Power cable fault in-trench locating system and method based on uwb ranging and sound

Abstract

This invention discloses a power cable fault trench location system based on UWB ranging and sound, comprising a pulse generator, a reference measuring station, and a mobile measuring station. The pulse generator periodically applies pulse signals to the power cable to excite the fault point to emit sound signals. The reference measuring station receives a first UWB signal and a first time-stamped sound signal and sends them to the mobile measuring station, and receives a second UWB signal sent by the mobile measuring station. After each installation and fixation, the mobile measuring station establishes communication with the reference measuring station, receives its own generated second UWB signal and a second time-stamped sound signal, and combines these with the first UWB signal and the first time-stamped sound signal sent by the reference measuring station each time to determine the final location of the fault point. Implementing this invention can overcome the shortcomings of existing acoustic-magnetic synchronization methods for locating power cable fault points, thereby achieving rapid and accurate location of power cable fault points.

Description

Technical Field

[0001] This invention relates to the field of power system technology, and in particular to a power cable fault location system and method based on UWB ranging and sound. Background Technology

[0002] Power cables are a crucial component of power systems and a vital guarantee for modern national economic development and people's lives. Especially in densely populated urban areas, the scale of power cable laying has become increasingly massive with the expansion of urbanization. To conserve limited urban land and maintain environmental aesthetics, most power cables are buried underground or in cable trenches, becoming the primary method of cable laying. As their service life extends, power cable faults are inevitable. While regular safety inspections and troubleshooting can effectively reduce the probability of cable failures, the inability to promptly locate fault points when they occur can cause significant inconvenience and economic losses to surrounding factories and residents. Therefore, power cable managers need to be able to quickly and accurately locate faulty cables to improve the reliability of power supply and reduce losses and maintenance costs. Thus, rapid and accurate power cable fault location not only has practical social significance but also possesses engineering value.

[0003] The environment in which buried power cables are located is relatively complex, making fault detection and location relatively difficult. The steps for power cable fault detection can be divided into three parts: determining the nature of the cable fault, roughly measuring the fault distance, tracing the path of the faulty power cable, and precisely pinpointing the location. Precise pinpointing means restricting the location of the fault to a very small area, thus avoiding the impact of large-scale excavation on surrounding areas and other pipelines, while improving the efficiency of fault removal.

[0004] Currently, the main method for troubleshooting power cable faults is the acoustic-magnetic synchronization method, which involves using a pulse generator to apply a high-voltage DC pulse signal to the faulty power cable. Under the action of the DC pulse signal, the fault point generates a discharge phenomenon and releases sound and magnetic field signals into the surrounding environment. These two signals are collected and analyzed to accurately locate the fault point.

[0005] However, the above-mentioned method of using acoustic-magnetic synchronization to determine the fault point of power cable has the following defects: (1) The sound signal will propagate along the power cable. Due to its fast propagation speed and slow attenuation, the overall accuracy of the fault point location is low when using the signal; (2) When the sound signal propagates in the trench, there will be a very serious multipath propagation phenomenon. Under the superposition of multipath effects, the sound signal will be strengthened and propagated further in the trench, which introduces a large error for distance discrimination and reduces the fault point location accuracy; (3) Near the fault point, the real path of the fault sound signal is submerged in the power cable propagation path and the superposition of trench multipaths, making it impossible to accurately determine the real location of the fault point.

[0006] Therefore, there is an urgent need for a new method for locating power cable faults that can overcome the shortcomings of the existing acoustic-magnetic synchronization method for locating power cable faults, thereby achieving rapid and accurate location of power cable faults. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a power cable fault trench location system and method based on UWB ranging and sound, which can solve the defects of the existing acoustic-magnetic synchronization method for locating power cable fault points, thereby realizing rapid and accurate location of power cable fault points.

[0008] To address the aforementioned technical problems, this invention provides a system for locating power cable faults in trenches based on UWB ranging and sound, comprising a pulse generator, a reference measuring station, and a mobile measuring station; wherein...

[0009] The pulse generator is applied to the power cable within the cable trench;

[0010] The reference measurement station is fixedly installed in the cable trench; the reference measurement station is equipped with a first UWB data transmission module and a first microphone connected to the power cable;

[0011] The mobile measuring station is installed in the 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 equipped with a second UWB data transmission module, a data calculation module, and a second microphone connected to the power cable. The second UWB data transmission module of the mobile measuring station is interconnected with the first UWB data transmission module of the reference measuring station.

[0012] The pulse generator is used to periodically apply a high-voltage DC pulse signal to the power cable so that when there is a fault point in the power cable, it can excite the fault point to emit a sound signal.

[0013] The reference measurement station is used to timestamp the first sound signal generated when the power cable is subjected to a high-voltage DC pulse signal by the pulse generator, which is collected in real time by the first microphone; generate a first UWB signal using the first UWB data transmission module; and send the timestamped first sound signal and the first UWB signal together to the mobile measurement station; and receive a second UWB signal sent by the mobile measurement station using the first UWB data transmission module; wherein the first UWB signal carries the ID number of the reference measurement station, its generated timestamp, and synchronization positioning information; the second UWB signal carries the ID number of the mobile measurement station, its generated timestamp, and synchronization positioning information.

[0014] The mobile measuring station, upon establishing communication with the reference measuring station after each installation and fixation operation, utilizes the second UWB data transmission module to generate a second UWB signal and send it to the reference measuring station, and receives a first UWB signal and a timestamped first audio signal sent by the reference measuring station. Furthermore, it timestamps the second audio signal generated when the power cable is subjected to a high-voltage DC pulse signal by the pulse generator, based on real-time acquisition by the second microphone.

[0015] Based on the second UWB signal obtained after each installation and fixation, and the second time-stamped sound signal, combined with the first UWB signal and the first time-stamped sound signal received from the reference measurement station each time, the final location of the fault point in the power cable is determined using the data calculation module.

[0016] The data calculation module includes:

[0017] The relative distance measurement submodule is used to determine the total number of times the mobile measuring station establishes communication with the reference measuring station after its mobile installation and fixation is k. Based on the second UWB signal generated by the mobile measuring station after 1 to k mobile installations and fixation and its corresponding first UWB signal received from the reference measuring station, and the first UWB signal generated by the reference measuring station after 1 to k mobile installations and fixation and its corresponding second UWB signal received from the mobile measuring station, the module obtains k relative distances between the mobile measuring station and the reference measuring station after 1 to k mobile installations and fixation. Furthermore, by combining these distances with the preset coordinate position of the reference measuring station, the module obtains the coordinate position of the mobile measuring station after 1 to k mobile installations and fixation; where k is a positive integer greater than 1.

