Single-phase earth fault signal first half wave skewness extraction method and related device thereof

Abstract

The invention discloses a single-phase earth fault signal first half-wave skewness extraction method and a related device thereof. The method comprises the steps of data acquisition and extraction of fault first half-wave signal sampling data; filtering and denoising processing is carried out on the data; performing standardization processing on the data; calculating the skewness of the signal; the skewness of the signal is obtained through calculation, so that the influence of environmental noise is eliminated, and a characteristic quantity used for representing whether a fault occurs or not is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of distribution network fault signal processing, and in particular relates to a method for extracting the first half-wave skewness of a single-phase grounding fault signal and a related device thereof. Background Art

[0002] The 10kV distribution network is an important part of the end link of power supply. It is directly distributed to the low-voltage transformer nodes where the load of power customers is concentrated. The environment involved in the line is diverse and complex. According to the statistics of production and operation data, about 80% of the accidental power outages in the distribution network are caused by single-phase grounding faults. In order to improve the power supply reliability during single-phase grounding faults, the system generally adopts the operation mode of neutral point small current grounding. This operation mode includes two types: neutral point ungrounded and grounded through arc suppression coil. The fault current flowing through the grounding point during the fault is relatively small, and the three-phase line voltage at this time is still consistent with normal operation, which does not affect the power supply of the lower level. The power regulations limit the system to operate with faults for 1 to 2 hours. However, during abnormal operation, the non-fault phase voltage value of the system is the original line voltage level. If the fault point is not located and the fault area is not isolated in time, it may break down the equipment at the weak voltage resistance caused by aging and other reasons in the line, causing multiple grounding short circuits and expanding the fault area. The system deteriorates from abnormal operation to fault power outage.

[0003] After the fault signal is transmitted to the substation through overhead lines or cables, it will be attenuated, and the interference of certain intensity of environmental noise will affect the effect of single-phase grounding fault diagnosis. Therefore, it is necessary to filter the signal to reduce the impact of environmental noise on the fault signal. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a method for extracting the first half-wave skewness of a single-phase grounding fault signal and a related device thereof in view of the deficiencies in the above-mentioned prior art, so as to solve the technical problem of the difficulty in line selection and positioning of a phase-to-ground fault.

[0005] The present invention adopts the following technical solutions:

[0006] A method for extracting the first half-wave skewness of a single-phase ground fault signal is proposed based on the 2-phase distribution network system operating frequency. N times as the sampling rate, extracting the first half-wave signal sampling data of the fault signal in the distribution network data; filtering and denoising the first half-wave signal sampling data; standardizing the first half-wave signal sampling data after filtering and denoising; calculating the skewness S of the signal based on the first half-wave signal sampling data after standardization, and obtaining the characteristic quantity used to characterize whether a fault occurs.

[0007] Preferably, the first half-wave signal sampling data x is:

[0008] x=s*x S+c*x C +l*x L

[0009] Among them, x S is the steady-state component of the fault signal, x C is the transient capacitance component of the fault signal, x L is the transient inductance component of the fault signal, s is the amplitude of the steady-state component of the fault signal, c is the transient capacitance component of the fault signal, and l is the transient inductance component of the fault signal.

[0010] Further preferably, the sampling rate f of the signal s for:

[0011] f s =2 N *f

[0012] Wherein, N is a positive integer and f is the operating frequency of the power grid.

[0013] Preferably, the first half-wave signal sampling data is filtered and denoised by hardware filtering and software filtering.

[0014] Further preferably, the hardware filtering adopts a second-order passive RC low-pass filter, and the software filtering adopts a twentieth-order FIR low-pass filter.

[0015] Preferably, the signal normalization process is:

[0016]

[0017] Among them, x is the signal collected and processed by low-pass filtering, μ x is the mean of the signal x, σ x is the standard deviation of signal x, and x′ is the standardized signal.

[0018] Preferably, the signal skewness S is calculated as follows:

[0019]

[0020] Among them, x i ′ is the i-th point of the standardized signal, μ x′ is the mean of the normalized signal, σ x′ is the standard deviation of the standardized signal, and n is the number of sampling points.

