Fault positioning method and system for overhead line of power distribution network, and storage medium

Abstract

The invention provides a fault positioning method and system for an overhead line of a power distribution network, and a storage medium. The method comprises the steps of obtaining a plurality of fault traveling wave magnetic field signals; performing the following steps on any signal: performing phase-mode transformation on the signal, extracting and decomposing a line mode component, determining a modulus maximum point, and determining the time corresponding to the point as a first fault traveling wave head arrival moment; carrying out clock synchronization on the moment, and obtaining a wave head arrival moment of a second fault traveling wave; obtaining a to-be-detected fault point and a line parameter; based on the wave head arrival moments of the plurality of second fault traveling waves, extracting a head end arrival moment and a tail end arrival moment; and performing fault positioning on the overhead line of the power distribution network based on the head end arrival time, the tail end arrival time and the fault line parameters. According to the fault positioning method for the overhead line of the power distribution network, interference to normal operation of the power distribution network can be avoided, and high-precision non-intrusive positioning of the overhead line of the power distribution network is realized through the tunneling magnetoresistive sensor.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power system fault detection, in particular to a fault positioning method and system for overhead lines of a distribution network and a storage medium. BACKGROUND

[0002] The distribution network is an important part of the power system. When a fault occurs in the overhead lines of the distribution network, timely and accurate positioning of the fault point is crucial for quickly repairing the lines and ensuring reliable power supply of the distribution network. At present, the mainstream fault positioning methods for overhead lines mainly include the signal injection method, the impedance method based on fault steady-state quantities, and the traveling wave method based on fault transient-state quantities. Among them, the traveling wave method is widely used in the field of overhead line fault positioning due to its high positioning accuracy. However, existing traveling wave positioning devices mostly rely on traditional electrical quantities such as voltage traveling waves and current traveling waves, and are designed as intrusive devices, which require power-off operation or live-line operation for installation and maintenance. At the same time, the topology of the distribution network is complex and has many branches, requiring a large number of positioning devices to be deployed. If intrusive traveling wave positioning devices are used, their installation and daily maintenance will inevitably affect the normal operation of the distribution network, making it difficult to achieve non-stop installation and maintenance.

[0003] Under the background of the prior art, there are two obvious deficiencies in the fault positioning of the distribution network. On the one hand, the related technologies generally use traditional intrusive traveling wave sensing technology, which requires the installation of voltage or current transformers at key nodes of the distribution network. This not only complicates the installation process, but also requires power-off operation, further increasing the disturbance to the normal operation of the distribution network. On the other hand, although the tunneling magnetic resistance sensor has advantages such as high sensitivity and wide dynamic range in the field of magnetic field detection, it has not been effectively applied to the fault positioning scenario of the distribution network. SUMMARY

[0004] The present application aims to provide a fault positioning method and system for overhead lines of a distribution network and a storage medium to solve the above technical problems and avoid disturbing the normal operation of the distribution network. The tunneling magnetic resistance sensor is used to achieve high-precision non-intrusive positioning of the overhead lines of the distribution network.

[0005] To solve the above technical problems, the present application provides a fault positioning method for overhead lines of a distribution network, comprising: Obtaining a plurality of fault traveling wave magnetic field signals; For any fault traveling wave magnetic field signal, the following steps are performed: performing a phase-to-magnitude transformation on the fault traveling wave magnetic field signal to extract the corresponding line-mode component; decomposing the line-mode component to determine the modulus maximum point, and determining the time corresponding to the modulus maximum point as the first fault traveling wave head arrival time; clock synchronizing the first fault traveling wave head arrival time to obtain the second fault traveling wave head arrival time; Obtaining a to-be-tested fault point and corresponding fault line parameters; Based on the arrival times of several second fault traveling wave fronts, the arrival times of the first second fault traveling wave fronts corresponding to the fault point under test and the arrival times of the last second fault traveling wave fronts corresponding to the fault point under test are extracted. Based on the arrival times of the second traveling wave front at the beginning and the second traveling wave front at the end, and the parameters of the faulted line, the distance from the fault point to the beginning and the distance from the fault point to the end are calculated to locate the fault in the overhead line of the distribution network.

