width, pulse rise time and pulse fall time.

4. The partial discharge detection device for subway cables according to claim 3, characterized in that: The pulse amplitude determination unit is specifically used for: Performing interpolation fitting on the current signal to obtain a current fluctuation curve; Determine at least one current peak position according to the current fluctuation curve; When the amplitude at the current peak position exceeds a preset amplitude threshold, the amplitude is determined as the pulse amplitude of the pulse current signal.

5. The partial discharge detection device for subway cables according to claim 3, characterized in that: The other feature extraction units are specifically used for: Determine the pulse start position and the pulse end position of the pulse current signal according to the pulse amplitude; Determining the pulse width of the pulse current signal according to the pulse start position and the pulse end position; The pulse rise time of the pulse current signal is determined according to the pulse start position and the pulse amplitude, and the pulse fall time of the pulse current signal is determined according to the pulse end position and the pulse amplitude.

6. The partial discharge detection device for subway cables according to claim 1, characterized in that: The partial discharge detection module comprises: A partial discharge verification unit, used to identify whether the pulse current signal meets the partial discharge anomaly according to the generation time of the pulse current signal and the spacing distance between the cable grounding wires; The partial discharge analysis unit is used to compare the pulse current characteristics with the pre-constructed partial discharge current characteristics to obtain a partial discharge detection result when the pulse current signal is identified as meeting the partial discharge anomaly; wherein the partial discharge detection result includes the partial discharge type and the partial discharge intensity.

7. The partial discharge detection device for subway cables according to claim 6, characterized in that: The partial discharge verification unit is also used for: When it is identified that the pulse current signal meets the local discharge anomaly, obtaining specification parameters of the cable insulation layer, and determining the propagation speed of the pulse current signal according to the specification parameters; The local discharge position is determined according to the generation time of the pulse current signal, the propagation speed and the spacing distance between the cable grounding wires.

8. A method for detecting partial discharge of subway cables, characterized in that: The method comprises: The current signal is obtained by a current signal acquisition module through a high-frequency current transformer arranged on the cable grounding wire; Identify whether there is a pulse current signal in the current signal by a pulse current identification module; When a pulse current signal is identified as existing in the current signal, the feature extraction module extracts features of the pulse current signal to obtain a pulse current feature; wherein the pulse current feature includes at least one of a pulse amplitude, a pulse width, a pulse rise time, and a pulse fall time; The pulse current characteristics are analyzed by a partial discharge detection module to obtain a partial discharge detection result.

9. The method for detecting partial discharge of subway cables according to claim 8, characterized in that: Identifying whether there is a pulse current signal in the current signal by a pulse current identification module includes: determining a probability density function of the current signal; Determining a first similarity between the probability density function and a preset normal current function, and determining a second similarity between the probability density function and a preset pulse current function; When the second similarity exceeds the first similarity, it is recognized that a pulse current signal exists in the current signal.

10. An electronic device, characterized in that: The method comprises a processor, a memory and a program or instruction stored in the memory and executable on the processor, wherein the program or instruction, when executed by the processor, implements the steps of the method for detecting partial discharge of a subway cable as described in any one of claims 8 to 9.

Images