[0021] In a second aspect, an embodiment of the present invention provides a system for extracting the first half-wave skewness of a single-phase ground fault signal, comprising:

[0022] The sampling module uses 2% of the distribution network system operating frequency N Times as sampling rate, extract the first half-wave signal sampling data of the fault signal in the distribution network data;

[0023] A filtering module performs filtering and denoising processing on the first half-wave signal sampling data obtained by the extraction module;

[0024] The standardization module performs standardization on the first half-wave signal sampling data after filtering and denoising by the filtering module;

[0025] The extraction module calculates the signal skewness S based on the first half-wave signal sampling data after the standardization processing by the standardization module, and obtains the characteristic quantity used to characterize whether the fault occurs.

[0026] In a third aspect, a chip comprises a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above-mentioned method for extracting the first half-wave skewness of a single-phase ground fault signal when executing the computer program.

[0027] In a fourth aspect, an embodiment of the present invention provides an electronic device, including a chip, which, when executed, implements the steps of the above-mentioned method for extracting the first half-wave skewness of a single-phase grounding fault signal.

[0028] Compared with the prior art, the present invention has at least the following beneficial effects:

[0029] A method for extracting the first half-wave skewness of a single-phase grounding fault signal can filter the extracted fault signal, calculate the signal skewness of the first half-wave after data standardization, and provide a characteristic quantity basis for locating the single-phase grounding fault.

[0030] Furthermore, the distribution network system operating frequency is 2 N times the sampling rate, which can reduce computational complexity and spectrum leakage.

[0031] Furthermore, filtering and denoising through hardware filtering and software filtering can filter out the high-frequency part of the signal, improve the signal-to-noise ratio of the signal, reduce the impact of noise on subsequent calculations, and improve the credibility of the results.

[0032] Furthermore, the hardware filtering uses a second-order passive RC low-pass filter to filter out noise signals and isolate the system's impact overvoltage. The software filtering uses a 20th-order FIR low-pass filter to ensure arbitrary amplitude-frequency characteristics while having strict linear phase-frequency characteristics.

[0033] Furthermore, the signal skewness S can reflect the asymmetry of the signal probability density function and the severity of the system failure.

[0034] It can be understood that the beneficial effects of the second to fourth aspects mentioned above can be found in the relevant description of the first aspect mentioned above, and will not be repeated here.

[0035] In summary, the present invention combines the advantages of software and hardware filtering and the waveform first half-wave signal skewness calculation method, and can process the single-line grounding fault signal into a characteristic quantity that characterizes the occurrence and location of the fault. At the same time, the calculation process is simple and has strong adaptability.

[0036] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a schematic diagram of the process of the present invention;

[0038] Figure 2 A schematic diagram of a computer device provided by an embodiment of the present invention.

[0039] Figure 3 The block diagram of a chip provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0040] 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 part of the embodiments of the present invention, not all of the embodiments. 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.

[0041] In the description of the present invention, it should be understood that the terms “include” and “comprises” indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0042] It should also be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0043] It should be further understood that the term "and / or" used in the present specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations. For example, A and / or B can be: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally means that the objects associated before and after are in an "or" relationship.

[0044] It should be understood that, although the terms first, second, third, etc. may be used to describe preset ranges, etc. in the embodiments of the present invention, these preset ranges should not be limited to these terms. These terms are only used to distinguish preset ranges from each other. For example, without departing from the scope of the embodiments of the present invention, the first preset range may also be referred to as the second preset range, and similarly, the second preset range may also be referred to as the first preset range.

[0045] The word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0046] Various structural schematic diagrams of the embodiments disclosed in the present invention are shown in the accompanying drawings. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0047] Skewness is a statistic used to measure the degree of asymmetry in a probability distribution or data set. It describes on which side of the mean the tail of the data distribution is heavier or longer. Skewness can help us understand the skewed nature of the data, that is, how the data is distributed relative to the mean.

[0048] The present invention provides a method for extracting the first half-wave skewness of a single-phase grounding fault signal. The method collects, filters and standardizes the system current and voltage signals, and finally obtains the skewness of the signal by calculation. The signal skewness is used to characterize whether a single-phase grounding fault occurs in the system. The method aims to eliminate the influence of environmental noise and obtain a characteristic quantity for characterizing whether a fault occurs.