[0006] In the above scheme, by performing phase-mode transformation on the fault traveling wave magnetic field signal and extracting the corresponding line mode components, the characteristic information of the fault traveling wave can be highlighted, laying the foundation for accurate identification of the arrival time of the fault traveling wave front. Next, by decomposing the line mode components to determine the modulus maxima, the time corresponding to the modulus maxima can be locked as the arrival time of the first fault traveling wave front, providing an initial time basis for subsequent time synchronization and fault location. Then, after clock synchronization to eliminate time deviations, the arrival times of the first and last second fault traveling wave fronts corresponding to the fault point under test are selected from several second fault traveling wave front arrival times, clarifying the time difference basis for the arrival of the fault traveling wave at both ends of the line. Finally, by calculating the distance from the fault point to the first and last ends, high-precision non-intrusive positioning of the distribution network overhead lines is achieved, avoiding interference with the normal operation of the distribution network and providing an accurate basis for rapid repair of faults in distribution network overhead lines and restoration of reliable power supply to the grid.

[0007] Furthermore, acquiring several fault traveling wave magnetic field signals includes: Several original fault traveling wave magnetic field signals were collected; The original fault traveling wave magnetic field signal is filtered and amplified to obtain several fault traveling wave magnetic field signals.

[0008] In the above scheme, by collecting several original fault traveling wave magnetic field signals, the initial magnetic field data generated when a fault occurs on an overhead line in the distribution network is directly obtained. This provides a basic data source for subsequent signal processing and fault location, ensuring that there are real and complete fault signals to rely on during the location process. Next, the original fault traveling wave magnetic field signals are filtered and amplified. On the one hand, this filters out useless information such as grid interference and environmental noise mixed in the original signal and reduces the interference of noise on subsequent signal analysis. On the other hand, it amplifies the weak fault traveling wave magnetic field signal, enhancing the identification of fault characteristics. Finally, the fault traveling wave magnetic field signal is obtained, providing high-quality signal input for subsequent phase mode transformation, wavefront identification, and other steps, thus improving the accuracy of subsequent location procedures.

[0009] Furthermore, the following steps are performed on any fault traveling wave magnetic field signal: performing a phase-mode transformation on the fault traveling wave magnetic field signal and extracting the corresponding linear mode component; including: For any fault traveling wave magnetic field signal, perform the following steps: Based on the fault traveling wave magnetic field signal, the corresponding three-phase current is obtained; The three-phase current is decomposed to extract the ground mode current, the first line mode current, and the second line mode current. The first line-mode current and the second line-mode current constitute the line-mode component.

[0010] In the above scheme, by acquiring the three-phase current corresponding to the fault traveling wave magnetic field signal, the conversion from the collected magnetic field physical quantity to the core electrical quantity of the power grid is realized, and the correlation between the magnetic field signal and the line fault current is established. Next, the acquired three-phase current is decomposed to extract the ground mode current, the first line mode current, and the second line mode current, transforming the complex three-phase fault signal into independent modulus signals, thus achieving decoupling of the three-phase current signals. Then, the ground mode component is discarded, and the first and second line mode currents are combined to form the line mode component, filtering out signal components more valuable for fault location, laying a high-quality signal foundation for subsequent accurate identification of the fault traveling wave front.

[0011] Further, the process of decomposing the linear mode components, determining the mode maxima, and defining the time corresponding to the mode maxima as the arrival time of the first fault traveling wavefront includes: Multi-scale wavelet decomposition of the linear mode components is performed, and wavelet transform coefficients at several scales are calculated. Based on the wavelet transform coefficients at several scales, the modulus maxima are determined, and the time corresponding to the modulus maxima is determined as the arrival time of the first fault traveling wave front.

[0012] In the above scheme, by performing multi-scale wavelet decomposition on the linear mode components and calculating wavelet transform coefficients at several scales, the temporal information of the signal can be preserved to capture the arrival time of the wavefront. Simultaneously, the abrupt change characteristics of the fault traveling wave can be highlighted through decomposition at different scales, while noise interference can be suppressed, providing data support for subsequent location of modulus maxima. By determining the modulus maxima and identifying their corresponding times as the arrival time of the first fault traveling wavefront, the initial abrupt change position of the fault traveling wave in the linear mode components is located—the modulus maxima correspond to the abrupt change time when the signal energy is strongest, i.e., the time when the fault traveling wavefront first arrives. This provides a crucial initial time reference for subsequent clock synchronization and fault location calculation.

