Fault positioning method and device of T connection line, terminal equipment and storage medium

Abstract

The embodiment of the application is suitable for the electric power technical field, and provides a fault positioning method and device of a T connection line, a terminal device and a storage medium. The method comprises the following steps: if a fault detection instruction fed back by any branch of the T connection line is received, voltage and current information of all branches on the T connection line is acquired; the voltage and current information comprises electrical components of at least two candidate dimensions; difference flow phase information is determined based on all the voltage and current information, and a target dimension used for fault positioning is determined from the candidate dimensions according to the difference flow phase information; and a fault position in the T connection line is identified according to the electrical components corresponding to all the branches in the target dimension. The method provided by the embodiment of the application can accurately position the fault of the T connection line.

Description

Technical Field

[0001] This application relates to the field of power technology, and in particular to a fault location method, device, terminal equipment, and storage medium for a T-connected line. Background Technology

[0002] In existing technologies, when a power transmission line fault occurs, fault location is mainly achieved using traveling wave ranging devices or line protection ranging methods. Traveling wave ranging devices locate the fault using current transformers and AD sampling chips. While they offer high accuracy, their high cost and significant engineering investment limit limit their application to T-connected lines. Line protection ranging methods primarily include single-end ranging and double-end ranging. Single-end ranging methods have low accuracy for faults caused by resistance faults, with significant discrepancies between the measured fault location and the actual fault location, making them unsuitable for T-connected circuits. Double-end ranging methods, when applied to T-connected lines, require calculating the virtual voltage at the T-connection point and then selecting the faulty branch based on this virtual voltage. This calculation process is cumbersome, and relying solely on the difference in virtual voltage for fault branch selection is susceptible to the fault location and high-resistance conditions. Incorrect fault branch selection leads to fault location failure. Therefore, existing technologies lack a convenient, effective, and applicable fault location method for T-connected lines suitable for various fault conditions. Summary of the Invention

[0003] In view of this, embodiments of this application provide a fault location method for T-connected lines to improve the accuracy of fault location for T-connected lines.

[0004] The first aspect of this application provides a fault location method for a T-connected line, including:

[0005] If a fault detection command is received from any branch within the T-connection, the voltage and current information of all branches on the T-connection is obtained; the voltage and current information contains electrical components of at least two candidate dimensions.

[0006] Differential current phase information is determined based on all the voltage and current information, and a target dimension for fault location is determined from the candidate dimensions based on the differential current phase information.

[0007] The location of the fault in the T-connection is identified based on the electrical components corresponding to all the branches in the target dimension.

[0008] A second aspect of this application provides a fault location device for a T-connected line, comprising:

[0009] The voltage and current information acquisition module is used to acquire the voltage and current information of all branches on the T-connection line if a fault detection command is received from any branch within the T-connection line; the voltage and current information includes electrical components of at least two candidate dimensions.

[0010] The target dimension determination module is used to determine differential current phase information based on all the voltage and current information, and to determine the target dimension for fault location from the candidate dimensions according to the differential current phase information;

[0011] The fault location identification module is used to identify the fault location in the T-connection line based on the electrical components corresponding to all the branches in the target dimension.

[0012] A third aspect of this application provides a terminal device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the fault location method for a T-connection line as described in the first aspect above.

[0013] A fourth aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the fault location method for a T-connected line as described in the first aspect above.

[0014] A fifth aspect of this application provides a computer program product that, when run on a computer, causes the computer to execute the fault location method for the T-connected line described in the first aspect.

[0015] Compared with the prior art, the embodiments of this application have the following advantages:

[0016] In this embodiment, when the line protection device receives a fault detection command from any branch within the T-connected line, it can acquire the voltage and current information of all branches on the T-connected line. Based on the voltage and current information of all branches, the line protection device can determine the differential current phase information of the T-connected line. Based on the differential current phase information, the line protection device can determine the dimension used for fault location from the electrical components of the two candidate dimensions contained in the voltage and current information. Based on the electrical components of all branches in the target dimension, the line protection device can identify the fault location in the T-connected line. The fault location method provided in this embodiment does not rely on an additional traveling wave ranging device; fault location can be completed using only the existing line protection device on the T-connected line. Therefore, the fault location on the T-connected line can be quickly and conveniently determined using the method provided in this embodiment. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of a T-connection line provided in an embodiment of this application;

[0019] Figure 2 This is a schematic diagram of a fault location method for a T-connected line provided in an embodiment of this application;

[0020] Figure 3 This is a schematic diagram of a fault location process for a T-connected line provided in an embodiment of this application;

[0021] Figure 4 This is a schematic diagram of a fault location device for a T-connected line provided in an embodiment of this application;

[0022] Figure 5 This is a schematic diagram of a terminal device provided in an embodiment of this application. Detailed Implementation

[0023] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0024] The technical solution of this application will be described below through specific embodiments.