[0049] The present invention provides a method for extracting the first half-wave skewness of a single-phase ground fault signal, comprising the following steps:

[0050] S1. Data collection and extraction of fault first half-wave signal sampling data;

[0051] Collect the current or voltage signal that needs to be processed. The collected current or voltage signal is as follows:

[0052] x=s*x S +c*x C +l*xL

[0053] Among them, x is the collected signal, x S is the steady-state component of the fault signal, x C is the transient capacitance component of the fault signal, x L is the transient inductance component of the fault signal, s is the amplitude of the steady-state component of the fault signal, c is the transient capacitance component of the fault signal, and l is the transient inductance component of the fault signal.

[0054] The sampling rate should be 2 times the system operating frequency. N times, the sampling rate of the signal is f s for:

[0055] f s =2 N *f

[0056] Wherein, N is a positive integer, generally greater than 4, and f is the operating frequency of the power grid, which is 50 Hz.

[0057] S2, filtering and denoising the data;

[0058] The low-pass filtering of the signal is achieved through hardware filtering and software filtering. The hardware filtering is a second-order passive RC low-pass filter, and the software filtering is a twentieth-order FIR low-pass filter.

[0059] S3, standardizing the filtered data;

[0060] The signal normalization process is:

[0061]

[0062] Among them, x is the signal collected and processed by low-pass filtering, μ x is the mean of the signal x, σ x is the standard deviation of signal x, and x′ is the standardized signal.

[0063] S4. Calculate the skewness S of the signal.

[0064] The signal skewness is calculated as follows:

[0065]

[0066] Among them, x i ′ is the i-th point of the standardized signal, μ x′ is the mean of the normalized signal, σ x′ is the standard deviation of the standardized signal, n is the number of sampling points, and S is the calculated signal skewness.

[0067] In another embodiment of the present invention, a system for extracting the first half-wave skewness of a single-phase grounding fault signal is provided. The system can be used to implement the above-mentioned method for extracting the first half-wave skewness of a single-phase grounding fault signal. Specifically, the system for extracting the first half-wave skewness of a single-phase grounding fault signal includes a sampling module, a filtering module, a standardization module and an extraction module.

[0068] Among them, the sampling module uses 2 of the distribution network system operating frequency N Times as sampling rate, extract the first half-wave signal sampling data of the fault signal in the distribution network data;

[0069] A filtering module performs filtering and denoising processing on the first half-wave signal sampling data obtained by the extraction module;

[0070] The standardization module performs standardization on the first half-wave signal sampling data after filtering and denoising by the filtering module;

[0071] The extraction module calculates the signal skewness S based on the first half-wave signal sampling data after the standardization processing by the standardization module, and obtains the characteristic quantity used to characterize whether the fault occurs.

[0072] In another embodiment of the present invention, a terminal device is provided, which includes a processor and a memory, wherein the memory is used to store a computer program, the computer program includes program instructions, and the processor is used to execute the program instructions stored in the computer storage medium. The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gates or transistor logic devices, discrete hardware components, etc. It is the computing core and control core of the terminal, which is suitable for implementing one or more instructions, and is specifically suitable for loading and executing one or more instructions to implement the corresponding method flow or corresponding function; the processor described in the embodiment of the present invention can be used for the operation of the first half-wave skewness extraction method of the single-phase grounding fault signal, including:

[0073] The distribution network system operating frequency is 2 Ntimes as the sampling rate, extracting the first half-wave signal sampling data of the fault signal in the distribution network data; filtering and denoising the first half-wave signal sampling data; standardizing the first half-wave signal sampling data after filtering and denoising; calculating the skewness S of the signal based on the first half-wave signal sampling data after standardization, and obtaining the characteristic quantity used to characterize whether a fault occurs.