[0013] Further, the step of clock synchronization of the arrival time of the first fault traveling wave front to obtain the arrival time of the second fault traveling wave front includes: Based on a preset second pulse signal and a clock synchronization algorithm, the arrival time of the first fault traveling wave front is synchronized with the clock to obtain the arrival time of the second fault traveling wave front.

[0014] In the above scheme, the arrival time of the first fault traveling wave head is synchronized by pre-setting a second pulse signal and a clock synchronization algorithm. This eliminates the time recording differences caused by hardware clock deviation, unifies the arrival time of the first fault traveling wave head to the same time reference, and generates the arrival time of the second fault traveling wave head with time consistency. This provides time-bias-free parameter support for subsequent deduction of the fault location and avoids positioning errors caused by clock asynchrony.

[0015] This invention provides a fault location system for overhead lines in a power distribution network, comprising a magnetic field signal acquisition unit, a data processing unit, a fault point identification unit, an arrival time extraction unit, and a fault location calculation unit, specifically: The magnetic field signal acquisition unit is used to acquire several fault traveling wave magnetic field signals; The data processing unit is configured to perform the following steps on any fault traveling wave magnetic field signal: perform phase mode transformation on the fault traveling wave magnetic field signal and extract the corresponding line mode component; decompose the line mode component, determine the mode maximum point, and determine the time corresponding to the mode maximum point as the arrival time of the first fault traveling wave wavefront; synchronize the clock at the arrival time of the first fault traveling wave wavefront and obtain the arrival time of the second fault traveling wave wavefront. The fault point identification unit is used to acquire the fault point to be tested and the corresponding fault line parameters; The arrival time extraction unit is used to extract the arrival time of the first second fault traveling wave wave corresponding to the fault point under test and the arrival time of the last second fault traveling wave wave corresponding to the fault point under test, based on the arrival times of several second fault traveling wave wave wave fronts. The fault location calculation unit is used to calculate the distance from the beginning of the fault point and the distance from the end of the fault point based on the arrival time of the second traveling wave front of the first fault, the arrival time of the second traveling wave front of the last fault, and the fault line parameters, so as to realize the fault location of the overhead line of the distribution network.

[0016] This invention provides a fault location system for overhead power distribution lines. In practical applications, it only requires a data processing unit. By performing phase-mode transformation on the fault traveling wave magnetic field signal and extracting the corresponding line mode components, it can highlight the characteristic information of the fault traveling wave, laying the foundation for accurate identification of the arrival time of the fault traveling wave front. Next, by decomposing the line mode components to determine the modulus maxima, the time corresponding to the modulus maxima can be locked as the arrival time of the first fault traveling wave front, providing an initial time basis for subsequent time synchronization and fault location. Then, using an arrival time extraction unit, after clock synchronization to eliminate time deviations, the arrival times of the first and last second fault traveling wave fronts corresponding to the fault point to be tested are selected from several second fault traveling wave front arrival times, clarifying the time difference basis for the arrival of the fault traveling wave at both ends of the line. Finally, using a fault location calculation unit, by calculating the distance of the fault point from the first and last ends, high-precision non-intrusive location of the overhead power distribution line is achieved, avoiding interference with the normal operation of the distribution network and providing an accurate basis for rapid repair of faults in overhead power distribution lines and restoration of reliable power supply to the grid.

[0017] Furthermore, the magnetic field signal acquisition unit is used to acquire several fault traveling wave magnetic field signals; including: Several original fault traveling wave magnetic field signals were collected; The original fault traveling wave magnetic field signal is filtered and amplified to obtain several fault traveling wave magnetic field signals.

