Power distribution network fault section positioning method and device based on sequence voltage amplitude distribution

Abstract

The invention belongs to the technical field of power system distribution network fault positioning, and provides a sequence voltage amplitude distribution-based power distribution network fault section positioning method and device. The sequence voltage amplitude distribution-based power distribution network fault section positioning method comprises the following steps of: receiving fault steady-state electrical quantity information uploaded by a terminal in a power distribution network in response to a short-circuit fault of the power distribution network; if the short-circuit fault is a symmetric fault, determining a first section of the short-circuit fault according to a position corresponding to a minimum value of a positive sequence voltage when the positive sequence voltage in the fault steady-state electrical quantity information is not zero or a plurality of corresponding positions when the positive sequence voltage closest to the system side is zero when the positive sequence voltage is zero; and if the short-circuit fault is an asymmetric fault, determining a second section of the short-circuit fault according to the position corresponding to the maximum value of the negative sequence voltage in the fault steady-state electrical quantity information. The invention provides the power distribution network fault section positioning method with better adaptability.

Description

Technical Field

[0001] This application belongs to the technical field related to power generation and power grids, particularly to the technical field of power system distribution network fault data location, and specifically relates to a method and device for locating fault sections in a distribution network based on the distribution of sequence voltage amplitudes. Background Art

[0002] Currently, Feeder Automation (FA) can greatly assist in shortening the fault power outage time and improving power supply reliability. When a fault occurs in the distribution network, FA can determine the fault section based on the fault information fed back by the terminal, control the opening and closing of line switches automatically or manually to isolate the fault section, and combine the distribution line topology and fault recovery algorithm to complete the power supply restoration work for the non-fault area. The commonly used current fault section location methods mainly analyze the fault information uploaded by Feeder Terminal Units (FTUs) to achieve fault isolation and power supply restoration. The location methods above have a relatively high fault tolerance, but there are problems such as large computational redundancy and complex model construction. Specifically, for the location method using correlation coefficients, when the fault current is weak, the difference in correlation coefficients on both sides of the fault point is small, and misjudgment is likely to occur; the matrix location algorithm uses local fault signals to locate the fault section, but it is easily invalidated in the case of distorted fault information; the fault location method using transient signals can detect instantaneous faults and has high sensitivity, but the effectiveness and accuracy of its location depend on the ability of the measurement device to obtain transient information. Summary of the Invention

[0003] The distribution network fault section location method based on the distribution of sequence voltage amplitudes provided by the present invention aims to provide a distribution network fault section location method with better adaptability in a distribution network with T-connected distributed power sources.

[0004] Another object of the present invention is to provide an audit device for system change operations. Still another object of the present invention is to provide an electronic device, which includes a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, the steps of the above-mentioned audit method for system change operations are implemented. Still another object of the present invention is to provide a readable medium, on which a computer program is stored, and when the computer program is executed by the processor, the steps of the above-mentioned audit method for system change operations are implemented.

[0005] In a first aspect, the present invention provides a distribution network fault section location method based on the distribution of sequence voltage amplitudes, and the method includes: Receiving the fault steady-state electrical quantity information uploaded by the terminal in the distribution network in response to a short-circuit fault occurring in the distribution network; If the short - circuit fault is a symmetrical fault, determine the first section of the short - circuit fault according to the position corresponding to the minimum value of the positive - sequence voltage when the positive - sequence voltage in the fault steady - state electrical quantity information becomes non - zero, or the position corresponding to the positive - sequence voltage closest to the system side when there are multiple zero positive - sequence voltages; If the short - circuit fault is an asymmetrical fault, determine the second section of the short - circuit fault according to the position corresponding to the maximum value of the negative - sequence voltage in the fault steady - state electrical quantity information; Further determine the section to which the short - circuit fault belongs in the first section according to whether there is a main - line protection in the first section, the positive - sequence voltages at both ends of the first section, and the impedance; Further determine the section to which the short - circuit fault belongs in the second section according to whether there is a main - line protection in the second section, the negative - sequence voltages at both ends of the second section, and the impedance.

[0006] In some embodiments of the present application, the first section includes a third section and a fourth section; if the short - circuit fault is a symmetrical fault, determining the first section of the short - circuit fault according to the position corresponding to the minimum value of the positive - sequence voltage when the positive - sequence voltage in the fault steady - state electrical quantity information becomes non - zero, or the position corresponding to the positive - sequence voltage closest to the system side when there are multiple zero positive - sequence voltages, includes: Determine the third section and the fourth section respectively on both sides of the position corresponding to the minimum value of the positive - sequence voltage when the positive - sequence voltage becomes non - zero, or on both sides of the position where the positive - sequence voltage becomes zero corresponding to the position where the positive - sequence voltage closest to the system side is zero.

[0007] In some embodiments of the present application, further determining the section to which the short - circuit fault belongs in the first section according to whether there is a main - line protection in the first section, the positive - sequence voltages at both ends of the first section, and the impedance, includes: If there is the main - line protection in the first section, determine the section of the short - circuit fault according to the difference between the positive - sequence voltages at both ends of any one of the third section and the fourth section, the impedance, and the positive - sequence current measured by the main - line protection; If there is no main - line protection in the first section, determine the section of the short - circuit fault according to the difference between the positive - sequence voltages at both ends of any one of the third section and the fourth section, the impedance, the positive - sequence current measured by the main - line protection of the upper - level circuit where the first section is located in the distribution network, and the positive - sequence currents of all branches of the upper - level circuit.

[0008] In some embodiments of the present application, the second section includes a fifth section and a sixth section; if the short - circuit fault is an asymmetric fault, determining the second section of the short - circuit fault according to the position corresponding to the maximum value of the negative - sequence voltage in the fault steady - state electrical quantity information includes: Determine the fifth section and the sixth section respectively on both sides of the position corresponding to the maximum value of the negative - sequence voltage.

[0009] In some embodiments of the present application, further determining the section to which the short - circuit fault belongs in the second section according to whether there is a main - line protection in the second section, the negative - sequence voltages at both ends of the second section, and the impedance includes: If there is the main - line protection in the second section, determine the section of the short - circuit fault according to the difference between the negative - sequence voltages at both ends of any one of the fifth section and the sixth section, the impedance, and the negative - sequence current measured by the main - line protection; If there is no main - line protection in the second section, determine the section of the short - circuit fault according to the difference between the negative - sequence voltages at both ends of any one of the fifth section and the sixth section, the impedance, the negative - sequence current measured by the main - line protection of the upper - level circuit where the second section is located in the distribution network, and the negative - sequence currents of all branches of the upper - level circuit.

[0010] In some embodiments of the present application, the time of the fault steady - state electrical quantity is from 20 ms to 150 ms after the short - circuit fault occurs.

