Power cable fault in-trench positioning system and method

Abstract

The invention discloses a power cable fault in-trench positioning system which comprises a pulse generator, a reference measurement station and a mobile measurement station. The pulse generator periodically applies pulse signals to the power cable to excite a fault point of the power cable to emit sound signals; the reference measurement station obtains a first coordinate position of the reference measurement station and a first magnetic signal, a vibration signal and a sound signal stamped with timestamps, and sends the first coordinate position and the first magnetic signal, the vibration signal and the sound signal to the mobile measurement station; the mobile measurement station establishes communication with the reference measurement station after being movably installed and fixed each time, and obtains a second coordinate position where the mobile measurement station is located each time and a second magnetic signal, a vibration signal and a sound signal which are stamped with timestamps; and the final position of the fault point is determined in combination with the first coordinate position obtained by the reference measurement station and the first magnetic signal, the vibration signal and the sound signal stamped with the time stamp. The method has the advantages of being good in stability, high in positioning precision, high in positioning speed and the like, and manpower troubleshooting and trench digging are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of power systems, and in particular, to a power cable fault in-ditch positioning system and method. Background Art

[0002] Power cables are an important part of power systems and an important guarantee for the development of the modern national economy and people's livelihood. Especially in urban areas with high population density, as the power system expands with the urbanization process, the scale of power cable laying becomes larger and larger. For the consideration of saving limited land area in the city and beautifying the environment, most power cables are buried underground or in cable trenches, which has become the main way of cable laying. As the service life extends, power cable faults are inevitable. Although regular safety inspections and fault troubleshooting of power cables can effectively reduce the probability of cable faults, if the fault point of the power cable cannot be located in time when a fault occurs, it will cause great inconvenience and economic losses to surrounding factories and residents. Therefore, it is necessary for power cable managers to quickly and accurately find the fault points of faulty cables, thereby improving the reliability of power cable power supply, reducing losses and maintenance costs. Therefore, fast and accurate power cable fault location not only has social practical significance but also has engineering practical value.

[0003] The environment where buried power cables are located is relatively complex, resulting in relatively difficult detection and location of power cable faults. The operation steps of power cable fault detection can be divided into determining the nature of the cable fault, roughly measuring the fault distance, searching for the path of the faulty power cable, and precisely locating the point. The so-called precise location is to limit the position of the fault point within a very small range, avoiding the impact of large-area excavation on surrounding and other pipelines, and at the same time improving the efficiency of fault troubleshooting.

[0004] However, the current power cable fault troubleshooting method still mainly relies on the original manual excavation of trenches for one-by-one investigation. Even with the support of relatively advanced devices such as sound discrimination and point searching, it is impossible to quickly and accurately find the location of the fault point of the power cable.

[0005] Therefore, there is an urgent need for a power cable fault location method with good stability, high positioning accuracy and fast positioning speed, which can achieve the purpose of reducing manual investigation and trench excavation. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a power cable fault in-ditch positioning system and method, which has the advantages of good stability, high positioning accuracy and fast positioning speed, and can achieve the purpose of reducing manual investigation and trench excavation.

[0007] To solve the above technical problems, an implementation system of a power cable fault in-ditch positioning system is provided in an embodiment of the present invention, including a pulse generator, a reference measurement station, and a mobile measurement station; wherein,

[0008] The pulse generator is loaded on the power cable in the cable trench;

[0009] The reference measurement station is fixedly installed in the cable trench; the reference measurement station is provided with a first satellite signal receiver, a first wireless communication module, and a first electromagnetic sensor, a first vibration sensor, and a first microphone all connected to the power cable;

[0010] The mobile measurement station is movably installed in the cable trench, and after each movable installation, it maintains a certain distance from the reference measurement station and establishes communication with the reference measurement station; the mobile measurement station is provided with a second satellite signal receiver, a second wireless communication module, a data calculation module, and a second electromagnetic sensor, a second vibration sensor, and a second microphone all connected to the power cable; the second wireless communication module of the mobile measurement station realizes communication interconnection and establishment with the first wireless communication module of the reference measurement station;

[0011] Among them, the pulse generator is used to periodically apply a high-voltage DC pulse signal to the power cable, so as to excite the fault point to emit a sound signal when there is a fault point in the power cable;

[0012] The reference measurement station is used to obtain its own first coordinate position based on the satellite by using the first satellite signal receiver, and timestamp the first magnetic signal, the first vibration signal, and the first sound signal generated when the power cable is applied with a high-voltage DC pulse signal by the pulse generator respectively by using the first electromagnetic sensor, the first vibration sensor, and the first microphone, and further use the first wireless communication module to send the obtained first coordinate position and the timestamped first magnetic signal, first vibration signal, and first sound signal to the mobile measurement station;

[0013] The mobile measurement station is used to, when establishing communication with the reference measurement station after each movable installation and fixation, obtain its own second coordinate position after each movable installation and fixation based on the satellite by using the second satellite signal receiver, and timestamp the second magnetic signal, the second vibration signal, and the second sound signal generated when the power cable is applied with a high-voltage DC pulse signal by the pulse generator respectively by using the second electromagnetic sensor, the second vibration sensor, and the second microphone, and further use the second wireless communication module to receive the first coordinate position and the timestamped first magnetic signal, first vibration signal, and first sound signal sent by the reference measurement station; and,

[0014] Based on the second coordinate positions obtained after each activity is installed and fixed, as well as the second magnetic signal, second vibration signal, and second sound signal with time stamps, and in combination with the first coordinate positions sent by the reference measurement station received each time, as well as the first magnetic signal, first vibration signal, and first sound signal with time stamps, the data calculation module determines the final position of the fault point in the power cable.

[0015] Wherein, an RTK system is formed between the mobile measurement station and the reference measurement station by using the satellite, the first satellite signal receiver, and the second satellite signal receiver.

[0016] Wherein, the data calculation module includes:

[0017] The ranging start time determination sub-module is used to determine that the total number of times the mobile measurement station establishes communication with the reference measurement station after being actively installed and fixed is k, and based on the second magnetic signal with time stamps collected by the mobile measurement station in the 1st to kth times or the first magnetic signal with time stamps collected by the reference measurement station in the 1st to kth times, k starting times corresponding to the 1st to kth times when the mobile measurement station and the reference measurement station synchronously measure magnetic signals, vibration signals, and sound signals are extracted; wherein, k is a positive integer greater than 1;

[0018] The first time-of-flight ranging sub-module is used to extract the k end times when the mobile measurement station measures the second vibration signal corresponding to the 1st to kth times and the k end times when the reference measurement station measures the first vibration signal corresponding to the 1st to kth times based on the second vibration signal with time stamps collected by the mobile measurement station in the 1st to kth times and the first vibration signal with time stamps collected by the reference measurement station in the 1st to kth times, and in combination with the first coordinate positions obtained by the reference measurement station in the 1st to kth times and the second coordinate positions obtained by the mobile measurement station in the 1st to kth times, k first propagation speeds of the vibration signal during flight in the power cable are estimated, and further in combination with the k starting times extracted by the ranging start time determination sub-module corresponding to the 1st to kth times, k first time-of-flight ranging distances obtained by the mobile measurement station and the reference measurement station respectively based on the flight time of the vibration signal in the 1st to kth times are calculated;

[0019] The first intensity ranging sub-module is used to fit and obtain k first intensity ranging distances obtained by the mobile measurement station and the reference measurement station respectively based on the intensity of the vibration signal in the 1st to kth times by using a preset first received signal strength model based on the second vibration signal with time stamps collected by the mobile measurement station in the 1st to kth times and the first vibration signal with time stamps collected by the reference measurement station in the 1st to kth times;

[0020] The second time-of-flight ranging sub-module is used to extract, based on the timestamped second sound signals collected by the mobile measurement station 1 to k times and the timestamped first sound signals collected by the reference measurement station 1 to k times, the k end times when the mobile measurement station measures the second sound signals 1 to k times and the k end times when the reference measurement station measures the first sound signals 1 to k times, and combine the first coordinate positions obtained by the reference measurement station 1 to k times and the second coordinate positions obtained by the mobile measurement station 1 to k times to estimate the k second propagation speeds when the sound signals fly in the power cable, and further combine the k start times extracted by the ranging start time determination sub-module corresponding to 1 to k times to calculate the k second time-of-flight ranging distances obtained by the mobile measurement station and the reference measurement station respectively 1 to k times based on the time-of-flight of the sound signals in the air;

[0021] The second intensity ranging sub-module is used to fit, based on the timestamped second sound signals collected by the mobile measurement station 1 to k times and the timestamped first sound signals collected by the reference measurement station 1 to k times, using a preset second received signal strength model, the k second intensity ranging distances obtained by the mobile measurement station and the reference measurement station respectively 1 to k times based on the intensity of the sound signals in the air;

