Transformer terminal unit-based distribution network fault location method and apparatus, device, and medium

Abstract

A transformer terminal unit-based distribution network fault location method and apparatus, a device, and a medium. The method comprises: acquiring a three-phase voltage vector and a three-phase current vector at a low-voltage side of each distribution transformer (S1); on the basis of the three-phase voltage vector and the three-phase current vector at the low-voltage side and a nameplate parameter, determining positive sequence voltage and negative sequence voltage at a distribution transformer high-voltage side (S2); on the basis of the negative sequence voltage at the distribution transformer high-voltage side, determining whether an interphase short-circuit fault occurs (S3); and if an interphase short-circuit fault has occurred, setting zero sequence voltage at the distribution transformer high-voltage side to be zero, and on the basis of the positive sequence voltage and the negative sequence voltage at the distribution transformer high-voltage side, determining a three-phase voltage vector at the distribution transformer high-voltage side (S4); and further determining two phases where the interphase short-circuit fault has occurred (S5) and a section where a fault point of the interphase short-circuit fault is located (S6). The solution does not require a power outage during mounting of a high-voltage sensor, has low cost and high accuracy, and is conducive to greatly reducing the fault repairing duration and enhancing the reliability of power supply.

Description

Distribution network fault location method, device, equipment and medium based on distribution transformer terminal Technical Field

[0001] The present invention relates to the technical field of power system distribution network fault detection, and in particular to a distribution network fault locating method, device, equipment and medium based on a distribution transformer terminal. Background Art

[0002] The power supply lines of the distribution network are complex, passing through mountains and fields, with many branches, harsh operating environment and complex equipment. Especially for the distribution networks in rural and mountainous areas, distribution line failures occur frequently, requiring operation and maintenance personnel to spend a lot of time, manpower and material costs to patrol the lines to find the fault location and repair the fault, which seriously affects the power supply reliability.

[0003] The technical means currently used mainly include using distribution automation switches and fault indicators to determine the fault section, and using traveling wave positioning devices to determine the fault location. Such technical means require the installation of voltage and current sensors on the primary side of the distribution network, which increases the investment cost of the power grid and the workload of operation and maintenance.

[0004] Summary of the Invention

[0005] Based on this, it is necessary to propose a distribution network fault location method, device, equipment and medium based on distribution transformer terminals to address the above problems.

[0006] To achieve the above objectives, the present application provides, in a first aspect, a distribution network fault location method based on a distribution transformer terminal, the method comprising:

[0007] Obtain the three-phase voltage vector and three-phase current vector of the monitoring terminal arranged on the low-voltage side of each distribution transformer in the distribution network system;

[0008] Determine the positive sequence voltage and negative sequence voltage of the high voltage side of each distribution transformer according to the three-phase voltage vector and the three-phase current vector of the monitoring terminal arranged on the low voltage side of each distribution transformer and the nameplate parameters of each distribution transformer;

[0009] Determining the occurrence of an interphase short circuit fault in the distribution network system according to the negative sequence voltage on the high-voltage side of each distribution transformer;

[0010] If an interphase short circuit fault occurs in the distribution network system, the zero-sequence voltage on the high-voltage side of each distribution transformer is set to zero, and the three-phase voltage vector on the high-voltage side of each distribution transformer is determined according to the positive-sequence voltage and the negative-sequence voltage on the high-voltage side of each distribution transformer;

[0011] Determining two phases in the distribution network system where interphase short circuit faults occur based on the three-phase voltage vectors on the high-voltage side of each distribution transformer;

[0012] According to the phase voltages of the two phases where the interphase short circuit fault occurs in the distribution network system, it is determined between which two distribution transformers the fault point where the interphase short circuit fault occurs in the distribution network system is located.

[0013] In some embodiments, in determining the positive-sequence voltage on the high-voltage side and the negative-sequence voltage on the high-voltage side of each distribution transformer according to the three-phase voltage vector, the three-phase current vector of the monitoring terminal arranged on the low-voltage side of each distribution transformer and the nameplate parameters of the distribution transformer, the nameplate parameters of each distribution transformer include: the high-voltage side rated voltage, the low-voltage side rated voltage, the distribution transformer impedance voltage percentage, and the distribution transformer rated capacity of each distribution transformer at the current operating position.

[0014] In some embodiments, determining the positive-sequence voltage and negative-sequence voltage on the high-voltage side of each distribution transformer according to the three-phase voltage vector and the three-phase current vector of the monitoring terminal arranged on the low-voltage side of each distribution transformer and the nameplate parameters of each distribution transformer includes:

[0015] Determine the positive sequence voltage and negative sequence voltage of the low voltage side of each distribution transformer according to the three-phase voltage vector of the monitoring terminal arranged on the low voltage side of each distribution transformer;

[0016] Determine the positive sequence current and negative sequence current of the low voltage side of each distribution transformer according to the three-phase current vector of the monitoring terminal arranged on the low voltage side of each distribution transformer;

[0017] According to the high-voltage side rated voltage, low-voltage side rated voltage, distribution transformer impedance voltage percentage, distribution transformer rated capacity, distribution transformer low-voltage side positive-sequence voltage, distribution transformer low-voltage side negative-sequence voltage, distribution transformer low-voltage side positive-sequence current, and distribution transformer low-voltage side negative-sequence current of each distribution transformer under the current operating gear, the distribution transformer high-voltage side positive-sequence voltage and distribution transformer high-voltage side negative-sequence voltage of each distribution transformer are determined accordingly.