[0025] like Figure 1 The diagram shown is a fault diagram of a T-connection line provided in an embodiment of this application. (Refer to...) Figure 1 In this embodiment, the T-connection line may include a first branch, a second branch, and a third branch. The first ends of the first branch, the second branch, and the third branch are shared, and the shared connection point can be... Figure 1 Point T in the diagram, the second end of the first branch, the second end of the second branch, and the second end of the third branch are all grounded. In such a case... Figure 1In the T-connected circuit shown, the first, second, and third branches can be arranged in a T-shape. For example, the first and second branches can be arranged on the same straight line, and the third branch can be perpendicular to the first and second branches. Specifically, the first branch may include a first resistor and a first AC power supply connected sequentially between the first and second ends of the first branch. The common connection point of the first resistor and the first AC power supply can serve as the first connection point of the T-connected circuit. L1 It can be used to represent the current value flowing through the first branch, U L1 This can be used to represent the voltage value at the first connection point. The second branch may include a second resistor and a second AC power supply connected sequentially between the first and second terminals of the second branch. The common connection point of the second resistor and the second AC power supply can serve as the second connection point of a T-connection line. L2 It can be used to represent the current value flowing through the second branch, U L2 This can be used to represent the voltage value at the second connection point. The third branch may include a third resistor and a third AC power supply connected sequentially between the first and second terminals of the third branch. The common connection point of the third resistor and the third AC power supply can serve as the third connection point of a T-connection circuit. L3 It can be used to represent the current value flowing through the third branch, U L3 It can be used to represent the voltage value at the third connection point. In, for example... Figure 1 In the T-connection shown, the first connection point, the second connection point, and the third connection point can be used to connect the three endpoints of the system, for example... Figure 1 Points M, N, and P in the T-connection are used. When a fault occurs in any branch of the T-connection line, the fault location can be indicated by the distance between the fault point and the connection point. For example, when a short circuit fault occurs in phases BC on the third branch, the fault point is... Figure 1 When the fault is at point F, the location of the fault on the third branch can be represented by the distance FP between point F and point P.

[0026] Reference Figure 2 This illustration shows a schematic diagram of a fault location method for a T-connected line according to an embodiment of this application. This fault location method can be applied to electronic equipment. Specifically, the electronic equipment can be a line protection device installed on the T-connected line. In this embodiment, an example of a line protection device installed on any branch of the T-connected line is used. Specifically, it may include the following steps:

[0027] S201. If a fault detection command is received from any branch within the T-connection line, the voltage and current information of all branches on the T-connection line is obtained; the voltage and current information includes electrical components of at least two candidate dimensions.

[0028] In this embodiment, after receiving a fault detection command, the line protection device on the T-connection can obtain the voltage and current information of all branches on the T-connection. The fault detection command can be issued by the line protection device of any branch on the T-connection. The voltage and current information obtained by the line protection device can contain multiple electrical components. Any electrical component can be represented by at least two candidate dimensions.

[0029] In one possible implementation, a T-connector can include multiple line protection devices, and each branch of the T-connector can include at least one line protection device. The T-connector can also include three phase wires, and each branch of the T-connector can be composed of all three phase wires. For example, a T-connector can include phase wires A, B, and C. The first branch of the T-connector can be composed of phase wires A1, B1, and C1; the second branch can be composed of phase wires A2, B2, and C2; and the third branch can be composed of phase wires A3, B3, and C3. When a line protection device in any branch of the T-connector detects a potential line fault, it can automatically generate a fault detection command. This line protection device can transmit the fault detection command to the remaining line protection devices on the T-connector via a three-terminal fiber optic differential channel. After receiving the fault detection command, the line protection devices on each branch can begin collecting the original three-phase data of the branch where the line protection device is located. For example, after receiving a fault detection command, the line protection device on the first branch can begin collecting A1 current and A1 voltage data on phase A1, B1 current and B1 voltage data on phase B1, and C1 current and C1 voltage data on phase C1. After collecting the original three-phase data of its respective branch, the line protection devices on each branch can transmit the original three-phase data of their branch to the line protection devices of other branches through a three-terminal fiber optic differential channel.

[0030] After acquiring the raw three-phase data of all branches, the line protection device on the T-connection can filter the raw three-phase data using differential filtering or full-cycle Fourier filtering to obtain filtered three-phase data. Based on the filtered three-phase data, the line protection device can generate voltage and current information for all branches.

[0031] In this embodiment, after acquiring the original three-phase data of all branches, the line protection device can extract the fundamental frequency component of each three-phase data through differential filtering or full-cycle Fourier transform filtering to achieve filtering of the original three-phase data. Since a fault in a power transmission line affects the current flowing through it, the original three-phase data collected by the line protection device when a fault occurs is the result of superimposing the attenuated DC component and harmonics onto the actual voltage and current values ​​of each phase line. Through differential filtering or full-cycle Fourier transform filtering, the line protection device can better filter out the attenuated DC component and harmonics in the original three-phase data, thereby improving the accuracy of fault location.