[0022] The third time-of-flight ranging sub-module is used to perform noise filtering on the timestamped second sound signals collected by the mobile measurement station 1 to k times and the timestamped first sound signals collected by the reference measurement station 1 to k times by using a preset multipath cancellation technique, further extract the k end times of the filtered second sound signals when the mobile measurement station measures 1 to k times and the k end times of the filtered first sound signals when the reference measurement station measures 1 to k times, and combine the first coordinate positions obtained by the reference measurement station 1 to k times and the second coordinate positions obtained by the mobile measurement station 1 to k times to estimate the k third propagation speeds when the filtered sound signals fly in the power cable, and combine the k start times extracted by the ranging start time determination sub-module corresponding to 1 to k times to calculate the k third time-of-flight ranging distances obtained by the mobile measurement station and the reference measurement station respectively 1 to k times based on the time-of-flight of the sound signals in the power cable;

[0023] The third intensity ranging sub-module is used to fit, based on the filtered second sound signals corresponding to the mobile measurement station 1 to k times and the filtered first sound signals corresponding to the reference measurement station 1 to k times, using a preset third received signal strength model, the k third intensity ranging distances of the mobile measurement station and the reference measurement station respectively 1 to k times based on the intensity of the sound signals in the power cable;

[0024] The fault point positioning sub-module is used to construct an objective function based on the k first flight ranging distances, k second flight ranging distances, k third flight ranging distances, k first intensity ranging distances, k second intensity ranging distances, and k third intensity ranging distances obtained by the mobile measurement station corresponding to 1 to k times, and the k first flight ranging distances, k second flight ranging distances, k third flight ranging distances, k first intensity ranging distances, k second intensity ranging distances, and k third intensity ranging distances obtained by the reference measurement station corresponding to 1 to k times, and in combination with six preset weighting weights, and use the particle swarm optimization algorithm and the Levenberg-Marquardt algorithm to find the optimal solution of the objective function, and the obtained optimal solution is output as the final position of the fault point in the power cable.

[0025] Among them, the objective function is Among them,

[0026] is the estimated position of the fault point in the power cable; p is the quantity to be estimated of the fault point position; the superscript j represents the measurement times, and j = 1, 2,..., k; the subscript r represents the reference measurement station; the subscript m represents the mobile measurement station; d represents the distance; the subscript i represents the type of measured distance; w i represents the i-th weighting weight, and represents the first flight ranging distance obtained by the reference measurement station corresponding to the k-th time, represents the first flight ranging distance obtained by the mobile measurement station corresponding to the k-th time, represents the first intensity ranging distance obtained by the reference measurement station corresponding to the k-th time, represents the first intensity ranging distance obtained by the mobile measurement station corresponding to the k-th time, represents the second flight ranging distance obtained by the reference measurement station corresponding to the k-th time, represents the second flight ranging distance obtained by the mobile measurement station corresponding to the k-th time, represents the second intensity ranging distance obtained by the reference measurement station corresponding to the k-th time, represents the second intensity ranging distance obtained by the mobile measurement station corresponding to the k-th time, represents the third flight ranging distance obtained by the reference measurement station corresponding to the k-th time, represents the third flight ranging distance obtained by the mobile measurement station corresponding to the k-th time; represents the third intensity ranging distance obtained by the reference measurement station corresponding to the k-th time, represents the third intensity ranging distance obtained by the mobile measurement station corresponding to the k-th time.

[0027] Among them, through the formula the first flight ranging distance corresponding to the reference measurement station at the k-th time is calculated as and the first flight ranging distance corresponding to the mobile measurement station at the k-th time Among them,

[0028] represents the first propagation speed corresponding to the k-th time when the vibration signal flies in the power cable, and represents the first coordinate position obtained by the reference measurement station at the k-th time; represents the second coordinate position obtained by the mobile measurement station at the k-th time;

[0029] Through the threshold method, represents the first vibration signal measured by the reference measurement station at the k-th time, represents the first vibration signal measured by the reference measurement station at the k-th time the end time of, represents the second vibration signal measured by the mobile measurement station at the k-th time, represents the second vibration signal measured by the mobile measurement station at the k-th time the end time of, f v is a fixed threshold parameter;

[0030] Through the threshold method, represents the first magnetic signal measured by the reference measurement station at the k-th time, represents the start time when the reference measurement station and the mobile measurement station synchronously measure magnetic signals, vibration signals and sound signals at the k-th time, f e is a fixed threshold parameter.

[0031] Among them, through the formula the second flight ranging distance corresponding to the reference measurement station at the k-th time is calculated as and the second flight ranging distance corresponding to the mobile measurement station at the k-th time Among them,

[0032] represents the second propagation speed corresponding to the k-th time when the sound signal flies in the air, and

[0033] Through the threshold method, represents the first sound signal measured by the reference measurement station at the k-th time, represents the end moment of the first sound signal measured by the reference measurement station corresponding to the k-th time represents the second sound signal measured by the mobile measurement station corresponding to the k-th time represents the second sound signal measured by the mobile measurement station corresponding to the k-th time end moment, f s is a fixed threshold parameter

[0034] Among them, through the formula the third flight ranging distance obtained by the reference measurement station corresponding to the k-th time is calculated and the third flight ranging distance obtained by the mobile measurement station corresponding to the k-th time Among them,

[0035] represents the third propagation speed corresponding to the k-th time when the sound signal flies in the power cable, and

[0036] through the threshold method, obtain represents the first sound signal measured by the reference measurement station corresponding to the k-th time the sound signal obtained after noise filtering represents the reference measurement station corresponding to the k-th time filtering the first sound signal the obtained sound signal end moment, represents the second sound signal measured by the mobile measurement station corresponding to the k-th time the sound signal obtained after noise filtering represents the mobile measurement station corresponding to the k-th time filtering the second sound signal the obtained sound signal end moment, f p is a fixed threshold parameter

[0037] Among them, through the formula calculate the first intensity ranging distance obtained by the reference measurement station corresponding to the k-th time

[0038] Through the formula calculate the first intensity ranging distance obtained by the mobile measurement station corresponding to the k-th time

[0039] Through the formula calculate the second intensity ranging distance obtained by the reference measurement station corresponding to the k-th time ​

[0040] Through the formula calculate the second intensity ranging distance corresponding to the mobile measurement station at the k-th time

[0041] Through the formula calculate the third intensity ranging distance corresponding to the reference measurement station at the k-th time

[0042] Through the formula calculate the third intensity ranging distance corresponding to the mobile measurement station at the k-th time

[0043] wherein, g v (·) represents a preset first received signal strength model, g s,1 (·) represents a preset second received signal strength model, g s,2 (·) represents a preset third received signal strength model, and these three received signal strength models are all functions of signal strength and distance and are fitted by specific experiments.

[0044] The embodiment of the present invention also provides a method for locating a fault in a power cable trench, which is implemented on the aforementioned power cable fault trench location system. The method includes the following steps:

[0045] The pulse generator periodically applies a high-voltage DC pulse signal to the power cable to excite the fault point to emit a sound signal when there is a fault point in the power cable;

[0046] The reference measurement station obtains its own first coordinate position, and stamps time stamps on the first magnetic signal, the first vibration signal, and the first sound signal generated when the power cable is applied with the high-voltage DC pulse signal by the pulse generator in real time, and further sends the obtained first coordinate position and the time-stamped first magnetic signal, first vibration signal, and first sound signal to the mobile measurement station;

[0047] When the mobile measurement station establishes communication with the reference measurement station after each active installation and fixation, it obtains the second coordinate position where it is located after each active installation and fixation, and stamps time stamps on the second magnetic signal, the second vibration signal, and the second sound signal generated when the power cable is applied with the high-voltage DC pulse signal by the pulse generator in real time, and combines the first coordinate position and the time-stamped first magnetic signal, first vibration signal, and first sound signal received from the reference measurement station each time to determine the final position of the fault point in the power cable.

