Power distribution network fault location method and system based on positive sequence component

Abstract

The invention discloses a power distribution network fault distance measurement method and system based on a positive sequence component, and the method comprises the steps: collecting the three-phase current and voltage data of two sides of a power distribution network line after the fault, and carrying out the preprocessing of the three-phase current and voltage data; converting the preprocessed data into a phasor form, and extracting a positive sequence component of the phasor form data; and calculating two positive-sequence fault voltages corresponding to the preset fault distance based on the positive-sequence component, and determining a fault positioning result according to phase angles and amplitudes of the two positive-sequence fault voltages. According to the method, the positions of real fault points are continuously approached by comparing the positive-sequence components of the fault points calculated at the two ends; considering the influence of the distributed capacitance on the distance measurement result, the distance measurement result is not influenced by transition resistance and unstable arc, and the distance measurement effect is good.

Description

Technical Field

[0001] The present invention relates to the technical field of distribution network interphase short circuit fault distance measurement, and in particular to a distribution network fault distance measurement method and system based on positive sequence components. Background Art

[0002] As the terminal link of the power system, the distribution network directly faces the vast number of power users and is a key hub for controlling and ensuring the quality of power supply. It not only bears the heavy responsibility of safely and economically distributing electric energy from the transmission system to each user end, but also profoundly affects the reliability of power supply to users. Once a distribution network fault occurs, especially a phase-to-phase fault, it may cause a power outage in a local area, affecting the normal life of residents and the continuity of corporate production activities; it may cause a large-scale power outage, which not only reduces production efficiency, but may also be accompanied by secondary disasters such as fires and traffic accidents, hindering the harmonious development of society. Fault distance measurement is of great significance to the rapid restoration of power supply in the distribution network, improving the reliability and continuity of power supply, and reducing power outage losses.

[0003] With the application of a large number of distributed power sources, the power system is undergoing an unprecedented transformation and upgrade. Although a large number of inverter-type distributed power sources are connected to the distribution network, in order to meet the power quality requirements, the output voltage and current of the distributed power sources are still mainly 50Hz sine waves. Although there will be certain harmonics, the traditional phasor calculation method still has a certain scope of application, and the phase-to-phase calculation method can still be used for fault distance measurement. However, the traditional distribution network fault distance measurement method usually does not consider the influence of distributed capacitance on the distance measurement results, and the distance measurement results are also easily affected by transition resistance and unstable arcs. Summary of the invention

[0004] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0005] In view of the above existing problems, the present invention is proposed.

[0006] Therefore, the present invention provides a distribution network fault distance measurement method and system based on positive sequence component to solve the problem that the traditional distribution network fault distance measurement method does not consider the influence of distributed capacitance on the distance measurement result, and the distance measurement result is also easily affected by transition resistance and unstable arc.

[0007] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0008] In a first aspect, an embodiment of the present invention provides a distribution network fault location method based on positive sequence components, comprising: collecting three-phase current and voltage data on both sides of a distribution network line after a fault, and preprocessing the three-phase current and voltage data;

[0009] Converting the preprocessed data into a phasor form and extracting a positive sequence component of the phasor form data;

[0010] Two positive-sequence fault voltages corresponding to a preset fault distance are calculated based on the positive-sequence component, and a fault location result is determined according to the phase angles and amplitudes of the two positive-sequence fault voltages.

[0011] As a preferred solution of the distribution network fault distance measurement method based on positive sequence components of the present invention, wherein: calculating two positive sequence fault voltages corresponding to a preset fault distance based on the positive sequence components includes: assuming that two initial acquisition ends of the line length L are the M side and the N side;

[0012] The positive sequence voltage at the fault point calculated from the M side is:

[0013]

[0014] in, is the positive sequence voltage and current on the M side, L is the total length of the line, L F is the distance from the M terminal to the fault point, r1, l1, c1 are the positive sequence resistance, positive sequence inductance and positive sequence capacitance per unit length of the line respectively, ω is the angular frequency, and j is the imaginary unit;

[0015] The positive sequence voltage at the fault point calculated from the N side is:

[0016]

[0017] in, is the positive sequence voltage and current on the N side, LL F is the distance from the N side to the fault point.