[0018] The sound signal decomposition submodule is used to extract the second sound signal with timestamps collected by the mobile measuring station from 1 to k times and the first sound signal with timestamps collected by the reference measuring station from 1 to k times, so as to obtain the signal segments extracted by the mobile measuring station and the reference measuring station respectively from 1 to k times. The preset ensemble empirical mode decomposition (EEMD) algorithm is used to decompose all 2k extracted signal segments to obtain the intrinsic mode function sets corresponding to the mobile measuring station and the reference measuring station from 1 to k times.

[0019] The signal time difference processing submodule is used to extract the cable propagation path signal and atmospheric propagation path signal corresponding to the mobile measuring station and the reference measuring station in the 1st to kth orders based on the eigenmode function groups of the mobile measuring station and the reference measuring station respectively output by the sound signal decomposition submodule, so as to further obtain the time delay difference formed by the mobile measuring station and the reference measuring station in the 1st to kth orders based on the propagation of sound signals in power cables and air;

[0020] The air propagation speed acquisition submodule is used to calculate the k first propagation speeds of the sound signal in the air based on the k relative distances formed between the mobile measuring station and the reference measuring station after the relative distance measurement submodule outputs the corresponding outputs from the relative distance measurement submodule after the relative distance measurement submodule. The relative distance measurement submodule is used to calculate the k relative distances between the mobile measuring station and the reference measuring station after the relative distance measurement submodule after the relative distance measurement submodule outputs the k relative distances ...

[0021] The cable propagation speed acquisition submodule is used to calculate the k second propagation speeds of sound signals in the power cable based on the k relative distances formed between the mobile measuring station and the reference measuring station after the mobile measuring station is installed and fixed in 1 to k activities, and combined with the cable propagation path signals extracted by the mobile measuring station and the reference measuring station in 1 to k activities.

[0022] The fault location submodule is used to construct an objective function based on the time delay difference formed by the mobile measuring station during the propagation of sound signals in the power cable and air from the 1st to the kth times, and its coordinate position after being moved and fixed, as well as the time delay difference formed by the reference measuring station during the propagation of sound signals in the power cable and air from the 1st to the kth times, and combined with the obtained k first propagation velocities of the sound signal in the air and k second propagation velocities in the power cable. The objective function is then optimized using the particle swarm optimization algorithm and the Levenberg-Marquardt algorithm, and the optimal solution is output as the final location of the fault point in the power cable.

[0023] Wherein, the objective function is in,

[0024] p represents the estimated location of the fault point in the power cable; p is the quantity to be estimated for the location of the fault point; the superscript j represents the number of measurements, and j = 1, 2, ..., k; the subscript i represents the type of measurement station, i = 1 represents the reference measurement station, and i = 2 represents the mobile measurement station; This represents the coordinate position of the i-th type of measurement station at the j-th measurement. Represents the coordinate position obtained by the reference measuring station at the j-th measurement, and all of them are defined as follows: Represents the coordinate position obtained by the mobile measuring station at the j-th time, and all of them are defined as follows: This represents the relative distance between the mobile measuring station and the reference measuring station after the j-th activity of installation and fixation. Let be the first propagation speed of the sound signal during its j-th propagation through the air; Let be the second propagation speed of the sound signal as it propagates in the j-th power cable; This represents the time delay difference formed at the i-th type of measurement station during the j-th time based on the propagation of sound signals in the power cable and air. This represents the time delay difference formed by the reference measuring station during the j-th propagation of the sound signal through the power cable and air. This represents the time delay difference formed when the mobile measuring station propagates the sound signal through the power cable and air for the jth time.

[0025] Among them, through the formula The intrinsic mode function set corresponding to the reference station at the k-th measurement is obtained; and, through the formula The intrinsic modulus function set corresponding to the k-th measurement station is obtained; where,

[0026] From IMF1 1,k In the process, the cable propagation path signal corresponding to the k-th measurement station is extracted; and from imf3 1,k ~imf5 1,k In the process, the atmospheric propagation path signal corresponding to the reference measurement station in the kth iteration is extracted;

[0027] From IMF1 2,k In the process, the cable propagation path signal corresponding to the k-th time of the mobile measuring station is extracted; and, from imf3 2,k ~imf5 2,k In the process, the atmospheric propagation path signal corresponding to the k-th measurement station is extracted;

[0028] m represents the maximum number of intrinsic moduli.

[0029] Among them, through the formula The time delay difference formed by the reference measuring station during the k-th propagation of the sound signal in the power cable and air was calculated. and the time delay difference formed by the mobile measuring station during the k-th propagation of the sound signal in the power cable and air. in,

[0030] By using the threshold method, we obtain This represents the time delay of the k-th measurement station of type i along the propagation path of the power cable. This represents the time delay of the reference measuring station on the propagation path of the power cable for the kth time. This represents the time delay of the k-th time the mobile measuring station travels along the propagation path of the power cable; This represents the time delay of the k-th measurement station of type i along the airborne propagation path. This represents the time delay of the reference measurement station on the airborne propagation path for the kth time. f represents the time delay of the k-th mobile measuring station along the airborne propagation path; s It is a fixed threshold parameter.

[0031] Among them, through the formula The first propagation speed of the sound signal during its k-th propagation through the air was calculated; and, using the formula... The second propagation speed of the sound signal when it propagates in the power cable for the kth time is calculated.

[0032] Wherein, the time delay of the reference measuring station on the air propagation path for the kth time. and the time delay of the k-th time of the mobile measuring station on the air propagation path. Each of these results was predicted using Bayesian filtering based on the time delays of the previous k-1 propagation paths.

[0033] This invention also provides a method for locating power cable faults in trenches based on UWB ranging and sound, which is implemented on the aforementioned power cable fault location system based on UWB ranging and sound. The method includes the following steps:

[0034] 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, it can excite the fault point to emit a sound signal.

[0035] The reference measurement station generates a first UWB signal and receives a second UWB signal sent by the mobile measurement station. It also timestamps a first sound signal generated when a high-voltage DC pulse signal is applied to the power cable by the pulse generator, based on real-time acquisition. Furthermore, it sends the timestamped first sound signal along with the first UWB signal to the mobile measurement station. The first UWB signal carries the ID number of the reference measurement station, its generated timestamp, and synchronization positioning information. The second UWB signal carries the ID number of the mobile measurement station, its generated timestamp, and synchronization positioning information.

[0036] Each time the mobile measuring station establishes communication with the reference measuring station after each installation and fixation, it generates a second UWB signal and sends it to the reference measuring station. It also timestamps the second sound signal generated when the power cable is subjected to a high-voltage DC pulse signal by the pulse generator. Furthermore, by combining the first UWB signal received from the reference measuring station and the timestamped first sound signal, the final location of the fault point in the power cable is determined.