[0018] In the above scheme, by collecting several original fault traveling wave magnetic field signals, the initial magnetic field data generated when a fault occurs on an overhead line in the distribution network is directly obtained. This provides a basic data source for subsequent signal processing and fault location, ensuring that there are real and complete fault signals to rely on during the location process. Next, the original fault traveling wave magnetic field signals are filtered and amplified. On the one hand, this filters out useless information such as grid interference and environmental noise mixed in the original signal and reduces the interference of noise on subsequent signal analysis. On the other hand, it amplifies the weak fault traveling wave magnetic field signal, enhancing the identification of fault characteristics. Finally, the fault traveling wave magnetic field signal is obtained, providing high-quality signal input for subsequent phase mode transformation, wavefront identification, and other steps, thus improving the accuracy of subsequent location procedures.

[0019] Furthermore, the data processing unit is configured to perform the following steps on any fault traveling wave magnetic field signal: perform phase-mode transformation on the fault traveling wave magnetic field signal and extract the corresponding linear mode component; including: For any fault traveling wave magnetic field signal, perform the following steps: Based on the fault traveling wave magnetic field signal, the corresponding three-phase current is obtained; The three-phase current is decomposed to extract the ground mode current, the first line mode current, and the second line mode current. The first line-mode current and the second line-mode current constitute the line-mode component.

[0020] In the above scheme, by acquiring the three-phase current corresponding to the fault traveling wave magnetic field signal, the conversion from the collected magnetic field physical quantity to the core electrical quantity of the power grid is realized, and the correlation between the magnetic field signal and the line fault current is established. Next, the acquired three-phase current is decomposed to extract the ground mode current, the first line mode current, and the second line mode current, transforming the complex three-phase fault signal into independent modulus signals, thus achieving decoupling of the three-phase current signals. Then, the ground mode component is discarded, and the first and second line mode currents are combined to form the line mode component, filtering out signal components more valuable for fault location, laying a high-quality signal foundation for subsequent accurate identification of the fault traveling wave front.

[0021] Further, the process of decomposing the linear mode components, determining the mode maxima, and defining the time corresponding to the mode maxima as the arrival time of the first fault traveling wavefront includes: Multi-scale wavelet decomposition of the linear mode components is performed, and wavelet transform coefficients at several scales are calculated. Based on the wavelet transform coefficients at several scales, the modulus maxima are determined, and the time corresponding to the modulus maxima is determined as the arrival time of the first fault traveling wave front.

[0022] In the above scheme, by performing multi-scale wavelet decomposition on the linear mode components and calculating wavelet transform coefficients at several scales, the temporal information of the signal can be preserved to capture the arrival time of the wavefront. Simultaneously, the abrupt change characteristics of the fault traveling wave can be highlighted through decomposition at different scales, while noise interference can be suppressed, providing data support for subsequent location of modulus maxima. By determining the modulus maxima and identifying their corresponding times as the arrival time of the first fault traveling wavefront, the initial abrupt change position of the fault traveling wave in the linear mode components is located—the modulus maxima correspond to the abrupt change time when the signal energy is strongest, i.e., the time when the fault traveling wavefront first arrives. This provides a crucial initial time reference for subsequent clock synchronization and fault location calculation.

[0023] The present invention provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, performs the functions of the system as described above. Attached Figure Description

[0024] Figure 1 A flowchart illustrating a fault location method for overhead lines in a power distribution network, as provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the installation of a non-intrusive fault location device for overhead power distribution lines according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the dual-end traveling wave positioning principle provided in an embodiment of the present invention; Figure 4 This is an architecture diagram of a fault location system for overhead power distribution lines provided in an embodiment of the present invention. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] This embodiment provides a fault location method for overhead lines in a distribution network. Please refer to the flowchart for details. Figure 1 ,include: Step S1: Acquire several fault traveling wave magnetic field signals; Step S2: For any fault traveling wave magnetic field signal, perform the following steps: perform phase mode transformation on the fault traveling wave magnetic field signal and extract the corresponding linear mode component; decompose the linear mode component, determine the mode maximum point, and determine the time corresponding to the mode maximum point as the arrival time of the first fault traveling wave wavefront; synchronize the clock for the arrival time of the first fault traveling wave wavefront and obtain the arrival time of the second fault traveling wave wavefront. Step S3: Obtain the fault point and the corresponding fault line parameters; Step S4: Based on the arrival times of several second fault traveling wave fronts, extract the arrival times of the first second fault traveling wave fronts corresponding to the fault point under test and the arrival times of the last second fault traveling wave fronts corresponding to the fault point under test. Step S5: Based on the arrival time of the second fault traveling wave front at the beginning end, the arrival time of the second fault traveling wave front at the end end, and the fault line parameters, calculate the distance from the beginning end and the distance from the end end of the fault point to achieve fault location of the overhead line of the distribution network.