[0018] As a preferred solution of the distribution network fault location method based on positive sequence component described in the present invention, wherein: according to the phase angle and amplitude of two positive sequence fault voltages, determining the fault location result includes: judging whether the amplitude difference and the phase angle difference of the two positive sequence fault voltages are equal, if they are equal, outputting the currently set fault distance; if they are not equal, determining the next assumed fault distance until the convergence condition is met;

[0019] The convergence condition is expressed as:

[0020]

[0021] in, U M1.Fare the phase angle and amplitude of the positive sequence voltage at the fault point calculated from the M side, U N1.F are the phase angle and amplitude of the positive sequence voltage at the fault point calculated from the N side, is the phase angle difference of the positive sequence voltage at the two fault points, ΔU is the amplitude difference of the positive sequence voltage at the two fault points, and λ is the proportional coefficient.

[0022] As a preferred solution of the distribution network fault location method based on positive sequence component described in the present invention, it also includes: the phase angle difference and amplitude difference of two positive sequence fault voltages are expressed as:

[0023]

[0024] in, U M1.F are the phase angle and amplitude of the positive sequence voltage at the fault point calculated from the M side, U N1.F They are respectively the phase angle and amplitude of the positive sequence voltage at the fault point calculated from the N side.

[0025] As a preferred solution of the distribution network fault distance measurement method based on positive sequence component described in the present invention, if the amplitude difference and phase angle difference of two positive sequence fault voltages are not equal, determining the next assumed fault distance includes:

[0026] like The real fault point is biased towards the N side. The midpoint of the right half of the current interval is selected as the new assumed fault point. The two positive sequence voltages are calculated again to compare the phase angle and amplitude until the convergence condition is met.

[0027] like The real fault point is biased towards the M side. The midpoint of the left half of the current interval is selected as the new assumed fault point. The two positive sequence voltages are calculated again to compare the phase angle and amplitude until the convergence condition is met.

[0028] As a preferred solution of the distribution network fault location method based on positive sequence component described in the present invention, wherein: the fault type of the fault point includes various phase-to-phase short circuit faults.

[0029] As a preferred solution of the distribution network fault location method based on positive sequence components described in the present invention, the preprocessing of the three-phase current and voltage data includes: using a Kalman filtering algorithm, using the statistical characteristics of the signal and the statistical characteristics of the noise to estimate the true value of the signal, and removing noise and harmonics in the signal by continuously updating the estimated value and the error covariance matrix.

[0030] In a second aspect, the present invention provides a distribution network fault location system based on positive sequence components, comprising:

[0031] A data acquisition and processing module is used to collect three-phase current and voltage data on both sides of the distribution network after a line fault occurs, and to pre-process the three-phase current and voltage data;

[0032] A data conversion and extraction module, used to convert the preprocessed data into a phasor form and extract the positive sequence component of the phasor form data;

[0033] The fault distance determination module is used to calculate two positive-sequence fault voltages corresponding to a preset fault distance based on the positive-sequence component, and determine the fault location result according to the phase angle and amplitude of the two positive-sequence fault voltages.

[0034] In a third aspect, the present invention provides an electronic device, comprising:

[0035] Memory and processor;

[0036] The memory is used to store computer executable instructions, and the processor is used to execute the computer executable instructions. When the computer executable instructions are executed by the processor, the steps of the distribution network fault location method based on positive sequence components are implemented.

[0037] In a fourth aspect, the present invention provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the steps of the distribution network fault location method based on positive-sequence components.

[0038] Compared with the prior art, the present invention has the following beneficial effects: In an active power distribution network, the present invention uses the dichotomy method to assume the fault distance based on the three-phase voltage and three-phase current of the busbars on both sides of the line, writes algebraic equations based on the positive-sequence components of the electrical quantities on both sides, and infers the two positive-sequence fault voltages corresponding to the set fault distance, and compares the amplitudes and phase angles of the two positive-sequence fault voltages to determine whether they are equal. If they are equal, the fault distance set at this time is output; if they are not equal, the next assumed fault distance is determined. The present invention continuously approaches the position of the actual fault point by comparing the size of the positive-sequence components of the fault point inferred at both ends; considering the influence of the distributed capacitance on the distance measurement result, the distance measurement result is not affected by the transition resistance and unstable arc, and the distance measurement effect is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0040] Figure 1A method flow chart of a distribution network fault location method and system based on positive sequence components according to an embodiment of the present invention;

