Fault detection and location method for distribution network

Abstract

The present application is about a method for detecting and locating fault points in a distribution network. The method includes: (1) detecting the current amplitude; (2) detecting whether the detection time is received; (3) obtaining the first fault reporting information and the second fault reporting information, and obtaining the current cycle information of N detection nodes according to the detection time; (4) judging whether a ground fault occurs and calculating the fault distance according to the current cycle information and the detection time. The solution provided by the present application monitors the current amplitude in the line in real time. When the current amplitude exceeds a preset threshold, the detection device sends information to the upper system and the remaining phase detection devices of the same detection node respectively; the upper system determines the fault line and the accurate position of the fault point on the fault line through the current cycle information and the corresponding detection time, thereby realizing online monitoring of the fault point of the distribution network.

Description

Technical Field

[0001] The present application relates to the technical field of power system control and automation, and in particular to a method for detecting and locating fault points in a distribution network. Background Art

[0002] The structure of the distribution network is complex, with many branches and long tributaries. When a fault occurs, it is necessary to manually patrol the lines one by one or use the distribution network line fault online monitoring system to determine the location of the fault. Manual patrol is time-consuming and inefficient.

[0003] The existing online monitoring system for distribution network line faults is based on zero-sequence voltage as the fault initiation element, but it faces the problem that it is difficult to collect zero-sequence voltage on overhead transmission lines, and can only achieve "section" positioning of the fault. However, the precise positioning of the fault point still requires manual line patrol, which results in long power outages and is time-consuming and labor-intensive. Summary of the invention

[0004] In order to overcome the problems existing in the related art, the present application provides a distribution network fault point detection and positioning method. When a fault occurs, by collecting the current cycle information of the three-phase line, the fault line in the three-phase line can be determined, and the accurate fault position on the fault line can be calculated based on the current cycle information.

[0005] The first aspect of the present application provides a method for detecting and locating a fault point in a distribution network, comprising the following steps:

[0006] (1) Detect current amplitude;

[0007] If the current amplitude exceeds the preset threshold, the first fault reporting information is sent to the upper system and the detection time is sent to the associated detection device; the first fault reporting information includes the detection time, current cycle information and detection node location information; the detection node is the branch three-phase circuit detection node; the associated detection device is the other phase line detection device of the same detection node; if not, continue to detect;

[0008] (2) detecting whether the detection time is received;

[0009] If yes, then send the second fault reporting information to the upper system; the second fault reporting information includes the detection node location information and the current cycle information corresponding to the detection time; if no, then continue the detection;

[0010] (3) obtaining the first fault reporting information and the second fault reporting information, and obtaining the current cycle information of the N detection nodes according to the detection time;

[0011] (4) Determine whether a ground fault occurs and calculate the fault distance based on the current cycle information and the detection time.

[0012] In one embodiment, if the current amplitude exceeds a preset threshold, sending the first fault reporting information to the upper system also includes: if the current amplitude exceeds the preset threshold, immediately sending a timing request to the satellite to obtain the satellite timing as the detection time.

[0013] In one implementation, before detecting the current amplitude, the method further includes: collecting current traveling wave data and storing the current traveling wave data.

[0014] In one implementation, the current cycle information is the current traveling wave data of the first 4 cycles and the last 8 cycles recorded at the detection time.

[0015] In one implementation, the detection node location information is satellite positioning information or detection node sequence number information.

[0016] In one embodiment, the obtaining of the current cycle information of the N detection nodes specifically includes: determining the fault line according to the detection node position information of the first fault reporting information, and obtaining the current cycle information of the N detection nodes adjacent to the fault line.

[0017] In one embodiment, judging whether a ground fault occurs according to the current cycle information and the detection time further includes: synthesizing the zero-sequence currents of the three-phase lines respectively according to the current cycle information of the detection node; and determining whether there is a fault line with a ground fault at the detection node according to the zero-sequence current phase difference of the fault line and the non-fault line being 180° and the zero-sequence current of the fault line being equal to the sum of the zero-sequence currents of the non-fault lines.

[0018] In one implementation, judging the fault type and calculating the fault distance according to the current cycle information and the detection time specifically includes:

[0019] The grounding position of the fault line is calculated according to the time difference when the transient wave head of the zero-sequence current reaches the detection devices at both ends of the branch line.

[0020] A second aspect of the present application provides a distribution network fault point detection system, comprising:

[0021] A detection unit, used to detect the current amplitude and collect the current traveling wave data;

[0022] A processing unit, used to control the detection unit, the timing unit, the storage unit and the communication unit;

[0023] A timing unit, used to obtain satellite timing time as the detection time;

[0024] A communication unit, used to send information to a host system and other detection nodes;

[0025] A storage unit, used to store the current traveling wave data collected by the detection unit;

[0026] The upper system is used to receive the current cycle information and the detection time, synthesize the three-phase zero-sequence current of the detection node, determine whether the detection node has the fault line; and calculate the position of the fault point on the fault line.