[0027] In this embodiment, please refer to Figure 2Multiple distribution network fault location devices are installed at key nodes along the overhead distribution lines (pre-set based on experience), fixed 1-2 meters below the conductors of the overhead line towers. Each device contains a tunneling magnetoresistive sensor array, leveraging the high sensitivity and wide dynamic range of these sensors to achieve high-precision acquisition of the traveling wave magnetic field signal from the overhead distribution lines. By performing phase-mode transformation on the fault traveling wave magnetic field signal and extracting the corresponding line mode components, high-precision, high-speed sampling of the fault traveling wave magnetic field signal can be achieved, highlighting the characteristic information of the fault traveling wave and laying the foundation for accurate identification of the arrival time of the fault traveling wave front. Then, by decomposing the line mode components to determine the modulus maxima, the time corresponding to the modulus maxima can be locked as the arrival time of the first fault traveling wave front, providing an initial time reference for subsequent time synchronization and fault location. Then, after clock synchronization to eliminate time deviations, the processed fault traveling wave magnetic field signal and the arrival time of the second fault traveling wave wavehead are transmitted to a remote host computer for storage. The arrival times of the first and last second fault traveling wave waveheads corresponding to the fault point under test are then selected from several arrival times, clarifying the time difference basis for the arrival of the fault traveling wave at both ends of the line. The remote host computer has a built-in fault location algorithm for overhead lines in the distribution network, used to accurately calibrate and locate faults using the fault traveling wave magnetic field signals from different location devices and the arrival times of the second fault traveling wave waveheads synchronized with clock information. Finally, the distance from the first end and the distance from the last end of the fault point are calculated using a dual-end traveling wave location algorithm. Please refer to [link to relevant documentation]. Figure 3 Two positioning devices are installed at the beginning and end of the line where the fault point F is located, respectively. Let the distance from the fault point to the beginning be... The distance from the fault point to the end is The total length of the line is The propagation speed of the traveling wave in the line is v, and the arrival time of the second fault traveling wave front at the beginning of the record is... The recorded arrival time of the second fault traveling wavefront at the end is... The distance from the fault point to the beginning position and the distance from the fault point to the end position The calculation formula is: The above steps achieve high-precision non-intrusive positioning of overhead lines in the distribution network, with a theoretical positioning error of less than [missing information]. Meters, meeting the fault location requirements of the distribution network; preventing the need for power outages for installation and maintenance after problems with traditional intrusive location devices, avoiding interference with the normal operation of the distribution network, and providing accurate basis for rapid repair of overhead line faults in the distribution network and restoration of reliable power supply to the grid.

[0028] Furthermore, acquiring several fault traveling wave magnetic field signals includes: Several original fault traveling wave magnetic field signals were collected; The original fault traveling wave magnetic field signal is filtered and amplified to obtain several fault traveling wave magnetic field signals.

[0029] In this embodiment, by collecting several original fault traveling wave magnetic field signals, the initial magnetic field data generated when a fault occurs on an overhead line in the distribution network is directly obtained. This provides a basic data source for subsequent signal processing and fault location, ensuring that there are real and complete fault signals to rely on during the location process. Next, the original fault traveling wave magnetic field signals are filtered and amplified by a signal conditioning circuit. On the one hand, this filters out useless information such as grid interference and environmental noise mixed in the original signal and reduces the interference of noise on subsequent signal analysis. On the other hand, it amplifies the weak fault traveling wave magnetic field signal, enhancing the identification of fault characteristics. Finally, the fault traveling wave magnetic field signal is obtained, providing high-quality signal input for subsequent phase mode transformation, wavefront identification, and other steps, thus improving the accuracy of the subsequent location process.

