Low-voltage user current-leakage localization method and apparatus, and storage medium

Abstract

The present application discloses a low-voltage user current-leakage localization method and apparatus, and a storage medium. The method comprises: performing clock synchronization processing on terminal devices mounted at ports in a power line network; calculating propagation delays between the ports on the basis of information collected by the terminal devices; using the calculated propagation delays between the ports in the power line network to calculate propagation distances between the ports; transmitting the propagation distances between the ports to a master node; the master node using the propagation distances between the ports to determine a unique tree topology network structure, so as to construct a power line topology based on an end-to-end delay; and using the constructed power line topology and an electromagnetic time reversal technology to localize a plurality of indoor current-leakage points, so as to implement multi-port collaborative time reversal-based current-leakage localization. In the present application, a power line carrier is used to implement topology construction of a low-voltage line network, and a current-leakage fault is sensed and localized. The present application can be widely used in the field of current-leakage localization.

Description

Low-voltage user electric leakage positioning method and device and storage medium TECHNICAL FIELD

[0001] The present application relates to the field of indoor electric leakage positioning, and in particular to a low-voltage user electric leakage positioning method and device and storage medium. BACKGROUND

[0002] As an important public infrastructure, the power distribution network plays an important role in ensuring power supply, supporting economic and social development, and serving the improvement of people's livelihood. Low-voltage distribution lines are distributed in densely populated areas, with extensive coverage and complex operating environment, and there are many electric leakage hazards. Electric leakage failure not only causes electric shock and endangers personal safety, but also may cause electrical fire due to the continuous deterioration of the electric leakage site. Therefore, timely and accurate elimination of the electric leakage site in the early stage of electric leakage is an important prerequisite for ensuring the safety of low-voltage power distribution network.

[0003] Unlike the medium and high voltage side, the low-voltage line network topology is complex and difficult to obtain. In addition, most of the low-voltage side lines are buried cables, buried in walls and underground, and cannot use conventional electric leakage current positioning equipment such as Rogowski coils, making it difficult to achieve low-voltage side electric leakage positioning. In addition, electric leakage has a certain concealment, which is affected by the environment and weather, such as high humidity of the wall in the back-to-south season, resulting in missed or misjudgment by maintenance personnel, leaving serious safety hazards. SUMMARY

[0004] To at least partially solve one of the technical problems existing in the prior art, the purpose of the present application is to provide a low-voltage user electric leakage positioning method and device based on power line carrier perception and storage medium.

[0005] The first technical solution adopted by the present application is:

[0006] A low-voltage user electric leakage positioning method, comprising the following steps:

[0007] Clock synchronization processing is performed on the terminal device installed at each port in the power line network;

[0008] After the clock synchronization processing, the propagation time delay between each port is calculated according to the information collected by the terminal device;

[0009] The propagation distance between each port is calculated using the propagation time delay calculated by each port in the power line network;

[0010] The propagation distance between each port is transmitted to the same terminal device node, and the terminal device node is referred to as the master node;

[0011] The master node determines a unique tree topology network structure by using the propagation distance of each port, and realizes automatic construction of the power line topology based on end-to-end delay.

[0012] The indoor multiple leakage points are positioned by using the constructed power line topology and the electromagnetic time reversal technology, so as to realize the time reversal leakage positioning of the multi-port cooperation.

[0013] Further, the clock synchronization processing of the terminal equipment installed in each port in the power line network comprises:

[0014] A broadband power line communication equipment (such as a smart meter and a smart switch) deployed at the selected power line network port is selected as a reference equipment for clock synchronization;

[0015] All terminal equipments measure the power line carrier delay of the reference equipment and send the clock information of the terminal equipment itself;

[0016] The clock of each terminal equipment is calibrated by the reference equipment according to the measured propagation delay, so as to realize high-precision clock synchronization of the equipment between each port based on the carrier.