[0041] Figure 2 A schematic diagram of a fault of a 10kV active distribution line of a distribution network fault location method and system based on positive sequence components according to an embodiment of the present invention;

[0042] Figure 3 A diagram of a binary fault location process of a distribution network fault location method and system based on positive sequence components according to an embodiment of the present invention;

[0043] Figure 4 The present invention is a flow chart of a fault location method and system for distribution network based on positive sequence components according to an embodiment of the present invention. DETAILED DESCRIPTION

[0044] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0045] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0046] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0047] The present invention is described in detail with reference to schematic diagrams. When describing the embodiments of the present invention, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0048] At the same time, in the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "upper, lower, inner and outer" are based on the directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first, second or third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0049] In the present invention, unless otherwise clearly specified and limited, the terms "install, connect, connect" should be understood in a broad sense, for example: it can be a fixed connection, a detachable connection or an integral connection; it can also be a mechanical connection, an electrical connection or a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0050] Example 1

[0051] Reference Figure 1 to Figure 4 , is an embodiment of the present invention, which provides a distribution network fault location method based on positive sequence components, such as Figure 1 Shown include:

[0052] S100: Collecting three-phase current and voltage data on both sides of the distribution network after the line fails, and preprocessing the three-phase current and voltage data;

[0053] S200: converting the preprocessed data into a phasor form, and extracting a positive sequence component of the phasor form data;

[0054] S300: Calculate two positive-sequence fault voltages corresponding to a preset fault distance based on the positive-sequence component, and determine the fault location result according to the phase angles and amplitudes of the two positive-sequence fault voltages.

[0055] It should be noted that traditional distribution network fault distance measurement methods usually do not consider the impact of distributed capacitance on the distance measurement results, and the distance measurement results are also easily affected by transition resistance and unstable arcs. The present application provides a distribution network fault distance measurement method based on positive-sequence components, which can continuously approach the position of the actual fault point by comparing the size of the positive-sequence components of the fault point inferred at both ends.

[0056] In an alternative embodiment, referring to Figure 2The figure is a fault diagram of a 10kV active distribution line, with an infinite power source on the left and a distributed power source on the right. The electrical quantities obtained at the M and N terminals are shown in the figure. Assuming the total length of the line is L, the voltage at any point on the line MN can be derived from the electrical quantities at the M and N terminals respectively. Similarly, when a line fault occurs, the positive sequence voltage at the fault point calculated from the electrical quantity at the M terminal is equal to the positive sequence voltage at the fault point calculated from the electrical quantity at the N terminal.

[0057] When the fault distance L F When the fault point is unknown, the binary method is used to find the fault point. First, assume that the fault point is in the middle of the line. Figure 3 The L1 point shown, based on the voltage and current on both sides, calculates the two positive sequence voltages of the fault point, compares the phase angle and amplitude of the two voltages, calculates the phase angle difference and the amplitude difference, determines the next search direction of the fault point according to the leading or lagging relationship of the phase, and determines whether the distance measurement result meets the requirements according to the phase angle difference and the amplitude difference. In this application, when the amplitude difference and phase angle difference of the two positive sequence voltages are both less than 5% of the mean, the two positive sequence voltages are considered equal.

[0058] If the positive sequence voltage at L1 calculated from the M side is ahead of the positive sequence voltage at L1 calculated from the N side, then the real fault point K should be in the middle position towards the N side, and then use the binary method to select a point halfway on the right half, calculate the two positive sequence voltages again, and compare the phase angle and amplitude again; if the positive sequence voltage at L1 calculated from the M side lags behind the positive sequence voltage at L1 calculated from the N side, then the real fault point K should be in the middle position towards the M side, and then use the binary method to select a point halfway on the left half, calculate the two positive sequence voltages again, and compare the phase angle and amplitude again. And so on, constantly approaching the real fault point.