[0030] Furthermore, the following steps are performed on any fault traveling wave magnetic field signal: performing a phase-mode transformation on the fault traveling wave magnetic field signal and extracting the corresponding linear mode component; including: For any fault traveling wave magnetic field signal, perform the following steps: Based on the fault traveling wave magnetic field signal, the corresponding three-phase current is obtained; The three-phase current is decomposed to extract the ground mode current, the first line mode current, and the second line mode current. The first line-mode current and the second line-mode current constitute the line-mode component.

[0031] In this embodiment, the three-phase current corresponding to the fault traveling wave magnetic field signal is obtained: based on the fault traveling wave magnetic field signals in the horizontal and vertical directions at different locations measured by the magnetic field sensor array, the three-phase current is inverted. , , The value of this value represents the transformation from the acquired magnetic field physical quantity to the core electrical quantity of the power grid, establishing the correlation between the magnetic field signal and the line fault current. Next, the acquired three-phase current is decomposed: the Karebauer transform is used to decompose the three-phase current into three independent moduli: Thus, the ground mode current is extracted. First line mode current Second line mode current The complex three-phase fault signal is converted into an independent modulus signal, realizing the decoupling processing of the three-phase current signal. Then, the ground mode component is discarded, and the first line mode current and the second line mode current are combined to form the line mode component, thus filtering out the signal components that are more valuable for fault location and laying a high-quality signal foundation for subsequent accurate identification of the traveling wave head of the fault.

[0032] Further, the process of decomposing the linear mode components, determining the mode maxima, and defining the time corresponding to the mode maxima as the arrival time of the first fault traveling wavefront includes: Multi-scale wavelet decomposition of the linear mode components is performed, and wavelet transform coefficients at several scales are calculated. Based on the wavelet transform coefficients at several scales, the modulus maxima are determined, and the time corresponding to the modulus maxima is determined as the arrival time of the first fault traveling wave front.

[0033] In this embodiment, the linear mode components are decomposed into multi-scale wavelet components using a fault traveling wave wavefront detection algorithm: Linear component Taking the mother wavelet function as an example... ,make Indicates to scale Scalability: ; Continuous wavelet transform It can be represented as: Suppose that the wavelet function is at the scale Below, in a certain neighborhood For everything have ,but These are the points where the modulus of the wavelet transform is maximized. The modulus maxima are determined by the wavelet transform. The traveling wave signal is decomposed into multiple scales using wavelet transform coefficients at several scales to find modulus maxima. The first occurrence of a modulus maxima is taken as the arrival time of the first fault traveling wave front. This method preserves the signal's temporal information to capture the arrival time of the wave front, highlights the abrupt changes in the fault traveling wave through decomposition at different scales, and suppresses noise interference, providing data support for subsequent modulus maxima location. By determining the modulus maxima that characterize the line fault (the point in the wavelet transform coefficients that first reaches the preset modulus maxima), a first detection signal representing the detected modulus maxima is generated. The fault traveling wave front recording data and time information corresponding to this first detection signal are sent to the wireless communication device to obtain the arrival time of the first fault traveling wave front. This locates the initial abrupt change position of the fault traveling wave in the line modulus component—the modulus maxima corresponds to the abrupt change time with the strongest signal energy, i.e., the time of the first arrival of the fault traveling wave front. This provides a crucial initial time reference for subsequent clock synchronization and fault location calculation.

[0034] Further, the step of clock synchronization of the arrival time of the first fault traveling wave front to obtain the arrival time of the second fault traveling wave front includes: Based on a preset second pulse signal and a clock synchronization algorithm, the arrival time of the first fault traveling wave front is synchronized with the clock to obtain the arrival time of the second fault traveling wave front.

[0035] In this embodiment, the arrival time of the first fault traveling wave front is synchronized using a preset second pulse signal from the satellite positioning system and a clock synchronization algorithm based on a high-precision temperature-controlled crystal oscillator. This enables high-precision clock synchronization between different positioning devices (synchronization error less than 100%). This eliminates time recording discrepancies caused by hardware clock deviations, unifying the arrival time of the first fault traveling wave front to the same time base, generating the arrival time of the second fault traveling wave front with time consistency, providing time-bias-free parameter support for subsequent fault location deduction, and avoiding positioning errors caused by clock asynchrony.