[0018] In some embodiments, determining the positive-sequence voltage and negative-sequence voltage of the high-voltage side of each distribution transformer according to the high-voltage side rated voltage, low-voltage side rated voltage, distribution transformer impedance voltage percentage, distribution transformer rated capacity, distribution transformer low-voltage side positive-sequence voltage, distribution transformer low-voltage side negative-sequence voltage, distribution transformer low-voltage side positive-sequence current, and distribution transformer low-voltage side negative-sequence current of each distribution transformer at the current operating gear includes:

[0019] according to Correspondingly determine the positive sequence voltage and negative sequence voltage of the high-voltage side of each distribution transformer, where ur is the positive sequence voltage of the high-voltage side of the distribution transformer; ui. is the negative sequence voltage of the high-voltage side of the distribution transformer; U 1e is the rated voltage of the high-voltage side of the distribution transformer at the current gear; U 2e The rated voltage of the low-voltage side of the distribution transformer at the current gear; It is the positive sequence voltage on the low voltage side of the distribution transformer; Negative sequence voltage on the low voltage side of the distribution transformer; It is the positive sequence current on the low voltage side of the distribution transformer; is the negative sequence current on the low voltage side of the distribution transformer; Z p is the percentage of distribution transformer impedance voltage; S is the rated capacity of distribution transformer; β is the rotation factor.

[0020] In some embodiments, determining the occurrence of an interphase short circuit fault in the distribution network system according to the negative sequence voltage on the high-voltage side of each distribution transformer includes:

[0021] If the negative sequence voltage amplitude on the high-voltage side of each distribution transformer exceeds a first threshold, an interphase short circuit fault occurs in the distribution network system;

[0022] If the negative sequence voltage amplitude on the high-voltage side of each distribution transformer does not exceed the first threshold, no interphase short circuit fault occurs in the distribution network system.

[0023] The first threshold is determined according to a rated phase voltage of the power distribution network system.

[0024] In some embodiments, if an interphase short circuit fault occurs in the distribution network system, the zero-sequence voltage on the high-voltage side of each distribution transformer is set to zero, and the three-phase voltage vector on the high-voltage side of each distribution transformer is determined according to the positive-sequence voltage and the negative-sequence voltage on the high-voltage side of each distribution transformer, specifically including:

[0025] If an interphase short circuit fault occurs in the distribution network system, the zero-sequence voltage on the high-voltage side of each distribution transformer is set to zero, and based on the positive-sequence voltage and negative-sequence voltage on the high-voltage side of each distribution transformer, the three-phase voltage vector on the high-voltage side of each distribution transformer is determined according to the symmetrical vector method.

[0026] In some embodiments, determining two phases in the distribution network system where interphase short circuit faults occur based on the three-phase voltage vector on the high-voltage side of each distribution transformer includes:

[0027] In the three-phase voltage vector on the high-voltage side of each distribution transformer, two phases with lower voltage amplitudes in the three-phase voltage vector on the high-voltage side of each distribution transformer are screened as the two phases where an interphase short circuit fault occurs in the distribution network system.

[0028] In some embodiments, determining between which two distribution transformers the fault point of the interphase short circuit fault in the distribution network system is located based on the phase voltages of the two phases in which the interphase short circuit fault occurs in the distribution network system includes:

[0029] Determining a phase difference between two phase voltages of each distribution transformer in the distribution network system where an interphase short circuit fault occurs;

[0030] If the phase difference of each distribution transformer is greater than a second threshold, determining that the fault point where the interphase short circuit fault occurs in the distribution network system is located between the distribution transformer with the smallest phase difference and an adjacent distribution transformer on the power supply side thereof;

[0031] If any of the phase differences of each distribution transformer is less than a second threshold, all distribution transformers with a phase difference less than the second threshold are screened, and the fault point where the inter-phase short circuit fault occurs in the distribution network system is determined to be between the distribution transformer closest to the power supply side among all the distribution transformers with a phase difference less than the second threshold and the adjacent distribution transformer on the power supply side.

[0032] To achieve the above-mentioned purpose, the second aspect of the present application provides a distribution network fault location device based on a distribution transformer terminal, the device comprising:

[0033] An acquisition module is used to obtain the three-phase voltage vector and the three-phase current vector of the monitoring terminal arranged on the low-voltage side of each distribution transformer in the distribution network system;

[0034] A determination module, configured to determine the positive sequence voltage and negative sequence voltage of the high voltage side of each distribution transformer according to the three-phase voltage vector and the three-phase current vector of the monitoring terminal arranged on the low voltage side of each distribution transformer and the nameplate parameters of each distribution transformer;

[0035] An interphase short circuit fault detection module is used to determine the occurrence of an interphase short circuit fault in the distribution network system according to the negative sequence voltage on the high-voltage side of each distribution transformer;

[0036] A three-phase voltage vector determination module is configured to set the zero-sequence voltage on the high-voltage side of each distribution transformer to zero if an interphase short-circuit fault occurs in the distribution network system, and determine the three-phase voltage vector on the high-voltage side of each distribution transformer according to the positive-sequence voltage and the negative-sequence voltage on the high-voltage side of each distribution transformer;

[0037] a fault phase determination module, which determines two phases in the distribution network system where interphase short circuit faults occur based on the three-phase voltage vectors on the high-voltage side of each distribution transformer;

[0038] The fault section determination module is used to determine between which two distribution transformers the fault point of the interphase short circuit fault in the distribution network system is located based on the phase voltages of the two phases where the interphase short circuit fault occurs in the distribution network system.