[0048] When the mobile measurement station establishes communication with the reference measurement station after each mobile installation and fixation, the specific steps for obtaining the second coordinate position where it is located after each mobile installation and fixation, timestamping the second magnetic signal, second vibration signal, and second sound signal generated when the high-voltage DC pulse signal is applied to the power cable by the pulse generator in real time, and determining the final position of the fault point in the power cable by combining the first coordinate position sent by the reference measurement station each time and the timestamped first magnetic signal, first vibration signal, and first sound signal include:

[0049] Determine that the total number of times the mobile measurement station establishes communication with the reference measurement station after mobile installation and fixation is k, and based on the timestamped second magnetic signals collected by the mobile measurement station during 1 to k times or the timestamped first magnetic signals collected by the reference measurement station during 1 to k times, extract k starting moments corresponding to 1 to k times when the magnetic signals, vibration signals, and sound signals are synchronously measured between the mobile measurement station and the reference measurement station; where k is a positive integer greater than 1;

[0050] Based on the timestamped second vibration signals collected by the mobile measurement station during 1 to k times and the timestamped first vibration signals collected by the reference measurement station during 1 to k times, extract k ending moments when the mobile measurement station measures the second vibration signals corresponding to 1 to k times and k ending moments when the reference measurement station measures the first vibration signals corresponding to 1 to k times, and combine the first coordinate positions obtained by the reference measurement station during 1 to k times and the second coordinate positions obtained by the mobile measurement station during 1 to k times to estimate k first propagation speeds when the vibration signals fly in the power cable, and further combine the k starting moments extracted corresponding to 1 to k times to calculate k first flight ranging distances obtained by the mobile measurement station and the reference measurement station respectively based on the flight time of the vibration signals during 1 to k times;

[0051] Based on the timestamped second vibration signals collected by the mobile measurement station during 1 to k times and the timestamped first vibration signals collected by the reference measurement station during 1 to k times, use a preset first received signal strength model to fit and obtain k first intensity ranging distances obtained by the mobile measurement station and the reference measurement station respectively based on the intensity of the vibration signals during 1 to k times;

[0052] Based on the timestamped second sound signals collected by the mobile measurement station 1 to k times and the timestamped first sound signals collected by the reference measurement station 1 to k times, extract the k end times when the mobile measurement station measures the second sound signals 1 to k times and the k end times when the reference measurement station measures the first sound signals 1 to k times, and combine the first coordinate positions obtained by the reference measurement station 1 to k times and the second coordinate positions obtained by the mobile measurement station 1 to k times to estimate the k second propagation speeds when the sound signals fly in the power cable, and further combine the k start times extracted corresponding to 1 to k times to calculate the k second flight ranging distances obtained by the mobile measurement station and the reference measurement station respectively 1 to k times based on the flight time of the sound signals in the air;

[0053] Based on the timestamped second sound signals collected by the mobile measurement station 1 to k times and the timestamped first sound signals collected by the reference measurement station 1 to k times, use the preset second received signal strength model to fit and obtain the k second intensity ranging distances obtained by the mobile measurement station and the reference measurement station respectively 1 to k times based on the intensity of the sound signals in the air;

[0054] Use the preset multipath cancellation technology to filter the noise of the timestamped second sound signals collected by the mobile measurement station 1 to k times and the timestamped first sound signals collected by the reference measurement station 1 to k times, further extract the k end times of the filtered second sound signals of the mobile measurement station 1 to k times and the k end times of the filtered first sound signals of the reference measurement station 1 to k times, and combine the first coordinate positions obtained by the reference measurement station 1 to k times and the second coordinate positions obtained by the mobile measurement station 1 to k times to estimate the k third propagation speeds when the filtered sound signals fly in the power cable, and combine the k start times extracted corresponding to 1 to k times to calculate the k third flight ranging distances obtained by the mobile measurement station and the reference measurement station respectively 1 to k times based on the flight time of the sound signals in the power cable;

[0055] Based on the filtered second sound signals of the mobile measurement station 1 to k times and the filtered first sound signals of the reference measurement station 1 to k times, use the preset third received signal strength model to fit and obtain the k third intensity ranging distances obtained by the mobile measurement station and the reference measurement station respectively 1 to k times based on the intensity of the sound signals in the power cable;

[0056] According to the k first flight ranging distances, k second flight ranging distances, k third flight ranging distances, k first intensity ranging distances, k second intensity ranging distances, and k third intensity ranging distances obtained by the mobile measurement station corresponding to the 1st to kth times, and the k first flight ranging distances, k second flight ranging distances, k third flight ranging distances, k first intensity ranging distances, k second intensity ranging distances, and k third intensity ranging distances obtained by the reference measurement station corresponding to the 1st to kth times, and combined with six preset weighted weights, an objective function is constructed, and the particle swarm optimization algorithm and the Levenberg-Marquardt algorithm are used to find the optimal solution of the objective function, and the obtained optimal solution is output as the final position of the fault point in the power cable.

[0057] Implementing the embodiments of the present invention has the following beneficial effects:

[0058] 1. The present invention can realize the rapid positioning of power cable faults based on satellites, vibration signals, magnetic signals, and sound signals, so as to quickly and accurately locate the fault points of power cables in the complex environment of cable trenches in cities, providing tools and means for the safe operation and risk management of power cables. Therefore, it has advantages such as good stability, high positioning accuracy, and fast positioning speed, and can achieve the purpose of reducing manual inspection and excavation of trenches.

[0059] 2. The present invention uses satellites to form an RTK system with a reference measurement station and a mobile measurement station, thereby obtaining high-precision position information. Then, based on the coordinate information of the reference measurement station and the mobile measurement station, the propagation speeds of vibration signals and sound signals in the power cable, as well as the propagation speed of sound signals in the atmosphere, are calibrated in real time, thereby improving the distance estimation accuracy.

[0060] 3. The present invention converts the problem of estimating the fault point position in the objective function into a non-linear weighted least squares problem, and then uses a heuristic algorithm to solve it to gradually improve the fault point positioning accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0061] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, obtaining other drawings based on these drawings still belongs to the scope of the present invention.

[0062] Figure 1 It is a schematic structural diagram of a power cable fault in-trench positioning system provided by an embodiment of the present invention;

[0063] Figure 2Schematic diagram of the functional structure of a reference measurement station in a power cable fault trench location system provided by an embodiment of the present invention;

[0064] Figure 3 Schematic diagram of the functional structure of a mobile measurement station in a power cable fault trench location system provided by an embodiment of the present invention;

[0065] Figure 4 Schematic diagram of the functional structure of a data calculation module included in a mobile measurement station in a power cable fault trench location system provided by an embodiment of the present invention;

[0066] Figure 5 Schematic diagram of the application scenario of a power cable fault trench location system provided by an embodiment of the present invention;

[0067] Figure 6 Flowchart of a power cable fault trench location method provided by an embodiment of the present invention. Detailed implementation manners

[0068] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0069] As Figures 1 to 3 shown, in an embodiment of the present invention, a power cable fault trench location system is proposed, which includes a pulse generator 1, a reference measurement station 2, and a mobile measurement station 3; among them,

[0070] The pulse generator 1 is loaded on the power cable L in the cable trench;

[0071] The reference measurement station 2 is fixedly installed in the cable trench; as Figure 2 shown, the reference measurement station 2 is provided with a first satellite signal receiver 21, a first wireless communication module 22, and a first electromagnetic sensor 23, a first vibration sensor 24, and a first microphone 25 all connected to the power cable L;

[0072] The mobile measurement station 3 is movably installed in the cable trench, and after each movable installation, it maintains a certain distance from the reference measurement station 2 and establishes communication with the reference measurement station 2; as Figure 3 shown, the mobile measurement station 3 is provided with a second satellite signal receiver 31, a second wireless communication module 32, a data calculation module 36, and a second electromagnetic sensor 33, a second vibration sensor 34, and a second microphone 35 all connected to the power cable L; the second wireless communication module 32 of the mobile measurement station 3 realizes communication interconnection and establishment with the first wireless communication module 22 of the reference measurement station 2;

[0073] At this time, the pulse generator 1 is used to periodically (for example, once every 30S) apply a high-voltage DC pulse signal to the power cable L to excite a fault point (not shown) in the power cable L to emit a sound signal when a fault occurs in the power cable L;

[0074] The reference measurement station 2 is used to obtain its own first coordinate position based on a satellite (such as a Beidou satellite) using the first satellite signal receiver 21, and to timestamp the first magnetic signal, the first vibration signal, and the first sound signal generated when the power cable L is applied with a high-voltage DC pulse signal by the pulse generator 1, which are respectively collected in real time by the first electromagnetic sensor 23, the first vibration sensor 24, and the first microphone 25. Further, the obtained first coordinate position and the timestamped first magnetic signal, first vibration signal, and first sound signal are all sent to the mobile measurement station 3 by using the first wireless communication module 22;

[0075] The mobile measurement station 3 is used to, when establishing communication with the reference measurement station 2 after each active installation and fixation, based on the satellite, use the second satellite signal receiver 31 to obtain its own second coordinate position after each active installation and fixation, and to timestamp the second magnetic signal, the second vibration signal, and the second sound signal generated when the power cable L is applied with a high-voltage DC pulse signal by the pulse generator 1, which are respectively collected in real time by the second electromagnetic sensor 33, the second vibration sensor 34, and the second microphone 35. Further, the mobile measurement station 3 uses the second wireless communication module 32 to receive the first coordinate position and the timestamped first magnetic signal, first vibration signal, and first sound signal sent by the reference measurement station 2; and,

[0076] According to the second coordinate position obtained after each active installation and fixation, and the timestamped second magnetic signal, second vibration signal, and second sound signal, and in combination with the first coordinate position and the timestamped first magnetic signal, first vibration signal, and first sound signal received from the reference measurement station 2 each time, the data calculation module 36 determines the final position of the fault point in the power cable.