[0011] In a second aspect, the present invention provides a device for locating a fault section in a distribution network based on the distribution of sequence - voltage amplitudes. The device includes: A fault - information receiving module, configured to receive the fault steady - state electrical quantity information uploaded by a terminal in the distribution network in response to a short - circuit fault occurring in the distribution network; A first - section determination module, configured to, if the short - circuit fault is a symmetric fault, determine the first section of the short - circuit fault according to the position corresponding to the minimum value of the positive - sequence voltage when the positive - sequence voltage becomes non - zero in the fault steady - state electrical quantity information or the position corresponding to the positive - sequence voltage closest to the system side when there are multiple zero positive - sequence voltages; A second - section determination module, configured to, if the short - circuit fault is an asymmetric fault, determine the second section of the short - circuit fault according to the position corresponding to the maximum value of the negative - sequence voltage in the fault steady - state electrical quantity information; A section - belonging determination first module, configured to further determine the section to which the short - circuit fault belongs in the first section according to whether there is a main - line protection in the first section, the positive - sequence voltages at both ends of the first section, and the impedance; The section determination second module is used to further determine the section to which the short - circuit fault belongs in the second section according to whether there is a main - line protection in the second section, the negative - sequence voltages at both ends of the second section, and the impedance in the second section.

[0012] In some embodiments of the present application, the first section includes a third section and a fourth section; the first - section determination module includes: The first - section determination unit is used to determine the third section and the fourth section respectively on both sides of the position corresponding to the minimum value of the positive - sequence voltage when the positive - sequence voltage becomes non - zero or on both sides of the position corresponding to the change of the positive - sequence voltage to zero at the position corresponding to the zero positive - sequence voltage closest to the system side.

[0013] In some embodiments of the present application, the section determination first module includes: The section determination first unit is used to, if there is the main - line protection in the first section, determine the section of the short - circuit fault according to the difference between the positive - sequence voltages at both ends of any one of the third section and the fourth section, the impedance, and the positive - sequence current measured by the main - line protection. The section determination second unit is used to, if there is no main - line protection in the first section, determine the section of the short - circuit fault according to the difference between the positive - sequence voltages at both ends of any one of the third section and the fourth section, the impedance, the positive - sequence current measured by the main - line protection of the upper - level circuit where the first section is located in the distribution network, and the positive - sequence currents of all branches of the upper - level circuit.

[0014] In some embodiments of the present application, the second section includes a fifth section and a sixth section; the second - section determination module includes: The second - section determination unit is used to determine the fifth section and the sixth section respectively on both sides of the position corresponding to the maximum value of the negative - sequence voltage.

[0015] In some embodiments of the present application, the section determination second module includes: The section determination third unit is used to, if there is the main - line protection in the second section, determine the section of the short - circuit fault according to the difference between the negative - sequence voltages at both ends of any one of the fifth section and the sixth section, the impedance, and the negative - sequence current measured by the main - line protection. The section determination fourth unit is used to, if there is no main - line protection in the second section, determine the section of the short - circuit fault according to the difference between the negative - sequence voltages at both ends of any one of the fifth section and the sixth section, the impedance, the negative - sequence current measured by the main - line protection of the upper - level circuit where the second section is located in the distribution network, and the negative - sequence currents of all branches of the upper - level circuit.

[0016] In some embodiments of the present application, the time to which the fault steady-state electrical quantity belongs is 20ms to 150ms after the short-circuit fault occurs.

[0017] In a third aspect, the present invention provides a computer program product, comprising a computer program / instruction, which, when executed by a processor, implements the steps of a method for locating a fault section of a distribution network based on sequence voltage amplitude distribution.

[0018] In a fourth aspect, the present invention provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the program, the processor implements the steps of a method for locating a fault section of a distribution network based on sequence voltage amplitude distribution.

[0019] In a fifth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of a method for locating a fault section of a distribution network based on sequence voltage amplitude distribution.

[0020] As can be seen from the above description, an embodiment of the present invention provides a method and device for locating a distribution network fault section based on sequence voltage amplitude distribution. The corresponding distribution network fault section locating method based on sequence voltage amplitude distribution includes: first, receiving fault steady-state electrical quantity information uploaded by a terminal in the distribution network in response to a short-circuit fault in the distribution network; if the short-circuit fault is a symmetrical fault, determining the first section of the short-circuit fault according to the position corresponding to the minimum value of the positive sequence voltage when the positive sequence voltage in the fault steady-state electrical quantity information is not zero or the position corresponding to the positive sequence voltage when the positive sequence voltage closest to the system side is zero when there are multiple positive sequence voltages that are zero, wherein the system side is the side connected to the high-voltage power grid; if the short-circuit fault is an asymmetrical fault, determining the second section of the short-circuit fault according to the position corresponding to the maximum value of the negative sequence voltage in the fault steady-state electrical quantity information; then, further determining the section to which the short-circuit fault belongs in the first section according to whether there is trunk line protection in the first section, the positive sequence voltage at both ends of the first section, and the impedance; finally, further determining the section to which the short-circuit fault belongs in the second section according to whether there is trunk line protection in the second section, the negative sequence voltage at both ends of the second section, and the impedance. Compared with the prior art, the present invention can produce the following positive effects: First, the sequence voltage amplitude information measured by the low-voltage substation fusion terminal is converted to reflect the sequence voltage amplitude on the main grid side with the low-voltage substation amplitude information, which can reduce the requirements for data synchronization and realize the location of fault sections at the substation level.

[0021] Second, the distribution law of the positive and negative sequence voltage amplitudes proposed in the present invention becomes more obvious with the increase of the IIDG access capacity, and therefore has good application prospects in distribution networks containing a high proportion of distributed power sources.

[0022] Thirdly, the principle of the fault section location method proposed by the present invention is simple. It only needs to add modules for locally calculating positive and negative sequence currents and voltages at the terminal, without additional communication costs and equipment installation costs, and is easy to implement in engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0024] Figure 1 It is a schematic flow chart of a method for locating a fault section in a distribution network based on the distribution of sequence voltage amplitudes in an embodiment of the present invention.

[0025] Figure 2 It is a schematic flow chart of step 400 of a method for locating a fault section in a distribution network based on the distribution of sequence voltage amplitudes in an embodiment of the present invention.

[0026] Figure 3 It is a schematic flow chart of step 500 of a method for locating a fault section in a distribution network based on the distribution of sequence voltage amplitudes in an embodiment of the present invention.

[0027] Figure 4 It is a schematic flow chart of a method for locating a fault section in a distribution network based on the distribution of sequence voltage amplitudes in a specific embodiment of the present invention.

[0028] Figure 5 It is a mind map of a method for locating a fault section in a distribution network based on the distribution of sequence voltage amplitudes in a specific embodiment of the present invention.

[0029] Figure 6 It is a schematic diagram of a simple distribution network with IIDG in a specific embodiment of the present invention.

[0030] Figure 7 It is a wiring diagram of a transformer with a YN, d11 connection method in a specific embodiment of the present invention.

[0031] Figure 8 In a specific embodiment of the present invention f equivalent circuit diagram when a symmetrical fault occurs at a point.

[0032] Figure 9 In a specific embodiment of the present invention f negative sequence network diagram when a BC two-phase interphase short circuit occurs at a point.

[0033] Figure 10Schematic diagram of positive sequence voltage amplitude distribution in the specific embodiment of the present invention.

[0034] Figure 11 Schematic diagram of negative sequence voltage amplitude distribution in the specific embodiment of the present invention.