[0036] Please see Figure 4 This embodiment provides a fault location system for overhead lines in a power distribution network, including a magnetic field signal acquisition unit, a data processing unit, a fault point identification unit, an arrival time extraction unit, and a fault location calculation unit, specifically: The magnetic field signal acquisition unit is used to acquire several fault traveling wave magnetic field signals; The data processing unit is configured to perform the following steps on any fault traveling wave magnetic field signal: perform phase mode transformation on the fault traveling wave magnetic field signal and extract the corresponding line mode component; decompose the line mode component, determine the mode maximum point, and determine the time corresponding to the mode maximum point as the arrival time of the first fault traveling wave wavefront; synchronize the clock at the arrival time of the first fault traveling wave wavefront and obtain the arrival time of the second fault traveling wave wavefront. The fault point identification unit is used to acquire the fault point to be tested and the corresponding fault line parameters; The arrival time extraction unit is used to extract the arrival time of the first second fault traveling wave wave corresponding to the fault point under test and the arrival time of the last second fault traveling wave wave corresponding to the fault point under test, based on the arrival times of several second fault traveling wave wave wave fronts. The fault location calculation unit is used to calculate the distance from the beginning of the fault point and the distance from the end of the fault point based on the arrival time of the second traveling wave front of the first fault, the arrival time of the second traveling wave front of the last fault, and the fault line parameters, so as to realize the fault location of the overhead line of the distribution network.

[0037] This embodiment provides a fault location system for overhead power distribution lines. In practical applications, multiple fault location devices only need to be installed at key nodes (pre-set based on experience) along the overhead power distribution line, fixed 1-2 meters below the conductor of the overhead power distribution line tower. Each fault location device contains a tunneling magnetoresistive sensor array, which utilizes the high sensitivity and wide dynamic range of the tunneling magnetoresistive sensor to achieve high-precision acquisition of the traveling wave magnetic field signal of the overhead power distribution line. A data processing unit performs phase-mode transformation on the fault traveling wave magnetic field signal and extracts the corresponding line mode components, enabling high-precision and high-speed sampling of the fault traveling wave magnetic field signal, highlighting the characteristic information of the fault traveling wave, and laying the foundation for subsequent accurate identification of the arrival time of the fault traveling wave front. Then, by decomposing the line mode components to determine the modulus maxima, the time corresponding to the modulus maxima can be locked as the arrival time of the first fault traveling wave front, providing an initial time basis for subsequent time synchronization and fault location. Then, an arrival time extraction unit is used. After clock synchronization to eliminate time deviation, the processed fault traveling wave magnetic field signal and the arrival time of the second fault traveling wave wavehead are transmitted to a remote host computer for storage. The arrival times of the first and last second fault traveling wave waveheads corresponding to the fault point under test are selected from several arrival times, clarifying the time difference basis for the arrival of the fault traveling wave at both ends of the line. The remote host computer has a built-in fault location algorithm for overhead lines in the distribution network, used to accurately calibrate and locate the fault traveling wave magnetic field signals from different positioning devices and the arrival times of the second fault traveling wave waveheads synchronized with clock information. Finally, a fault location calculation unit is used to calculate the distance from the fault point to the first end and the distance from the fault point to the last end using a dual-end traveling wave location algorithm: two positioning devices are installed at the first and last ends of the line where the fault point is located, respectively. Let the distance from the fault point to the first end be... The distance from the fault point to the end is The total length of the line is The propagation speed of the traveling wave in the line is v, and the arrival time of the second fault traveling wave front at the beginning of the record is... The recorded arrival time of the second fault traveling wavefront at the end is... The distance from the fault point to the beginning position and the distance from the fault point to the end position The calculation formula is: The above steps achieve high-precision non-intrusive positioning of overhead lines in the distribution network, with a theoretical positioning error of less than [missing information]. Meters, meeting the fault location requirements of the distribution network; preventing the need for power outages for installation and maintenance after problems with traditional intrusive location devices, avoiding interference with the normal operation of the distribution network, and providing accurate basis for rapid repair of overhead line faults in the distribution network and restoration of reliable power supply to the grid.