[0077] It can be understood that first, a reference station is randomly selected (as long as it is as far away from the fault point as possible), and then the reference measurement station 2 is placed on this reference station; secondly, the position of the mobile measurement station 3 can be changed multiple times. Each time the position is changed, the mobile measurement station 3 first forms an RTK system with the reference measurement station 2 using satellites, the first satellite signal receiver 21, and the second satellite signal receiver 22, so as to obtain high-precision position information in the local coordinate system, and then synchronously measure the magnetic signal, vibration signal, and sound signal. After that, the mobile measurement station 3 statistically analyzes the measurement results each time to estimate the final position of the fault point in the power cable. At this time, the number of times of establishing communication and performing measurements between the mobile measurement station 3 and the reference measurement station 2 can be to measure multiple times or only once at this position when the position is changed once, which is specifically set according to the actual situation.

[0078] It should be noted that the electromagnetic sensors, vibration sensors, and microphones used in the reference measurement station 2 and the mobile measurement station 3 have the same structures, and the sampling frequency of the magnetic signal is 1 kHz, the sampling frequency of the vibration signal is 2 kHz, and the sampling frequency of the sound signal is 48 kHz.

[0079] In the embodiment of the present invention, after each communication measurement is completed, the data collected by the reference measurement station 2 is sent to the mobile measurement station 3, and a fast position estimation of the fault point is performed in the data calculation module 36 of the mobile measurement station 3.

[0080] As Figure 4 shown, the data calculation module 36 includes a ranging start time determination sub-module 361, a first time-of-flight ranging sub-module 362, a first intensity ranging sub-module 363, a second time-of-flight ranging sub-module 364, a second intensity ranging sub-module 365, a third time-of-flight ranging sub-module 366, a third intensity ranging sub-module 367, and a fault point positioning sub-module 368.

[0081] The ranging start time determination sub-module 361 is used to determine that the total number of times of establishing communication with the reference measurement station after the mobile measurement station 3 is fixedly installed and moved (i.e., the total number of measurements) is k, and based on the second magnetic signals with time stamps collected by the mobile measurement station 3 in the 1 - kth times or the first magnetic signals with time stamps collected by the reference measurement station 2 in the 1 - kth times, k start times corresponding to the 1 - kth times of synchronously measuring the magnetic signal, vibration signal, and sound signal between the mobile measurement station 3 and the reference measurement station 2 are extracted; where k is a positive integer greater than 1;

[0082] For example, first, for the kth measurement, the first magnetic signal measured by the reference measurement station 2 and marked with a time stamp is denoted as and the second magnetic signal measured by the mobile measurement station 3 and marked with a time stamp is denoted as

[0083] Secondly, through the threshold formula (1), the starting time when the magnetic signal, vibration signal, and sound signal are synchronously measured at the k-th measurement is obtained.

[0084]

[0085] where f e is a fixed threshold parameter, which is usually taken as 0.9 according to experimental determination.

[0086] By analogy, the corresponding starting times can be determined in the 1st to k-th measurements.

[0087] It can be understood that the starting time of the second magnetic signal can also be determined by the threshold method and is specifically designed flexibly according to the actual situation.

[0088] The first time-of-flight ranging sub-module 362 is configured to, based on the timestamped second vibration signals collected by the mobile measurement station 3 in the 1st to k-th times and the timestamped first vibration signals collected by the reference measurement station 2 in the 1st to k-th times, extract the k end times when the mobile measurement station 3 measures the second vibration signal in the 1st to k-th times and the k end times when the reference measurement station 2 measures the first vibration signal in the 1st to k-th times, and in combination with the first coordinate positions obtained by the reference measurement station 2 in the 1st to k-th times and the second coordinate positions obtained by the mobile measurement station 3 in the 1st to k-th times, estimate the k first propagation speeds of the vibration signal when flying in the power cable L, and further in combination with the k starting times extracted by the ranging start time determination sub-module 361 corresponding to the 1st to k-th times, calculate the k first time-of-flight ranging distances obtained by the mobile measurement station 3 and the reference measurement station 2 respectively in the 1st to k-th times based on the time of flight of the vibration signal;

[0089] For example, first, for the k-th measurement, the timestamped first vibration signal measured by the reference measurement station 2 is denoted as and the timestamped second vibration signal measured by the mobile measurement station 3 is denoted as

[0090] Secondly, through the threshold formula (2), the end time when the reference measurement station 2 measures the first vibration signal at the k-th measurement and the end time when the mobile measurement station 3 measures the second vibration signal at the k-th measurement

[0091]

[0092] where f vis a fixed threshold parameter, which is usually taken as 0.3 according to experimental measurements;

[0093] Next, through formula (3), the first propagation speed corresponding to the k-th time when the vibration signal flies in the power cable L is estimated

[0094]

[0095] Among them, represents the first coordinate position obtained by the reference measurement station 2 at the k-th time; represents the second coordinate position obtained by the mobile measurement station 3 at the k-th time;

[0096] Finally, through formula (4), the first flight ranging distance corresponding to the k-th time obtained by the reference measurement station 2 is calculated and the first flight ranging distance corresponding to the k-th time obtained by the mobile measurement station 3

[0097]

[0098] And so on, the first flight ranging distances of the reference measurement station 2 and the mobile measurement station 3 based on the flight of the vibration signal in the power cable L can be determined in the 1st to k-th measurements. It should be noted that since the reference measurement station 2 is in a fixed position, the first coordinate position obtained by each measurement will remain unchanged.

[0099] The first intensity ranging sub-module 363 is used to, based on the timestamped second vibration signals collected by the mobile measurement station 3 in the 1st to k-th times and the timestamped first vibration signals collected by the reference measurement station 2 in the 1st to k-th times, use a preset first received signal strength model to fit and obtain k first intensity ranging distances of the mobile measurement station 3 and the reference measurement station 2 respectively based on the intensity of the vibration signal in the 1st to k-th times;

[0100] For example, based on the reference measurement station 2 measuring the timestamped first vibration signal and the mobile measurement station 3 measuring the timestamped second vibration signal Through formulas (5) and (6), the first intensity ranging distance corresponding to the k-th time obtained by the reference measurement station 2 is calculated respectively and the first intensity ranging distance corresponding to the k-th time obtained by the mobile measurement station 3

[0101]

[0102] Among them, g v(·) represents a preset first received signal strength model, and this received signal strength model is a function of signal strength and distance and is obtained by fitting specific experiments.

[0103] And so on, the first strength ranging distances of the reference measurement station 2 and the mobile measurement station 3 based on the vibration signal strength can be determined in the 1st to kth measurements.

[0104] The second time-of-flight ranging sub-module 364 is configured to extract, based on the timestamped second sound signals collected by the mobile measurement station 3 in the 1st to kth times and the timestamped first sound signals collected by the reference measurement station 2 in the 1st to kth times, the k end times when the mobile measurement station 3 measures the second sound signals in the 1st to kth times and the k end times when the reference measurement station 2 measures the first sound signals in the 1st to kth times, and in combination with the first coordinate positions obtained by the reference measurement station 2 in the 1st to kth times and the second coordinate positions obtained by the mobile measurement station 3 in the 1st to kth times, estimate the k second propagation speeds when the sound signals fly in the power cable L, and further in combination with the k start times extracted by the ranging start time determination sub-module 361 corresponding to the 1st to kth times, calculate the k second time-of-flight ranging distances obtained by the mobile measurement station 3 and the reference measurement station 2 respectively in the 1st to kth times based on the time of flight of the sound signals in the air;

[0105] For example, first, for the kth measurement, the timestamped first sound signal measured by the reference measurement station 2 is denoted as and the timestamped second sound signal measured by the mobile measurement station 3 is denoted as

[0106] Secondly, through the threshold method formula (7), the end time of the first sound signal measured by the reference measurement station 2 in the kth measurement is obtained and the end time of the second sound signal measured by the mobile measurement station 3 in the kth measurement is obtained

[0107]

[0108] where f s is a fixed threshold parameter, which is usually taken as 0.3 according to experimental determination;

[0109] Then, through formula (8), the second propagation speed

[0110]

[0111] Finally, through Equation (9), the second flight ranging distance corresponding to the reference measurement station 2 at the k-th time is calculated. and the second flight ranging distance corresponding to the mobile measurement station 3 at the k-th time

[0112]

[0113] And so on, the second flight ranging distances of the reference measurement station 2 and the mobile measurement station 3 based on the flight of the sound signal in the air can be determined during the 1st to k-th measurements.