[0017] Further, each terminal equipment does not need to realize clock synchronization with a satellite clock, but needs to ensure that the clocks of each terminal equipment are as synchronized as possible.

[0018] Further, the calculation of the propagation delay between each port according to the data collected by the terminal equipment comprises:

[0019] Suppose that the terminal equipments of any two ports of the power line network are i and j, and the propagation delay t ij between the two terminal equipments i and j is obtained at the terminal equipment i by using a delay measurement module.

[0020] The calculation formula of the propagation delay t ij is: t ij = [(t4-t1)-(t3-t2)] / 2

[0021] In the formula, the terminal equipment i sends a ranging data packet at t1, the terminal equipment j receives it at t2, and after processing, the data packet is sent to the terminal equipment i at t3, and the terminal equipment i receives it at t4.

[0022] Further, the calculation formula of the propagation distance between the ports is: d ij =v p t ij

[0023] In the formula, v p represents the propagation speed of the signal in the power line network topology, and tij This is to account for the transmission delay.

[0024] Furthermore, the formula for calculating the propagation speed is:

[0025] In the formula, L represents the equivalent inductance per unit length of the power line, and C represents the equivalent capacitance per unit length of the power line.

[0026] Furthermore, the master node utilizes the propagation distance d of each port. ij In determining a unique tree-structured network topology, it is necessary to determine the number of nodes K in the network topology, given the node set D for each port and the root node s; let V represent the determined set of tree nodes and their distances to the root node s; first, take a node from set D and denote it as i, then take nodes from set V and denote them as j, and use the three nodes i, j, and s to calculate the distance q between node j and the root node s in the network topology. j The expression is: q j =(d is +d js -d ij ) / 2

[0027] In the formula, d is d represents the distance between node i and node s. js d represents the distance between node j and node s. ij This represents the distance between node i and node j.

[0028] Furthermore, the master node uses the propagation distance of each port to determine a unique tree-like topology network structure, including:

[0029] Obtain multiple distances q j Then, the maximum distance q j The corresponding node is denoted as k, and the position of node k is determined according to a preset rule; the preset rule is: when When , the parent node of node i is s, node i is added to set V and removed from node set D; when At that time, the distance q k This is the distance between the intermediate node k and the root node s. The parent node of node i is k. Add the intermediate node k and node i to set V and remove them from the node set D.

[0030] Traverse all distances until the node set D is empty, and obtain a unique result set V, which contains the structure and distance information of the tree network topology; where Δd represents the resolution of the electrical length.

[0031] Furthermore, the principle of the electromagnetic time reversal technology is as follows:

[0032] wherein U(x,t) represents the voltage on the power line, x is the position on the power line, and t is the time; L represents the unit length equivalent inductance of the power line, and C represents the unit length equivalent capacitance of the power line;

[0033] wherein according to the time reversal invariance of the wave equation, if U(x,t) is a solution of the wave equation, then U(x,-t) is also a solution of the wave equation.

[0034] The second technical solution adopted by the present application is:

[0035] A low-voltage user electric leakage positioning device, comprising:

[0036] at least one processor;

[0037] at least one memory for storing at least one program;

[0038] When the at least one program is executed by the at least one processor, the at least one processor implements the above method.

[0039] The third technical solution adopted by the present application is:

[0040] A computer-readable storage medium, wherein a processor-executable program is stored, and the processor-executable program is used to execute the above method when executed by a processor.

[0041] The beneficial effects of the present application are: the present application realizes high-precision device clock synchronization and automatic construction of power line network topology, provides topology information for electric leakage positioning, and realizes indoor electric leakage positioning by combining the acquired power line topology information with electromagnetic time reversal technology and noise spatial data. BRIEF DESCRIPTION OF DRAWINGS

[0042] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following introduces the drawings of the related technical solutions in the embodiments of the present application or the prior art. It should be understood that the drawings in the following introduction are only for the convenience of clearly describing part of the embodiments of the technical solutions of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor on the basis of these drawings.