[0035] Figure 12 Block diagram of a distribution network fault section location device based on sequence voltage amplitude distribution in the embodiment of the present invention.

[0036] Figure 13 Block diagram of the first module 40 for determining the section to which it belongs in the embodiment of the present invention.

[0037] Figure 14 Block diagram of the second module 50 for determining the section to which it belongs in the embodiment of the present invention.

[0038] Figure 15 Schematic diagram of the structure of an electronic device in the embodiment of the present invention. Specific embodiment

[0039] To make the objectives, 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 with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0040] Those skilled in the art should understand that the embodiments of the present invention may be provided as a method, a system, or a computer program product. Therefore, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0041] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned drawings are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices. Without conflict, the embodiments in this application and the features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0042] As the last link in the transmission and distribution of electric energy, the distribution network undertakes the important task of safely and efficiently distributing electric energy to users. The distribution network is large in scale and has many branches, making it more prone to failures. Moreover, the large-scale access of inverter-interfaced distributed generators (IIDGs) also increases the instability of power supply. Therefore, the distribution network needs to ensure higher power supply reliability and power supply quality.

[0043] Based on this, and to solve at least a part of the technical problems in the background art of this application, an embodiment of the present invention provides a specific implementation manner of a distribution network fault section location method based on the sequence voltage amplitude distribution. See Figure 1 , and the method includes: Step 100: Receive the fault steady-state electrical quantity information uploaded by the terminals in the distribution network in response to a short-circuit fault occurring in the distribution network; Step 200: If the short-circuit fault is a symmetrical fault, determine the first section of the short-circuit fault according to the position corresponding to the minimum value of the positive-sequence voltage when the positive-sequence voltage in the fault steady-state electrical quantity information becomes non-zero or the position corresponding to the positive-sequence voltage closest to the system side when there are multiple zero positive-sequence voltages; Step 300: If the short-circuit fault is an asymmetrical fault, determine the second section of the short-circuit fault according to the position corresponding to the maximum value of the negative-sequence voltage in the fault steady-state electrical quantity information; Step 400: Further determine the section to which the short-circuit fault belongs according to whether there is a main line protection in the first section, the positive-sequence voltages at both ends of the first section, and the impedance in the first section; Step 500: Further determine the section to which the short-circuit fault belongs according to whether there is a main line protection in the second section, the negative-sequence voltages at both ends of the second section, and the impedance in the second section.

[0044] As can be seen from the above description, an embodiment of the present invention provides a method for locating a fault section in a distribution network based on the distribution of sequence voltage amplitudes, including: receiving the fault steady-state electrical quantity information uploaded by a terminal in the distribution network in response to a short-circuit fault occurring in the distribution network; if the short-circuit fault is a symmetrical fault, determining the first section of the short-circuit fault according to the position corresponding to the minimum value of the positive-sequence voltage when the positive-sequence voltage in the fault steady-state electrical quantity information is not zero or the position corresponding to the positive-sequence voltage closest to the system side when there are multiple zero positive-sequence voltages, where the system side is the side connected to the high-voltage power grid; if the short-circuit fault is an asymmetrical fault, determining the second section of the short-circuit fault according to the position corresponding to the maximum value of the negative-sequence voltage in the fault steady-state electrical quantity information; then, further determining the section to which the short-circuit fault belongs in the first section according to whether there is a main line protection in the first section, the positive-sequence voltages at both ends of the first section, and the impedance; finally, further determining the section to which the short-circuit fault belongs in the second section according to whether there is a main line protection in the second section, the negative-sequence voltages at both ends of the second section, and the impedance. The present invention fully utilizes the measurement information of FTUs at the main line and branch line and the integrated terminal of the low-voltage substation area to analyze the relationship between the positive-sequence and negative-sequence voltages on both sides of the substation area transformer and the distribution law of the positive-sequence and negative-sequence voltage amplitudes of the distribution line, and proposes a method for finding the position corresponding to the minimum value of the positive-sequence voltage when the positive-sequence voltage is not zero or the position corresponding to the positive-sequence voltage closest to the system side when there are multiple zero positive-sequence voltages, and the position point with the maximum negative-sequence voltage amplitude to determine the fault section, which has good adaptability in a distribution network containing multiple T-connected distributed power sources.

[0045] In step 100, the fault steady-state electrical quantity information includes positive-sequence voltage and negative-sequence voltage. Considering the influence of the IIDG control strategy, the fault transient time is generally within 20 ms, while the main line protection operation time is above 150 ms. Therefore, the time to which the fault steady-state electrical quantity belongs is from 20 ms to 150 ms after the short-circuit fault occurs.

[0046] Furthermore, to fully utilize the electrical quantity distribution law in the fault steady state to achieve substation area-level fault section location and be unaffected by the synchronization of information uploaded by each terminal, each terminal needs to upload the fault steady-state electrical quantity information. The positive-sequence voltage, negative-sequence voltage, and other electrical quantity values within 20 ms, 30 ms, 40 ms, etc. after the fault occurs can be calculated according to different data windows, and whether the different values reach the stable value can be compared. The average value of multiple steady-state values can be used as the final uploaded electrical quantity steady-state value information.

[0047] For steps 200 and 300, the method for determining whether the short-circuit fault is a symmetrical fault includes: if the corresponding distribution terminals upload short-circuit faults of phases A, B, and C respectively, it can be considered that the system has a symmetrical short-circuit fault; otherwise, it is an asymmetrical short-circuit fault.

[0048] In addition, the first section in step 200 and the second section in step 300 are for the preliminary judgment of the section where the short-circuit fault occurs, while steps 400 and 500 are for further accurate judgment of the section where the short-circuit fault occurs within the preliminarily judged section.

[0049] It should be noted that the system side in step 200 refers to the side connected to the high-voltage power grid or the side connected to the main power supply of the distribution network, that is, the main network side.

[0050] In some embodiments of the present invention, the first section includes a third section and a fourth section; for step 200, specifically, when a symmetrical fault occurs in the distribution network line, first judge the changing trend of the positive-sequence voltage. If there is no distributed power source connected, starting from the busbar, check that the positive-sequence voltage changes slowly from high to low. After the positive-sequence voltage reaches 0, the positive-sequence voltage uploaded by the subsequent terminals will basically remain unchanged or decrease slowly. At this time, the positions on both sides corresponding to the position of the measuring device closest to the system side when multiple positive-sequence voltages become zero are the third section and the fourth section respectively.

[0051] In another case, if there is a distributed power source connected to the system, starting from the busbar, check that the positive-sequence voltage changes slowly from high to low. After the positive-sequence voltage reaches 0, the positive-sequence voltage may rise at the photovoltaic grid connection point. Find the position corresponding to the measuring device with the minimum positive-sequence voltage (or when there are multiple minimum values with approximately the same magnitude, take the first minimum value as the standard), so as to find two suspected fault intervals (the third section and the fourth section), which are distributed at the positions on both sides corresponding to the position of the measuring device with the minimum positive-sequence voltage.