[0114] The second intensity ranging sub-module 365 is configured to, based on the time-stamped second sound signals collected by the mobile measurement station 3 during the 1st to k-th times and the time-stamped first sound signals collected by the reference measurement station 2 during the 1st to k-th times, use a preset second received signal strength model to fit and obtain k second intensity ranging distances of the mobile measurement station 3 and the reference measurement station 2 respectively during the 1st to k-th times based on the intensity of the sound signal in the air;

[0115] For example, based on the reference measurement station 2's measurement of the time-stamped first sound signal and the mobile measurement station 3's measurement of the time-stamped second sound signal Through Equations (10) and (11), the second intensity ranging distance corresponding to the reference measurement station 2 at the k-th time is calculated respectively and the second intensity ranging distance corresponding to the mobile measurement station 3 at the k-th time

[0116]

[0117] where g s,1 (·) represents the preset second received signal strength model, and this received signal strength model is a function of the signal strength and the distance and is obtained by fitting specific experiments.

[0118] And so on, the second intensity ranging distances of the reference measurement station 2 and the mobile measurement station 3 based on the sound signal intensity can be determined during the 1st to k-th measurements.

[0119] The third time-of-flight ranging sub-module 366 is configured to use a preset multipath cancellation technique to perform noise filtering on the timestamped second sound signals collected by the mobile measurement station 3 for 1 to k times and the timestamped first sound signals collected by the reference measurement station 2 for 1 to k times, further extract the k end times of the filtered second sound signals corresponding to the mobile measurement station 3 for 1 to k times and the k end times of the filtered first sound signals corresponding to the reference measurement station 2 for 1 to k times, and combine the first coordinate positions obtained by the reference measurement station 2 for 1 to k times and the second coordinate positions obtained by the mobile measurement station 3 for 1 to k times to estimate the k third propagation speeds when the sound signals fly in the power cable L after filtering, and combine the k start times extracted by the ranging start time determination sub-module 361 corresponding to 1 to k times to calculate the k third time-of-flight ranging distances obtained by the mobile measurement station 3 and the reference measurement station 2 respectively for 1 to k times based on the time of flight of the sound signals in the power cable L;

[0120] For example, first, for the k-th measurement, using the multipath cancellation technique, at the reference measurement station 2, the timestamped first sound signal and at the mobile measurement station 3, the timestamped second sound signal are used to eliminate the sound signals propagated through the air to obtain the first sound signal measured by the reference measurement station 2 corresponding to the k-th measurement and the sound signal obtained after noise filtering and the second sound signal measured by the mobile measurement station 3 corresponding to the k-th measurement and the sound signal obtained after noise filtering

[0121] Secondly, through the threshold formula (12), the end time of the first sound signal measured by the reference measurement station 2 corresponding to the k-th measurement and the end time of the second sound signal measured by the mobile measurement station 3 corresponding to the k-th measurement and the sound signal obtained after noise filtering are obtained

[0122]

[0123] where f p is a fixed threshold parameter, which is usually taken as 0.3 according to experimental determination;

[0124] Then, through formula (13), the third propagation speed corresponding to the k-th time when the sound signal flies in the power cable L is estimated

[0125]

[0126] Finally, through formula (14), the third flight ranging distance corresponding to the reference measurement station 2 at the k-th time is calculated. and the third flight ranging distance corresponding to the mobile measurement station 3 at the k-th time.

[0127]

[0128] And so on, the third flight ranging distances of the reference measurement station 2 and the mobile measurement station 3 based on the sound signal flying in the power cable L can be determined during the 1st to k-th measurements.

[0129] The third intensity ranging sub-module 367 is configured to, based on the second sound signals corresponding to the mobile measurement station 3 after filtering during the 1st to k-th times and the first sound signals corresponding to the reference measurement station after filtering during the 1st to k-th times, use a preset third received signal strength model to fit k third intensity ranging distances of the mobile measurement station and the reference measurement station respectively based on the intensity of the sound signal in the power cable during the 1st to k-th times;

[0130] For example, based on the first sound signal measured by the reference measurement station 2 corresponding to the k-th time the sound signal obtained after noise filtering and the second sound signal measured by the mobile measurement station 3 corresponding to the k-th time the sound signal obtained after noise filtering Through formulas (15) and (16), the third intensity ranging distance corresponding to the reference measurement station 2 at the k-th time is calculated respectively and the third intensity ranging distance corresponding to the mobile measurement station 3 at the k-th time.

[0131]

[0132] where g s,2 (·) represents a preset third received signal strength model, and this received signal strength model is a function of the signal strength and the distance and is fitted from specific experiments.

[0133] And so on, the third intensity ranging distances of the reference measurement station 2 and the mobile measurement station 3 based on the sound signal in the power cable L can be determined during the 1st to k-th measurements.

[0134] The fault point positioning sub-module 368 is configured to construct an objective function based on the k first flight ranging distances, k second flight ranging distances, k third flight ranging distances, k first intensity ranging distances, k second intensity ranging distances, and k third intensity ranging distances obtained by the mobile measurement station 3 corresponding to the 1st to kth times, and the k first flight ranging distances, k second flight ranging distances, k third flight ranging distances, k first intensity ranging distances, k second intensity ranging distances, and k third intensity ranging distances obtained by the reference measurement station 2 corresponding to the 1st to kth times, and in combination with six preset weighting factors. Then, the particle swarm optimization algorithm and the Levenberg-Marquardt algorithm are used to find the optimal solution of the objective function, and the obtained optimal solution is output as the final position of the fault point in the power cable.

[0135] Among them, the expression of the objective function is shown in the following formula (17):

[0136]

[0137] Among them, is the estimated position of the fault point in the power cable L; p is the quantity to be estimated for the fault point position; the superscript j represents the number of measurements, and j = 1, 2,..., k; the subscript r represents the reference measurement station 2; the subscript m represents the mobile measurement station 3; d represents the distance; the subscript i represents the type of measured distance; w i represents the ith weighting factor, and

[0138] At this time, the inventor found that the method of estimating the position through this objective function can be transformed into a non-linear least squares problem. Since the measurement information will increase with the increase in the number of measurements, it is necessary to use intelligent search algorithms, Newton's descent method, or the Levenberg-Marquardt algorithm for solution. Therefore, the particle swarm optimization algorithm and the Levenberg-Marquardt algorithm are used to find the optimal solution of the objective function, and the obtained optimal solution is output as the final position of the fault point in the power cable.

[0139] It should be noted that using intelligent search algorithms, Newton's descent method, or the Levenberg-Marquardt algorithm to solve non-linear least squares problems is a common technical means in this field and will not be elaborated here.

[0140] As Figure 5 shown, the application scenario of a power cable fault trench positioning system in an embodiment of the present invention is further described as follows:

[0141] In Figure 5In it, for locating the cable fault point in the urban cable trench, a total of 1 reference measurement station, 1 mobile measurement station and 1 pulse generator are used. At this time, the pulse generator is used to apply a high-voltage pulse electrical signal to the faulty cable according to a fixed period, so as to stimulate the fault point to emit a sound signal. The reference measurement station is arranged at a position far from the fault point, and it can be within the range of 20 to 30 meters, and its coordinates do not need to be manually calibrated. The mobile measurement station is carried by the operator. After measuring 3 to 5 times at a single measurement position, it moves a certain distance in the direction of the fault point. After 2 to 3 transformations, the exact position of the fault point can be obtained.

[0142] During each measurement, the reference measurement station and the mobile measurement station are synchronized in time through Beidou satellites. During the kth measurement process, the positions of the reference measurement station and the mobile measurement station obtained are respectively and

[0143] The pulse generating device generates a high-voltage pulse signal once every 30 seconds in turn, stimulates the fault point to emit a sound signal, and respectively collects magnetic signals through the electromagnetic sensors correspondingly set on the reference measurement station and the mobile measurement station, collects vibration signals through vibration sensors, and collects sound signals through microphones. At this time, the sampling frequency of the magnetic signal is 1 kHz, the sampling frequency of the vibration signal is 2 kHz, and the sampling frequency of the sound signal is 48 kHz.

[0144] The reference measurement station encapsulates the first coordinate position obtained by Beidou positioning together with the first magnetic signal, the first vibration signal and the first sound signal with time stamps into a data packet, and then sends it to the mobile measurement station through the first wireless communication module.

[0145] Based on the second coordinate position obtained by Beidou positioning, and based on its own second magnetic signal, second vibration signal and second sound signal with time stamps, the mobile measurement station combines the first coordinate position of the reference measurement station with the first magnetic signal, the first vibration signal and the first sound signal with time stamps, and estimates various types of distances according to the above formulas (1) to (16). Furthermore, the particle swarm optimization algorithm (PSO) is used to estimate the position of the fault point based on formula (17), and then it is used as an initial value to perform accurate solution based on the LM algorithm to obtain the coordinates of the fault point Among them, the weight is set to w = [0.2, 0.1, 0.3, 0.1, 0.2, 0.1].