[0043] Fig. 1 is a step flow chart of a low-voltage user electric leakage positioning method based on power line carrier sensing in an embodiment of the present application;

[0044] Fig. 2 is an automatic construction diagram of a power line network topology in an embodiment of the present application;

[0045] Fig. 3 is a high-precision positioning result diagram of multiple electric leakage faults in an embodiment of the present application. DETAILED DESCRIPTION

[0046] The embodiments of the present application are described below in detail with examples shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary only, for the purpose of explaining the present application, and should not be understood as a limitation of the present application. For the step numbers in the following embodiments, they are only set for the convenience of illustrating the description, and the order between the steps is not limited in any way, and the execution order of each step in the embodiments can be adaptively adjusted according to the understanding of those skilled in the art.

[0047] In the description of the present application, it should be understood that the orientation description, such as the orientation or position relationship indicated by up, down, front, back, left, right, etc. is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0048] In the description of the present application, the meaning of several is one or more, and the meaning of multiple is two or more than two, greater than, less than, more than, etc. are understood as not including the number, and above, below, etc. are understood as including the number. If it is described as first, second, it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the order of indicated technical features. In addition, "and / or" describes the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B can represent: A exists alone, A and B exist together, and B exists alone. The character " / " generally represents an "or" relationship between the front and rear associated objects.

[0049] In the description of the present application, unless otherwise explicitly limited, the words such as setting, installing, connecting, etc. should be broadly understood, and those skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical solution.

[0050] In view of the existing technical problems, the present application carries out research on leakage positioning of low-voltage cable network with unknown complex topology, aiming to further improve the safety of low-voltage distribution network side power utilization, and provide convenient and efficient leakage point accurate positioning algorithm and device for power grid users. The present application intends to use power line carrier to realize the topology construction of low-voltage line network, and to perceive and position the leakage fault. On this basis, the present application develops a leakage detection technical solution to facilitate power grid personnel to quickly eliminate and repair faults, and to provide value-added services such as line aging evaluation and power utilization quality evaluation, and to improve the user's power utilization experience.

[0051] As shown in FIG. 1, the embodiment provides a low-voltage user leakage positioning method based on power line carrier sensing. The method is directed to a low-voltage user leakage scenario, overcomes the difficulties of unknown and complex low-voltage side topology, and cable buried in wall and hidden leakage point, and realizes power line topology sensing and accurate positioning of leakage point in combination with power line carrier. The method specifically includes the following steps.

[0052] S101, select one of the broadband power line communication devices (such as smart meters and smart switches) deployed at the power line network port as a reference device for clock synchronization, and measure the power line carrier time delay of the reference device through other terminal devices, while sending the clock information of the terminal device itself.

[0053] It should be noted that the terminal devices in step S1 do not need to achieve clock synchronization with the satellite clock, but need to ensure that the clocks of the terminal devices are as synchronized as possible.

[0054] S102, calibrate the clock of each terminal device using the propagation delay measured by the reference device, and realize high-precision device clock synchronization between each port based on carrier.

[0055] S103, use the data obtained by the terminal devices at the network ports after clock synchronization to perform point-to-point time delay measurement. Assuming that the devices at any two ports of the power line network are i and j, the propagation time delay between the two devices i and j can be obtained at device i using the time delay measurement module. ij ;

[0056] Specifically, the propagation time delay t ij in step S103 is expressed as follows: t ij = [(t4-t1)-(t3-t2)] / 2

[0057] Wherein, device i sends the ranging data packet at t1, device j receives it at t2, after processing, the data packet is sent to device i at t3, and device i receives it at t4.

[0058] S104, use the propagation time delay t ij measured by each port of the power line network to calculate the distance d ij between each port, and then transmit the distance of each port to a same device node, and the node is called a master node.