[0059] In the embodiment of the present application, the ranging process is as follows: Figure 4 As shown:

[0060] In the embodiment of the present application, the three-phase voltage on the M side after the fault is collected Three-phase current And N side three-phase voltage Three-phase current

[0061] Furthermore, considering that the harmonics caused by the equipment in the power grid and the noise in the data measurement will reduce the data quality and affect the accuracy of the analysis, it is necessary to preprocess the data and eliminate the bad data.

[0062] In an optional embodiment, the preprocessed signal is represented as a phasor through Fourier transform, and the positive sequence component is extracted using a symmetric component method.

[0063] In an embodiment of the present application, preprocessing of three-phase current and voltage data includes: using a Kalman filter algorithm to estimate the true value of the signal using the statistical characteristics of the signal and the statistical characteristics of the noise, and removing noise and harmonics in the signal by continuously updating the estimated value and the error covariance matrix.

[0064] In the embodiment of the present application, calculating two positive-sequence fault voltages corresponding to a preset fault distance based on the positive-sequence component includes: assuming that two initial acquisition ends of the line length L are the M side and the N side;

[0065] The positive sequence voltage at the fault point calculated from the M side is:

[0066]

[0067] in, is the positive sequence voltage and current on the M side, L is the total length of the line, L F is the distance from the M terminal to the fault point, r1, l1, c1 are the positive sequence resistance, positive sequence inductance and positive sequence capacitance per unit length of the line respectively, ω is the angular frequency, and j is the imaginary unit;

[0068] The positive sequence voltage at the fault point calculated from the N side is:

[0069]

[0070] in, is the positive sequence voltage and current on the N side, LL F is the distance from the N side to the fault point.

[0071] It should be noted that the preset lines in the embodiments of the present application are uniform, that is, the line impedance per unit length remains unchanged.

[0072] In an optional embodiment, a binary search method may be used to find the fault point. First, the fault point is assumed to be in the middle of the line. Two positive-sequence voltages at the fault point are deduced based on the voltages and currents on both sides. The phase angles and amplitudes of the two voltages are compared to calculate the phase angle difference and the amplitude difference.

[0073] In the embodiment of the present application, according to the phase angle and amplitude of the two positive-sequence fault voltages, determining the fault location result includes: judging whether the amplitude difference and the phase angle difference of the two positive-sequence fault voltages are equal, if they are equal, outputting the currently set fault distance; if they are not equal, determining the next assumed fault distance until the convergence condition is met;

[0074] The convergence condition is expressed as:

[0075]

[0076] in, U M1.Fare the phase angle and amplitude of the positive sequence voltage at the fault point calculated from the M side, U N1.F are the phase angle and amplitude of the positive sequence voltage at the fault point calculated from the N side, is the phase angle difference of the positive sequence voltage at the two fault points, ΔU is the amplitude difference of the positive sequence voltage at the two fault points, and λ is the proportional coefficient.

[0077] In an optional embodiment, the proportionality factor may be 5%.

[0078] In the embodiment of the present application, the phase angle difference and amplitude difference of the two positive sequence fault voltages are expressed as:

[0079]

[0080] in, U M1.F are the phase angle and amplitude of the positive sequence voltage at the fault point calculated from the M side, U N1.F They are respectively the phase angle and amplitude of the positive sequence voltage at the fault point calculated from the N side.

[0081] In the embodiment of the present application, if the amplitude difference and the phase angle difference of the two positive sequence fault voltages are not equal, determining the next assumed fault distance includes:

[0082] like The real fault point is biased towards the N side. The midpoint of the right half of the current interval is selected as the new assumed fault point. The two positive sequence voltages are calculated again to compare the phase angle and amplitude until the convergence condition is met.

[0083] like The real fault point is biased towards the M side. The midpoint of the left half of the current interval is selected as the new assumed fault point. The two positive sequence voltages are calculated again to compare the phase angle and amplitude until the convergence condition is met.

[0084] In the embodiment of the present application, the fault type of the fault point includes various phase-to-phase short circuit faults.

[0085] The above is a schematic scheme of a distribution network fault distance measurement method based on positive sequence components in this embodiment. It should be noted that the technical scheme of the distribution network fault distance measurement system based on positive sequence components and the technical scheme of the distribution network fault distance measurement method based on positive sequence components belong to the same concept, and the details of the technical scheme of the distribution network fault distance measurement system based on positive sequence components in this embodiment that are not described in detail can all be referred to the description of the technical scheme of the distribution network fault distance measurement method based on positive sequence components.