[0146] As Figure 6 shown, in the embodiment of the present invention, a method for locating a power cable fault in a trench is provided, which is implemented on the power cable fault trench locating system in the embodiment of the present invention. The method includes the following steps:

[0147] Step S1: The pulse generator periodically applies a high-voltage DC pulse signal to the power cable to excite a sound signal emitted from a fault point in the power cable when there is a fault point;

[0148] Step S2: The reference measurement station obtains the first coordinate position where it is located, and stamps time stamps on the first magnetic signal, the first vibration signal, and the first sound signal generated when the power cable is applied with the high-voltage DC pulse signal by the pulse generator in real time, and further sends the obtained first coordinate position and the time-stamped first magnetic signal, first vibration signal, and first sound signal to the mobile measurement station;

[0149] Step S3: When the mobile measurement station establishes communication with the reference measurement station after each active installation and fixation, it obtains the second coordinate position where it is located after each active installation and fixation, and stamps time stamps on the second magnetic signal, the second vibration signal, and the second sound signal generated when the power cable is applied with the high-voltage DC pulse signal in real time, and combines the first coordinate position and the time-stamped first magnetic signal, first vibration signal, and first sound signal received from the reference measurement station each time to determine the final position of the fault point in the power cable.

[0150] Specifically, in step S1, the pulse generator periodically (for example, once every 30S) applies a high-voltage DC pulse signal to the power cable to excite a sound signal emitted from a fault point in the power cable when there is a fault point.

[0151] In step S2, the reference measurement station is based on a satellite (such as the Beidou satellite), uses the first satellite signal receiver to obtain the first coordinate position where it is located, and stamps time stamps on the first magnetic signal, the first vibration signal, and the first sound signal generated when the power cable is applied with the high-voltage DC pulse signal by the first electromagnetic sensor, the first vibration sensor, and the first microphone respectively in real time, and further uses the first wireless communication module to send the obtained first coordinate position and the time-stamped first magnetic signal, first vibration signal, and first sound signal to the mobile measurement station.

[0152] In step S3, first, determine that the total number of times the mobile measurement station establishes communication with the reference measurement station after active installation and fixation is k, and based on the time-stamped second magnetic signal collected by the mobile measurement station in the 1st to kth times or the time-stamped first magnetic signal collected by the reference measurement station in the 1st to kth times, extract k starting moments corresponding to the 1st to kth times when the mobile measurement station and the reference measurement station synchronously measure magnetic signals, vibration signals, and sound signals; where k is a positive integer greater than 1;

[0153] Secondly, based on the timestamped second vibration signals collected by the mobile measurement station for 1 to k times and the timestamped first vibration signals collected by the reference measurement station for 1 to k times, extract the k end times when the mobile measurement station measures the second vibration signals correspondingly for 1 to k times and the k end times when the reference measurement station measures the first vibration signals correspondingly for 1 to k times, and combine the first coordinate positions obtained by the reference measurement station for 1 to k times and the second coordinate positions obtained by the mobile measurement station for 1 to k times to estimate the k first propagation speeds when the vibration signals fly in the power cable, and further combine the k start times extracted corresponding to 1 to k times to calculate the k first flight ranging distances obtained by the mobile measurement station and the reference measurement station respectively for 1 to k times based on the flight time of the vibration signals;

[0154] Next, based on the timestamped second vibration signals collected by the mobile measurement station for 1 to k times and the timestamped first vibration signals collected by the reference measurement station for 1 to k times, use the preset first received signal strength model to fit and obtain the k first strength ranging distances obtained by the mobile measurement station and the reference measurement station respectively for 1 to k times based on the strength of the vibration signals;

[0155] Next, based on the timestamped second sound signals collected by the mobile measurement station for 1 to k times and the timestamped first sound signals collected by the reference measurement station for 1 to k times, extract the k end times when the mobile measurement station measures the second sound signals correspondingly for 1 to k times and the k end times when the reference measurement station measures the first sound signals correspondingly for 1 to k times, and combine the first coordinate positions obtained by the reference measurement station for 1 to k times and the second coordinate positions obtained by the mobile measurement station for 1 to k times to estimate the k second propagation speeds when the sound signals fly in the power cable, and further combine the k start times extracted corresponding to 1 to k times to calculate the k second flight ranging distances obtained by the mobile measurement station and the reference measurement station respectively for 1 to k times based on the flight time of the sound signals in the air;

[0156] Next, based on the timestamped second sound signals collected by the mobile measurement station for 1 to k times and the timestamped first sound signals collected by the reference measurement station for 1 to k times, use the preset second received signal strength model to fit and obtain the k second strength ranging distances obtained by the mobile measurement station and the reference measurement station respectively for 1 to k times based on the strength of the sound signals in the air;

[0157] Next, using the preset multipath cancellation technology, perform noise filtering on the timestamped second sound signals collected by the mobile measurement station 1 to k times and the timestamped first sound signals collected by the reference measurement station 1 to k times, and further extract the k end times of the filtered second sound signals corresponding to the mobile measurement station 1 to k times and the k end times of the filtered first sound signals corresponding to the reference measurement station 1 to k times. Combine the first coordinate positions obtained by the reference measurement station 1 to k times and the second coordinate positions obtained by the mobile measurement station 1 to k times to estimate the k third propagation speeds when the sound signals fly in the power cable after filtering. Combine the k start times extracted corresponding to 1 to k times to calculate the k third flight ranging distances obtained by the mobile measurement station and the reference measurement station respectively based on the flight time of the sound signals in the power cable 1 to k times;

[0158] Next, based on the filtered second sound signals corresponding to the mobile measurement station 1 to k times and the filtered first sound signals corresponding to the reference measurement station 1 to k times, use the preset third received signal strength model to fit and obtain the k third strength ranging distances of the mobile measurement station and the reference measurement station respectively based on the strength of the sound signals in the power cable 1 to k times;

[0159] Finally, according to the k first flight ranging distances, k second flight ranging distances, k third flight ranging distances, k first strength ranging distances, k second strength ranging distances, and k third strength ranging distances obtained by the mobile measurement station corresponding to 1 to k times, and the k first flight ranging distances, k second flight ranging distances, k third flight ranging distances, k first strength ranging distances, k second strength ranging distances, and k third strength ranging distances obtained by the reference measurement station corresponding to 1 to k times, and combine the preset six weighting weights to construct an objective function, and use the particle swarm optimization algorithm and the Levenberg-Marquardt algorithm to find the optimal solution of the objective function. The obtained optimal solution is output as the final position of the fault point in the power cable.

[0160] Implementing the embodiments of the present invention has the following beneficial effects:

[0161] 1. The present invention can achieve rapid fault location of power cables based on satellites, vibration signals, magnetic signals, and sound signals, thereby enabling rapid and accurate location of fault points of power cables in the complex environment of cable trenches in cities, providing tools and means for the safe operation and risk management of power cables. Therefore, it has advantages such as good stability, high positioning accuracy, and fast positioning speed, and can achieve the purpose of reducing manual inspections and excavating trenches;

[0162] 2. The present invention utilizes satellites to form an RTK system with a reference measurement station and a mobile measurement station, thereby obtaining high-precision position information. Then, based on the coordinate information of the reference measurement station and the mobile measurement station, the propagation speeds of vibration signals and acoustic signals in the power cable, as well as the propagation speed of acoustic signals in the atmosphere, are calibrated in real time, thereby improving the distance estimation accuracy.

[0163] 3. The present invention converts the problem of estimating the position of the fault point in the objective function into a non-linear weighted least squares problem, and then uses a heuristic algorithm to solve it, so that the positioning accuracy of the fault point will be gradually improved.

[0164] It should be noted that in the above system embodiments, the included system modules are only divided according to functional logic, but are not limited to the above division, as long as the corresponding functions can be achieved; in addition, the specific names of the functional modules are only for easy distinction from each other and do not limit the protection scope of the present invention.

[0165] Those of ordinary skill in the art can understand that all or part of the steps in the methods of the above embodiments can be completed by instructing relevant hardware through a program, and the program can be stored in a computer-readable storage medium, such as ROM / RAM, disk, optical disc, etc.