[0059] Specifically, the propagation distance calculation expression using the propagation time delay of each port in step S104 is as follows: d ij =v p t ij

[0060] where v p represents the propagation speed of signals in the power line network topology.

[0061] In addition, the expression of the propagation speed required in the calculation of the propagation distance is:

[0062] where L represents the equivalent inductance per unit length of the power line, and C represents the equivalent capacitance per unit length of the power line.

[0063] S105, the master node determines the distance d ij of each port, and determines a unique tree topology network structure, and implements automatic construction of the power line topology based on the end-to-end delay.

[0064] As an optional implementation, in step S105, the master node determines the transmission distance d ij of each port, and determines a unique tree topology network structure. j j is js ij

[0065] In addition, in step S105, the master node determines the transmission distance of each port to determine a unique tree topology network structure, and calculates a plurality of q j After that, the node corresponding to the maximum q j distance is recorded as k, and then the position of the node needs to be determined according to the rules. The rules are as follows: when , the parent node of node i is s, node i is added to V, and D is removed from D; when , q k is the distance between the intermediate node k and the root node s, the parent node of node i is k, the intermediate node k and node i are added to V, and D is removed from D. Such a cycle continues until D is empty, at which time a unique result V is obtained, which contains the structure and distance information of the tree network topology. Where Δd represents the resolution of the electrical length.

[0066] S106, using the constructed power line topology and electromagnetic time reversal technology to locate multiple leakage points in the room, and realizing multi-port cooperative time reversal leakage positioning.

[0067] ​​​​​The relevant principle of the time reversal technique is:

[0068] Wherein according to the time reversal invariance of wave equation, if U(x, t) is a solution of wave equation, then U(x, -t) is also a solution of wave equation.

[0069] The above method is explained in detail in combination with specific embodiments.

[0070] Referring to FIG. 1, the present example provides a low-voltage user leakage positioning method based on power line carrier sensing. In the present example, a three-port network containing four nodes is used to obtain the time delay between the end-to-end, and the power line topology network is automatically constructed, as shown in FIG. 2. A known probe signal (Gaussian pulse signal) is actively sent to the network, and the leakage positioning is performed in combination with the time reversal technique and noise spatial data, wherein the number of leakage is two, and the number of ports N is three.

[0071] S201, select the broadband power line communication device 1 deployed at the port 1 of the power line network port as a clock synchronization reference device, and the device 2 at the port 2 and the device 3 at the port 3 perform power line carrier time delay measurement on the reference device, while sending the clock information of the device itself.

[0072] S202, calibrate the clock of the other two terminal devices using the propagation time delay measured by the reference device 1, and realize high-precision device clock synchronization between the three ports based on the carrier.

[0073] S203, use the data obtained by the measurement terminal at each port of the network after clock synchronization to perform point-to-point time delay measurement. Assuming that the devices of any two ports of the power line network are i and j, the propagation time delay between the two devices i and j can be obtained at the device i using the time delay measurement module. ij , t 12 , t 13 , t 23 .

[0074] S204, use the propagation time delays t 12 , t 13 , t 23 obtained by measuring each port of the power line network to know the relationship expression between the propagation time delays of each port: t 12 = t 14 + t 24 t 13 = t 14 + t 34 t 23 = t 24 + t 34

[0075] In addition, the node 1 is set as the master node, and according to the propagation delay, the distance expression between the various ports can be obtained as: d 12 = v p t 12 d 13 = v p t 13 d 23 = v p t 23

[0076] wherein v p represents the propagation speed of the signal in the power line network topology.

[0077] S205, the master node utilizes the known distance d ij of each port to calculate the distance q4 between the intermediate node 4 and the master node 1, to determine a unique tree-shaped topology network structure, and the constructed topology result is consistent with the topology in FIG. 2.

[0078] S206, the indoor multiple electric leakage points are positioned by utilizing the constructed power line topology and the electromagnetic time reversal technology, to realize the time reversal electric leakage positioning of the multi-port cooperation.