[0027] The present application proposes a method for detecting and locating fault points in a distribution network, by setting current detection nodes at both ends of each branch line, and each detection node includes 3 detection devices to detect three-phase circuits respectively. The detection device monitors the current amplitude in the line in real time. When the current amplitude exceeds the preset threshold, the detection device sends information to the upper system and the remaining phase detection devices of the same detection node respectively; the upper system receives the current cycle information and the corresponding detection time, and requests the fault node and the detection node adjacent to the fault point to obtain the current cycle information corresponding to the detection time; the upper system calculates the time when the zero-sequence current transient wave in the fault line reaches the detection devices at both ends of the branch line through the two-terminal current traveling wave method, and then determines the exact position of the fault point on the branch line.

[0028] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above and other objects, features and advantages of the present application will become more apparent through a more detailed description of exemplary embodiments of the present application in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the present application.

[0030] Figure 1 It is a flow chart of a method for detecting and locating a fault point in a distribution network shown in an embodiment of the present application;

[0031] Figure 2 A schematic diagram of the installation of a distribution network fault point detection system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0032] The preferred embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present application are shown in the accompanying drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.

[0033] The terms used in this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The singular forms of "a", "said" and "the" used in this application and the appended claims are also intended to include plural forms unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items.

[0034] It should be understood that although the terms "first", "second", "third", etc. may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of this application, the first information may also be referred to as the second information, and similarly, the second information may also be referred to as the first information. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0035] Embodiment 1

[0036] Figure 1 It is a flow chart of a method for detecting and locating fault points in a distribution network shown in an embodiment of the present application.

[0037] See also Figure 1 , including the following steps:

[0038] S1, detection current amplitude;

[0039] If the current amplitude of the line exceeds the preset threshold, the first fault reporting information is sent to the upper system and the detection time is sent to the associated detection device; the first fault reporting information includes the detection time, current cycle information and detection node location information; the detection node is the branch three-phase circuit detection node; the associated detection device is the other phase line detection device of the same detection node; if not, continue to detect;

[0040] In an embodiment of the present application, the distribution network branch line is a three-phase line. By setting detection nodes at both ends of each branch line, each detection node is provided with three detection devices to perform synchronous detection of the A phase, B phase and C phase lines of the three-phase line.

[0041] Furthermore, if the current amplitude exceeds a preset threshold, a timing request is immediately sent to the satellite to obtain the satellite timing time as the detection time.

[0042] Furthermore, before detecting the current amplitude, the method further includes: collecting current traveling wave data and storing the current traveling wave data.

[0043] Furthermore, the current amplitude is the current amplitude collected after passing through a filter and an amplifying circuit.

[0044] Furthermore, a Rogowski coil is used to collect the current traveling wave data.

[0045] Furthermore, the data sampling frequency of the current traveling wave data is 12.8 kHz and the sampling bit width is 16 bits.

[0046] Furthermore, the current cycle information is the current traveling wave data of the first 4 and last 8 cycles recorded during the detection time.

[0047] Furthermore, the detection node location information is satellite positioning information or detection node sequence number information.

[0048] In the embodiment of the present application, when a fault occurs in at least one phase line, the detection device detects that the current amplitude of the fault line exceeds a preset threshold, immediately obtains the timing time through satellite timing, and uses the timing time as the detection time, and packages it into the first fault reporting information; at the same time, the detection device uses the current traveling wave data of the first 4 and last 8 cycles with the detection time as the starting point as the current cycle information, and packages it into the first fault reporting information. After the detection device obtains the detection node location information and packages it into the first fault reporting information, it sends the first fault reporting information to the upper system; after the detection device sends the first fault reporting information, it sends the detection time to the remaining phase detection devices of the detection node.

[0049] S2. Detect whether the detection time is received;

[0050] If yes, then send the second fault reporting information to the upper system; the second fault reporting information includes the detection node location information and the current frequency information corresponding to the detection time;

[0051] If not, continue testing;

[0052] In an embodiment of the present application, in the same detection node, after the detection device on the non-fault line receives the detection time sent by the detection device on the faulty line, the current traveling wave data of the first 4 and last 8 cycles of the detection time are packaged as the current cycle information into the second fault reporting information; at the same time, after the detection node location information is packaged into the second fault reporting information, the second fault reporting information is sent to the upper system.