[0037] The specific steps for determining the final location of the fault point in the power cable by combining the received first UWB signal from the reference measurement station after each installation and fixation operation include:

[0038] The total number of times the mobile measuring station establishes communication with the reference measuring station after its mobile installation and fixation is determined to be k. Based on the second UWB signal generated by the mobile measuring station after 1 to k mobile installations and fixation and its corresponding first UWB signal received from the reference measuring station, and the first UWB signal generated by the reference measuring station after 1 to k mobile installations and fixation and its corresponding second UWB signal received from the mobile measuring station, k relative distances formed between the mobile measuring station and the reference measuring station after 1 to k mobile installations and fixation are obtained. Furthermore, combined with the preset coordinate position of the reference measuring station, the coordinate position of the mobile measuring station after 1 to k mobile installations and fixation is obtained; where k is a positive integer greater than 1.

[0039] The second time-stamped sound signals collected by the mobile measuring station from 1 to k times and the first time-stamped sound signals collected by the reference measuring station from 1 to k times are segmented to obtain the signal segments corresponding to the mobile measuring station and the reference measuring station from 1 to k times respectively. Then, the 2k segmented signal segments are decomposed using a preset ensemble empirical mode decomposition (EEMD) algorithm to obtain the intrinsic mode function sets corresponding to the mobile measuring station and the reference measuring station from 1 to k times respectively.

[0040] Based on the intrinsic mode function sets of the mobile measuring station and the reference measuring station at times 1 to k, the cable propagation path signal and atmospheric propagation path signal corresponding to the mobile measuring station and the reference measuring station at times 1 to k are extracted, so as to further obtain the time delay difference formed by the mobile measuring station and the reference measuring station at times 1 to k based on the propagation of sound signals in power cables and air;

[0041] Based on the k relative distances formed between the mobile measuring station and the reference measuring station after installation and fixation in 1 to k activities, and combined with the atmospheric propagation path signals extracted by the mobile measuring station and the reference measuring station in 1 to k activities respectively, the k first propagation speeds of the sound signal in the air are calculated.

[0042] Based on the k relative distances formed between the mobile measuring station and the reference measuring station after the mobile measuring station is installed and fixed in 1 to k activities, and combined with the cable propagation path signals extracted by the mobile measuring station and the reference measuring station in 1 to k activities respectively, the k second propagation speeds of the sound signal in the power cable are calculated.

[0043] Based on the time delay difference and coordinate position of the mobile measuring station during the propagation of sound signals in the power cable and air from the 1st to the kth times, and the time delay difference and coordinate position of the reference measuring station during the propagation of sound signals in the power cable and air from the 1st to the kth times, and combined with the k first propagation velocities of the sound signal in the air and the k second propagation velocities in the power cable, an objective function is constructed. The particle swarm optimization algorithm and the Levenberg-Marquardt algorithm are used to find the optimal solution of the objective function, and the output of the optimal solution is the final location of the fault point in the power cable.

[0044] Implementing the embodiments of the present invention has the following beneficial effects:

[0045] 1. This invention achieves rapid location of cable faults based on UWB system and sound technology, and integrates synchronous data transmission between reference measurement station and mobile measurement station, which greatly reduces system complexity and power consumption, thereby solving the defects of existing acoustic-magnetic synchronization method for locating power cable faults;

[0046] 2. This invention utilizes a reference measuring station and a mobile measuring station to form a relative coordinate system, thereby obtaining high-precision position information within the local coordinate system. Based on the relative distance between the reference measuring station and the mobile measuring station, the propagation speed of power cables and sound signals in the air is calibrated in real time, thereby improving the accuracy of fault location.

[0047] 3. This invention transforms the fault location estimation problem in the objective function into a nonlinear weighted least squares problem, and then uses a heuristic algorithm to solve it, thereby gradually improving the fault location accuracy. Attached Figure Description

[0048] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, obtaining other drawings based on these drawings without creative effort still falls within the scope of the present invention.

[0049] Figure 1 A schematic diagram of a power cable fault trench location system based on UWB ranging and sound provided in an embodiment of the present invention;

[0050] Figure 2 A schematic diagram of the functional structure of a reference measuring station and a mobile measuring station in a power cable fault trench location system based on UWB ranging and sound, provided in an embodiment of the present invention;

[0051] Figure 3 A functional structure diagram of the data calculation module contained in a mobile measuring station in a power cable fault trench location system based on UWB ranging and sound, provided for an embodiment of the present invention;

[0052] Figure 4 This is a schematic diagram illustrating the propagation of sound signals within a power cable trench in a power cable fault location system based on UWB ranging and sound, provided as an embodiment of the present invention.

[0053] Figure 5 A schematic diagram of multipath component analysis of sound signals in a power cable fault trench location system based on UWB ranging and sound, provided for an embodiment of the present invention;

[0054] Figure 6A schematic diagram illustrating an application scenario of a power cable fault trench location system based on UWB ranging and sound, provided in an embodiment of the present invention;

[0055] Figure 7 This is a flowchart illustrating a method for locating power cable faults in a trench based on UWB ranging and sound, as provided in an embodiment of the present invention. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of this invention clearer, the 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 merely illustrative and not intended to limit the invention.

[0057] like Figure 1 and Figure 2 As shown in the embodiment of the present invention, a power cable fault trench location system based on UWB ranging and sound is proposed, comprising a pulse generator 1, a reference measuring station 2, and a mobile measuring station 3; wherein,

[0058] Pulse generator 1 is applied to power cable L inside the cable trench;

[0059] Reference measurement station 2 is fixedly installed in the cable trench; reference measurement station 2 is equipped with a first UWB data transmission module 21 and a first microphone 22 connected to the power cable L;

[0060] The mobile measuring station 3 is installed in the cable trench, and after each installation, it maintains a certain distance from the reference measuring station 2 and establishes communication with the reference measuring station 2. The mobile measuring station 3 is equipped with a second UWB data transmission module 31, a data calculation module 33, and a second microphone 32 connected to the power cable L. The second UWB data transmission module 31 of the mobile measuring station 3 communicates with the first UWB data transmission module 21 of the reference measuring station 2 and can realize functions such as positioning, ranging, and time synchronization.

[0061] Among them, pulse generator 1 is used to periodically (once every 30 seconds) apply a high voltage DC pulse signal to the power cable L so that when there is a fault point in the power cable L, the fault point can be excited to emit a sound signal.

[0062] Reference station 2 is used to timestamp the first sound signal generated when a high-voltage DC pulse signal is applied to the power cable L by the pulse generator 1, which is collected in real time by the first microphone 22, and to generate a first UWB signal using the first UWB data transmission module 21. The timestamped first sound signal and the first UWB signal are then sent together to mobile station 3. Additionally, the first UWB data transmission module 21 is used to receive a second UWB signal sent by mobile station 3. The first UWB signal carries the ID number of the reference station, its generated timestamp, and synchronization positioning information. The second UWB signal carries the ID number of the mobile station, its generated timestamp, and synchronization positioning information.

[0063] Mobile measuring station 3, when establishing communication with reference measuring station 2 after each installation and fixation, generates a second UWB signal using the second UWB data transmission module 31 and sends it to reference measuring station 2, and receives a first UWB signal and a timestamped first audio signal sent by reference measuring station 2. Furthermore, it timestamps the second audio signal generated when a high-voltage DC pulse signal is applied to the power cable L by pulse generator 1, based on real-time acquisition by the second microphone 32.