[0079] The data measured by the three ports in step S206 includes the transmitted signal and the received signal, and the scattering parameters can be calculated by utilizing the signals of each port. Generally, the incident wave voltage a i and the outgoing voltage b j of each port are utilized to describe,

[0080] The scattering parameters of the three ports in step S206 can construct the scattering matrix expression as:

[0081] In step S206, the time reversal operator can be constructed by utilizing the scattering matrix wherein, represents the Hermitian conjugate transpose, and S s (ω) represents the scattering matrix. And the time reversal operator is subjected to eigenvalue decomposition:

[0082] wherein, Λ(ω) is a real diagonal matrix containing eigenvalues, and U(ω) is an eigenvector matrix. The eigenvalues in the real diagonal matrix Λ(ω) are sorted, and the smallest eigenvalue min(λ i (ω)) is selected and constitutes the noise space U N (ω).

[0083] In step S206, the spatial energy spectrum can be constructed by utilizing the noise space to position the electric leakage point, and the spatial energy spectrum calculation formula is:

[0084] wherein g(x, ω) is a vector composed of the Green's functions of the normal measured network, defined as the voltage frequency-domain distribution values at each location x of the measured network when the excitation source is applied at each test port respectively, which can be obtained according to the transmission line theory and the related knowledge of electromagnetic topology. Φ(x, ω) will form a peak at the leakage location, and the accurate positioning of multiple leakage locations can be realized by searching the peak location in the distribution of Φ(x, ω). Referring to FIG. 3, FIG. 3 is a high-precision positioning result diagram of multiple leakage faults.

[0085] In summary, the present application has at least the following advantages and beneficial effects relative to the prior art:

[0086] (1) The present application realizes the automatic construction of the power line network topology. The low-voltage line network topology is complex and most of the cables are buried in walls and underground, which cannot be used with conventional leakage current positioning equipment such as clamp meters and Rogowski coils, making it difficult to realize low-voltage side leakage positioning. The present application can realize the automatic construction of topology information and provide topology information for low-voltage side leakage positioning.

[0087] (2) The multi-port cooperative time reversal leakage point positioning technology adopted by the present application can realize the accurate positioning of multiple leakage points.

[0088] The embodiment also provides a low-voltage user leakage positioning device, which comprises:

[0089] at least one processor;

[0090] at least one memory for storing at least one program;

[0091] When the at least one program is executed by the at least one processor, the at least one processor realizes the method shown in FIG. 1.

[0092] The low-voltage user leakage positioning device of the embodiment can execute the low-voltage user leakage positioning method provided by the method embodiment of the present application, can execute any combination of the method embodiment implementation steps, and has the corresponding functions and beneficial effects of the method.

[0093] The embodiment of the present application also discloses a computer program product or a computer program, which comprises computer instructions stored in a computer readable storage medium. The processor of the computer device can read the computer instructions from the computer readable storage medium, and the processor executes the computer instructions to make the computer device execute the method shown in FIG. 1.

[0094] The embodiment also provides a storage medium storing instructions or programs for implementing the low-voltage user leakage positioning method provided in the embodiment of the application. When the instructions or programs are run, any combination of the method embodiments can be implemented to have the corresponding functions and advantages of the method.

[0095] In some alternative embodiments, the functions / operations mentioned in the block diagram can not occur in the order mentioned in the operation diagram. For example, depending on the functions / operations involved, two blocks shown in succession can actually be executed substantially simultaneously or the blocks can sometimes be executed in reverse order. In addition, the embodiments presented and described in the flowcharts of the present application are provided by way of example, with the purpose of providing a more comprehensive understanding of the technology. The disclosed method is not limited to the operations and logical flows presented herein. Alternative embodiments are contemplated in which the order of various operations is changed and in which sub-operations described as part of larger operations are independently executed.