[0032] In one possible implementation, the line protection device can perform component conversion calculations on the filtered three-phase data of each branch using a symmetrical component conversion method, thereby generating the electrical components corresponding to each branch. The electrical components generated by the line protection device can include positive-sequence and negative-sequence electrical components, also known as positive-sequence and negative-sequence components. For example, after acquiring the three-phase data of the first branch, the line protection device can perform component conversion on the three-phase data of the first branch using the symmetrical component conversion method to generate the electrical components of the first branch. Each electrical component of the first branch can be represented in vector form. The electrical components of the first branch can include voltage components and current components.

[0033] In one possible implementation, each electrical component of the first branch can include two candidate dimensions. Therefore, each electrical component of the first branch can include a positive-sequence dimension and a negative-sequence dimension. For example, the line protection device can detect the voltage value U of phase A1 on the first branch. A1 The voltage value U of phase B1 line B1 The voltage value U of phase line C1 C1 Substitute the components into the transformation matrix of the symmetric component transformation method to perform component decomposition and generate the positive sequence voltage component of the first branch. and negative sequence voltage components The line protection device can also measure the current value I of phase A1 on the first branch. A1 The current value I of phase B1 B1 The current value I of phase line C1 C1 Substitute the components into the transformation matrix of the symmetric component transformation method to perform component decomposition and generate the positive sequence current component of the first branch. and negative sequence current components The line protection device can detect the voltage value U of phase A2 on the second branch. A2 The voltage value U of phase B2 line B2 The voltage value U of phase line C2 C2Substitute the components into the transformation matrix of the symmetric component transformation method to perform component decomposition and generate the positive sequence voltage component of the second branch. and negative sequence voltage components The line protection device can also measure the current value I of phase A2 on the second branch. A2 The current value I of phase B2 B2 The current value I of phase line C2 C2 Substitute the components into the transformation matrix of the symmetric component transformation method to perform component decomposition and generate the positive sequence current component of the second branch. and negative sequence current components The line protection device can detect the voltage value U of phase A3 on the third branch. A3 The voltage value U of phase B3 line B3 The voltage value U of phase line C3 C3 Substitute the components into the transformation matrix of the symmetric component transformation method to perform component decomposition and generate the positive sequence voltage component of the second branch. and negative sequence voltage components The line protection device can also measure the current value I of phase A3 on the second branch. A3 The current value I of phase B3 B3 The current value I of phase line C3 C3 Substitute the components into the transformation matrix of the symmetric component transformation method to perform component decomposition and generate the positive sequence current component of the second branch. and negative sequence current components

[0034] S202. Determine the differential current phase information based on all the voltage and current information, and determine the target dimension for fault location from the candidate dimensions according to the differential current phase information;

[0035] In this embodiment, after acquiring the voltage and current information of all branches, the line protection device can determine the differential current phase information of the T-connected line based on the voltage and current information of all branches. After determining the differential current phase information, the line protection device can select from multiple candidate dimensions of the electrical components based on the differential current phase information and determine the target dimension for fault location.

[0036] In this embodiment, after acquiring the voltage and current information of all branches, the line protection device can determine the original three-wire data of all branches on the T-connection from the voltage and current information. The original three-wire data may include the original voltage and current values ​​of all phase lines on the branches. Based on the original three-wire data, the line protection device can determine the phase differential current value of each phase line in the T-connection line.

[0037] In this embodiment, the line protection device can determine whether the difference between the phase differential current value of each phase line and the preset rated differential current value is greater than zero. By determining whether the difference corresponding to each phase differential current value is greater than zero, the line protection device can determine the number of phase lines whose phase differential current value is greater than the preset rated differential current value.

[0038] In one possible implementation, since the phase difference current value corresponding to each phase line can be in vector form, the line protection device can first take the complex part of each phase difference current value for amplitude calculation and determine the numerical value of each phase difference current value before determining the difference value corresponding to each phase difference current value.

[0039] In one possible implementation, the preset rated differential current value can be calculated using the following formula:

[0040] I 额定 =0.1*I n

[0041] Among them, I 额定 The rated differential current value can be preset in the line protection device; I n I can represent the secondary rated value of the current transformer in the branch where the line protection device is located. n It can usually be 5 amps or 1 amp.

[0042] In this embodiment, after determining the number of phase lines whose differential current value is greater than a preset rated differential current value, the line protection device can use this number as differential current phase information. After determining the differential current phase information, the line protection device can determine the relationship between the differential current phase information and the total number of phase lines. If the line protection device determines that the differential current phase information is equal to the total number of phase lines in the T-connection, then the line protection device can determine the positive-sequence dimension among the candidate dimensions as the target dimension, meaning the line protection device can locate the fault through the positive-sequence component among multiple electrical components. If the line protection device determines that the differential current phase information is equal to 0, then the line protection device can determine that the received fault detection command is an erroneous command, meaning no line fault has occurred on the T-connection. Therefore, the line protection device can skip fault location calculation and end the fault detection process. If the line protection device determines that the differential current phase information is greater than 0 and less than the total number of phase lines, then the line protection device can determine the negative-sequence dimension among the candidate dimensions as the target dimension, meaning the line protection device can locate the fault through the negative-sequence component among multiple electrical components.