[0064] Based on the second UWB signal obtained after each installation and fixation, and the second time-stamped sound signal, combined with the first UWB signal and the first time-stamped sound signal received from the reference measurement station 2 each time, the data calculation module 33 determines the final location of the fault point in the power cable L.

[0065] Understandably, a reference station is first randomly selected (as far away from the fault point as possible), and then reference measuring station 2 is placed at that reference station. Secondly, the position of the mobile measuring station 3 can be changed multiple times. Each time the position is changed, the mobile measuring station 3 establishes a relative coordinate system with the reference measuring station 2 via the UWB communication protocol, thereby obtaining high-precision position information within the local coordinate system. Then, a synchronous measurement sound signal is performed. Afterwards, the mobile measuring station 3 analyzes each measurement result to estimate the final location of the fault point in the power cable. The number of times the mobile measuring station 3 establishes communication and performs measurements with the reference measuring station 2 can be determined by changing the position once and measuring multiple times at that location, or measuring only once, depending on the actual situation.

[0066] It should be noted that the microphones used in reference station 2 and mobile station 3 have the same structure, and the sampling frequency of the sound signal is 48kHz.

[0067] In this embodiment of the 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 the fault point is quickly estimated in the data calculation module 33 of the mobile measurement station 3.

[0068] like Figure 3 As shown, the data calculation module 33 includes a relative distance measurement submodule 331, a sound signal decomposition submodule 332, a signal time difference processing submodule 333, an air propagation speed acquisition submodule 334, a cable propagation speed acquisition submodule 335, and a fault point location submodule 336.

[0069] At this time, the relative distance measurement submodule 331 is used to determine the total number of times (i.e., the total number of measurements) that the mobile measuring station 3 establishes communication with the reference measuring station 2 after the mobile measuring station 3 is installed and fixed is k. Based on the second UWB signal generated by the mobile measuring station 3 after the 1st to kth installations and fixed is and the corresponding first UWB signal received from the reference measuring station 2, and the first UWB signal generated by the reference measuring station 2 after the 1st to kth installations and fixed is and the corresponding second UWB signal received from the mobile measuring station 3, the k relative distances formed between the mobile measuring station 3 and the reference measuring station 2 after the 1st to kth installations and fixed is obtained. Furthermore, combined with the preset coordinate position of the reference measuring station 2, the coordinate position of the mobile measuring station 3 after the 1st to kth installations and fixed is obtained; where k is a positive integer greater than 1.

[0070] It should be noted that the relative distance measurement submodule 331 is based on the UWB ranging principle to obtain the k relative distances formed between the mobile measuring station 3 and the reference measuring station 2 after 1 to k installation and fixation operations. Here, the UWB ranging principle is implemented based on the two-way time-of-flight (TW-TOF) method, meaning that each UWB data transmission module generates an independent timestamp from startup. For example, the first UWB data transmission module 21 of the reference measuring station 2 transmits a request-type first UWB signal at its timestamp Ta1, enabling the second UWB data transmission module 22 of the mobile measuring station 2 to receive the first UWB signal at its timestamp Tb1. After processing the first UWB signal, the second UWB data transmission module 22 of the mobile measuring station 2 transmits a response-type second UWB signal at time Tb2, which is received by the first UWB data transmission module 21 of the reference measuring station 2 at its own timestamp Ta. Therefore, the flight time of the pulse signal between the two UWB data transmission modules can be calculated, and the relative distance of flight can be determined as S = speed of light C × [(Ta2-Ta1)-(Tb2-Tb1)].

[0071] For example, in the k-th measurement, the mobile measuring station 3 and the reference measuring station 2 perform positioning, time synchronization, and distance measurement via the UWB communication protocol. The coordinate position obtained by the reference measuring station 2 in the k-th measurement is denoted as... The coordinate position obtained by the mobile surveying station 3 at the k-th time is: in, The distance between the mobile measuring station 3 and the reference measuring station 2 during the k-th measurement is obtained through the UWB distance measurement principle.

[0072] At this time, the sound signal decomposition submodule 332 is used to extract the second sound signal with timestamps collected by the mobile measurement station 3 in the 1 to k times and the first sound signal with timestamps collected by the reference measurement station 2 in the 1 to k times, so as to obtain the signal segments extracted by the mobile measurement station 3 and the reference measurement station 2 respectively in the 1 to k times. Then, the preset ensemble empirical mode decomposition (EEMD) algorithm is used to decompose all 2k extracted signal segments to obtain the intrinsic mode function groups corresponding to the mobile measurement station 3 and the reference measurement station 2 in the 1 to k times.

[0073] For example, firstly, for the k-th measurement, the first time-stamped sound signal collected by reference station 2 is denoted as... And record the second sound signal collected by the mobile measuring station 3 with a timestamp as

[0074] Next, as Figure 4 and Figure 5 As shown, the propagation paths of sound signals are mainly divided into power cable propagation paths, atmospheric line-of-sight propagation paths, and atmospheric multipath propagation paths. Since the propagation speed of sound signals in power cables is greater than 5000 m / s, while the propagation speed in air is approximately 340 m / s, both reference station 2 and mobile station 3 will first receive the signal from the power cable propagation path, followed by the signal from the atmospheric line-of-sight propagation path. There is a certain time delay difference between the two (e.g., ...). Figure 5 As shown in the figure, when the mobile measuring station 3 gradually approaches the fault point, the time delay difference gradually decreases and becomes difficult to separate, which is the biggest difficulty and challenge currently faced by the acoustic-magnetic synchronization method.

[0075] Since the sound signal excited at the fault point is a typical pulse signal with broadband characteristics, and the high-frequency components of broadband signals attenuate much more in the atmosphere than in metallic media, empirical mode decomposition (EMD) can be used to separate the signal on the power cable propagation path from the signal on the atmospheric propagation path. To further improve the decomposition accuracy and avoid aliasing, integrated empirical mode decomposition (EEMD) can be used. Therefore, for the k-th measurement, the first sound signal... Second sound signal Performing EEMD decomposition separately, the resulting set of Intrinsic Mode Functions (IMFs) is denoted as... That is, the set of eigenmode functions corresponding to reference station 2 at the kth time; and, denoted as That is, the intrinsic modulus function set corresponding to the kth time of the mobile measuring station 3. Where m is the maximum number of intrinsic moduli.

[0076] It should be noted that the maximum number of iterations of EEMD is predefined to be limited to 100, the added noise signal-to-noise ratio is 20dB, and the maximum number of decomposition layers of the intrinsic mode function set is 10.

[0077] At this time, the signal time difference processing submodule 333 is used to extract the cable propagation path signal and atmospheric propagation path signal corresponding to the eigenmode function groups of the mobile measuring station 3 and the reference measuring station 2 at times 1 to k based on the output of the sound signal decomposition submodule 332, so as to further obtain the time delay difference formed by the sound signal propagating in the power cable and air at times 1 to k based on the sound signal.