[0039] To achieve the above-mentioned objective, the third aspect of the present application provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor performs the following steps:

[0040] Obtain the three-phase voltage vector and three-phase current vector of the monitoring terminal arranged on the low-voltage side of each distribution transformer in the distribution network system;

[0041] Determine the positive sequence voltage and negative sequence voltage of the high voltage side of each distribution transformer according to the three-phase voltage vector and the three-phase current vector of the monitoring terminal arranged on the low voltage side of each distribution transformer and the nameplate parameters of each distribution transformer;

[0042] Determining the occurrence of an interphase short circuit fault in the distribution network system according to the negative sequence voltage on the high-voltage side of each distribution transformer;

[0043] If an interphase short circuit fault occurs in the distribution network system, the zero-sequence voltage on the high-voltage side of each distribution transformer is set to zero, and the three-phase voltage vector on the high-voltage side of each distribution transformer is determined according to the positive-sequence voltage and the negative-sequence voltage on the high-voltage side of each distribution transformer;

[0044] Determining two phases in the distribution network system where interphase short circuit faults occur based on the three-phase voltage vectors on the high-voltage side of each distribution transformer;

[0045] According to the phase voltages of the two phases where the interphase short circuit fault occurs in the distribution network system, it is determined between which two distribution transformers the fault point where the interphase short circuit fault occurs in the distribution network system is located.

[0046] To achieve the above-mentioned object, the fourth aspect of the present application provides a computer-readable storage medium storing a computer program. When the computer program is executed by a processor, the processor performs the following steps:

[0047] Obtain the three-phase voltage vector and three-phase current vector of the monitoring terminal arranged on the low-voltage side of each distribution transformer in the distribution network system;

[0048] Determine the positive sequence voltage and negative sequence voltage of the high voltage side of each distribution transformer according to the three-phase voltage vector and the three-phase current vector of the monitoring terminal arranged on the low voltage side of each distribution transformer and the nameplate parameters of each distribution transformer;

[0049] Determining the occurrence of an interphase short circuit fault in the distribution network system according to the negative sequence voltage on the high-voltage side of each distribution transformer;

[0050] If an interphase short circuit fault occurs in the distribution network system, the zero-sequence voltage on the high-voltage side of each distribution transformer is set to zero, and the three-phase voltage vector on the high-voltage side of each distribution transformer is determined according to the positive-sequence voltage and the negative-sequence voltage on the high-voltage side of each distribution transformer;

[0051] Determining two phases in the distribution network system where interphase short circuit faults occur based on the three-phase voltage vectors on the high-voltage side of each distribution transformer;

[0052] According to the phase voltages of the two phases where the interphase short circuit fault occurs in the distribution network system, it is determined between which two distribution transformers the fault point where the interphase short circuit fault occurs in the distribution network system is located.

[0053] The embodiments of the present invention have the following beneficial effects:

[0054] The present invention adopts a method of voltage and current vector terminals on the low-voltage side of a distribution transformer, uses the distribution transformer as a primary sensor, calculates the voltage vector on the high-voltage side of the distribution transformer by inversion, and determines the occurrence of an interphase short-circuit fault in the distribution network system according to the negative-sequence voltage on the high-voltage side of the distribution transformer; if an interphase short-circuit fault occurs, the zero-sequence voltage on the high-voltage side of the distribution transformer is set to zero, and the three-phase voltage on the high-voltage side of the distribution transformer is determined according to the positive-sequence voltage and the negative-sequence voltage on the high-voltage side of the distribution transformer; and based on the three-phase voltage vector on the high-voltage side of the distribution transformer, the fault is located, which reduces the investment cost of the sensor and the workload of operation and maintenance, and can locate the fault point between two distribution transformers, and can also locate the distribution transformer fault, thereby improving the positioning accuracy, reducing the fault finding time, and improving the power supply reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 paying any creative work.

[0056] in:

[0057] FIG1 is a schematic flow chart of a method for locating a distribution network fault based on a distribution transformer terminal in one embodiment;

[0058] FIG2 is a structural diagram of a distribution network in one embodiment;

[0059] FIG3 is a structural diagram of a distribution network fault location device based on a distribution transformer terminal in one embodiment;

[0060] FIG4 is a schematic diagram of the structure of a computer device in one embodiment;

[0061] FIG5 is a schematic diagram of the structure of a computer-readable storage medium in one embodiment. DETAILED DESCRIPTION

[0062] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0063] In an embodiment of the present application, a distribution network fault location method based on a distribution transformer terminal is provided. Please refer to Figure 1. Figure 1 is a flow chart of a distribution network fault location method based on a distribution transformer terminal in one embodiment. The distribution network fault location method based on a distribution transformer terminal includes steps S1 to S6.

[0064] Step S1, obtaining the three-phase voltage vector and the three-phase current vector of the monitoring terminal arranged on the low-voltage side of each distribution transformer in the distribution network system;

[0065] Specifically, the three-phase voltage vector of each distribution transformer in the distribution network system must be obtained simultaneously, that is, when each monitoring terminal samples the three-phase voltage, the maximum time difference does not exceed 1ms.

[0066] Step S2, determining the positive sequence voltage and negative sequence voltage of the high voltage side of each distribution transformer according to the three-phase voltage vector and the three-phase current vector of the monitoring terminal arranged on the low voltage side of each distribution transformer and the nameplate parameters of each distribution transformer;

[0067] In some embodiments, in determining the positive-sequence voltage on the high-voltage side and the negative-sequence voltage on the high-voltage side of each distribution transformer according to the three-phase voltage vector, the three-phase current vector of the monitoring terminal arranged on the low-voltage side of each distribution transformer and the nameplate parameters of the distribution transformer, the nameplate parameters of each distribution transformer include: the high-voltage side rated voltage, the low-voltage side rated voltage, the distribution transformer impedance voltage percentage, and the distribution transformer rated capacity of each distribution transformer at the current operating position.