[0052] In some embodiments of the present invention, see Figure 2 , step 400 includes: Step 401: If the main line protection exists in the first section, determine the section of the short-circuit fault according to the difference in positive-sequence voltage, impedance at both ends of any one of the third section and the fourth section, and the positive-sequence current measured by the main line protection; For the two suspected fault intervals (the third section and the fourth section) judged in step 200, it is necessary to further determine the minimum fault interval. To further realize the fault location between branches or between substations under asynchronous information, classification and discussion are carried out according to whether two adjacent sections contain main line protection: For a symmetrical fault, classify and discuss whether the two adjacent sections on both sides of the position corresponding to the measuring device with the minimum positive-sequence voltage when the positive-sequence voltage is not zero or the position corresponding to the measuring device closest to the system side when multiple positive-sequence voltages become zero contain the main line protection. If both of the two adjacent sections contain the main line protection, at this time, if the ratio of the difference between the positive-sequence voltages at both ends of the current section to the impedance of this section is equal to the positive-sequence current measured by the main line protection, the fault is located in the other section; otherwise, the current section is the fault section.

[0053] Step 402: If the main line protection does not exist in the first section, determine the section of the short-circuit fault according to the difference between the positive-sequence voltages at both ends of any one of the third section and the fourth section, the impedance, the positive-sequence current measured by the main line protection of the upper-level circuit where the first section is located in the distribution network, and the positive-sequence currents of all branches of the upper-level circuit.

[0054] If neither of the two adjacent sections contains the main line protection, add the positive-sequence current values of each branch in the current section as the positive-sequence measured current on the main line of this section. If the ratio of the difference between the positive-sequence voltages at both ends of the current section to the impedance of this section is equal to the sum of the positive-sequence current measured by the upper-level main protection of the current section and the positive-sequence current values of all branches within the range from the upper-level main protection to the section, the fault is located in the other section; otherwise, the current section is the fault section.

[0055] In some embodiments of the present invention, the second section includes a fifth section and a sixth section; Step 300 includes: determining the fifth section and the sixth section respectively on both sides of the position corresponding to the maximum negative-sequence voltage.

[0056] Specifically, when an asymmetrical fault occurs in the line of the distribution network, judge the change trend of the negative-sequence voltage. Start from the bus and check that the negative-sequence voltage changes slowly from low to high, and then changes slowly from high to low after reaching the peak value. Find the maximum value of the negative-sequence voltage (or when there are multiple maximum values with approximately the same magnitude, take the first maximum value as the maximum value), so as to find two suspected fault intervals (the fifth section and the sixth section), which are distributed at the positions corresponding to both sides of the maximum negative-sequence voltage.

[0057] In some embodiments of the present invention, referring to Figure 3 , Step 500 includes: Step 501: If the main line protection exists in the second section, determine the section of the short-circuit fault according to the difference between the negative-sequence voltages at both ends of any one of the fifth section and the sixth section, the impedance, and the negative-sequence current measured by the main line protection. For the two suspicious fault intervals (the fifth section and the sixth section) determined in step 300, it is necessary to further determine the minimum fault interval. To further achieve fault location between sections of branches or between substations under asynchronous information, classification and discussion are carried out according to whether the two adjacent sections contain main line protection: For an asymmetrical fault, for a suspicious section with main line protection, if the ratio of the difference in negative sequence voltage at both ends of the current section to the impedance of the current section is equal to the negative sequence current measured by the main line protection, the fault is located in another section; otherwise, this section is the fault section. Step 502: If the main line protection does not exist in the second section, determine the section of the short - circuit fault according to the difference in negative sequence voltage, impedance at both ends of any one of the fifth section and the sixth section, the negative sequence current measured by the main line protection of the upper - level circuit where the second section is located in the distribution network, and the negative sequence currents of all branches of the upper - level circuit.

[0058] If neither of the two adjacent sections contains main line protection, add the negative sequence current measured by the main protection of the upper - level of the current section to the sum of the negative sequence current values of all branches within the range from the upper - level main protection to the section as the negative sequence measurement current on the main line of the current section. If the ratio of the difference in negative sequence voltage at both ends of the current section to the impedance of the current section is equal to the sum of the negative sequence current measured by the main protection of the upper - level of the current section and the negative sequence current values of all branches within the range from the upper - level main protection to the section, the fault is located in another section; otherwise, this section is the fault section.

[0059] In some embodiments of the present invention, the time of the fault steady - state electrical quantity is from 20 ms to 150 ms after the occurrence of the short - circuit fault.

[0060] As can be seen from the above description, to achieve fault section location at the substation level in an active distribution network, the present invention makes full use of the measurement information of FTUs at the main line and branch lines and the integrated terminal of the low - voltage substation area, analyzes the relationship between the positive - sequence and negative - sequence voltages on both sides of the substation transformer and the distribution law of the positive - sequence and negative - sequence voltage amplitudes of the distribution line, and proposes a method to determine the fault section by finding the position point with zero positive - sequence voltage amplitude and the maximum negative - sequence voltage amplitude, which has good adaptability in a distribution network with multiple T - connected distributed power sources.

[0061] To further illustrate the solution, see Figure 4 and Figure 5 , the specific implementation manner of a distribution network fault section location method based on the distribution of sequence voltage amplitudes provided by the present invention includes the following steps: The purpose of the present invention is to make full use of the measurement information of FTUs at the main line and branch lines and the integrated terminal of the low - voltage substation area, and provide a method for locating fault sections at the substation level that can adapt to the access of distributed power sources through the distribution law of positive - sequence and negative - sequence voltage amplitudes of the distribution line.

[0062] S1: When a short - circuit fault occurs in the distribution line, the terminal is started by setting the sudden change values of current and voltage.

[0063] When a short - circuit fault occurs in the distribution line, the terminal in the distribution network is started by setting the sudden change values of current and voltage. The sudden change starting values can be based on the common fixed values used for the start of the fault recorder (the sudden change value of voltage can be taken as 0.05 U N or 0.1 I N , and the sudden change value of current can be taken as 0.1 I N or 0.2 I N , and it can be further determined according to the actual engineering experience of the manufacturer). Among them, the sudden change starting fixed value of voltage can also be set according to the allowable change range of normal voltage, etc. (for example, if the normal voltage change range is 0.88 pu~1.1 pu, then the sudden change value of voltage can be taken as 0.15 U N ).

[0064] Specifically, here, taking the example shown in Figure 6 (A~I are the measuring points of the positive - sequence voltage amplitude) to elaborate on the technical solutions of steps S1 to S4 in detail. First, after each terminal is started by the set sudden change values of current and voltage, it uploads the steady - state positive - and negative - sequence voltage amplitude information and determines whether the fault is symmetrical. For the integrated terminal in the low - voltage area, due to the connection of the area transformer, it is necessary to convert the positive - and negative - sequence voltage amplitudes measured by the integrated terminal in the low - voltage area. The area transformer is in the YN, d11 connection mode, as shown in Figure 7 ( Figure 7 In it, the variables with capital - letter subscripts are the components on the YN side, and the variables with lowercase - letter subscripts are the components on the d11 side. Therefore, , and are used to represent the phase voltages of the YN - side winding respectively, and , and are used to represent the line voltages of the YN side respectively; , and are used to represent the phase voltages of the d11 - side winding respectively, , and are used to represent the line voltages of the d11 side respectively, , and are used to represent the phase - to - ground voltages of the d11 side respectively. Let the transformation ratio between the YN side and the d side of the transformer be n , that is, the ratio of the line - voltage amplitudes of the two - side windings isn , the ratio of the phase voltage amplitudes is . The two windings are both headed by the same polarity, and are in the same phase, and are in opposite phases.). The positive and negative sequence voltage amplitudes are converted according to the following formula:

[0065] In the formula, the subscripts (1) and (2) represent the positive sequence and negative sequence components respectively, and the same applies hereinafter.