[0043] In this embodiment, different fault types in a T-connected line result in different electrical components that better reflect the fault characteristics. When a three-phase fault occurs in a T-connected line, the positive-sequence component better reflects the fault characteristics. Therefore, using the positive-sequence component for fault location is more suitable when a three-phase fault occurs in a T-connected line. When an asymmetrical fault occurs in a T-connected line, the negative-sequence component better reflects the fault characteristics. Therefore, using the negative-sequence component for fault location is more suitable when an asymmetrical fault occurs in a T-connected line. Therefore, this embodiment provides differential current phase information to determine the target dimension for fault location from two candidate dimensions, which can further improve the accuracy of fault location.

[0044] In one possible implementation, the raw three-wire data acquired by the line protection device may include the raw voltage and current values ​​of any phase line on each branch. The line protection device can determine the phase differential current value corresponding to each phase line in the T-connected line using multiple raw current values ​​from the raw three-wire data. After acquiring the voltage and current information of all branches, the line protection device can determine multiple raw current values ​​of each phase line on different branches. Based on a pre-set conversion factor, the line protection device can calculate the raw current values ​​of the three phase lines in all branches and generate converted current values ​​for the three phase lines in all branches. Based on the converted current values ​​of all branches, the line protection device can determine the phase differential current value corresponding to each of the three phase lines within the T-connected line.

[0045] In one possible implementation, the current conversion factor for a branch of a T-connected line can be equal to the CT ratio of that branch divided by the CT ratio of the branch where the line protection device is located. That is, the current conversion factor can be expressed by the following formula:

[0046]

[0047] Where, k N CT can represent the current conversion factor corresponding to a branch of a T-connected line; N can represent the branch number used to calculate the current conversion factor; n can represent the branch number where the line protection device currently used for fault location is located; N This can represent the ratio between the transformed currents on both sides of the current transformer in the branch for which the current conversion factor is calculated, i.e., the CT ratio of the branch for which the current conversion factor is calculated; CT n It can represent the ratio between the currents converted on both sides of the current transformer in the branch where the line protection device is located, that is, the CT ratio of the branch where the line protection device is located.

[0048] In one possible implementation, the equivalent current value of a branch on the T-connection can be equal to the original current value of that branch multiplied by the conversion factor.

[0049] In one possible implementation, the phase difference current value of any phase line in a T-connected line can be equal to the vector sum of the current values ​​of that phase line in each branch.

[0050] For example, after acquiring the original three-phase data of all branches, the first line protection device located on the first branch can determine the A1 phase current value I of the first branch. A1 The current value I of phase B1 B1 The current value I of phase line C1 C1 The first line protection device can also determine the A2 phase current value I of the second branch. A2 The current value I of phase B2 B2 The current value I of phase line C2 C2 The first line protection device can also determine the A3 phase current value I of the third branch. A3 The current value I of phase B3 B3 The current value I of phase line C3 C3 The first line protection device located on the first branch can also determine the CT ratio of the first branch based on the original three-phase data of all branches. L1 The second branch CT transformer ratio CT L2 CT ratio of the third branch CT L3 Based on the pre-set current conversion factor formula and the CT ratio of each branch, the first line protection device located on the first branch can determine the first current conversion factor k for the first branch. L1 The second current conversion factor k for the second branch L2 The third current conversion factor k of the third branch L3 The current conversion factor for each branch can be represented by the following formula:

[0051]

[0052] After determining the current conversion factor for each branch, the first line protection device located on the first branch can calculate the converted current of the three phase lines of each branch based on the current conversion factor. Specifically, the first line protection device located on the first branch can multiply the original current value of the first branch by the current conversion factor k corresponding to the first branch. L1 The first line protection device can also multiply the original current value of the second branch by the current conversion factor k corresponding to the second branch. L2 The first line protection device can also multiply the original current value of the third branch by the current conversion factor k corresponding to the third branch. L3The first line protection device generates the equivalent current value for the third branch. After generating the equivalent current values ​​for all branches on the T-connection, it can determine the phase differential current value corresponding to each phase line based on the equivalent current values ​​of all branches.

[0053] Specifically, the first line protection device can calculate the equivalent current value I` of phase A1 on the first branch. A1 The equivalent current value I` of phase A2 on the second branch. A2 The equivalent current value I` of phase A3 on the third branch. A3 The vector sum between them is used to generate the phase difference current value I corresponding to phase line A. da The first line protection device can also calculate the equivalent current value I` of phase B1 on the first branch. B1 The calculated current value I` of phase B2 on the second branch. B2 The calculated current value I` of phase B3 on the third branch. B3 The vector sum between them is used to generate the phase difference current value I corresponding to phase line B. db The first line protection device can also calculate the equivalent current value I` of phase C1 on the first branch. C1 The equivalent current value I` of phase C2 on the second branch. C2 The calculated current value I` of phase C3 on the third branch. C3 The vector sum between them is used to generate the phase difference current value I corresponding to phase line C. dc .