[0068] In some embodiments, determining the positive-sequence voltage and negative-sequence voltage on the high-voltage side of each distribution transformer according to the three-phase voltage vector and the three-phase current vector of the monitoring terminal arranged on the low-voltage side of each distribution transformer and the nameplate parameters of each distribution transformer includes:

[0069] Determine the positive sequence voltage and negative sequence voltage of the low voltage side of each distribution transformer according to the three-phase voltage vector of the monitoring terminal arranged on the low voltage side of each distribution transformer;

[0070] Determine the positive sequence current and negative sequence current of the low voltage side of each distribution transformer according to the three-phase current vector of the monitoring terminal arranged on the low voltage side of each distribution transformer;

[0071] According to the high-voltage side rated voltage, low-voltage side rated voltage, distribution transformer impedance voltage percentage, distribution transformer rated capacity, distribution transformer low-voltage side positive-sequence voltage, distribution transformer low-voltage side negative-sequence voltage, distribution transformer low-voltage side positive-sequence current, and distribution transformer low-voltage side negative-sequence current of each distribution transformer under the current operating gear, the distribution transformer high-voltage side positive-sequence voltage and distribution transformer high-voltage side negative-sequence voltage of each distribution transformer are determined accordingly.

[0072] In some embodiments, determining the positive-sequence voltage and negative-sequence voltage of the high-voltage side of each distribution transformer according to the high-voltage side rated voltage, low-voltage side rated voltage, distribution transformer impedance voltage percentage, distribution transformer rated capacity, distribution transformer low-voltage side positive-sequence voltage, distribution transformer low-voltage side negative-sequence voltage, distribution transformer low-voltage side positive-sequence current, and distribution transformer low-voltage side negative-sequence current of each distribution transformer at the current operating gear includes:

[0073] according to Correspondingly determine the positive sequence voltage and negative sequence voltage of the high-voltage side of each distribution transformer, where ur is the positive sequence voltage of the high-voltage side of the distribution transformer; ui. is the negative sequence voltage of the high-voltage side of the distribution transformer; U 1e is the rated voltage of the high-voltage side of the distribution transformer at the current gear; U 2e The rated voltage of the low-voltage side of the distribution transformer at the current gear; It is the positive sequence voltage on the low voltage side of the distribution transformer; Negative sequence voltage on the low voltage side of the distribution transformer; It is the positive sequence current on the low voltage side of the distribution transformer; is the negative sequence current on the low voltage side of the distribution transformer; Z p is the percentage of distribution transformer impedance voltage; S is the rated capacity of distribution transformer; β is the rotation factor.

[0074] Specifically, when the distribution transformer connection group is Dy11, β=e j30。, when the distribution transformer connection group is Dy1, β=e -j30。 .

[0075] Step S3, determining the occurrence of an interphase short circuit fault in the distribution network system according to the negative sequence voltage on the high-voltage side of each distribution transformer;

[0076] In some embodiments, determining the occurrence of an interphase short circuit fault in the distribution network system according to the negative sequence voltage on the high-voltage side of each distribution transformer includes:

[0077] If the negative sequence voltage amplitude on the high-voltage side of each distribution transformer exceeds a first threshold, an interphase short circuit fault occurs in the distribution network system;

[0078] If the negative sequence voltage amplitude on the high-voltage side of each distribution transformer does not exceed the first threshold, no interphase short circuit fault occurs in the distribution network system.

[0079] The first threshold is determined according to a rated phase voltage of the power distribution network system.

[0080] In some embodiments, the first threshold value ranges from 10% to 30% of the rated phase voltage of the power distribution network system.

[0081] Specifically, the rated phase voltage of the distribution system is a basic parameter of the distribution system. For example, a 10 kV distribution system has a nominal voltage of 10 kV and a rated phase voltage of 10 / 1.732 kV. The rated phase voltage can be understood as a known value and does not need to be obtained.

[0082] Step S4: if an interphase short circuit fault occurs in the distribution network system, the zero-sequence voltage on the high-voltage side of each distribution transformer is set to zero, and the three-phase voltage vector on the high-voltage side of each distribution transformer is determined according to the positive-sequence voltage and the negative-sequence voltage on the high-voltage side of each distribution transformer;

[0083] In some embodiments, if an interphase short circuit fault occurs in the distribution network system, the zero-sequence voltage on the high-voltage side of each distribution transformer is set to zero, and the three-phase voltage vector on the high-voltage side of each distribution transformer is determined according to the positive-sequence voltage and the negative-sequence voltage on the high-voltage side of each distribution transformer, specifically including:

[0084] If an interphase short circuit fault occurs in the distribution network system, the zero-sequence voltage on the high-voltage side of each distribution transformer is set to zero, and based on the positive-sequence voltage and negative-sequence voltage on the high-voltage side of each distribution transformer, the three-phase voltage vector on the high-voltage side of each distribution transformer is determined according to the symmetrical vector method.

[0085] Specifically, the zero-sequence voltage on the high-voltage side of each distribution transformer is set to zero, and the three-phase voltage on the high-voltage side of the distribution transformer is calculated using the symmetrical vector method based on the positive-sequence voltage and negative-sequence voltage on the high-voltage side of the distribution transformer;

[0086] Since the positive sequence voltage, negative sequence voltage and zero sequence voltage on the high voltage side of the distribution transformer are known, according to Determine the three-phase voltage vector on the high-voltage side of the distribution transformer, where is the three-phase voltage vector; α is the rotation factor, It is the positive sequence voltage on the high voltage side of the distribution transformer; It is the negative sequence voltage on the high voltage side of the distribution transformer.

[0087] Step S5, determining two phases in the distribution network system where interphase short circuit faults occur based on the three-phase voltage vector on the high-voltage side of each distribution transformer, comprising:

[0088] In the three-phase voltage vector on the high-voltage side of each distribution transformer, two phases with lower voltage amplitudes in the three-phase voltage vector on the high-voltage side of each distribution transformer are screened as the two phases where an interphase short circuit fault occurs in the distribution network system.

[0089] It should be noted that the two phases with lower voltage amplitudes in the three-phase voltage vector on the high-voltage side of each distribution transformer are the same.

[0090] Step S6: determining between which two distribution transformers the fault point of the interphase short circuit fault in the distribution network system is located based on the phase voltages of the two phases where the interphase short circuit fault occurs in the distribution network system.