[0066] S2: Receive the processed fault steady-state electrical quantity information uploaded by each terminal and judge whether the fault is symmetrical.

[0067] Considering the influence of the IIDG control strategy, its fault transient time is usually within 20 ms, while the main line protection operation time is above 150 ms. Therefore, in order to make full use of the distribution law of electrical quantities in the fault steady state to realize the fault section location at the substation area level and not be affected by the synchronization of the information uploaded by each terminal, each terminal needs to upload the fault steady-state electrical quantity information, and the positive sequence voltage, negative sequence voltage and other electrical quantity values within 20 ms, 30 ms, 40 ms, etc. after the fault can be calculated according to different data windows, and whether the different values reach the stable value can be compared. The average value of multiple steady-state values can be used as the final uploaded electrical quantity steady-state value information. If the A, B, and C phase short-circuit faults are uploaded by the corresponding distribution terminals respectively, it can be considered that the system has a symmetrical short-circuit fault, otherwise it is an asymmetrical short-circuit fault.

[0068] The low-voltage substation area integrated terminal uploads the processed information to the feeder automation master station. The master station comprehensively discriminates the positive and negative sequence voltage amplitude information uploaded by the FTU and the low-voltage substation area integrated terminal to determine the fault section. If the A, B, and C phase short-circuit faults are uploaded by the terminals respectively, it can be considered that the system has a symmetrical short-circuit fault, otherwise it is an asymmetrical short-circuit fault.

[0069] Secondly, after obtaining the sequence voltage amplitude information of each FTU and the integrated terminal converted to the main network side, the master station locates the fault section in combination with the positive and negative sequence voltage distribution laws. The equivalent impedance of the system load is relatively large and is generally ignored and treated as an equivalent open circuit.

[0070] S3: The master station uses the positive and negative sequence voltage distribution laws uploaded by each terminal to achieve more accurate fault section location at the substation area level.

[0071] (a)When a symmetrical fault occurs on the line, judge the changing trend of the positive-sequence voltage. If there is no distributed power source connected, starting from the busbar, check that the positive-sequence voltage changes slowly from high to low. After the positive-sequence voltage becomes 0, the positive-sequence voltage uploaded by the subsequent terminals will basically remain unchanged or decrease slowly. If there is a distributed power source connected to the system, on the basis of the above positive-sequence voltage change, the positive-sequence voltage may rise at the PV grid connection point. Locate the position corresponding to the measuring device with the minimum positive-sequence voltage when all positive-sequence voltages are not zero, or the position corresponding to the measuring device closest to the system side when there are multiple positive-sequence voltages becoming zero, and find two suspected fault intervals, which are respectively distributed on both sides of the position corresponding to the measuring device with the minimum positive-sequence voltage when all positive-sequence voltages are not zero, or the position corresponding to the measuring device closest to the system side when there are multiple positive-sequence voltages becoming zero.

[0072] When a symmetrical fault occurs on the line, the equivalent circuit diagram is as Figure 8 shown ( Figure 8 in is the equivalent electromotive force of the system, Z s is the equivalent impedance of the system, , , are the grid connection point voltages of three DGs respectively, Z AB , Z BC , Z CD , Z DE , Z Ef , Z fF , Z FG , Z GH , Z HI are the impedances of each line segment).

[0073] (1)The positive-sequence voltage at the measurement point on the left side of the fault point f is:

[0074] In the formula, . Taking the comparison of , as an example, subtracting the two gives:

[0075] And the equivalent electromotive force of the system is:

[0076] Wherein, is the current of the system power supply branch, so it can be obtained that:

[0077] Therefore, it can be obtained that the f amplitude of the positive-sequence voltage on the left side of the fault point decreases as it approaches the fault point.

[0078] (2) The positive-sequence voltage at the measurement point on the right side of the fault point f is:

[0079] It can be obtained that the f amplitude of the positive-sequence voltage on the right side of the fault point increases as it moves away from the fault point.

[0080] In summary, the schematic diagram of the variation law of the positive-sequence voltage amplitude is as shown in Figure 9 (the subscript (2) represents the negative-sequence component, is the negative-sequence fault voltage). The position point with the minimum positive-sequence voltage amplitude is F. Therefore, the fault occurs in one of the EF and FG sections adjacent to point F.

[0081] (b) When an asymmetrical fault occurs on the line, judge the variation trend of the negative-sequence voltage. Starting from the busbar, check that the negative-sequence voltage changes slowly from low to high, and then changes slowly from high to low after reaching the peak value. Find the maximum value of the negative-sequence voltage (or when there are multiple maximum values with approximately the same magnitude, take the first maximum value as the maximum value), and find two suspected fault intervals, which are respectively located on both sides of the maximum value of the negative-sequence voltage.

[0082] When an asymmetrical fault occurs on the line, the negative-sequence network diagram is as shown in Figure 10 shown.

[0083] (1) The negative-sequence voltage at the measurement point on the left side of the fault point f is:

[0084]

[0085] Therefore, it can be obtained that the f amplitude of the negative-sequence voltage on the left side of the fault point increases as it approaches the fault point.

[0086] (2) The negative-sequence voltage at the measurement point on the right side of the fault point f is:

[0087] It can be obtained that the amplitude of the negative-sequence voltage on the right side of the fault point f decreases as it moves away from the fault point.

[0088] In summary, the variation law of the negative-sequence voltage amplitude is as shown in the appendixFigure 11 As shown, the position point with the minimum negative-sequence voltage amplitude is F. Therefore, the fault occurs in one of the adjacent EF and FG sections of point F.

[0089] S4: For the two suspected fault intervals determined in step S3, further determine the minimum fault interval.

[0090] To further achieve fault location for the sections between branches or between substations under asynchronous information, classification discussions are carried out according to whether the two adjacent sections contain main line protection: For asymmetrical faults, for the suspected section containing main line protection, if the ratio of the difference in negative-sequence voltages at both ends of the section to the impedance of the section is equal to the negative-sequence current measured by the main line protection, the fault is located in the other section; otherwise, this section is the fault section. If neither of the two adjacent sections contains main line protection, the sum of the negative-sequence current measured by the upper-level main protection within a certain section and the negative-sequence currents of all branches within the range from the upper-level main protection to the section is used as the negative-sequence measured current on the main line of this section, and then the analysis is still carried out as described above to finally determine the fault section.