[0096] In addition, although the present application is described in the context of functional modules, it should be understood that, unless otherwise stated to the contrary, one or more of the described functions and / or features can be integrated in a single physical device and / or software module, or one or more functions and / or features can be implemented in separate physical devices or software modules. It can also be understood that a detailed discussion of the actual implementation of each module is unnecessary for an understanding of the present application. Rather, given the properties, functions and internal relationships of the various functional modules in the devices disclosed herein, the actual implementation of the module will be within the routine skill of an engineer, given the benefit of this disclosure. Therefore, a person skilled in the art can implement the present application as set forth in the claims without undue experimentation using ordinary skill. It can also be understood that the disclosed specific concepts are merely illustrative and are not intended to limit the scope of the present application, which is determined by the full scope of the appended claims and their equivalents.

[0097] If the functions are implemented in the form of software function units and sold or used as independent products, they can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application essentially or the parts of the prior art that make contributions or parts of the technical solutions can be embodied in the form of a software product, which is stored in a storage medium and includes a number of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various media that can store program codes.

[0098] The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a list of executable instructions for implementing logic functions, which can be embodied in any computer readable medium for use by or in connection with an instruction execution system, apparatus or device, such as a computer-based system, a system including a processor or other system that can fetch instructions from an instruction execution system, apparatus or device and execute the instructions, or in conjunction with these instruction execution systems, apparatus or devices. For the purpose of this specification, "computer readable medium" can be any device that can contain, store, communicate, propagate or transport programs for use by or in connection with an instruction execution system, apparatus or device, or in conjunction with these instruction execution systems, apparatus or devices.

[0099] More specific examples (non-exhaustive list) of computer readable medium include the following: electrical connections having one or more wires (electronic devices), portable computer diskette (magnetic devices), random access memory (RAM), read only memory (ROM), erasable programmable read only memory (EPROM or flash memory), fiber optic devices, and portable compact disk read only memory (CDROM). In addition, the computer readable medium can even be paper or other suitable medium on which the program can be printed, because the program can be obtained electronically, for example, by optical scanning of the paper or other medium, followed by editing, interpreting or otherwise processing the obtained program with the aid of a computer, and then storing it in a computer memory.

[0100] It should be understood that portions of the application can be realized with hardware, software, firmware or a combination thereof. In the foregoing description, multiple steps or methods can be realized as software or firmware to be executed by a suitable instruction executing system. For example, if realized with hardware, and as in another embodiment, any one or a combination of the following technologies known in the art can be used: discrete logic circuitry having logic gates for implementing logic functions on data signals, application specific integrated circuits having appropriate combinational logic gates, programmable gate arrays (PGA), field programmable gate arrays (FPGA), and the like.

[0101] In the above description of the present specification, the description of the terms "one embodiment", "another embodiment", or "certain embodiments" or the like means that the specific features, structures, materials or characteristics described in connection with the embodiments or examples are included in at least one embodiment or example of the present application. In the present specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Also, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0102] Although the embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made thereto without departing from the principles and spirit of the present application, the scope of which is defined by the claims and their equivalents.

[0103] The above is a specific description of the preferred embodiments of the present application, but the present application is not limited to the above-described embodiments, and those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present application, and these equivalent modifications or substitutions are included in the scope defined by the claims of the present application.

Claims

1. A low voltage user earth leakage location method characterised by, The method comprises the following steps: clock synchronization processing is performed on terminal devices installed at each port in a power line network; propagation time delays between each port are calculated according to information collected by the terminal devices after the clock synchronization processing; propagation distances between each port are calculated using the propagation time delays calculated at each port in the power line network; the propagation distances between each port are transmitted to a same terminal device node, which is referred to as a master node; a unique tree topology network structure is determined by the master node using the propagation distances of each port, and a power line topology based on end-to-end time delays is constructed; a plurality of electric leakage points are located indoors using the constructed power line topology and electromagnetic time reversal technology, so as to realize time reversal electric leakage location in cooperation with a plurality of ports.