[0091] In some embodiments, determining between which two distribution transformers the fault point of the interphase short circuit fault in the distribution network system is located based on the phase voltages of the two phases in which the interphase short circuit fault occurs in the distribution network system includes:

[0092] Determining a phase difference between two phase voltages of each distribution transformer in the distribution network system where an interphase short circuit fault occurs;

[0093] If the phase difference of each distribution transformer is greater than a second threshold, determining that the fault point where the interphase short circuit fault occurs in the distribution network system is located between the distribution transformer with the smallest phase difference and an adjacent distribution transformer on the power supply side thereof;

[0094] If any of the phase differences of each distribution transformer is less than a second threshold, all distribution transformers with a phase difference less than the second threshold are screened, and the fault point where the inter-phase short circuit fault occurs in the distribution network system is determined to be between the distribution transformer closest to the power supply side among all the distribution transformers with a phase difference less than the second threshold and the adjacent distribution transformer on the power supply side.

[0095] Specifically, the second threshold value can be customized according to actual conditions. In an embodiment of the present application, the second threshold value is 5°. In determining between which two distribution transformers the fault point of the interphase short circuit fault in the distribution network system is located based on the phase voltages of the two phases where the interphase short circuit fault occurs in the distribution network system, the phase difference of the faulty phases when the interphase short circuit fault occurs in each distribution transformer is first determined, that is, the phase difference between the two phases with lower voltage amplitudes in the three-phase voltage vector on the high-voltage side of each distribution transformer. If the phase difference between the two faulty phases of each distribution transformer is greater than 5°, then the fault point of the interphase short circuit fault in the distribution network system is determined to be between the distribution transformer with the smallest phase difference and an adjacent distribution transformer on the power supply side of the distribution transformer with the smallest phase difference.

[0096] If the phase difference between the two faulty phases of each distribution transformer is less than 5°, screen all distribution transformers with a phase difference less than 5°, and determine the fault point where the inter-phase short circuit fault occurs in the distribution network system. The fault point is located between the distribution transformer closest to the power supply among all the distribution transformers with a phase difference less than 5° and the adjacent distribution transformer on the power supply side of the distribution transformer closest to the power supply among all the distribution transformers with a phase difference less than 5°.

[0097] By adopting the technical solution of this embodiment, a method of using voltage and current vector terminals on the low-voltage side of the distribution transformer is proposed. The distribution transformer is used as a primary sensor, and the voltage vector on the high-voltage side of the distribution transformer is calculated by inversion to locate the fault. This reduces the investment cost of the sensor and the workload of operation and maintenance. The fault point can be located between two distribution transformers, and the distribution transformer fault can also be located, thereby improving positioning accuracy, reducing fault finding time, and improving power supply reliability.

[0098] The technical solution of this application is further described below with reference to specific embodiments:

[0099] For example, in the distribution network structure diagram of an embodiment shown in FIG2 , PB1 to PB4 are four distribution transformers of the outgoing line, respectively referred to as distribution transformer 1, distribution transformer 2, distribution transformer 3 and distribution transformer 4. The data combination consisting of the three-phase voltage vectors on the low-voltage side of distribution transformer n; The data combination consisting of the three-phase current vectors on the low-voltage side of distribution transformer n; It is a data combination composed of three-phase voltage vectors on the high-voltage side of distribution transformer n. The positive sequence voltage and negative sequence voltage on the low voltage side of distribution transformer n can be calculated by The positive sequence current and negative sequence current of the low voltage side of distribution transformer n can be calculated; further, the positive sequence voltage, negative sequence voltage, positive sequence current, negative sequence current and nameplate parameters of distribution transformer n are obtained according to the calculation. Calculate the positive sequence voltage and negative sequence voltage on the high voltage side of distribution transformer n, further set the zero sequence voltage on the high voltage side of distribution transformer n to 0, and calculate the positive sequence voltage and negative sequence voltage on the high voltage side of distribution transformer n Finally, according to Determine between which two distribution transformers the faulty two phases and faulty section of the phase-to-phase short circuit fault are located.

[0100] In an embodiment of the present application, a distribution network fault locating device based on a distribution transformer terminal is provided. Please refer to Figure 3, which is a structural diagram of the distribution network fault locating device based on a distribution transformer terminal in one embodiment. The distribution network fault locating device based on the distribution transformer terminal includes: an acquisition module 201, a determination module 202, a phase-to-phase short circuit fault detection module 203, a three-phase voltage vector determination module 204, a fault phase determination module 205 and a fault section determination module 206.

[0101] The acquisition module 201 is configured to acquire the three-phase voltage vector and the three-phase current vector of the monitoring terminal arranged on the low-voltage side of each distribution transformer in the distribution network system;

[0102] The determination module 202 is configured to determine the positive sequence voltage and the negative sequence voltage on the high voltage side of each distribution transformer according to the three-phase voltage vector and the three-phase current vector of the monitoring terminal arranged on the low voltage side of each distribution transformer and the nameplate parameters of each distribution transformer;

[0103] The interphase short circuit fault detection module 203 is configured to determine the occurrence of the interphase short circuit fault in the distribution network system according to the negative sequence voltage on the high-voltage side of each distribution transformer;

[0104] The three-phase voltage vector determination module 204 is configured to set the zero-sequence voltage on the high-voltage side of each distribution transformer to zero if an inter-phase short circuit fault occurs in the distribution network system, and determine the three-phase voltage vector on the high-voltage side of each distribution transformer according to the positive-sequence voltage and the negative-sequence voltage on the high-voltage side of each distribution transformer;

[0105] The fault phase determination module 205 is configured to determine the two phases in the distribution network system where interphase short circuit faults occur based on the three-phase voltage vectors on the high-voltage side of each distribution transformer;

[0106] The fault section determination module 206 is configured to determine between which two distribution transformers the fault point of the interphase short circuit fault in the distribution network system is located according to the phase voltages of the two phases where the interphase short circuit fault occurs in the distribution network system.