[0053] S3, obtaining the first fault reporting information and the second fault reporting information, and obtaining the current cycle information of the N detection nodes according to the detection time;

[0054] In an embodiment of the present application, after receiving the first fault reporting information and the second fault reporting information, the upper system extracts the detection time and the detection node location information, determines the branch line where the fault occurs, and sends the detection time to at least two of the detection nodes at both ends of the detection nodes on the branch line that have obtained the detection node location information; the upper system obtains the current frequency information corresponding to the detection time sent by at least two of the detection nodes.

[0055] S4. Determine whether a ground fault occurs and calculate a fault distance according to the current cycle information and the detection time.

[0056] Furthermore, the zero-sequence currents of the three-phase lines are synthesized respectively according to the current cycle information of the detection node; and it is determined whether the detection node has the fault line with a ground fault based on the fact that the phase difference between the zero-sequence currents of the fault line and the non-fault line is 180° and the zero-sequence current of the fault line is equal to the sum of the zero-sequence currents of the non-fault lines.

[0057] Furthermore, the grounding position of the fault line is calculated based on the time difference between the transient wave head of the zero-sequence current reaching the detection devices at both ends of the branch line.

[0058] In the embodiment of the present application, the current cycle information of phase A, phase B and phase C of the same detection node is obtained to synthesize the zero-sequence current. The faulty phase circuit is determined according to the zero-sequence current phase difference of each phase on the three-phase line and the magnitude of the zero-sequence current of each phase.

[0059] In an embodiment of the present application, the zero-sequence current cycle information of the two detection nodes before and after the fault line is obtained, and the location of the fault is calculated based on the time when the transient wave head of the zero-sequence current reaches the two detection nodes before and after.

[0060] In the embodiment of the present application, the synchronous detection of the current wave of the three-phase line is realized by setting the detection device in the three-phase line of the branch line; the detection device can record the current wave data for 3 hours, and the detection devices of the same detection node are connected to each other in communication, and the detection device can also be connected to the host system in communication. When a fault occurs, the detection device can detect the occurrence of the fault in the first time, and request the other phases of the detection device of the same detection node to send the current cycle information corresponding to the detection time to the host system; the host system obtains the current cycle information; the fault line and the accurate position of the fault point on the fault line are determined according to the current cycle information.

[0061] Embodiment 2

[0062] Based on the distribution network fault point detection and positioning method of embodiment 1, the present application also provides a distribution network fault point detection system of embodiment 2, including:

[0063] A detection unit, used to detect the current amplitude and collect the current traveling wave data;

[0064] A processing unit, used to control the detection unit, the timing unit, the storage unit and the communication unit;

[0065] A timing unit, used to obtain satellite timing time as the detection time;

[0066] A communication unit, used to send information to a host system and other detection nodes;

[0067] A storage unit, used to store the current traveling wave data collected by the detection unit;

[0068] The upper system is used to receive the current cycle information and the detection time, synthesize the three-phase zero-sequence current of the detection node, and determine whether the fault line exists at the detection node; determine the fault line and the accurate position of the fault point on the fault line according to the current cycle information.

[0069] In the embodiment of the present application, the current amplitude is detected in real time by the detection unit, and the current traveling wave data is collected. When a fault occurs, the timing unit obtains the satellite timing as the detection time, and the processing unit sends the current cycle information and the detection time in the storage unit to the host system through the communication unit. The host system receives the current cycle information and the detection time, synthesizes the three-phase zero-sequence current of the detection node, and determines the fault line and the accurate position of the fault point on the fault line according to the current cycle information.

[0070] In the embodiment of the present application, the detection unit is arranged at the detection node of each line; Figure 2 A schematic diagram of the installation of a distribution network fault point detection system provided in an embodiment of the present application; Figure 2As shown, the distribution network line 110 and the line 210 are connected in parallel on the trunk line 10, and the detection node 211 and the detection node 212 are respectively set at both ends of the line 210; the detection node 111 and the detection node 112 are respectively set at both ends of the line 110; the line 120 is connected between the detection node 111 and the detection node 112 of the line 110; the detection node 121 and the detection node 122 are also set at both ends of the line 120. The trunk line 10 and the branch line connected to the trunk line 10 are all three-phase lines, and the detection node includes 3 groups of detection devices for detecting the current amplitude of the three-phase line, collecting the current traveling wave data, and realizing the communication function between each unit.

[0071] Regarding the device in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated again here.

[0072] The scheme of the present application has been described in detail above with reference to the accompanying drawings. In the above embodiments, the description of each embodiment has its own emphasis. For the part that is not described in detail in a certain embodiment, refer to the relevant description of other embodiments. Those skilled in the art should also know that the actions and modules involved in the description are not necessarily required for the present application. In addition, it can be understood that the steps in the method of the embodiment of the present application can be adjusted in order, merged and deleted according to actual needs, and the modules in the device of the embodiment of the present application can be merged, divided and deleted according to actual needs.