[0091] For symmetrical faults, the above-mentioned classification discussions are still carried out according to whether the two adjacent sections at the position point of the minimum positive-sequence voltage contain main line protection. If both of the two adjacent sections contain main line protection, if the ratio of the difference in positive-sequence voltages at both ends of the section to the impedance of the section is equal to the positive-sequence current measured by the main line protection, the fault is located in the other section; otherwise, this section is the fault section. If neither of the two adjacent sections contains main line protection, the sum of the positive-sequence current measured by the upper-level main protection within a certain section and the positive-sequence currents of all branches within the range from the upper-level main protection to the section is used as the positive-sequence measured current on the main line of this section, and then the analysis is still carried out as described above to finally determine the fault section.

[0092] Specifically, calculate whether the ratio of the difference in sequence voltages between the two terminals within a certain section to the impedance of the section is equal to the sequence current of this section to further determine the fault section. When a symmetrical fault occurs on the line, for the FG section with main protection, the ratio of the difference in positive-sequence voltages at both ends of the FG section to the impedance of the section is equal to the positive-sequence current measured by the main line protection. Therefore, the fault is located in the EF section. When an asymmetrical fault occurs on the line, for the FG section with main protection, the ratio of the difference in negative-sequence voltages at both ends of the FG section to the impedance of the section is equal to the negative-sequence current measured by the main line protection. Therefore, the fault is located in the EF section.

[0093] Based on the same inventive concept, an embodiment of the present application further provides a distribution network fault section location device based on the sequence voltage amplitude distribution, which can be used to implement the method described in the above embodiment, such as the following embodiment. Since the principle of the distribution network fault section location device based on the sequence voltage amplitude distribution for solving problems is similar to that of the distribution network fault section location method based on the sequence voltage amplitude distribution, the implementation of the distribution network fault section location device based on the sequence voltage amplitude distribution can refer to the implementation of the distribution network fault section location method based on the sequence voltage amplitude distribution, and the repeated parts will not be elaborated. As used hereinafter, the term "unit" or "module" can be a combination of software and / or hardware that can achieve a predetermined function. Although the systems described in the following embodiments are preferably implemented in software, implementation in hardware, or a combination of software and hardware is also possible and contemplated.

[0094] An embodiment of the present invention provides a specific implementation manner of a distribution network fault section location device based on the sequence voltage amplitude distribution that can implement the distribution network fault section location method based on the sequence voltage amplitude distribution, see Figure 12 , a distribution network fault section location device based on the sequence voltage amplitude distribution specifically includes the following content: A fault information receiving module 10, configured to receive the fault steady-state electrical quantity information uploaded by the terminals in the distribution network in response to a short-circuit fault occurring in the distribution network; A first section determination module 20, configured to, if the short-circuit fault is a symmetrical fault, determine the first section of the short-circuit fault according to the position corresponding to the minimum value of the positive sequence voltage when the positive sequence voltage in the fault steady-state electrical quantity information becomes non-zero or the position corresponding to the positive sequence voltage closest to the system side when there are multiple zero positive sequence voltages; A second section determination module 30, configured to, if the short-circuit fault is an asymmetrical fault, determine the second section of the short-circuit fault according to the position corresponding to the maximum value of the negative sequence voltage in the fault steady-state electrical quantity information; A belonging section determination first module 40, configured to further determine the belonging section of the short-circuit fault according to whether there is a main line protection in the first section, the positive sequence voltages at both ends of the first section, and the impedance in the first section; A belonging section determination second module 50, configured to further determine the belonging section of the short-circuit fault according to whether there is a main line protection in the second section, the negative sequence voltages at both ends of the second section, and the impedance in the second section.

[0095] In some embodiments of the present application, the first section includes a third section and a fourth section; the first section determination module includes: The first section determination unit is configured to determine the third section and the fourth section respectively on both sides of the position corresponding to the minimum value of the positive-sequence voltage when the positive-sequence voltage becomes non-zero, or on both sides of the position corresponding to the change of the positive-sequence voltage to zero at the position where the positive-sequence voltage closest to the system side is zero.

[0096] In some embodiments of the present application, referring to Figure 13 , the first module 40 for determining the section includes: The first unit 40a for determining the section is configured to, if the main line protection exists in the first section, determine the section of the short-circuit fault according to the difference in positive-sequence voltage, impedance, and the positive-sequence current measured by the main line protection at both ends of any one of the third section and the fourth section; The second unit 40b for determining the section is configured to, if the main line protection does not exist in the first section, determine the section of the short-circuit fault according to the difference in positive-sequence voltage, impedance, the positive-sequence current measured by the main line protection of the upper-level circuit where the first section is located in the distribution network, and the positive-sequence currents of all branches of the upper-level circuit.

[0097] In some embodiments of the present application, the second section includes a fifth section and a sixth section; the second module 50 for determining the section includes: The second section determination unit is configured to determine the fifth section and the sixth section respectively on both sides of the position corresponding to the maximum value of the negative-sequence voltage.

[0098] In some embodiments of the present application, referring to Figure 14 , the second module 50 for determining the section includes: The third unit 50a for determining the section is configured to, if the main line protection exists in the second section, determine the section of the short-circuit fault according to the difference in negative-sequence voltage, impedance, and the negative-sequence current measured by the main line protection at both ends of any one of the fifth section and the sixth section; The fourth unit 50b for determining the section is configured to, if the main line protection does not exist in the second section, determine the section of the short-circuit fault according to the difference in negative-sequence voltage, impedance, the negative-sequence current measured by the main line protection of the upper-level circuit where the second section is located in the distribution network, and the negative-sequence currents of all branches of the upper-level circuit.

[0099] In some embodiments of the present application, the time of the fault steady-state electrical quantity is from 20 ms to 150 ms after the short-circuit fault occurs.

[0100] As can be seen from the above description, an embodiment of the present invention provides a distribution network fault section location device based on the sequence voltage amplitude distribution, including: a fault information receiving module, configured to receive the fault steady-state electrical quantity information uploaded by the terminal in the distribution network in response to a short-circuit fault occurring in the distribution network; a first section determination module, configured to, if the short-circuit fault is a symmetrical fault, determine the first section of the short-circuit fault according to the position corresponding to the minimum value of the positive-sequence voltage when the positive-sequence voltage in the fault steady-state electrical quantity information becomes non-zero or the position corresponding to the positive-sequence voltage when there are multiple zero positive-sequence voltages and the positive-sequence voltage closest to the system side is zero; a second section determination module, configured to, if the short-circuit fault is an asymmetrical fault, determine the second section of the short-circuit fault according to the position corresponding to the maximum value of the negative-sequence voltage in the fault steady-state electrical quantity information; a first section determination module for the belonging section, configured to further determine the belonging section of the short-circuit fault according to whether there is a main line protection in the first section, the positive-sequence voltages at both ends of the first section, and the impedance in the first section; a second section determination module for the belonging section, configured to further determine the belonging section of the short-circuit fault according to whether there is a main line protection in the second section, the negative-sequence voltages at both ends of the second section, and the impedance in the second section. Compared with the prior art, the positive effects that the present invention can produce include the following points: First, the sequence voltage amplitude information measured by the integrated terminal in the low-voltage station area is converted, and the sequence voltage amplitude on the main network side is reflected by the amplitude information in the low-voltage station area, which can reduce the requirement for data synchronization and realize the fault section location at the station area level.