[0107] In some embodiments, the determination module 202 is further configured to determine the positive-sequence voltage and negative-sequence voltage on the high-voltage side of each distribution transformer according to the three-phase voltage vector and the three-phase current vector of the monitoring terminal arranged on the low-voltage side of each distribution transformer and the nameplate parameters of each distribution transformer, including:

[0108] Determine the positive sequence voltage and negative sequence voltage of the low voltage side of each distribution transformer according to the three-phase voltage vector of the monitoring terminal arranged on the low voltage side of each distribution transformer;

[0109] Determine the positive sequence current and negative sequence current of the low voltage side of each distribution transformer according to the three-phase current vector of the monitoring terminal arranged on the low voltage side of each distribution transformer;

[0110] According to the high-voltage side rated voltage, low-voltage side rated voltage, distribution transformer impedance voltage percentage, distribution transformer rated capacity, distribution transformer low-voltage side positive-sequence voltage, distribution transformer low-voltage side negative-sequence voltage, distribution transformer low-voltage side positive-sequence current, and distribution transformer low-voltage side negative-sequence current of each distribution transformer under the current operating gear, the distribution transformer high-voltage side positive-sequence voltage and distribution transformer high-voltage side negative-sequence voltage of each distribution transformer are determined accordingly.

[0111] The nameplate parameters of each distribution transformer include: the high-voltage side rated voltage, the low-voltage side rated voltage, the distribution transformer impedance voltage percentage, and the distribution transformer rated capacity of each distribution transformer at the current operating position.

[0112] Specifically, root Correspondingly determine the positive sequence voltage and negative sequence voltage of the high-voltage side of each distribution transformer, where ur is the positive sequence voltage of the high-voltage side of the distribution transformer; ui. is the negative sequence voltage of the high-voltage side of the distribution transformer; U 1e is the rated voltage of the high-voltage side of the distribution transformer at the current gear; U 2e The rated voltage of the low-voltage side of the distribution transformer at the current gear; It is the positive sequence voltage on the low voltage side of the distribution transformer; Negative sequence voltage on the low voltage side of the distribution transformer; It is the positive sequence current on the low voltage side of the distribution transformer; is the negative sequence current on the low voltage side of the distribution transformer; Z p is the percentage of distribution transformer impedance voltage; S is the rated capacity of distribution transformer; β is the rotation factor.

[0113] In some embodiments, the interphase short circuit fault detection module 203 is further configured to detect that an interphase short circuit fault occurs in the distribution network system if the negative sequence voltage amplitude on the high-voltage side of each distribution transformer exceeds a first threshold;

[0114] If the negative sequence voltage amplitude on the high-voltage side of each distribution transformer does not exceed the first threshold, no interphase short circuit fault occurs in the distribution network system.

[0115] The first threshold is determined according to a rated phase voltage of the power distribution network system.

[0116] In some embodiments, the three-phase voltage vector determination module 204 is further configured to set the zero-sequence voltage on the high-voltage side of each distribution transformer to zero if an inter-phase short circuit fault occurs in the distribution network system, and determine the three-phase voltage vector on the high-voltage side of each distribution transformer according to the symmetrical vector method based on the positive-sequence voltage and negative-sequence voltage on the high-voltage side of each distribution transformer.

[0117] In some embodiments, the fault phase determination module 205 is further configured to screen the two phases with lower voltage amplitudes in the three-phase voltage vector on the high-voltage side of each distribution transformer as the two phases where an inter-phase short circuit fault occurs in the distribution network system.

[0118] In some embodiments, the fault section determination module 206 is further configured to determine a phase difference between two phases of each distribution transformer having an inter-phase short circuit fault in the distribution network system;

[0119] If the phase difference of each distribution transformer is greater than a second threshold, determining that the fault point where the interphase short circuit fault occurs in the distribution network system is located between the distribution transformer with the smallest phase difference and an adjacent distribution transformer on the power supply side thereof;

[0120] If any of the phase differences of each distribution transformer is less than a second threshold, all distribution transformers with a phase difference less than the second threshold are screened, and the fault point where the inter-phase short circuit fault occurs in the distribution network system is determined to be between the distribution transformer closest to the power supply side among all the distribution transformers with a phase difference less than the second threshold and the adjacent distribution transformer on the power supply side.

[0121] For other details about the implementation of the above technical solution by each module in the distribution network fault locating device based on the distribution transformer terminal, please refer to the description of the distribution network fault locating method based on the distribution transformer terminal provided above, which will not be repeated here.

[0122] In an embodiment of the present application, a computer device is provided. Please refer to FIG4 , which is a schematic diagram of the structure of a computer device in one embodiment. The device includes a memory 301 and a processor 302. The memory 301 stores a computer program. When the computer program is executed by the processor 302, the processor 302 performs the following steps:

[0123] Obtain the three-phase voltage vector and three-phase current vector of the monitoring terminal arranged on the low-voltage side of each distribution transformer in the distribution network system;

[0124] Determine the positive sequence voltage and negative sequence voltage of the high voltage side of each distribution transformer according to the three-phase voltage vector and the three-phase current vector of the monitoring terminal arranged on the low voltage side of each distribution transformer and the nameplate parameters of each distribution transformer;

[0125] Determining the occurrence of an interphase short circuit fault in the distribution network system according to the negative sequence voltage on the high-voltage side of each distribution transformer;

[0126] If an interphase short circuit fault occurs in the distribution network system, the zero-sequence voltage on the high-voltage side of each distribution transformer is set to zero, and the three-phase voltage vector on the high-voltage side of each distribution transformer is determined according to the positive-sequence voltage and the negative-sequence voltage on the high-voltage side of each distribution transformer;

[0127] Determining two phases in the distribution network system where interphase short circuit faults occur based on the three-phase voltage vectors on the high-voltage side of each distribution transformer;

[0128] According to the phase voltages of the two phases where the interphase short circuit fault occurs in the distribution network system, it is determined between which two distribution transformers the fault point where the interphase short circuit fault occurs in the distribution network system is located.