[0078] For example, firstly, for the k-th measurement, imf1 i,k Normally, signals contain high-frequency components, but in signal denoising applications, they are considered to carry a large amount of high-frequency noise. However, in this invention, because the pulse signal is a broadband signal, the sound signal propagating along the power cable path will be obscured by the IMF1 signal. i,k It constitutes the main component. Therefore, from IMF1 1,k Extract the cable propagation path signal corresponding to the kth measurement station 2, and extract it from IMF1. 2,k Extract the cable propagation path signal corresponding to the kth time of the mobile measuring station 3.

[0079] Because atmospheric propagation attenuates high-frequency components of sound signals relatively quickly, it is possible to... A strong atmospheric propagation path signal was observed, thus enabling the separation of the power cable propagation path signal from the atmospheric propagation path signal. Therefore, from IMF3... 1,k ~imf5 1,k Extract the atmospheric propagation path signal of reference station 2 at the kth time; and extract it from IMF3. 2,k ~imf5 2,k Extract the atmospheric propagation path signal corresponding to the kth time of the mobile measurement station 3.

[0080] Secondly, the time delay of the i-th type of measurement station on the power cable propagation path for the kth time is obtained using the threshold method formula (1). The time delay of the i-th measurement station on the k-th time along the airborne propagation path

[0081]

[0082] in, This represents the time delay of reference station 2 on the propagation path of the power cable during the k-th iteration. The time delay of the k-th propagation path of the mobile measuring station 3 on the power cable represents the time delay of the k-th time. This represents the time delay of reference station 2 on the airborne propagation path for the kth time. f represents the time delay of the k-th time along the airborne propagation path of the mobile measuring station 3; s It is a fixed threshold parameter.

[0083] Furthermore, using formula (2), the time delay difference of the sound signal propagating in the power cable and the atmosphere can be obtained.

[0084]

[0085] in, The time delay difference formed by reference station 2 during the kth time based on the propagation of sound signals in the power cable and air; This represents the time delay difference formed by mobile measuring station 3 during the kth time based on the propagation of sound signals in the power cable and air.

[0086] It should be noted that the time delay of reference station 2 on the airborne propagation path for the kth time... and the time delay of the k-th time on the airborne propagation path of the mobile measuring station 3 Both can be predicted using Bayesian filtering based on the time delay of the previous k-1 propagation paths.

[0087] For example, to improve the estimation accuracy of the time delay of the sound signal on the air propagation path, the time delay of the reference measuring station 2 and the mobile measuring station 3 on the air propagation path at the k-th time can be estimated based on the measurement data of the previous k-1 times and the following equation (3). and Make predictions.

[0088]

[0089] Then, from the first Time and Cut off at different times and The signal is padded with zeros at the end to the same length, denoted as and

[0090] Next, the acquired acoustic signals were processed based on the EEMD algorithm. and The resulting intrinsic modulus function set is decomposed into the following groups: and

[0091] Furthermore, based on equation (1), the time delays of reference station 2 and mobile station 3 on the k-th airborne propagation path are obtained again. and Then update the posterior probability according to equation (4).

[0092]

[0093] in, It is a normalization constant to ensure It is worth noting that when i=1, the reference measurement station is 2. Since the reference measurement station 2 is stationary, the Bayesian filtering can be equivalent to the mean filtering.

[0094] At this time, the air propagation speed acquisition submodule 334 is used to calculate the k first propagation speeds of the sound signal in the air based on the k relative distances formed between the mobile measuring station 3 and the reference measuring station 2 after the mobile measuring station 3 is fixed in the 1st to kth activities, and combined with the atmospheric propagation path signals extracted by the mobile measuring station 3 and the reference measuring station 2 in the 1st to kth activities.

[0095] For example, for the k-th measurement, based on equation (1) and through formula (5), the first propagation speed of the sound signal when it propagates in the air for the k-th time is calculated.

[0096]

[0097] At this time, the cable propagation speed acquisition submodule 335 is used to calculate the k second propagation speeds of the sound signal in the power cable based on the k relative distances formed between the mobile measuring station 3 and the reference measuring station 2 after the mobile measuring station 3 has been fixed in 1 to k activities, and combined with the cable propagation path signals extracted by the mobile measuring station 3 and the reference measuring station 2 in 1 to k activities.

[0098] For example, for the k-th measurement, based on equation (1) and through formula (6), the second propagation speed of the sound signal when it propagates in the power cable for the k-th time is calculated.

[0099]

[0100] At this time, the fault location submodule 336 is used to construct an objective function based on the time delay difference formed by the mobile measuring station 3 during the propagation of sound signals in the power cable and air from the 1st to the kth times, as well as its coordinate position after being installed and fixed, and the time delay difference formed by the reference measuring station 2 during the propagation of sound signals in the power cable and air from the 1st to the kth times, and combined with the obtained k first propagation speeds of the sound signal in the air and k second propagation speeds in the power cable. The objective function is then optimized using the particle swarm optimization algorithm and the Levenberg-Marquardt algorithm, and the output of the optimal solution is the final location of the fault point in the power cable.

[0101] The objective function is expressed as shown in equation (7):

[0102]

[0103] in, is the estimated location of the fault point in power cable L; p is the quantity to be estimated for the location of the fault point; the superscript j represents the number of measurements, and j = 1, 2, ..., k; the subscript i represents the type of measurement station, i = 1 represents reference measurement station 2, i = 2 represents mobile measurement station 3; This represents the coordinate position of the i-th type of measurement station at the j-th measurement. The coordinates of reference station 2 at the j-th measurement are all... Represents the coordinate position obtained by the mobile measuring station 3 at the j-th time, and all of them are... This represents the relative distance between the mobile measuring station 3 and the reference measuring station 2 after the j-th activity is installed and fixed; Let be the first propagation speed of the sound signal during its j-th propagation through the air; Let be the second propagation speed of the sound signal as it propagates in the j-th power cable; This represents the time delay difference formed at the i-th type of measurement station during the j-th time based on the propagation of sound signals in the power cable and air. The time delay difference formed by reference station 2 during the j-th propagation of the sound signal in the power cable and air. This represents the time delay difference formed by mobile measuring station 3 during the j-th propagation of the sound signal in the power cable and air.

[0104] At this point, the inventors discovered that the method for estimating the location using this objective function can be transformed into a nonlinear least squares problem. Since the measurement information increases with the number of measurements, it is necessary to use intelligent search algorithms, Newton's descent method, or the Levenberg-Marquardt algorithm to solve it. Therefore, particle swarm optimization and the Levenberg-Marquardt algorithm are used to find the optimal solution for the objective function, and the output of the optimal solution is the final location of the fault point in the power cable.