[0086] In this embodiment, a distribution network fault location system based on positive sequence components includes:

[0087] The data acquisition and processing module is used to collect the three-phase current and voltage data on both sides of the distribution network after the line fault occurs, and pre-process the three-phase current and voltage data;

[0088] A data conversion and extraction module is used to convert the preprocessed data into a phasor form and extract the positive sequence component of the phasor form data;

[0089] The fault distance determination module is used to calculate two positive-sequence fault voltages corresponding to a preset fault distance based on the positive-sequence component, and determine the fault location result according to the phase angle and amplitude of the two positive-sequence fault voltages.

[0090] This embodiment further provides an electronic device, which is applicable to the case of a distribution network fault location method based on a positive sequence component, and includes:

[0091] A memory and a processor; the memory is used to store computer executable instructions, and the processor is used to execute computer executable instructions to implement the distribution network fault location method based on positive sequence components as proposed in the above embodiment.

[0092] This embodiment further provides a storage medium on which a computer program is stored. When the program is executed by a processor, the method for fault location measurement in a distribution network based on positive sequence components as proposed in the above embodiment is implemented.

[0093] The storage medium proposed in this embodiment and the distribution network fault location method based on positive sequence components proposed in the above embodiment belong to the same inventive concept. The technical details not fully described in this embodiment can be referred to the above embodiment, and this embodiment has the same beneficial effects as the above embodiment.

[0094] Through the above description of the implementation methods, the technicians in the relevant field can clearly understand that the present invention can be implemented by means of software and necessary general hardware, and of course can also be implemented by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art can be embodied in the form of a software product, and the computer software product can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory (ReadOnly, Memory, ROM), random access memory (RandomAccess Memory, RAM), flash memory (FLASH), hard disk or optical disk, etc., including a number of instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform the methods of various embodiments of the present invention.

[0095] Example 2

[0096] Reference Figure 2Tables 1 and 2 are an embodiment of the present invention. This embodiment is different from the first embodiment in that this embodiment verifies the beneficial effects of the present invention through simulation examples.

[0097] This embodiment is built in PSCAD / EMTDC simulation software as follows Figure 2 The 10kV AC distribution network model with DG shown in the figure has a system rated capacity of 100MVA and a rated voltage of 10.5kV; the distributed power source is a 5MW photovoltaic power source, and the grid-connected inverter adopts a constant power control strategy. The line electrical parameters are shown in Table 1:

[0098] Table 1 10kV distribution network electrical parameters

[0099]

[0100]

[0101] Set BC phase short circuit faults at different distances to obtain the ranging results and ranging errors, as shown in Table 2:

[0102] Table 2 Ranging results

[0103] Fault setting distance / km Measuring distance / km Ranging error 2.1 2.109375 0.009375 4.1 4.0625 0.0375 5.0 5 0 6.0 5.9375 0.0625 8.4 8.4375 0.0375

[0104] It can be seen from Table 2 that the distance measurement error of the present invention is small, the distance measurement accuracy is high, and it has good application value.

[0105] In summary, the present invention continuously approaches the position of the real fault point by comparing the size of the positive sequence component of the fault point calculated at both ends. In the active distribution network, according to the three-phase voltage and three-phase current of the busbars on both sides of the line, the fault distance is assumed by using the dichotomy method, and algebraic equations are written based on the positive sequence components of the electrical quantities on both sides to calculate the two positive sequence fault voltages corresponding to the set fault distance. The amplitudes and phase angles of the two positive sequence fault voltages are compared to determine whether they are equal. If they are equal, the fault distance set at this time is output; if they are not equal, the next assumed fault distance is determined. The present invention continuously approaches the position of the real fault point by comparing the size of the positive sequence component of the fault point calculated at both ends; considering the influence of the distributed capacitance on the distance measurement result, the distance measurement result is not affected by the transition resistance and unstable arc, and the distance measurement effect is better.