[0054] Specifically, in such Figure 1 In the T-connection line shown, when a short-circuit fault occurs in phases BC of the third branch, the line protection device can determine |I da -0.1*I n >0 is not true, |I db -0.1*I n >0 is true, |I dc -0.1*I n Since >0 is true, the line protection device can determine that the differential current phase information is 2 at this time. Because Figure 1 The T-connection shown can contain three phase lines: A, B, and C. Therefore, the line protection device can determine that the differential current phase information is less than the total number of phase lines. Thus, the line protection device can determine that the target dimension for fault location is the negative sequence dimension; that is, the line protection device can locate faults through the negative sequence component among multiple electrical components.

[0055] S203. Identify the fault location in the T-connection line based on the electrical components corresponding to all the branches in the target dimension.

[0056] In this embodiment, after determining the target dimension based on differential current phase information, the line protection device can determine the electrical components corresponding to all branches under the target dimension. After determining the electrical components corresponding to all branches under the target dimension, the line protection device can identify the fault location in the T-connected line based on the determined electrical components.

[0057] In one possible implementation, after determining the electrical components of all branches in the target dimension, the line protection device can first determine the impedance value of each branch. The line protection device can obtain the total length of each branch. Based on the total length of each branch, the line protection device can determine the impedance value of each branch. After determining the impedance value of each branch, the line protection device can calculate the branch components of each branch based on the impedance value and the electrical components. When calculating the branch components of a particular branch, the line protection device can import the impedance value and voltage component of the branch currently being calculated, as well as the electrical components of other branches, into a pre-set branch component conversion function. The line protection device can then calculate the branch components of each branch based on the pre-set branch component conversion function. After calculating the branch components of each branch, the line protection device can determine the fault location of the T-connected line based on multiple branch components.

[0058] In one possible implementation, the impedance value of a branch can be equal to the unit positive sequence impedance value of that branch multiplied by the total length of that branch.

[0059] In one possible implementation, the branch component transformation function can be expressed as follows:

[0060]

[0061]

[0062]

[0063] Where, α L1 It can represent the branch component of the first branch; α L2 It can represent the branch component of the second branch; α L3 It can represent the branch component of the third branch; Re() can represent taking the real part of the complex number for calculation; φ can be 1 or 2. When the line protection device judges the target dimension as a positive sequence dimension, φ can be 1, and when the line protection device judges the target dimension as a negative sequence dimension, φ can be 2. This can represent the impedance value of the first branch; This can represent the impedance value of the second branch; This can represent the impedance value of the third branch; It can represent the positive or negative sequence components of the phase difference current value of the phase line. The phase difference current value I can be obtained from phase line A. da Phase difference current value I of phase line B db The phase difference current value I of phase line C dc Calculated using the symmetric component calculation method; It can represent the positive-sequence voltage component or the negative-sequence voltage component of the first branch; It can represent the positive-sequence voltage component or the negative-sequence voltage component of the second branch; It can represent the positive-sequence voltage component or the negative-sequence voltage component of the third branch; It can represent the positive sequence current component or the negative sequence current component of the first branch; It can represent the positive sequence current component or the negative sequence current component of the second branch; It can represent the positive sequence current component or the negative sequence current component of the third branch.

[0064] Specifically, in such Figure 1 In the T-connected line shown, a short circuit fault occurred in phase BC of the third branch. Since the line protection device has determined the target dimension to be the negative sequence dimension based on the differential current phase information, the electrical components of each branch in the negative sequence dimension can be imported into the pre-set branch component conversion function.

[0065] Taking the first branch as an example, the calculation process of the branch components of the non-faulty branch can be as follows.

[0066]

[0067] Taking the third branch as an example, the calculation process of the branch component of the faulty branch can be as follows.

[0068]

[0069] Therefore, for Figure 1 The T-connection shown indicates that the line protection device can determine the branch component of the first branch as follows: The branch components of the second branch are The branch components of the third branch are Therefore, the line protection device can obtain α. L1 ≥1, α L2 ≥1 and α L3 ≤1. Wherein, It can represent the impedance value corresponding to the distance FP between the fault point F and the endpoint P.

[0070] In this embodiment, the line protection device can calculate the branch component corresponding to each branch based on the electrical components of all branches, and determine the fault location of the T-connected line based on the branch components of all branches. Therefore, the method provided in this embodiment for fault location of the T-connected line does not require pre-selection of the faulty branch before fault location. Thus, the fault location method provided in this embodiment is simpler and more effective, with more convenient steps. Moreover, the method provided in this embodiment does not rely on pre-selection of the faulty branch, resulting in higher accuracy.

[0071] In one possible implementation, after obtaining the branch components of each branch, the line protection device can determine whether all branch components are 1. If all branch components are 1, the line protection device can determine that the fault location of the T-connected line is at the junction of the T-connected line, and the fault distance of any branch is the branch length. If any branch component is not 1, the line protection device can determine the faulty branch and fault distance of the T-connected line based on pre-set abnormal branch detection conditions and the branch components of all branches. The line protection device can then generate the fault location of the T-connected line based on the obtained faulty branch and fault distance.