[0101] Second, the positive and negative sequence voltage amplitude distribution laws proposed by the present invention become more obvious as the access capacity of the IIDG increases, so it has good application prospects in distribution networks with a high proportion of distributed power sources.

[0102] Third, the principle of the present invention is simple. Only a module for locally calculating positive and negative sequence currents and voltages needs to be added to the terminal, without additional communication costs and equipment installation costs, and it is easy to implement in engineering.

[0103] An embodiment of the present application also provides a specific implementation manner of an electronic device capable of implementing all steps in the distribution network fault section location method based on the sequence voltage amplitude distribution in the above embodiment. Refer to Figure 15 , and the electronic device specifically includes the following content: A processor 1201, a memory 1202, a communication interface 1203, and a bus 1204; Among them, the processor 1201, the memory 1202, and the communication interface 1203 communicate with each other through the bus 1204; the communication interface 1203 is used to realize information transmission between related devices such as server-side devices and client-side devices; The processor 1201 is used to call the computer program in the memory 1202. When the processor executes the computer program, all steps in the method for locating the fault section of the distribution network based on the sequence voltage amplitude distribution in the above embodiments are implemented. For example, when the processor executes the computer program, the following steps are implemented: Step 100: Receive the fault steady-state electrical quantity information uploaded by the terminal in the distribution network in response to a short-circuit fault occurring in the distribution network; Step 200: If the short-circuit fault is a symmetrical fault, determine the first section of the short-circuit fault according to the position corresponding to the minimum value of the positive-sequence voltage when the positive-sequence voltage in the fault steady-state electrical quantity information becomes non-zero or the position corresponding to the positive-sequence voltage closest to the system side when there are multiple zero positive-sequence voltages; Step 300: If the short-circuit fault is an asymmetrical fault, determine the second section of the short-circuit fault according to the position corresponding to the maximum value of the negative-sequence voltage in the fault steady-state electrical quantity information; Step 400: Further determine the section to which the short-circuit fault belongs in the first section according to whether there is a main line protection in the first section, the positive-sequence voltages at both ends of the first section, and the impedance; Step 500: Further determine the section to which the short-circuit fault belongs in the second section according to whether there is a main line protection in the second section, the negative-sequence voltages at both ends of the second section, and the impedance.

[0104] An embodiment of the present application further provides a computer-readable storage medium capable of implementing all steps in the method for locating the fault section of the distribution network based on the sequence voltage amplitude distribution in the above embodiments. A computer program is stored on the computer-readable storage medium. When the computer program is executed by a processor, all steps in the method for locating the fault section of the distribution network based on the sequence voltage amplitude distribution in the above embodiments are implemented. For example, when the processor executes the computer program, the following steps are implemented: Step 100: Receive the fault steady-state electrical quantity information uploaded by the terminal in the distribution network in response to a short-circuit fault occurring in the distribution network; Step 200: If the short-circuit fault is a symmetrical fault, determine the first section of the short-circuit fault according to the position corresponding to the minimum value of the positive-sequence voltage when the positive-sequence voltage in the fault steady-state electrical quantity information becomes non-zero or the position corresponding to the positive-sequence voltage closest to the system side when there are multiple zero positive-sequence voltages; Step 300: If the short-circuit fault is an asymmetrical fault, determine the second section of the short-circuit fault according to the position corresponding to the maximum value of the negative-sequence voltage in the fault steady-state electrical quantity information; Step 400: Further determine the section to which the short-circuit fault belongs in the first section according to whether there is a main line protection in the first section, the positive-sequence voltages at both ends of the first section, and the impedance; Step 500: Further determine the section to which the short-circuit fault belongs in the second section according to whether there is main line protection in the second section, the negative sequence voltage at both ends of the second section, and the impedance.

[0105] Each embodiment in this specification is described in a progressive manner. For the same or similar parts among the embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. In particular, for the hardware + program type embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can refer to the partial description of the method embodiments.

[0106] The specific embodiments of this specification are described above. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims can be performed in a different order than in the embodiments and still achieve the desired result. Additionally, the processes depicted in the figures do not necessarily require the specific order or sequential order shown to achieve the desired result. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0107] Although this application provides method operation steps such as in the embodiments or flowcharts, based on routine or non-creative labor, there may be more or fewer operation steps. The order of steps listed in the embodiments is only one way among many execution orders of the steps and does not represent the only execution order. When the actual device or client product is executed, it can be executed in the order shown in the embodiments or the figures or in parallel (such as in an environment of parallel processors or multi-threaded processing).

[0108] For convenience of description, when describing the above device, it is divided into various modules according to functions for separate description. Of course, when implementing the embodiments of this specification, the functions of each module can be implemented in the same or multiple software and / or hardware, or the modules implementing the same function can be realized by a combination of multiple sub-modules or sub-units, etc. The device embodiments described above are only illustrative. For example, the division of the units is only a logical function division, and there can be other division methods in actual implementation. For example, 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 displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces. The indirect couplings or communication connections of the devices or units can be in electrical, mechanical or other forms.

[0109] Those skilled in the art also know that in addition to implementing the controller in the form of pure computer-readable program code, it is entirely possible to logically program the method steps so that the controller can be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, embedded microcontrollers, etc. to achieve the same function. Therefore, such a controller can be considered a hardware component, and the devices included therein for implementing various functions can also be regarded as the structures within the hardware component. Or even, the devices for implementing various functions can be regarded as either software modules for implementing the method or structures within the hardware component.

[0110] In a typical configuration, a computing device includes one or more processors (CPUs), an input / output interface, a network interface, and memory.

[0111] Memory may include non-permanent memory in the form of computer-readable media, random access memory (RAM), and / or non-volatile memory such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0112] The embodiments of this specification can be described in the general context of computer-executable instructions executed by a computer, such as program modules. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform specific tasks or implement specific abstract data types. The embodiments of this specification can also be practiced in a distributed computing environment where tasks are performed by remote processing devices connected through a communication network. In a distributed computing environment, program modules can be located in local and remote computer storage media including storage devices.

[0113] Each embodiment in this specification is described in a progressive manner. For the same or similar parts among the embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments. In particular, for system embodiments, since they are basically similar to method embodiments, the description is relatively simple. For related parts, reference can be made to the description of the method embodiments. In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the embodiments of this specification. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0114] The above are only examples of the embodiments of this specification, and are not used to limit the embodiments of this specification. For those skilled in the art, various modifications and variations can be made to the embodiments of this specification. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the embodiments of this specification shall be included within the scope of the claims of the embodiments of this specification.

Claims

1. A method for locating fault sections in a distribution network based on sequence voltage amplitude distribution, characterized in that: include: Receiving fault steady-state electrical quantity information uploaded by a terminal in the distribution network in response to a short circuit fault in the distribution network; If the short-circuit fault is a symmetrical fault, the first section of the short-circuit fault is determined according to the position corresponding to the minimum value of the positive sequence voltage when the positive sequence voltage in the fault steady-state electrical quantity information is not zero or the position corresponding to the positive sequence voltage closest to the system side when there are multiple positive sequence voltages are zero, wherein the system side is the side connected to the high-voltage power grid. If the short-circuit fault is an asymmetric fault, determining the second section of the short-circuit fault according to the position corresponding to the maximum value of the negative sequence voltage in the fault steady-state electrical quantity information; Further determining the section to which the short-circuit fault belongs in the first section according to whether there is trunk line protection in the first section, the positive sequence voltage at both ends of the first section, and the impedance; The section to which the short circuit fault belongs is further determined in the second section according to whether there is main line protection in the second section, the negative sequence voltage at both ends of the second section, and the impedance.