[0073] In addition, the method according to the present application may also be implemented as a computer program or a computer program product, which includes computer program code instructions for executing some or all of the steps in the above method of the present application.

[0074] Alternatively, the present application can also be implemented as a non-temporary machine-readable storage medium (or computer-readable storage medium, or machine-readable storage medium) on which executable code (or computer program, or computer instruction code) is stored. When the executable code (or computer program, or computer instruction code) is executed by a processor of an electronic device (or electronic device, server, etc.), the processor executes part or all of the steps of the above-mentioned method according to the present application.

[0075] Those skilled in the art will further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the application herein may be implemented as electronic hardware, computer software, or combinations of both.

[0076] The flow chart and block diagram in the accompanying drawings show the possible architecture, function and operation of the system and method according to multiple embodiments of the present application. In this regard, each square box in the flow chart or block diagram can represent a part of a module, a program segment or a code, and the part of the module, the program segment or the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two continuous square boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or the flow chart, and the combination of the square boxes in the block diagram and / or the flow chart can be implemented with a dedicated hardware-based system that performs the specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0077] The embodiments of the present application have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or improvements to the technology in the market, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein.

Claims

1. A method for detecting and locating fault points in a distribution network, characterized in that: The following steps are involved: S1, detection current amplitude; If the current amplitude exceeds the preset threshold, a first fault reporting information is sent to the upper system and the detection time is sent to the associated detection device; the first fault reporting information includes the detection time, current cycle information and detection node location information; The detection node is a branch three-phase circuit detection node; the associated detection device is the remaining phase line detection device of the same detection node; If not, continue testing; S2. Detect whether the detection time is received; If yes, then send the second fault reporting information to the upper system; the second fault reporting information includes the detection node location information and the current frequency information corresponding to the detection time; If not, continue testing; S3, obtaining the first fault reporting information and the second fault reporting information, and obtaining the current cycle information of N detection nodes according to the detection time; N is an integer greater than zero; S4. Determine whether a ground fault occurs and calculate a fault distance according to the current cycle information and the detection time.

2. A method for detecting and locating a fault point in a distribution network according to claim 1, characterized in that: If the current amplitude exceeds the preset threshold, sending the first fault reporting information to the upper system also includes: If the current amplitude exceeds a preset threshold, a timing request is immediately sent to the satellite to obtain the satellite timing time as the detection time.

3. A method for detecting and locating a fault point in a distribution network according to claim 1, characterized in that: The detection current amplitude also includes: Collect current traveling wave data and store the current traveling wave data.

4. A method for detecting and locating a fault point in a distribution network according to claim 3, characterized in that: The current cycle information is the current traveling wave data of the first 4 cycles and the last 8 cycles recorded during the detection time.

5. A method for detecting and locating a fault point in a distribution network according to claim 1, characterized in that: The detection node location information is satellite positioning information or detection node sequence number information.

6. A method for detecting and locating a fault point in a distribution network according to claim 1, characterized in that: The step of obtaining the current cycle information of the N detection nodes specifically includes: The fault line is determined according to the detection node position information of the first fault reporting information, and the current cycle information of the N detection nodes adjacent to the fault line is obtained.

7. A method for detecting and locating a fault point in a distribution network according to claim 1, characterized in that: The determining whether a ground fault occurs according to the current cycle information and the detection time further includes: Synthesize zero-sequence currents of three-phase lines respectively according to the current cycle information of the detection nodes; According to the zero-sequence current phase difference between the fault line and the non-fault line being 180° and the zero-sequence current of the fault line being equal to the sum of the zero-sequence currents of the non-fault lines, it is determined whether the detection node has the fault line with a ground fault.

8. A method for detecting and locating a fault point in a distribution network according to claim 7, characterized in that: The determining of the fault type and calculating the fault distance according to the current cycle information and the detection time specifically includes: The grounding position of the fault line is calculated according to the time difference when the transient wave head of the zero-sequence current reaches the detection devices at both ends of the branch line.

9. A distribution network fault point detection system, based on the distribution network fault point detection and positioning method according to any one of claims 1 to 8, characterized in that: include: A detection unit, used to detect the current amplitude and collect the current traveling wave data; A timing unit, used to obtain satellite timing time as the detection time; A communication unit, used to send information to a host system and other detection nodes; A storage unit, used to store the current traveling wave data collected by the detection unit; A processing unit, used to control the detection unit, the timing unit, the storage unit and the communication unit; A host system, used for receiving the current cycle information and the detection time, synthesizing the three-phase zero-sequence current of the detection node, and determining whether there is a fault line at the detection node; The position of the fault point on the fault line is calculated.

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