[0105] It should be noted that using intelligent search algorithms, Newton's descent method, or Levenberg-Marquardt algorithm to solve nonlinear least squares problems are common techniques in this field, and will not be elaborated upon here.

[0106] like Figure 6 As shown, the application scenario of a power cable fault trench location system based on UWB ranging and sound in an embodiment of the present invention is further explained as follows:

[0107] exist Figure 6 In this method, to locate cable faults within urban cable trenches, a total of one reference measuring station, one mobile measuring station, and one pulse generator are used. The pulse generator delivers high-voltage pulse signals to the faulty cable at fixed intervals, triggering the fault point to emit an audible signal. The reference measuring station is positioned 20-30 meters away from the fault point, and its coordinates do not require manual calibration. The mobile measuring station is carried by the operator. After measuring 3-5 times at a single location, it is moved a certain distance towards the fault point. After 2-3 adjustments, the precise location of the fault point can be obtained.

[0108] First, the reference station and the rover station synchronize their clocks using the UWB communication protocol. During the k-th measurement, the coordinates of the reference station are denoted as... The coordinates of the moving reference station are

[0109] The pulse generator produces a high-voltage pulse signal every 30 seconds, triggering the fault point to emit an audio signal. The audio signal is then collected by microphones located at the reference and mobile measurement stations. The sampling frequency of the audio signal is 48kHz.

[0110] The reference measurement station encapsulates the first time-stamped audio signal and the first UWB signal together into a data packet, which is then sent to the mobile measurement station via the first UWB data transmission module.

[0111] The mobile measuring station, based on its own generated second UWB signal and timestamped second sound signal, combined with the first UWB signal and timestamped first sound signal generated by the reference measuring station, constructs the objective function (7) according to the above formulas (1) to (6). Furthermore, it uses the particle swarm optimization algorithm (PSO) to estimate the location of the fault point based on formula (7), and then uses it as the initial value to perform an accurate solution based on the LM algorithm to obtain the coordinates of the fault point.

[0112] like Figure 7 As shown, this is an embodiment of the present invention providing a method for locating power cable faults in trenches based on UWB ranging and sound. It is implemented on the power cable fault location system based on UWB ranging and sound in this embodiment of the present invention. The method includes the following steps:

[0113] Step S1: 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, it can excite the fault point to emit a sound signal.

[0114] Step S2: The reference measurement station generates a first UWB signal and receives a second UWB signal sent by the mobile measurement station. It timestamps a first sound signal generated when a high-voltage DC pulse signal is applied to the power cable by the pulse generator, based on real-time acquisition. The timestamped first sound signal is then sent to the mobile measurement station along with the first UWB signal. The first UWB signal carries the ID number of the reference measurement station, its generated timestamp, and synchronization positioning information. The second UWB signal carries the ID number of the mobile measurement station, its generated timestamp, and synchronization positioning information.

[0115] Step S3: After each installation and fixation, when the mobile measuring station establishes communication with the reference measuring station, it generates a second UWB signal and sends it to the reference measuring station. It also timestamps the second sound signal generated when the power cable is subjected to a high-voltage DC pulse signal by the pulse generator. Furthermore, by combining the first UWB signal received from the reference measuring station and the timestamped first sound signal, the final location of the fault point in the power cable is determined.

[0116] The specific process is as follows: In step S1, the pulse generator periodically (e.g., once every 30 seconds) 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 excited to emit a sound signal.

[0117] In step S2, the reference measuring station generates a first UWB signal carrying the ID number of the reference measuring station, its generated timestamp, and synchronization positioning information; receives a second UWB signal sent by the mobile measuring station carrying the ID number of the mobile measuring station, its generated timestamp, and synchronization positioning information; timestamps the first sound signal generated when a high-voltage DC pulse signal is applied to the power cable by a pulse generator in real time; and further sends the timestamped first sound signal and the first UWB signal together to the mobile measuring station.

[0118] In step S3, firstly, the total number of times the mobile measuring station establishes communication with the reference measuring station after its mobile installation and fixation is determined to be k. Based on the second UWB signal generated by the mobile measuring station after 1 to k mobile installations and fixation and its corresponding first UWB signal received from the reference measuring station, and the first UWB signal generated by the reference measuring station after 1 to k mobile installations and fixation and its corresponding second UWB signal received from the mobile measuring station, k relative distances formed between the mobile measuring station and the reference measuring station after 1 to k mobile installations and fixation are obtained. Furthermore, combined with the preset coordinate position of the reference measuring station, the coordinate position of the mobile measuring station after 1 to k mobile installations and fixation is obtained; where k is a positive integer greater than 1.

[0119] Next, the second time-stamped sound signals collected by the mobile measuring station from the 1st to the kth times and the first time-stamped sound signals collected by the reference measuring station from the 1st to the kth times are segmented to obtain the signal segments corresponding to the 1st to the kth times for the mobile measuring station and the reference measuring station respectively. Then, the preset ensemble empirical mode decomposition (EEMD) algorithm is used to decompose all 2k segmented signals to obtain the intrinsic mode function sets corresponding to the 1st to the kth times for the mobile measuring station and the reference measuring station respectively.

[0120] Next, based on the intrinsic mode function sets of the mobile measuring station and the reference measuring station at times 1 to k, the cable propagation path signal and atmospheric propagation path signal corresponding to the mobile measuring station and the reference measuring station at times 1 to k are extracted, so as to further obtain the time delay difference formed by the mobile measuring station and the reference measuring station at times 1 to k based on the propagation of sound signals in the power cable and the air.

[0121] Next, based on the k relative distances formed between the mobile measuring station and the reference measuring station after installation and fixation in the 1st to kth activities, and combined with the atmospheric propagation path signals extracted by the mobile measuring station and the reference measuring station in the 1st to kth activities, the k first propagation velocities of the sound signal in the air are calculated.

[0122] Next, based on the k relative distances formed between the mobile measuring station and the reference measuring station after installation and fixation in the 1st to kth activities, and combined with the cable propagation path signals extracted by the mobile measuring station and the reference measuring station in the 1st to kth activities, the k second propagation velocities of the sound signal in the power cable are calculated.

[0123] Finally, based on the time delay difference formed by the mobile measuring station during the propagation of sound signals in the power cable and air from the 1st to the kth times, and its coordinate position after being installed and fixed, as well as the time delay difference formed by the reference measuring station during the propagation of sound signals in the power cable and air from the 1st to the kth times, and combined with the k first propagation velocities of the sound signal in the air and the k second propagation velocities in the power cable, an objective function is constructed. The particle swarm optimization algorithm and the Levenberg-Marquardt algorithm are used to find the optimal solution of the objective function. The output of the optimal solution is the final location of the fault point in the power cable.