2. The method for locating a fault section of a distribution network according to claim 1, characterized in that: The first section includes a third section and a fourth section; if the short-circuit fault is a symmetrical fault, the first section of the short-circuit fault is determined according to the position corresponding to the minimum value of the positive sequence voltage when the positive sequence voltage in the fault steady-state electrical quantity information becomes non-zero or the position corresponding to the positive sequence voltage closest to the system side when there are multiple positive sequence voltages that are zero, including: The third section and the fourth section are respectively determined on both sides of the position corresponding to the minimum value of the positive sequence voltage when the positive sequence voltage becomes non-zero or on both sides of the position corresponding to the positive sequence voltage closest to the system side is zero.

3. The method for locating a fault section of a distribution network according to claim 2, characterized in that: Further determining in the first section the section to which the short-circuit fault belongs according to whether the first section has trunk line protection, the positive sequence voltage at both ends of the first section, and the impedance includes: If the main line protection exists in the first section, the section of the short circuit fault is determined according to the difference in positive sequence voltages at both ends of any section of the third section and the fourth section, the impedance and the positive sequence current measured by the main line protection; If the main line protection does not exist in the first section, the section of the short-circuit fault is determined based on the difference in positive-sequence voltages at both ends of the third section and any one of the fourth sections, the impedance, the positive-sequence current measured by the main line protection of the upper-level circuit in the distribution network where the first section is located, and the positive-sequence current of all branches of the upper-level circuit.

4. The method for locating a fault section of a distribution network according to claim 1, characterized in that: The second section includes a fifth section and a sixth section; If the short-circuit fault is an asymmetric fault, determining the second section of the short-circuit fault according to the position corresponding to the maximum value of the negative sequence voltage in the fault steady-state electrical quantity information includes: The fifth section and the sixth section are respectively determined on both sides of the position corresponding to the maximum value of the negative sequence voltage.

5. The method for locating a fault section of a distribution network according to claim 4, characterized in that: Further determining in the second section the section to which the short-circuit fault belongs according to whether the second section has trunk line protection, the negative sequence voltage at both ends of the second section, and the impedance includes: If the main line protection exists in the second section, the section of the short circuit fault is determined according to the difference between the negative sequence voltages at both ends of any section of the fifth section and the sixth section, the impedance and the negative sequence current measured by the main line protection; If the main line protection does not exist in the second section, the section of the short-circuit fault is determined based on the difference in negative-sequence voltages at both ends of the fifth section and any one of the sixth sections, the impedance, the negative-sequence current measured by the main line protection of the upper-level circuit in the distribution network where the second section is located, and the negative-sequence current of all branches of the upper-level circuit.

6. The method for locating a fault section of a distribution network according to any one of claims 1 to 5, characterized in that: The time period of the fault steady-state electrical quantity is 20ms to 150ms after the short-circuit fault occurs.

7. A distribution network fault section location device based on sequence voltage amplitude distribution, characterized in that: include: A fault information receiving module, used for receiving fault steady-state electrical quantity information uploaded by a terminal in the distribution network in response to a short circuit fault in the distribution network; A first section judgment module is used to determine the first section of the short-circuit fault according to the position corresponding to the minimum value of the positive sequence voltage when the positive sequence voltage in the fault steady-state electrical quantity information becomes non-zero or the position corresponding to the positive sequence voltage closest to the system side when there are multiple positive sequence voltages that are zero if the short-circuit fault is a symmetrical fault; A second section judgment module, for determining a second section of the short-circuit fault according to a position corresponding to a maximum value of a negative sequence voltage in the fault steady-state electrical quantity information if the short-circuit fault is an asymmetric fault; A first section determination module, used for further determining the section to which the short-circuit fault belongs in the first section according to whether there is trunk line protection in the first section, the positive sequence voltage at both ends of the first section, and the impedance; The second section determination module is used to further determine the section to which the short circuit fault belongs in the second section according to whether there is main line protection in the second section, the negative sequence voltage at both ends of the second section, and the impedance.

8. The device for locating a fault section of a distribution network according to claim 7, characterized in that: The first section includes a third section and a fourth section; the first section determination module includes: The first section judgment unit is used to respectively determine the third section and the fourth section on both sides of the position corresponding to the minimum value of the positive sequence voltage when the positive sequence voltage becomes non-zero or on both sides of the position corresponding to the position when the positive sequence voltage closest to the system side is zero and the positive sequence voltage becomes zero.

9. The device for locating a fault section of a distribution network according to claim 8, characterized in that: The first module for determining the section to which the user belongs includes: a first section determination unit, configured to determine the section of the short-circuit fault according to the difference in positive sequence voltages at both ends of any section of the third section and the fourth section, the impedance, and the positive sequence current measured by the main line protection if the main line protection exists in the first section; The second section judgment unit is used to determine the section of the short-circuit fault if the main line protection does not exist in the first section, based on the difference in positive sequence voltages at both ends of the third section and any one of the fourth sections, the impedance, the positive sequence current measured by the main line protection of the upper-level circuit in the distribution network where the first section is located, and the positive sequence current of all branches of the upper-level circuit.

10. The device for locating a fault section of a distribution network according to claim 7, characterized in that: The second section includes a fifth section and a sixth section; the second section determination module includes: The second section determination unit is used to respectively determine the fifth section and the sixth section on both sides of the position corresponding to the maximum value of the negative sequence voltage.

11. The device for locating a fault section of a distribution network according to claim 10, characterized in that: The second module for determining the section to which the user belongs includes: a third section determination unit, for determining the section of the short-circuit fault according to the difference in negative sequence voltages at both ends of any section of the fifth section and the sixth section, the impedance, and the negative sequence current measured by the main line protection if the main line protection exists in the second section; The fourth section determination unit is used to determine the section of the short-circuit fault if the main line protection does not exist in the second section, based on the difference in negative sequence voltages at both ends of the fifth section and any one of the sixth sections, the impedance, the negative sequence current measured by the main line protection of the upper-level circuit in the distribution network where the second section is located, and the negative sequence current of all branches of the upper-level circuit.

12. The device for locating a fault section of a distribution network according to any one of claims 7 to 11, characterized in that: The time period of the fault steady-state electrical quantity is 20ms to 150ms after the short-circuit fault occurs.

13. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instruction is executed by a processor, the steps of the method for locating a fault section of a distribution network based on sequence voltage amplitude distribution as described in any one of claims 1 to 6 are implemented.

14. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the steps of the method for locating a fault section in a distribution network based on sequence voltage amplitude distribution as described in any one of claims 1 to 6 are implemented.

15. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for locating a fault section of a distribution network based on sequence voltage amplitude distribution as described in any one of claims 1 to 6 are implemented.

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