[0129] Among them, the processor 302 can also be called a CPU (Central Processing Unit), and the processor 302 may be an integrated circuit chip with signal processing capabilities; the processor 302 can also be a general-purpose processor, DSP (Digital Signal Processor), ASIC (Application Specific Integrated Circuit), FPGA (Field Programmable Gate Array) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, among which the general-purpose processor can be a microprocessor or the processor 301 can also be any conventional processor, etc.

[0130] In an embodiment of the present application, a computer-readable storage medium is provided. Please refer to FIG. 5 , which is a schematic diagram of the structure of a computer-readable storage medium in one embodiment. The storage medium stores a readable computer program 401. The computer program 401 may be stored in the storage medium in the form of a software product and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) or a processor to perform the following steps:

[0131] Obtain the three-phase voltage vector and three-phase current vector of the monitoring terminal arranged on the low-voltage side of each distribution transformer in the distribution network system;

[0132] Determine the positive sequence voltage and negative sequence voltage of the high voltage side of each distribution transformer according to the three-phase voltage vector and the three-phase current vector of the monitoring terminal arranged on the low voltage side of each distribution transformer and the nameplate parameters of each distribution transformer;

[0133] Determining the occurrence of an interphase short circuit fault in the distribution network system according to the negative sequence voltage on the high-voltage side of each distribution transformer;

[0134] If an interphase short circuit fault occurs in the distribution network system, the zero-sequence voltage on the high-voltage side of each distribution transformer is set to zero, and the three-phase voltage vector on the high-voltage side of each distribution transformer is determined according to the positive-sequence voltage and the negative-sequence voltage on the high-voltage side of each distribution transformer;

[0135] Determining two phases in the distribution network system where interphase short circuit faults occur based on the three-phase voltage vectors on the high-voltage side of each distribution transformer;

[0136] According to the phase voltages of the two phases where the interphase short circuit fault occurs in the distribution network system, it is determined between which two distribution transformers the fault point where the interphase short circuit fault occurs in the distribution network system is located.

[0137] The aforementioned storage media include: USB flash drives, mobile hard drives, magnetic disks or optical disks, ROM (Read-Only Memory), RAM (Random Access Memory), and other media that can store program codes, or terminal devices such as computers, service machines, mobile phones, and tablets.

[0138] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program. The program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0139] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0140] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A distribution network fault location method based on distribution transformer terminal, characterized in that: The method comprises: Obtain the three-phase voltage vector and three-phase current vector of the monitoring terminal arranged on the low-voltage side of each distribution transformer in the distribution network system; Determine the positive sequence voltage and negative sequence voltage of the high voltage side of each distribution transformer according to the three-phase voltage vector and the three-phase current vector of the monitoring terminal arranged on the low voltage side of each distribution transformer and the nameplate parameters of each distribution transformer; Determining the occurrence of an interphase short circuit fault in the distribution network system according to the negative sequence voltage on the high-voltage side of each distribution transformer; If an interphase short circuit fault occurs in the distribution network system, the zero-sequence voltage on the high-voltage side of each distribution transformer is set to zero, and the three-phase voltage vector on the high-voltage side of each distribution transformer is determined according to the positive-sequence voltage and the negative-sequence voltage on the high-voltage side of each distribution transformer; Determining two phases in the distribution network system where interphase short circuit faults occur based on the three-phase voltage vectors on the high-voltage side of each distribution transformer; According to the phase voltages of the two phases where the interphase short circuit fault occurs in the distribution network system, it is determined between which two distribution transformers the fault point where the interphase short circuit fault occurs in the distribution network system is located.

2. The distribution network fault location method based on distribution transformer terminal according to claim 1 is characterized in that: In the determination of the positive-sequence voltage on the high-voltage side and the negative-sequence voltage on the high-voltage side of each distribution transformer according to the three-phase voltage vector, the three-phase current vector of the monitoring terminal arranged on the low-voltage side of each distribution transformer and the nameplate parameters of the distribution transformer, the nameplate parameters of each distribution transformer include: the high-voltage side rated voltage, the low-voltage side rated voltage, the distribution transformer impedance voltage percentage, and the distribution transformer rated capacity of each distribution transformer under the current operating gear.

3. The distribution network fault location method based on distribution transformer terminal according to claim 2 is characterized in that: The determining of the positive sequence voltage and negative sequence voltage on the high voltage side of each distribution transformer according to the three-phase voltage vector and the three-phase current vector of the monitoring terminal arranged on the low voltage side of each distribution transformer and the nameplate parameters of each distribution transformer includes: Determine the positive sequence voltage and negative sequence voltage of the low voltage side of each distribution transformer according to the three-phase voltage vector of the monitoring terminal arranged on the low voltage side of each distribution transformer; Determine the positive sequence current and negative sequence current of the low voltage side of each distribution transformer according to the three-phase current vector of the monitoring terminal arranged on the low voltage side of each distribution transformer; According to the high-voltage side rated voltage, low-voltage side rated voltage, distribution transformer impedance voltage percentage, distribution transformer rated capacity, distribution transformer low-voltage side positive-sequence voltage, distribution transformer low-voltage side negative-sequence voltage, distribution transformer low-voltage side positive-sequence current, and distribution transformer low-voltage side negative-sequence current of each distribution transformer under the current operating gear, the distribution transformer high-voltage side positive-sequence voltage and distribution transformer high-voltage side negative-sequence voltage of each distribution transformer are determined accordingly.