[0166] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A power cable fault trench positioning system, characterized in that: It includes a pulse generator, a reference measuring station and a mobile measuring station; wherein, The pulse generator is loaded on the power cable in the cable trench; The reference measuring station is fixedly installed in the cable trench; the reference measuring station is provided with a first satellite signal receiver, a first wireless communication module, and a first electromagnetic sensor, a first vibration sensor and a first microphone connected to the power cable; The mobile measuring station is installed in a cable trench, and after each installation, it maintains a certain distance from the reference measuring station and establishes communication with the reference measuring station; the mobile measuring station is provided with a second satellite signal receiver, a second wireless communication module, a data calculation module, and a second electromagnetic sensor, a second vibration sensor and a second microphone connected to the power cable; the second wireless communication module of the mobile measuring station realizes communication interconnection and establishment with the first wireless communication module of the reference measuring station; The pulse generator is used to periodically apply a high-voltage DC pulse signal to the power cable, so that when a fault point exists in the power cable, the fault point can be stimulated to emit a sound signal; The reference measurement station is used to obtain the first coordinate position of itself based on the satellite using the first satellite signal receiver, and to timestamp the first magnetic signal, the first vibration signal and the first sound signal generated when the power cable is applied with a high-voltage DC pulse signal by the pulse generator and collected in real time by the first electromagnetic sensor, the first vibration sensor and the first microphone, respectively, and further to send the obtained first coordinate position and the first magnetic signal, the first vibration signal and the first sound signal with the timestamp to the mobile measurement station using the first wireless communication module; The mobile measuring station is used to establish communication with the reference measuring station after each active installation and fixation, based on the satellite, using the second satellite signal receiver to obtain the second coordinate position of the mobile measuring station after each active installation and fixation, and to timestamp the second magnetic signal, the second vibration signal and the second sound signal generated when the power cable is applied with a high-voltage DC pulse signal by the pulse generator using the second electromagnetic sensor, the second vibration sensor and the second microphone, respectively, and further use the second wireless communication module to receive the first coordinate position sent by the reference measuring station and the first magnetic signal, the first vibration signal and the first sound signal with the timestamp; and The final position of the fault point in the power cable is determined using the data calculation module based on the second coordinate position obtained after each active installation and fixation, and the second magnetic signal, second vibration signal and second sound signal with a time stamp, and combined with the first coordinate position and the first magnetic signal, first vibration signal and first sound signal with a time stamp sent by the reference measurement station each time.

2. The power cable fault trench positioning system according to claim 1, characterized in that: The satellite, the first satellite signal receiver and the second satellite signal receiver are used to form an RTK system between the mobile measurement station and the reference measurement station.

3. The power cable fault trench positioning system according to claim 2, characterized in that: The data calculation module includes: The ranging start time determination submodule is used to determine that the total number of times the mobile measurement station establishes communication with the reference measurement station after being installed and fixed is k, and based on the second magnetic signal with a time stamp collected by the mobile measurement station at 1 to k times or the first magnetic signal with a time stamp collected by the reference measurement station at 1 to k times, extract k starting times corresponding to 1 to k times when the mobile measurement station and the reference measurement station synchronously measure the magnetic signal, the vibration signal and the sound signal; wherein k is a positive integer greater than 1; A first time-of-flight ranging submodule, for extracting, based on the second vibration signal with a time stamp collected by the mobile measuring station at 1 to k times and the first vibration signal with a time stamp collected by the reference measuring station at 1 to k times, k end times of the second vibration signal measured by the mobile measuring station at 1 to k times and k end times of the first vibration signal measured by the reference measuring station at 1 to k times, and estimating, in combination with the first coordinate position obtained by the reference measuring station at 1 to k times and the second coordinate position obtained by the mobile measuring station at 1 to k times, k first propagation speeds of the vibration signal when flying in the power cable, and further calculating, in combination with the k start times extracted by the ranging start time determination submodule at 1 to k times, k first flight ranging distances obtained by the mobile measuring station and the reference measuring station at 1 to k times of the flight time based on the vibration signal; A first intensity ranging submodule is used to fit, based on the second vibration signal with time stamp collected by the mobile measurement station at 1 to k times and the first vibration signal with time stamp collected by the reference measurement station at 1 to k times, and to obtain k first intensity ranging distances obtained by the mobile measurement station and the reference measurement station based on the intensity of the vibration signal at 1 to k times respectively by using a preset first received signal intensity model; A second time-of-flight ranging submodule is used to extract, based on the second sound signal with a time stamp collected by the mobile measuring station at 1 to k times and the first sound signal with a time stamp collected by the reference measuring station at 1 to k times, k end times of the second sound signal measured by the mobile measuring station at 1 to k times and k end times of the first sound signal measured by the reference measuring station at 1 to k times, and estimate k second propagation speeds of the sound signal when flying in the power cable in combination with the first coordinate position obtained by the reference measuring station at 1 to k times and the second coordinate position obtained by the mobile measuring station at 1 to k times, and further calculate k second flight ranging distances obtained by the mobile measuring station and the reference measuring station based on the flight time of the sound signal in the air at 1 to k times in combination with the k starting times extracted by the ranging starting time determination submodule; A second intensity ranging submodule is used to fit, based on the second sound signal with time stamp collected by the mobile measurement station at 1 to k times and the first sound signal with time stamp collected by the reference measurement station at 1 to k times, obtain k second intensity ranging distances obtained by the mobile measurement station and the reference measurement station based on the intensity of the sound signal in the air at 1 to k times respectively by using a preset second received signal strength model; A third time-of-flight ranging submodule is used to use a preset multipath elimination technology to perform noise filtering on the second sound signal with a time stamp collected by the mobile measuring station at 1 to k times and the first sound signal with a time stamp collected by the reference measuring station at 1 to k times, further extract k end times of the second sound signal after filtering corresponding to the mobile measuring station at 1 to k times and k end times of the first sound signal after filtering corresponding to the reference measuring station at 1 to k times, and estimate k third propagation speeds of the sound signal when it flies in the power cable after filtering in combination with the first coordinate position obtained by the reference measuring station at 1 to k times and the second coordinate position obtained by the mobile measuring station at 1 to k times, and calculate k third flight ranging distances obtained by the mobile measuring station and the reference measuring station at 1 to k times based on the flight time of the sound signal in the power cable in combination with the k starting times extracted by the ranging starting time determination submodule at 1 to k times; A third strength ranging submodule is used to fit the second sound signal after filtering corresponding to 1 to k times at the mobile measuring station and the first sound signal after filtering corresponding to 1 to k times at the reference measuring station, using a preset third received signal strength model, to obtain k third strength ranging distances of the mobile measuring station and the reference measuring station based on the strength of the sound signal in the power cable at 1 to k times; The fault point locating submodule is used to construct an objective function according to the k first flight ranging distances, k second flight ranging distances, k third flight ranging distances, k first intensity ranging distances, k second intensity ranging distances and k third intensity ranging distances obtained by the mobile measuring station in 1 to k corresponding times, and the k first flight ranging distances, k second flight ranging distances, k third flight ranging distances, k first intensity ranging distances, k second intensity ranging distances and k third intensity ranging distances obtained by the reference measuring station in 1 to k corresponding times, and in combination with six preset weighted weights, and use a particle swarm optimization algorithm and a Levenberg-Marquardt algorithm to find an optimal solution for the objective function, and the optimal solution obtained is output as the final position of the fault point in the power cable.

4. The power cable fault trench positioning system according to claim 3, characterized in that: The objective function is in, is the estimated position of the fault point in the power cable; p is the quantity to be estimated at the fault point position; the superscript j represents the number of measurements, and j = 1, 2, ..., k; the subscript r represents the reference measurement station; the subscript m represents the mobile measurement station; d represents the distance; the subscript i represents the type of measurement distance; w i represents the i-th weight, and represents the first flight distance measured by the reference measuring station at the kth correspondence, represents the first flight ranging distance obtained by the mobile measuring station at the kth correspondence, represents the first intensity ranging distance obtained by the reference measuring station at the kth correspondence, represents the first intensity ranging distance obtained by the mobile measuring station at the kth correspondence, represents the second flight distance measured by the reference measuring station at the kth correspondence, represents the second flight ranging distance obtained by the mobile measuring station at the kth correspondence, represents the second intensity ranging distance obtained by the reference measuring station at the kth correspondence, represents the second intensity ranging distance obtained by the mobile measuring station at the kth correspondence, represents the third flight ranging distance obtained by the reference measuring station at the kth correspondence, represents the third flight ranging distance obtained by the mobile measuring station at the kth correspondence; represents the third intensity ranging distance obtained by the reference measuring station at the kth correspondence, represents the third intensity ranging distance obtained by the mobile measuring station in the kth correspondence.

5. The power cable fault trench positioning system as claimed in claim 4, characterized in that: By formula The first flight distance obtained by the reference measuring station at the kth time is calculated and the first flight distance obtained by the mobile measuring station at the kth corresponding time in, represents the first propagation velocity of the vibration signal corresponding to the kth time when it flies in the power cable, and represents the first coordinate position of the reference measuring station obtained at the kth time; represents the second coordinate position of the mobile measuring station obtained at the kth time; Through the threshold method, we get represents the first vibration signal measured at the reference measurement station at the kth time, Indicates that the reference measurement station measures the first vibration signal at the kth time The end moment, represents the second vibration signal measured by the mobile measuring station at the kth corresponding time, Indicates that the mobile measuring station measures the second vibration signal at the kth corresponding time The end time, f v is a fixed threshold parameter; Through the threshold method, we get represents the first magnetic signal measured at the reference measuring station at the kth time, represents the starting time when the reference measuring station and the mobile measuring station synchronously measure the magnetic signal, vibration signal and sound signal for the kth time, f e is a fixed threshold parameter.