[0074] See also Figure 2 , the terminal device is a computer device, and the computer device 60 of this embodiment includes: a processor 61, a memory 62, and a computer program 63 stored in the memory 62 and executable on the processor 61. When the computer program 63 is executed by the processor 61, the method for calculating the fluid composition in the reservoir transformation wellbore in the embodiment is realized. To avoid repetition, it is not described one by one here. Alternatively, when the computer program 63 is executed by the processor 61, the functions of each model / unit in the first half-wave deflection extraction system of the single-phase grounding fault signal in the embodiment are realized. To avoid repetition, it is not described one by one here.

[0075] The computer device 60 may be a computing device such as a desktop computer, a notebook, a PDA, or a cloud server. The computer device 60 may include, but is not limited to, a processor 61 and a memory 62. Those skilled in the art will appreciate that Figure 2 This is only an example of the computer device 60 and does not constitute a limitation of the computer device 60. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the computer device may also include input and output devices, network access devices, buses, etc.

[0076] The processor 61 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc.

[0077] The memory 62 may be an internal storage unit of the computer device 60, such as a hard disk or memory of the computer device 60. The memory 62 may also be an external storage device of the computer device 60, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc., equipped on the computer device 60.

[0078] Furthermore, the memory 62 may include both an internal storage unit of the computer device 60 and an external storage device. The memory 62 is used to store computer programs and other programs and data required by the computer device. The memory 62 may also be used to temporarily store data that has been output or is to be output.

[0079] See also Figure 3 , the terminal device is a chip, and the chip 600 of this embodiment includes a processor 622, which may be one or more, and a memory 632 for storing a computer program executable by the processor 622. The computer program stored in the memory 632 may include one or more modules, each corresponding to a set of instructions. In addition, the processor 622 may be configured to execute the computer program to execute the above-mentioned single-phase ground fault signal first half-wave skewness extraction method.

[0080] In addition, the chip 600 may further include a power supply component 626 and a communication component 650, wherein the power supply component 626 may be configured to perform power management of the chip 600, and the communication component 650 may be configured to implement communication, for example, wired or wireless communication, of the chip 600. In addition, the chip 600 may further include an input / output (I / O) interface 658. The chip 600 may operate based on an operating system stored in the memory 632.

[0081] In another embodiment of the present invention, the present invention further provides a storage medium, specifically a computer-readable storage medium (Memory), which is a memory device in a terminal device for storing programs and data. It can be understood that the computer-readable storage medium here can include both the built-in storage medium in the terminal device and the extended storage medium supported by the terminal device. The computer-readable storage medium provides a storage space, which stores the operating system of the terminal. In addition, one or more instructions suitable for being loaded and executed by the processor are also stored in the storage space, and these instructions can be one or more computer programs (including program codes). It should be noted that the computer-readable storage medium here can be a high-speed RAM memory, or a non-volatile memory (Non-Volatile Memory), such as at least one disk memory.

[0082] The processor may load and execute one or more instructions stored in a computer-readable storage medium to implement the corresponding steps of the method for extracting the first half-wave deflection of a single-phase ground fault signal in the above embodiment; the processor may load and execute the following steps of one or more instructions in the computer-readable storage medium:

[0083] The distribution network system operating frequency is 2 N times as the sampling rate, extracting the first half-wave signal sampling data of the fault signal in the distribution network data; filtering and denoising the first half-wave signal sampling data; standardizing the first half-wave signal sampling data after filtering and denoising; calculating the skewness S of the signal based on the first half-wave signal sampling data after standardization, and obtaining the characteristic quantity used to characterize whether a fault occurs.

[0084] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but is only for selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0085] The present invention proposes a method for extracting the first half-wave deflection of a single-phase grounding fault signal and a related device thereof. The effect simulation is carried out using MATLAB / Simulink simulation software, and a complete set of simulation models of the distribution network is built, including transformers, lines, distribution transformers and loads, etc., with a total of 16 outgoing lines, with a length of 10km to 17.5km. Based on this model, a study on the extraction of the first half-wave deflection of a single-phase grounding fault signal is carried out. Single-phase grounding faults with different transition resistance values ​​and fault phases on different lines and different positions are set respectively. The method of the present invention is used to extract the first half-wave deflection of the signal in real time.

[0086] The results show that the signal first half-wave skewness feature extracted by the first half-wave skewness extraction method proposed in the present invention has obvious distinction before and after the fault occurs, has strong robustness, and changes monotonically with the fault location, which can be used as a basis for positioning.