4. The distribution network fault location method based on distribution transformer terminal according to claim 3 is characterized in that: Determining the positive-sequence voltage and negative-sequence voltage of the high-voltage side of each distribution transformer according to the high-voltage side rated voltage, low-voltage side rated voltage, distribution transformer impedance voltage percentage, distribution transformer rated capacity, distribution transformer low-voltage side positive-sequence voltage, distribution transformer low-voltage side negative-sequence voltage, distribution transformer low-voltage side positive-sequence current, and distribution transformer low-voltage side negative-sequence current of each distribution transformer at the current operating gear includes: according to Correspondingly determine the positive sequence voltage and negative sequence voltage of the high-voltage side of each distribution transformer, where ur is the positive sequence voltage of the high-voltage side of the distribution transformer; ui. is the negative sequence voltage of the high-voltage side of the distribution transformer; U 1e is the rated voltage of the high-voltage side of the distribution transformer at the current gear; U 2e The rated voltage of the low-voltage side of the distribution transformer at the current gear; It is the positive sequence voltage on the low voltage side of the distribution transformer; Negative sequence voltage on the low voltage side of the distribution transformer; It is the positive sequence current on the low voltage side of the distribution transformer; is the negative sequence current on the low voltage side of the distribution transformer; Z p is the percentage of distribution transformer impedance voltage; S is the rated capacity of distribution transformer; β is the rotation factor.

5. The distribution network fault location method based on distribution transformer terminal according to claim 4 is characterized in that: The determining the occurrence of the interphase short circuit fault in the distribution network system according to the negative sequence voltage on the high-voltage side of each distribution transformer includes: If the negative sequence voltage amplitude on the high-voltage side of each distribution transformer exceeds a first threshold, an interphase short circuit fault occurs in the distribution network system; If the negative sequence voltage amplitude on the high-voltage side of each distribution transformer does not exceed the first threshold, no interphase short circuit fault occurs in the distribution network system. The first threshold is determined according to a rated phase voltage of the power distribution network system.

6. The distribution network fault location method based on distribution transformer terminal according to claim 5, characterized in that: If an interphase short circuit fault occurs in the distribution network system, the zero-sequence voltage on the high-voltage side of each distribution transformer is set to zero, and the three-phase voltage vector on the high-voltage side of each distribution transformer is determined according to the positive-sequence voltage and the negative-sequence voltage on the high-voltage side of each distribution transformer. Specifically, the method includes: If an interphase short circuit fault occurs in the distribution network system, the zero-sequence voltage on the high-voltage side of each distribution transformer is set to zero, and based on the positive-sequence voltage and negative-sequence voltage on the high-voltage side of each distribution transformer, the three-phase voltage vector on the high-voltage side of each distribution transformer is determined according to the symmetrical vector method.

7. The distribution network fault location method based on distribution transformer terminal according to claim 6, characterized in that: The step of determining two phases in the distribution network system where interphase short circuit faults occur based on the three-phase voltage vector on the high-voltage side of each distribution transformer comprises: In the three-phase voltage vector on the high-voltage side of each distribution transformer, two phases with lower voltage amplitudes in the three-phase voltage vector on the high-voltage side of each distribution transformer are screened as the two phases where an interphase short circuit fault occurs in the distribution network system.

8. The distribution network fault location method based on distribution transformer terminal according to claim 7 is characterized in that: The determining, based on the phase voltages of the two phases in the distribution network system where the interphase short circuit fault occurs, between which two distribution transformers the fault point of the interphase short circuit fault in the distribution network system is located comprises: Determine the two phases of each distribution transformer that have a phase-to-phase short circuit fault in the distribution network system. The phase difference of the phase voltage; If the phase difference of each distribution transformer is greater than a second threshold, determining that the fault point where the interphase short circuit fault occurs in the distribution network system is located between the distribution transformer with the smallest phase difference and an adjacent distribution transformer on the power supply side thereof; If any of the phase differences of each distribution transformer is less than a second threshold, all distribution transformers with a phase difference less than the second threshold are screened, and the fault point where the inter-phase short circuit fault occurs in the distribution network system is determined to be between the distribution transformer closest to the power supply side among all the distribution transformers with a phase difference less than the second threshold and the adjacent distribution transformer on the power supply side.

9. A distribution network fault location device based on a distribution transformer terminal, characterized in that: The device comprises: An acquisition module is used to obtain the three-phase voltage vector and the three-phase current vector of the monitoring terminal arranged on the low-voltage side of each distribution transformer in the distribution network system; A determination module, configured to determine the positive sequence voltage and negative sequence voltage of the high voltage side of each distribution transformer according to the three-phase voltage vector and the three-phase current vector of the monitoring terminal arranged on the low voltage side of each distribution transformer and the nameplate parameters of each distribution transformer; An interphase short circuit fault detection module is used to determine the occurrence of an interphase short circuit fault in the distribution network system according to the negative sequence voltage on the high-voltage side of each distribution transformer; A three-phase voltage vector determination module is configured to set the zero-sequence voltage on the high-voltage side of each distribution transformer to zero if an interphase short-circuit fault occurs in the distribution network system, and determine the three-phase voltage vector on the high-voltage side of each distribution transformer according to the positive-sequence voltage and the negative-sequence voltage on the high-voltage side of each distribution transformer; a fault phase determination module, which determines two phases in the distribution network system where interphase short circuit faults occur based on the three-phase voltage vectors on the high-voltage side of each distribution transformer; The fault section determination module is used to determine between which two distribution transformers the fault point of the interphase short circuit fault in the distribution network system is located based on the phase voltages of the two phases where the interphase short circuit fault occurs in the distribution network system.

10. A computer device comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor is caused to perform the steps of the method according to any one of claims 1 to 8.

11. A computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor is caused to perform the steps of the method according to any one of claims 1 to 8.

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