[0072] In one possible implementation, before determining the fault location of the T-connected line based on the branch components, the line protection device can also determine whether the generated multiple branch components are less than 0. If any branch component is less than 0, the line protection device can assign a value of 0 to all branch components less than 0.

[0073] In this embodiment, the line protection device performs error correction on the branch components corresponding to each branch by determining whether the branch component is less than 0 and assigning a value of 0 to the branch components that are less than 0. This effectively avoids calculation deviations of the branch components caused by sampling errors of the line protection device and line parameter errors when the fault point is located at the outlet of a branch. Therefore, after error correction, the effectiveness of the fault location method provided in this embodiment can be further improved.

[0074] In one possible implementation, if any branch component is not equal to 1, the line protection device can determine the faulty branch from multiple branch components. If the line protection device determines that the branch component corresponding to any branch is within a pre-set fault component range, it can identify the branch whose branch component is within the pre-set fault component range as the faulty branch. After determining the faulty branch, the line protection device can obtain the total length of the branch corresponding to the faulty branch. Based on the total length of the faulty branch and the branch component corresponding to the faulty branch, the line protection device can determine the fault distance of the faulty branch.

[0075] In this embodiment of the application, if the branch component corresponding to a certain branch is less than 1, and the branch components of all other branches are greater than 1, then the line protection device can identify the branch with a branch component less than 1 as a faulty branch.

[0076] In this embodiment of the application, the formula for calculating the fault distance can be as follows:

[0077] L = α 故障 *L 全长

[0078] Where L can represent the fault distance, α 故障 L can represent the branch component corresponding to the faulty branch. 全长 It can represent the total length of the branch corresponding to the faulty branch.

[0079] Specifically, in the embodiments of this application, the relationship between each branch component and the fault location can be as follows:

[0080] As shown in Table 1:

[0081]

[0082] As shown in Table 1, when the branch component of all branches is equal to 1, the line protection device can determine the fault point as the junction of the T-connection line, and the fault distance is the total length of each branch. When the branch component corresponding to the first branch is less than 1, and the branch components of the second and third branches are both greater than 1, the line protection device can determine the faulty branch as the first branch; when the branch component corresponding to the second branch is less than 1, and the branch components of the first and third branches are both greater than 1, the line protection device can determine the faulty branch as the second branch; when the branch component corresponding to the third branch is less than 1, and the branch components of the second and first branches are both greater than 1, the line protection device can determine the faulty branch as the third branch. Based on the branch component and total length of the faulty branch, the line protection device can determine the fault distance of each branch.

[0083] like Figure 3The diagram illustrates a fault location process according to an embodiment of this application. Upon receiving a fault detection command, the line protection devices on each branch of the T-connection can begin collecting the original three-phase data of the branch where the line protection device is located, and transmit the collected original three-phase data to other line protection devices via a three-terminal fiber optic differential channel. After receiving the original three-phase data from all branches, any line protection device on the T-connection can filter the received data and calculate the voltage and current information of each branch. Based on the voltage and current information of all branches, the line protection device can determine the differential current phase information of the T-connection. Based on the differential current phase information, the line protection device can select from multiple electrical components contained in the voltage and current information and select the electrical component used for fault location. By importing the electrical components corresponding to each branch into a pre-set branch component conversion function, the line protection device can determine the branch components corresponding to each branch. After calculating the branch components corresponding to each branch, the line protection device can first perform error correction on the branch components corresponding to each branch. In essence, the line protection device can determine whether there are branch components with values ​​less than 0. If such components exist, the device assigns them a value of 0. After error correction, the device checks if all branch components are equal to 1. If so, the device identifies the fault point of the T-connected line as the T-connection point, and the fault distance as the total length of the branch containing the protection device. If any branch component is not equal to 1, the device identifies the branch whose component falls within a pre-defined fault component range as the faulty branch. Based on the branch component and total length of the faulty branch, the device determines the fault distance between the fault point and the branch endpoint.

[0084] In this embodiment, the line protection device can determine the differential current phase information of the T-connected line based on the voltage and current information of all branches. Based on the differential current phase information of the T-connected line, the line protection device can select positive-sequence or negative-sequence components from the electrical components for fault location. By importing the selected electrical components into a pre-set branch component conversion function, the line protection device can determine the branch components corresponding to each branch. Based on the branch components corresponding to each branch, the line protection device can select the faulty branch of the T-connected line and calculate the fault distance. The method provided in this embodiment for fault location of the T-connected line is not only convenient and reliable, but also achieves accurate fault location under metallic faults, high-resistance faults, and weak feeder-side faults in the T-connected line. Therefore, the fault location method provided in this embodiment is not only simple and efficient, but also widely applicable.

[0085] It should be noted that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0086] Reference Figure 4 This diagram illustrates a fault location device for a T-connected line according to an embodiment of this application. Specifically, it may include a voltage and current information acquisition module 401, a target dimension determination module 402, and a fault location identification module 403, wherein:

[0087] The voltage and current information acquisition module 401 is used to acquire the voltage and current information of all branches on the T-connection line if a fault detection command is received from any branch within the T-connection line; the voltage and current information includes electrical components of at least two candidate dimensions.