[0124] Implementing the embodiments of the present invention has the following beneficial effects:

[0125] 1. This invention achieves rapid location of cable faults based on UWB system and sound technology, and integrates synchronous data transmission between reference measurement station and mobile measurement station, which greatly reduces system complexity and power consumption, thereby solving the defects of existing acoustic-magnetic synchronization method for locating power cable faults;

[0126] 2. This invention utilizes a reference measuring station and a mobile measuring station to form a relative coordinate system, thereby obtaining high-precision position information within the local coordinate system. Based on the relative distance between the reference measuring station and the mobile measuring station, the propagation speed of power cables and sound signals in the air is calibrated in real time, thereby improving the accuracy of fault location.

[0127] 3. This invention transforms the fault location estimation problem in the objective function into a nonlinear weighted least squares problem, and then uses a heuristic algorithm to solve it, thereby gradually improving the fault location accuracy.

[0128] It is worth noting that the various system modules included in the above system embodiments 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 each functional module are only for easy differentiation and are not used to limit the scope of protection of the present invention.

[0129] Those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, such as ROM / RAM, disk, optical disk, etc.

[0130] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A power cable fault trench location system based on UWB ranging and sound, characterized in that, It includes a pulse generator, a reference measuring station, and a mobile measuring station; among which, The pulse generator is applied to the power cable within the cable trench; The reference measurement station is fixedly installed in the cable trench; the reference measurement station is equipped with a first UWB data transmission module and a first microphone connected to the power cable; The mobile measuring station is installed in the 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 equipped with a second UWB data transmission module, a data calculation module, and a second microphone connected to the power cable. The second UWB data transmission module of the mobile measuring station is interconnected with the first UWB data transmission 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 there is a fault point in the power cable, it can excite the fault point to emit a sound signal. The reference measurement station is used to timestamp the first sound signal generated when the power cable is subjected to a high-voltage DC pulse signal by the pulse generator, which is collected in real time by the first microphone; generate a first UWB signal using the first UWB data transmission module; and send the timestamped first sound signal and the first UWB signal together to the mobile measurement station; and receive a second UWB signal sent by the mobile measurement station using the first UWB data transmission module; wherein the first UWB signal carries the ID number of the reference measurement station, its generated timestamp, and synchronization positioning information; the second UWB signal carries the ID number of the mobile measurement station, its generated timestamp, and synchronization positioning information. The mobile measuring station, upon establishing communication with the reference measuring station after each installation and fixation operation, utilizes the second UWB data transmission module to generate a second UWB signal and send it to the reference measuring station, and receives a first UWB signal and a timestamped first audio signal sent by the reference measuring station. Furthermore, it timestamps the second audio signal generated when the power cable is subjected to a high-voltage DC pulse signal by the pulse generator, based on real-time acquisition by the second microphone. Based on the second UWB signal obtained after each installation and fixation, and the second time-stamped sound signal, combined with the first UWB signal and the first time-stamped sound signal received from the reference measurement station each time, the final location of the fault point in the power cable is determined using the data calculation module.

2. The power cable fault trench location system based on UWB ranging and sound as described in claim 1, characterized in that, The data calculation module includes: The relative distance measurement submodule is used to determine the total number of times the mobile measuring station establishes communication with the reference measuring station after its mobile installation and fixation is k. Based on the second UWB signal generated by the mobile measuring station after 1 to k mobile installations and fixation and its corresponding first UWB signal received from the reference measuring station, and the first UWB signal generated by the reference measuring station after 1 to k mobile installations and fixation and its corresponding second UWB signal received from the mobile measuring station, the module obtains k relative distances between the mobile measuring station and the reference measuring station after 1 to k mobile installations and fixation. Furthermore, by combining these distances with the preset coordinate position of the reference measuring station, the module obtains the coordinate position of the mobile measuring station after 1 to k mobile installations and fixation; where k is a positive integer greater than 1. The sound signal decomposition submodule is used to extract the second sound signal with timestamps collected by the mobile measuring station from 1 to k times and the first sound signal with timestamps collected by the reference measuring station from 1 to k times, so as to obtain the signal segments extracted by the mobile measuring station and the reference measuring station respectively from 1 to k times. The preset ensemble empirical mode decomposition (EEMD) algorithm is used to decompose all 2k extracted signal segments to obtain the intrinsic mode function sets corresponding to the mobile measuring station and the reference measuring station from 1 to k times. The signal time difference processing submodule is used to extract the cable propagation path signal and atmospheric propagation path signal corresponding to the mobile measuring station and the reference measuring station in the 1st to kth orders based on the eigenmode function groups of the mobile measuring station and the reference measuring station respectively output by the sound signal decomposition submodule, so as to further obtain the time delay difference formed by the mobile measuring station and the reference measuring station in the 1st to kth orders based on the propagation of sound signals in power cables and air; The air propagation speed acquisition submodule is used to calculate the k first propagation speeds of the sound signal in the air based on the k relative distances formed between the mobile measuring station and the reference measuring station after the relative distance measurement submodule outputs the corresponding outputs from the relative distance measurement submodule after the relative distance measurement submodule. The relative distance measurement submodule is used to calculate the k relative distances between the mobile measuring station and the reference measuring station after the relative distance measurement submodule after the relative distance measurement submodule outputs the k relative distances ... The cable propagation speed acquisition submodule is used to calculate the k second propagation speeds of sound signals in the power cable based on the k relative distances formed between the mobile measuring station and the reference measuring station after the mobile measuring station is installed and fixed in 1 to k activities, and combined with the cable propagation path signals extracted by the mobile measuring station and the reference measuring station in 1 to k activities. The fault location submodule is used to construct an objective function based on the time delay difference formed by the mobile measuring station during the propagation of sound signals in the power cable and air from the 1st to the kth times, and its coordinate position after being moved and fixed, as well as the time delay difference formed by the reference measuring station during the propagation of sound signals in the power cable and air from the 1st to the kth times, and combined with the obtained k first propagation velocities of the sound signal in the air and k second propagation velocities in the power cable. The objective function is then optimized using the particle swarm optimization algorithm and the Levenberg-Marquardt algorithm, and the optimal solution is output as the final location of the fault point in the power cable.

3. The power cable fault trench location system based on UWB ranging and sound as described in claim 2, characterized in that, The objective function is: in, p represents the estimated location of the fault point in the power cable; p is the quantity to be estimated for the location of the fault point; the superscript j represents the number of measurements, and j = 1, 2, ..., k; the subscript i represents the type of measurement station, i = 1 represents the reference measurement station, and i = 2 represents the mobile measurement station; This represents the coordinate position of the i-th type of measurement station at the j-th measurement. Represents the coordinate position obtained by the reference measuring station at the j-th measurement, and all of them are defined as follows: Represents the coordinate position obtained by the mobile measuring station at the j-th time, and all of them are defined as follows: This represents the relative distance between the mobile measuring station and the reference measuring station after the j-th activity of installation and fixation. Let be the first propagation speed of the sound signal during its j-th propagation through the air; Let be the second propagation speed of the sound signal as it propagates in the j-th power cable; This represents the time delay difference formed at the i-th type of measurement station during the j-th time based on the propagation of sound signals in the power cable and air. This represents the time delay difference formed by the reference measuring station during the j-th propagation of the sound signal through the power cable and air. This represents the time delay difference formed when the mobile measuring station propagates the sound signal through the power cable and air for the jth time.