[0087] In summary, the present invention provides a method for extracting the first half-wave skewness of a single-phase grounding fault signal and a related device, which filters and standardizes the collected current or voltage signal, obtains the skewness of the signal by calculation, and aims to eliminate the influence of environmental noise and obtain a characteristic quantity for characterizing whether a fault occurs.

[0088] The technicians in the relevant field can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiment can be integrated in a processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit. The above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application. The specific working process of the units and modules in the above-mentioned system can refer to the corresponding process in the aforementioned method embodiment, which will not be repeated here.

[0089] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0090] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed in the present invention can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0091] In the embodiments provided by the present invention, it should be understood that the disclosed devices / terminals and methods can be implemented in other ways. For example, the device / terminal embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0092] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0093] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0094] If the integrated module / unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM), electric carrier signal, telecommunication signal and software distribution medium, etc. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, computer-readable media do not include electric carrier signals and telecommunication signals.

[0095] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1A device that provides the functions specified in a block or multiple blocks.

[0096] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0097] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0098] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for extracting the first half-wave skewness of a single-phase ground fault signal, characterized in that: The distribution network system operating frequency is 2 N times as the sampling rate, extracting the first half-wave signal sampling data of the fault signal in the distribution network data; filtering and denoising the first half-wave signal sampling data; standardizing the first half-wave signal sampling data after filtering and denoising; calculating the skewness S of the signal based on the first half-wave signal sampling data after standardization, and obtaining the characteristic quantity used to characterize whether a fault occurs.

2. The method for extracting the first half-wave skewness of a single-phase ground fault signal according to claim 1, characterized in that: The first half-wave signal sampling data x is: x=s*x S +c*x C +l*x L Among them, x S is the steady-state component of the fault signal, x C is the transient capacitance component of the fault signal, x L is the transient inductance component of the fault signal, s is the amplitude of the steady-state component of the fault signal, c is the transient capacitance component of the fault signal, and l is the transient inductance component of the fault signal.

3. The method for extracting the first half-wave skewness of a single-phase ground fault signal according to claim 2, characterized in that: The sampling rate of the signal is f s for: f s =2 N *f Wherein, N is a positive integer and f is the operating frequency of the power grid.

4. The method for extracting the first half-wave skewness of a single-phase ground fault signal according to claim 1, characterized in that: The first half-wave signal sampling data is filtered and denoised through hardware filtering and software filtering.

5. The method for extracting the first half-wave skewness of a single-phase ground fault signal according to claim 4, characterized in that: The hardware filter uses a second-order passive RC low-pass filter, and the software filter uses a 20th-order FIR low-pass filter.

6. The method for extracting the first half-wave skewness of a single-phase ground fault signal according to claim 1, characterized in that: The signal normalization process is: Among them, x is the signal collected and processed by low-pass filtering, μ x is the mean of the signal x, σ x is the standard deviation of signal x, and x′ is the standardized signal.

7. The method for extracting the first half-wave skewness of a single-phase ground fault signal according to claim 1, characterized in that: The signal skewness S is calculated as follows: Among them, x i ′ is the i-th point of the standardized signal, μ x′ is the mean of the normalized signal, σ x′ is the standard deviation of the standardized signal, and n is the number of sampling points.

8. A system for extracting the first half-wave skewness of a single-phase ground fault signal, characterized in that: include: The sampling module uses 2% of the distribution network system operating frequency N Times as sampling rate, extract the first half-wave signal sampling data of the fault signal in the distribution network data; A filtering module performs filtering and denoising processing on the first half-wave signal sampling data obtained by the extraction module; The standardization module performs standardization on the first half-wave signal sampling data after filtering and denoising by the filtering module; The extraction module calculates the signal skewness S based on the first half-wave signal sampling data after the standardization processing by the standardization module, and obtains the characteristic quantity used to characterize whether the fault occurs.

9. A chip, characterized in that: a memory having a computer program stored thereon; A processor, configured to execute the computer program in the memory to implement the steps of the method according to any one of claims 1 to 7.

10. An electronic device, characterized in that: Comprising the chip as claimed in claim 9.

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