[0088] The target dimension determination module 402 is used to determine differential current phase information based on all the voltage and current information, and to determine the target dimension for fault location from the candidate dimensions according to the differential current phase information.

[0089] The fault location identification module 403 is used to identify the fault location in the T-connection line based on the electrical components corresponding to all the branches in the target dimension.

[0090] The target dimension determination module 402 can also be used to determine the phase differential current value of each phase line in the T-connected line based on the original three-wire data of all the branches; determine the number of phase lines whose phase differential current value is greater than the preset rated differential current value, and use the number of phase lines as the differential current phase information; if the differential current phase information is equal to the total number of phase lines in the T-connected line, then the positive sequence dimension is determined as the target dimension; if the differential current phase information is greater than 0 and less than the total number of phase lines, then the negative sequence dimension is determined as the target dimension; if the differential current phase information is equal to 0, then the fault detection process ends.

[0091] The target dimension determination module 402 can also be used to calculate the original current values ​​of the three phase lines of all branches according to the preset conversion coefficient to generate the converted current values ​​of the three phase lines of all branches; and determine the phase difference current value corresponding to the three phase lines according to the converted current values ​​of all branches.

[0092] The target dimension determination module 402 can also be used to determine the impedance value of each branch according to the total length of each branch; import the impedance value, voltage component and electrical components of other branches except the branch into a preset branch component conversion function to calculate the branch component corresponding to the branch; and determine the fault location of the T-connection line according to all the branch components.

[0093] The target dimension determination module 402 can also be used to identify the fault location of the T-connection line as the junction of the T-connection line if all the branch components are 1; if any of the branch components are not 1, then the faulty branch and the fault distance are determined according to the preset abnormal branch detection conditions and all the branch components; and the fault location is generated according to the faulty branch and the fault distance.

[0094] The target dimension determination module 402 can also be used to identify the branch as the faulty branch if the branch component of any branch is within a preset fault component range; obtain the total length of the faulty branch; and determine the fault distance of the faulty branch based on the total length of the branch and the branch component corresponding to the faulty branch.

[0095] The target dimension determination module 402 can also be used to assign the value of the branch component that is less than 0 to 0 if any of the branch components is less than 0.

[0096] As the apparatus embodiments are basically similar to the method embodiments, they are described in a relatively simple manner. For relevant details, please refer to the description in the method embodiment section.

[0097] Reference Figure 5 The diagram illustrates a terminal device provided in an embodiment of this application. Figure 5 As shown, the terminal device 500 in this embodiment includes: a processor 510, a memory 520, and a computer program 521 stored in the memory 520 and executable on the processor 510. When the processor 510 executes the computer program 521, it implements the steps in various embodiments of the fault location method for the T-connected line described above, for example... Figure 2 The steps S201 to S203 are shown. Alternatively, when the processor 510 executes the computer program 521, it implements the functions of each module / unit in the above-described device embodiments, for example... Figure 4 The functions of modules 401 to 405 are shown.

[0098] For example, the computer program 521 can be divided into one or more modules / units, which are stored in the memory 520 and executed by the processor 510 to complete this application. The one or more modules / units can be a series of computer program instruction segments capable of performing specific functions, which can be used to describe the execution process of the computer program 521 in the terminal device 500. For example, the computer program 521 can be divided into a voltage and current information acquisition module, a target dimension determination module, and a fault location identification module, with the specific functions of each module as follows:

[0099] The voltage and current information acquisition module is used to acquire the voltage and current information of all branches on the T-connection line if a fault detection command is received from any branch within the T-connection line; the voltage and current information includes electrical components of at least two candidate dimensions.

[0100] The target dimension determination module is used to determine differential current phase information based on all the voltage and current information, and to determine the target dimension for fault location from the candidate dimensions according to the differential current phase information;

[0101] The fault location identification module is used to identify the fault location in the T-connection line based on the electrical components corresponding to all the branches in the target dimension.

[0102] The terminal device 500 may be the line protection device in the foregoing embodiments. The terminal device 500 may include, but is not limited to, a processor 510 and a memory 520. Those skilled in the art will understand that... Figure 5 This is merely one example of terminal device 500 and does not constitute a limitation on terminal device 500. It may include more or fewer components than shown, or combine certain components, or different components. For example, terminal device 500 may also include input / output devices, network access devices, buses, etc.

[0103] The processor 510 can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor can be a microprocessor or any conventional processor.

[0104] The memory 520 can be an internal storage unit of the terminal device 500, such as a hard disk or memory of the terminal device 500. The memory 520 can also be an external storage device of the terminal device 500, such as a plug-in hard disk, Smart Media Card (SMC), Secure Digital (SD) card, Flash Card, etc., equipped on the terminal device 500. Furthermore, the memory 520 can include both internal and external storage units of the terminal device 500. The memory 520 is used to store the computer program 521 and other programs and data required by the terminal device 500. The memory 520 can also be used to temporarily store data that has been output or will be output.