2. The low voltage user earth leakage location method as claimed in claim 1 wherein, The clock synchronization processing performed on the terminal devices installed at each port in the power line network comprises: a broadband power line communication device already deployed at a port of the power line network is selected as a reference device for clock synchronization; all terminal devices perform power line carrier time delay measurement on the reference device, and simultaneously send clock information of the terminal devices themselves; clocks of each terminal device are calibrated by the reference device according to the measured propagation time delays, so as to realize carrier-based device clock synchronization between each port.

3. The low voltage user earth leakage location method as claimed in claim 1 wherein, The calculation of the propagation time delays between each port according to data collected by the terminal devices comprises: Assuming that the terminal devices of any two ports of the power line network are i and j respectively, the propagation delay t between the two terminal devices i and j is obtained at the terminal device i by using the delay measurement module ij ; propagation delay t ij The formula for calculating t is: t ij = [(t4-t1)-(t3-t2)] / 2 In the formula, terminal device i sends a ranging data packet at t1, terminal device j receives it at t2, and the data packet is sent to terminal device i after processing at t3, and terminal device i receives it at t4.

4. The low voltage user earth leakage location method as claimed in claim 1 wherein, The formula for calculating the propagation distance between ports is: d ij = v p t ij where v p represents the propagation speed of signals in the power line network topology, t ij is the propagation time delay.

5. A low voltage user earth leakage location method as claimed in claim 4 wherein, The calculation formula of the propagation speed is: In the formula, L represents the unit length equivalent inductance of the power line, and C represents the unit length equivalent capacitance of the power line.

6. The low voltage user earth leakage location method as claimed in claim 1 wherein, The master node utilizes the propagation distance d of each port ij In the process of determining the unique tree structure network topology, the number of nodes K of the network topology needs to be determined, the node set D of each port is known, and the root node s is known; V represents the determined tree node set and their distance to the root node s; first, a node in the set D is taken out and marked as i, then a node in the set V is taken out in turn and marked as j, and the distance q between the node j and the master node s in the network topology is calculated by using the three nodes i, j and s j , and the expression is: j = (d is +d js -d ij ) / 2 where d is denotes the distance between node i and node s, d js denotes the distance between node j and node s, d ij denotes the distance between node i and node j.

7. A low voltage user earth leakage location method as claimed in claim 6 wherein, The determination of a unique tree topology network structure by the master node using the propagation distances of each port comprises: A plurality of distances q are obtained j Afterwards, the largest distance q j The corresponding node is denoted as k, and the position of the node k is determined according to a preset rule; the preset rule is that when If s is not in V, then the parent of node i is s, node i is added to the set V, and removed from the set D of nodes. At time t, distance q k is the distance between intermediate node k and root node s, the parent node of node i is k, intermediate node k and node i are added to set V, and are removed from node set D; all distances are traversed until the node set D is empty, and a unique result set V is obtained, which contains the structure and distance information of the tree network topology; wherein Δd represents the resolution of the electrical length.

8. The low voltage user earth leakage location method as claimed in claim 1 wherein, The principle of the electromagnetic time reversal technique is as follows: In the formula, U(x, t) represents the voltage on the power line, x is the position on the power line, and t is the time; L represents the unit length equivalent inductance of the power line, and C represents the unit length equivalent capacitance of the power line; According to the time reversal invariance of the wave equation, if U(x, t) is a solution of the wave equation, then U(x, -t) is also a solution of the wave equation.

9. A low voltage consumer earth leakage locating device, characterised in that, The method comprises: at least one processor; at least one memory for storing at least one program; when the at least one program is executed by the at least one processor, the at least one processor implements the method of any one of claims 1-8.

10. A computer readable storage medium having stored therein a program which is executable by a processor, characterized in that, The program executable by the processor, when executed by the processor, is used to execute the method of any one of claims 1-8.

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