6. The power cable fault trench positioning system as claimed in claim 5, characterized in that: By formula The second flight distance obtained by the reference measuring station at the kth time is calculated and the second flight distance obtained by the mobile measuring station at the kth time in, represents the second propagation speed of the sound signal when it flies in the air corresponding to the kth time, and Through the threshold method, we get represents the first sound signal measured at the reference measurement station at the kth corresponding time, Indicates that the reference measurement station measures the first sound signal at the kth time The end moment, represents the second sound signal measured by the mobile measuring station at the kth corresponding time, Indicates that the mobile measuring station measures the second sound signal at the kth corresponding time The end time, f s is a fixed threshold parameter.

7. The power cable fault trench positioning system as claimed in claim 6, characterized in that: By formula The third flight distance obtained by the reference measuring station at the kth corresponding time is calculated and the third flight distance obtained by the mobile measuring station at the kth corresponding time in, represents the third propagation speed of the sound signal corresponding to the kth time when it flies in the power cable, and Through the threshold method, we get Represents the first sound signal measured at the reference measurement station at the kth time The sound signal obtained after noise filtering, The reference measurement station corresponds to filtering the first sound signal at the kth time. The resulting sound signal The end moment, Represents the second sound signal measured by the mobile measuring station at the kth corresponding time The sound signal obtained after noise filtering, Indicates that the mobile measuring station has corresponded to the second sound signal for the kth time The resulting sound signal The end time, f p is a fixed threshold parameter.

8. The power cable fault trench positioning system as claimed in claim 7, characterized in that: By formula Calculate the first intensity distance measured by the reference measuring station at the kth corresponding time By formula The first intensity ranging distance obtained by the mobile measuring station at the kth corresponding time is calculated By formula Calculate the second intensity ranging distance obtained by the reference measurement station at the kth correspondence By formula The second intensity ranging distance obtained by the mobile measuring station at the kth corresponding time is calculated By formula Calculate the third intensity ranging distance obtained by the reference measuring station at the kth correspondence By formula The third intensity ranging distance obtained by the mobile measuring station at the kth corresponding time is calculated Among them, g v (·) represents the preset first received signal strength model, g s,1 (·) represents the preset second received signal strength model, g s,2 (·) represents a preset third received signal strength model, and these three received signal strength models are all functions of signal strength and distance and are fitted by specific experiments.

9. A method for locating a power cable fault in a trench, characterized in that: The method is implemented on the power cable fault trench positioning system as claimed in claim 8, and the method comprises the following steps: The pulse generator periodically applies a high-voltage DC pulse signal to the power cable, so that when there is a fault point in the power cable, the fault point can be stimulated to emit a sound signal; The reference measuring station obtains its own first coordinate position, and timestamps the first magnetic signal, the first vibration signal and the first sound signal generated when the high-voltage DC pulse signal is applied to the power cable by the pulse generator, and further sends the obtained first coordinate position and the first magnetic signal, the first vibration signal and the first sound signal with the timestamp to the mobile measuring station; When the mobile measuring station establishes communication with the reference measuring station after each active installation and fixation, it obtains its own second coordinate position after each active installation and fixation, and timestamps the second magnetic signal, second vibration signal and second sound signal generated when the power cable is applied with a high-voltage DC pulse signal by the pulse generator in real time, and determines the final position of the fault point in the power cable in combination with the first coordinate position sent by the reference measuring station each time and the first magnetic signal, first vibration signal and first sound signal with a timestamp.

10. The method for locating a power cable fault in a trench according to claim 9, characterized in that: The mobile measuring station establishes communication with the reference measuring station after each active installation and fixation, obtains the second coordinate position of itself after each active installation and fixation, and timestamps the second magnetic signal, the second vibration signal, and the second sound signal generated when the power cable is applied with a high-voltage DC pulse signal by the pulse generator in real time, and determines the final position of the fault point in the power cable in combination with the first coordinate position received from the reference measuring station each time and the first magnetic signal, the first vibration signal, and the first sound signal with a timestamp, and the specific steps include: Determine that the total number of times the mobile measurement station establishes communication with the reference measurement station after being movably installed and fixed is k, and extract k starting times corresponding to 1 to k times when the mobile measurement station and the reference measurement station synchronously measure magnetic signals, vibration signals, and sound signals based on the second magnetic signals with time stamps collected by the mobile measurement station at times 1 to k or the first magnetic signals with time stamps collected by the reference measurement station at times 1 to k; wherein k is a positive integer greater than 1; Based on the second vibration signal with a time stamp collected by the mobile measuring station at 1 to k times and the first vibration signal with a time stamp collected by the reference measuring station at 1 to k times, k end times of the second vibration signal measured by the mobile measuring station at 1 to k times and k end times of the first vibration signal measured by the reference measuring station at 1 to k times are extracted, and in combination with the first coordinate position obtained by the reference measuring station at 1 to k times and the second coordinate position obtained by the mobile measuring station at 1 to k times, k first propagation speeds of the vibration signal when flying in the power cable are estimated, and further in combination with the k starting times extracted at the corresponding 1 to k times, k first flight ranging distances obtained by the mobile measuring station and the reference measuring station at 1 to k times based on the flight time of the vibration signal are calculated; Based on the second vibration signal with time stamp collected by the mobile measurement station at 1 to k times and the first vibration signal with time stamp collected by the reference measurement station at 1 to k times, a preset first received signal strength model is used to fit k first intensity ranging distances obtained by the mobile measurement station and the reference measurement station based on the intensity of the vibration signal at 1 to k times; Based on the second sound signal with a time stamp collected by the mobile measuring station at 1 to k times and the first sound signal with a time stamp collected by the reference measuring station at 1 to k times, k end times corresponding to the second sound signal measured by the mobile measuring station at 1 to k times and k end times corresponding to the first sound signal measured by the reference measuring station at 1 to k times are extracted, and in combination with the first coordinate position obtained by the reference measuring station at 1 to k times and the second coordinate position obtained by the mobile measuring station at 1 to k times, k second propagation speeds of the sound signal when flying in the power cable are estimated, and further corresponding to the k starting times extracted at 1 to k times, k second flight ranging distances obtained by the mobile measuring station and the reference measuring station based on the flight time of the sound signal in the air at 1 to k times are calculated; Based on the second sound signal with a time stamp collected by the mobile measuring station at 1 to k times and the first sound signal with a time stamp collected by the reference measuring station at 1 to k times, a preset second received signal strength model is used to fit k second intensity ranging distances obtained by the mobile measuring station and the reference measuring station based on the intensity of the sound signal in the air at 1 to k times; Using a preset multipath elimination technology, noise is filtered on the second sound signal with a time stamp collected by the mobile measuring station at 1 to k times and the first sound signal with a time stamp collected by the reference measuring station at 1 to k times, and k end times of the second sound signal after filtering corresponding to the mobile measuring station at 1 to k times and k end times of the first sound signal after filtering corresponding to the reference measuring station at 1 to k times are further extracted, and in combination with the first coordinate position obtained by the reference measuring station at 1 to k times and the second coordinate position obtained by the mobile measuring station at 1 to k times, k third propagation speeds of the sound signal when flying in the power cable after filtering are estimated, and in combination with the k starting times extracted corresponding to 1 to k times, k third flight ranging distances obtained by the mobile measuring station and the reference measuring station at 1 to k times based on the flight time of the sound signal in the power cable are calculated; Based on the second sound signal after filtering corresponding to 1 to k times at the mobile measuring station and the first sound signal after filtering corresponding to 1 to k times at the reference measuring station, using a preset third received signal strength model, k third intensity ranging distances of the mobile measuring station and the reference measuring station based on the intensity of the sound signal in the power cable at 1 to k times are fitted; According to the k first flight ranging distances, k second flight ranging distances, k third flight ranging distances, k first intensity ranging distances, k second intensity ranging distances and k third intensity ranging distances obtained by the mobile measuring station in 1 to k corresponding times, and the k first flight ranging distances, k second flight ranging distances, k third flight ranging distances, k first intensity ranging distances, k second intensity ranging distances and k third intensity ranging distances obtained by the reference measuring station in 1 to k corresponding times, and in combination with six preset weighted weights, an objective function is constructed, and a particle swarm optimization algorithm and a Levenberg-Marquardt algorithm are used to find an optimal solution to the objective function, and the optimal solution obtained is output as the final position of the fault point in the power cable.

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