[0105] This application also discloses a terminal device, including a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the fault location method for the T-connection line as described in the foregoing embodiments.

[0106] This application also discloses a computer-readable storage medium storing a computer program that, when executed by a processor, implements the fault location method for T-connected lines as described in the foregoing embodiments.

[0107] This application also discloses a computer program product that, when run on a computer, causes the computer to execute the fault location method for the T-connected line described in the foregoing embodiments.

[0108] The embodiments described above are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A fault location method for a T-connected line, characterized in that, include: If a fault detection command is received from any branch within the T-connection line, the voltage and current information of all branches on the T-connection line is obtained. The voltage and current information includes electrical components in at least two candidate dimensions; Differential current phase information is determined based on all the voltage and current information, and a target dimension for fault location is determined from the candidate dimensions based on the differential current phase information. Based on the electrical components corresponding to all the branches in the target dimension, identify the fault location in the T-connection line; The T-connection includes three phase lines, and each branch is constructed based on these three phase lines; the candidate dimensions include positive-sequence and negative-sequence dimensions; the voltage and current information includes raw three-wire data; determining differential current phase information based on all the voltage and current information, and determining the target dimension for fault location from the candidate dimensions based on the differential current phase information, includes: Based on the original three-wire data of all the branches, determine the phase difference current value of each phase wire in the T-connection line; The number of phase lines whose phase differential current value is greater than the preset rated differential current value is determined, and the number of phase lines is used as the differential current phase information; If the differential phase information is equal to the total number of phase lines in the T-connection line, then the positive sequence dimension is determined as the target dimension. If the differential phase information is greater than 0 and less than the total number of phase lines, then the negative order dimension is determined to be the target dimension; If the differential phase information is equal to 0, the fault detection process ends.

2. The method according to claim 1, characterized in that, The step of determining the phase difference current value of each phase line in the T-connection line based on the original three-wire data of all the branches includes: The original current values ​​of the three phase lines of all branches are calculated based on the preset conversion coefficients to generate the converted current values ​​of the three phase lines of all branches. The phase difference current values ​​corresponding to the three phase lines are determined based on the converted current values ​​of all the branches.

3. The method according to claim 1 or 2, characterized in that, The electrical components include voltage components; identifying the fault location in the T-connection line based on the electrical components corresponding to all the branches in the target dimension includes: The impedance value of each branch is determined based on the total length of the branch corresponding to each branch. The impedance value and voltage component of the branch, as well as the electrical components of other branches besides the branch, are imported into a preset branch component conversion function to calculate the branch component corresponding to the branch. The fault location of the T-connection is determined based on all the branch components.

4. The method according to claim 3, characterized in that, Determining the fault location of the T-connector based on all the branch components includes: If all the branch components are 1, then the fault location of the T-connection line is identified as the junction of the T-connection line. If any of the branch components is not 1, the faulty branch and the fault distance are determined according to the preset abnormal branch detection conditions and all the branch components. The fault location is generated based on the faulty branch and the fault distance.

5. The method according to claim 4, characterized in that, If any of the branch components is not equal to 1, then based on the preset abnormal branch detection conditions and all the branch components, the faulty branch and the fault distance are determined, including: If any branch component of a branch is within a preset fault component range, then the branch is identified as the faulty branch. Obtain the total length of the faulty branch; The fault distance of the faulty branch is determined based on the total length of the branch and the branch component corresponding to the faulty branch.

6. The method according to claim 4, characterized in that, Before determining the fault distance of the faulty branch based on the total length of the branch and the fault component, the following steps are included: If any of the branch components is less than 0, then the branch component less than 0 is assigned a value of 0.

7. A fault location device for a T-connected line, characterized in that, include: The voltage and current information acquisition module is used to acquire the voltage and current information of all branches on the T-connection line if a fault detection command is received from any branch within the T-connection line. The voltage and current information includes electrical components in at least two candidate dimensions; The target dimension determination module is used to determine differential current phase information based on all the voltage and current information, and to determine the target dimension for fault location from the candidate dimensions according to the differential current phase information; The fault location identification module is used to identify the fault location in the T-connection line based on the electrical components corresponding to all the branches in the target dimension. The T-connection includes three phase lines, and each branch is constructed based on the three phase lines; the candidate dimension includes a positive-sequence dimension and a negative-sequence dimension; the voltage and current information includes the original three-wire data; the target dimension determination module is also used for: Based on the original three-wire data of all the branches, determine the phase difference current value of each phase wire in the T-connection line; The number of phase lines whose phase differential current value is greater than the preset rated differential current value is determined, and the number of phase lines is used as the differential current phase information; If the differential phase information is equal to the total number of phase lines in the T-connection line, then the positive sequence dimension is determined as the target dimension. If the differential phase information is greater than 0 and less than the total number of phase lines, then the negative order dimension is determined to be the target dimension; If the differential phase information is equal to 0, the fault detection process ends.

8. A terminal 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 computer program, it implements the fault location method for the T-connection line as described in any one of claims 1-6.

9. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by the processor, it implements the fault location method for T-connected lines as described in any one of claims 1-6.

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