4. The power cable fault trench location system based on UWB ranging and sound as described in claim 3, characterized in that, Through formula The intrinsic mode function set corresponding to the reference station at the k-th measurement is obtained; and, through the formula The intrinsic modulus function set corresponding to the k-th measurement station is obtained; where, From IMF1 1,k In the process, the cable propagation path signal corresponding to the k-th measurement station is extracted; and from imf3 1,k ~imf5 1,k In the process, the atmospheric propagation path signal corresponding to the reference measurement station in the kth iteration is extracted; From IMF1 2,k In the process, the cable propagation path signal corresponding to the k-th time of the mobile measuring station is extracted; and, from imf3 2,k ~imf5 2,k In the process, the atmospheric propagation path signal corresponding to the k-th measurement station is extracted; m represents the maximum number of intrinsic moduli.

5. The power cable fault trench location system based on UWB ranging and sound as described in claim 4, characterized in that, Through formula The time delay difference formed by the reference measuring station during the k-th propagation of the sound signal in the power cable and air was calculated. and the time delay difference formed by the mobile measuring station during the k-th propagation of the sound signal in the power cable and air. in, By using the threshold method, we obtain i = 1, 2; This represents the time delay of the k-th measurement station of type i along the propagation path of the power cable. This represents the time delay of the reference measuring station on the propagation path of the power cable for the kth time. This represents the time delay of the k-th time the mobile measuring station travels along the propagation path of the power cable; This represents the time delay of the k-th measurement station of type i along the airborne propagation path. This represents the time delay of the reference measurement station on the airborne propagation path for the kth time. f represents the time delay of the k-th mobile measuring station along the airborne propagation path; s It is a fixed threshold parameter.

6. The power cable fault trench location system based on UWB ranging and sound as described in claim 5, characterized in that, Through formula The first propagation speed of the sound signal during its k-th propagation through the air was calculated; and, using the formula... The second propagation speed of the sound signal when it propagates in the power cable for the kth time is calculated.

7. The power cable fault trench location system based on UWB ranging and sound as described in claim 6, characterized in that, The k-th time delay of the reference measuring station on the airborne propagation path and the time delay of the k-th time of the mobile measuring station on the air propagation path. Each of these results was predicted using Bayesian filtering based on the time delays of the previous k-1 propagation paths.

8. A method for locating power cable faults in a trench based on UWB ranging and sound, characterized in that, It is implemented in the power cable fault trench location system based on UWB ranging and sound as described in claim 7, and the method includes 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, it can excite the fault point to emit a sound signal. The reference measurement station generates a first UWB signal and receives a second UWB signal sent by the mobile measurement station. It also timestamps a first sound signal generated when a high-voltage DC pulse signal is applied to the power cable by the pulse generator, based on real-time acquisition. Furthermore, it sends the timestamped first sound signal along with the first UWB signal to the mobile measurement station. The first UWB signal carries the ID number of the reference measurement station, its generated timestamp, and synchronization positioning information. The second UWB signal carries the ID number of the mobile measurement station, its generated timestamp, and synchronization positioning information. Each time the mobile measuring station establishes communication with the reference measuring station after each installation and fixation, it generates a second UWB signal and sends it to the reference measuring station. It also timestamps the second sound signal generated when the power cable is subjected to a high-voltage DC pulse signal by the pulse generator. Furthermore, by combining the first UWB signal received from the reference measuring station and the timestamped first sound signal, the final location of the fault point in the power cable is determined.

9. The method for locating power cable faults in trenches based on UWB ranging and sound as described in claim 8, characterized in that, Each time the mobile measuring station establishes communication with the reference measuring station after each installation and fixation, it generates a second UWB signal and sends it to the reference measuring station. It also timestamps the second sound signal generated when the power cable is subjected to a high-voltage DC pulse signal by the pulse generator. Furthermore, by combining the received first UWB signal from the reference measuring station with the timestamped first sound signal, the specific steps for determining the final location of the fault point in the power cable include: The total number of times the mobile measuring station establishes communication with the reference measuring station after its mobile installation and fixation is determined to be k. Based on the second UWB signal generated by the mobile measuring station after 1 to k mobile installations and fixation and its corresponding first UWB signal received from the reference measuring station, and the first UWB signal generated by the reference measuring station after 1 to k mobile installations and fixation and its corresponding second UWB signal received from the mobile measuring station, k relative distances formed between the mobile measuring station and the reference measuring station after 1 to k mobile installations and fixation are obtained. Furthermore, combined with the preset coordinate position of the reference measuring station, the coordinate position of the mobile measuring station after 1 to k mobile installations and fixation is obtained; where k is a positive integer greater than 1. The second time-stamped sound signals collected by the mobile measuring station from 1 to k times and the first time-stamped sound signals collected by the reference measuring station from 1 to k times are segmented to obtain the signal segments corresponding to the mobile measuring station and the reference measuring station from 1 to k times respectively. Then, the 2k segmented signal segments are decomposed using a preset ensemble empirical mode decomposition (EEMD) algorithm to obtain the intrinsic mode function sets corresponding to the mobile measuring station and the reference measuring station from 1 to k times respectively. Based on the intrinsic mode function sets of the mobile measuring station and the reference measuring station at times 1 to k, the cable propagation path signal and atmospheric propagation path signal corresponding to the mobile measuring station and the reference measuring station at times 1 to k are extracted, so as to further obtain the time delay difference formed by the mobile measuring station and the reference measuring station at times 1 to k based on the propagation of sound signals in power cables and air; Based on the k relative distances formed between the mobile measuring station and the reference measuring station after installation and fixation in 1 to k activities, and combined with the atmospheric propagation path signals extracted by the mobile measuring station and the reference measuring station in 1 to k activities respectively, the k first propagation speeds of the sound signal in the air are calculated. Based on the k relative distances formed between the mobile measuring station and the reference measuring station after the mobile measuring station is installed and fixed in 1 to k activities, and combined with the cable propagation path signals extracted by the mobile measuring station and the reference measuring station in 1 to k activities respectively, the k second propagation speeds of the sound signal in the power cable are calculated. Based on the time delay difference and coordinate position of the mobile measuring station during the propagation of sound signals in the power cable and air from the 1st to the kth times, and the time delay difference and coordinate position of the reference measuring station during the propagation of sound signals in the power cable and air from the 1st to the kth times, and combined with the k first propagation velocities of the sound signal in the air and the k second propagation velocities in the power cable, an objective function is constructed. The particle swarm optimization algorithm and the Levenberg-Marquardt algorithm are used to find the optimal solution of the objective function, and the output of the optimal solution is the final location of the fault point in the power cable.

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