[0106] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A distribution network fault location method based on positive sequence component, characterized in that: include: Collect the three-phase current and voltage data on both sides of the distribution network after the line fault, and pre-process the three-phase current and voltage data; Convert the preprocessed data into phasor form and extract the positive sequence component of the phasor form data; Two positive-sequence fault voltages corresponding to a preset fault distance are calculated based on the positive-sequence component, and the fault location result is determined according to the phase angles and amplitudes of the two positive-sequence fault voltages.

2. The distribution network fault location method based on positive sequence component according to claim 1, characterized in that: Calculating two positive-sequence fault voltages corresponding to a preset fault distance based on the positive-sequence component includes: assuming that two initial acquisition ends of the line length L are the M side and the N side; The positive sequence voltage at the fault point calculated from the M side is: in, is the positive sequence voltage and current on the M side, L is the total length of the line, L F is the distance from the M terminal to the fault point, r1, l1, c1 are the positive sequence resistance, positive sequence inductance and positive sequence capacitance per unit length of the line respectively, ω is the angular frequency, and j is the imaginary unit; The positive sequence voltage at the fault point calculated from the N side is: in, is the positive sequence voltage and current on the N side, LL F is the distance from the N side to the fault point.

3. The distribution network fault location method based on positive sequence component according to claim 2, characterized in that: According to the phase angle and amplitude of the two positive sequence fault voltages, the fault location result is determined, including: judging whether the amplitude difference and the phase angle difference of the two positive sequence fault voltages are equal, if they are equal, outputting the currently set fault distance; if they are not equal, determining the next assumed fault distance until the convergence condition is met; The convergence condition is expressed as: in, U M1.F are the phase angle and amplitude of the positive sequence voltage at the fault point calculated from the M side, U N1.F are the phase angle and amplitude of the positive sequence voltage at the fault point calculated from the N side, is the phase angle difference of the positive sequence voltage at the two fault points, ΔU is the amplitude difference of the positive sequence voltage at the two fault points, and λ is the proportional coefficient.

4. The distribution network fault location method based on positive sequence component according to claim 3, characterized in that: Also includes: The phase angle difference and amplitude difference of two positive sequence fault voltages are expressed as: in, U M1.F are the phase angle and amplitude of the positive sequence voltage at the fault point calculated from the M side, U N1.F They are respectively the phase angle and amplitude of the positive sequence voltage at the fault point calculated from the N side.

5. The distribution network fault location method based on positive sequence component according to claim 4, characterized in that: If the amplitude difference and phase angle difference of the two positive sequence fault voltages are not equal, then the next assumed fault distance is determined by: like The real fault point is biased towards the N side. The midpoint of the right half of the current interval is selected as the new assumed fault point. The two positive sequence voltages are calculated again to compare the phase angle and amplitude until the convergence condition is met. like The real fault point is biased towards the M side. The midpoint of the left half of the current interval is selected as the new assumed fault point. The two positive sequence voltages are calculated again to compare the phase angle and amplitude until the convergence condition is met.

6. The distribution network fault location method based on positive sequence component according to claim 5, characterized in that: The fault types of the fault point include various phase-to-phase short circuit faults.

7. The distribution network fault location method based on positive sequence component according to claim 1, characterized in that: The three-phase current and voltage data are preprocessed by using a Kalman filter algorithm to estimate the true value of the signal using the statistical characteristics of the signal and the statistical characteristics of the noise, and removing noise and harmonics in the signal by continuously updating the estimated value and the error covariance matrix.

8. A distribution network fault location system based on positive sequence component, characterized in that: include: A data acquisition and processing module is used to collect three-phase current and voltage data on both sides of the distribution network after a line fault occurs, and to pre-process the three-phase current and voltage data; A data conversion and extraction module, used to convert the preprocessed data into a phasor form and extract the positive sequence component of the phasor form data; The fault distance determination module is used to calculate two positive-sequence fault voltages corresponding to a preset fault distance based on the positive-sequence component, and determine the fault location result according to the phase angle and amplitude of the two positive-sequence fault voltages.

9. An electronic device, comprising: Memory and processor; The memory is used to store computer executable instructions, and the processor is used to execute the computer executable instructions. When the computer executable instructions are executed by the processor, the steps of the distribution network fault location method based on positive sequence components as described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the steps of the distribution network fault location method based on positive sequence components as claimed in any one of claims 1 to 7.

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