[0038] Furthermore, the magnetic field signal acquisition unit is used to acquire several fault traveling wave magnetic field signals; including: Several original fault traveling wave magnetic field signals were collected; The original fault traveling wave magnetic field signal is filtered and amplified to obtain several fault traveling wave magnetic field signals.

[0039] In this embodiment, by collecting several original fault traveling wave magnetic field signals, the initial magnetic field data generated when a fault occurs on an overhead line in the distribution network is directly obtained. This provides a basic data source for subsequent signal processing and fault location, ensuring that there are real and complete fault signals to rely on during the location process. Next, the original fault traveling wave magnetic field signals are filtered and amplified by a signal conditioning circuit. On the one hand, this filters out useless information such as grid interference and environmental noise mixed in the original signal and reduces the interference of noise on subsequent signal analysis. On the other hand, it amplifies the weak fault traveling wave magnetic field signal, enhancing the identification of fault characteristics. Finally, the fault traveling wave magnetic field signal is obtained, providing high-quality signal input for subsequent phase mode transformation, wavefront identification, and other steps, thus improving the accuracy of the subsequent location process.

[0040] Furthermore, the data processing unit is configured to perform the following steps on any fault traveling wave magnetic field signal: perform phase-mode transformation on the fault traveling wave magnetic field signal and extract the corresponding linear mode component; including: For any fault traveling wave magnetic field signal, perform the following steps: Based on the fault traveling wave magnetic field signal, the corresponding three-phase current is obtained; The three-phase current is decomposed to extract the ground mode current, the first line mode current, and the second line mode current. The first line-mode current and the second line-mode current constitute the line-mode component.

[0041] In this embodiment, the three-phase current corresponding to the fault traveling wave magnetic field signal is obtained: based on the fault traveling wave magnetic field signals in the horizontal and vertical directions at different locations measured by the magnetic field sensor array, the three-phase current is inverted. , , The value of this value represents the transformation from the acquired magnetic field physical quantity to the core electrical quantity of the power grid, establishing the correlation between the magnetic field signal and the line fault current. Next, the acquired three-phase current is decomposed: the Karebauer transform is used to decompose the three-phase current into three independent moduli: Thus, the ground mode current is extracted. First line mode current Second line mode current The complex three-phase fault signal is converted into an independent modulus signal, realizing the decoupling processing of the three-phase current signal. Then, the ground mode component is discarded, and the first line mode current and the second line mode current are combined to form the line mode component, thus filtering out the signal components that are more valuable for fault location and laying a high-quality signal foundation for subsequent accurate identification of the traveling wave head of the fault.

[0042] Further, the process of decomposing the linear mode components, determining the mode maxima, and defining the time corresponding to the mode maxima as the arrival time of the first fault traveling wavefront includes: Multi-scale wavelet decomposition of the linear mode components is performed, and wavelet transform coefficients at several scales are calculated. Based on the wavelet transform coefficients at several scales, the modulus maxima are determined, and the time corresponding to the modulus maxima is determined as the arrival time of the first fault traveling wave front.

[0043] In this embodiment, the linear mode components are decomposed into multi-scale wavelet components using a fault traveling wave wavefront detection algorithm: Linear component Taking the mother wavelet function as an example... ,make Indicates to scale Scalability: ; Continuous wavelet transform It can be represented as: Suppose that the wavelet function is at the scale Below, in a certain neighborhood For everything have ,but These are the points where the modulus of the wavelet transform is maximized. The modulus maxima are determined by the wavelet transform. The traveling wave signal is decomposed into multiple scales using wavelet transform coefficients at several scales to find modulus maxima. The first occurrence of a modulus maxima is taken as the arrival time of the first fault traveling wave front. This method preserves the signal's temporal information to capture the arrival time of the wave front, highlights the abrupt changes in the fault traveling wave through decomposition at different scales, and suppresses noise interference, providing data support for subsequent modulus maxima location. By determining the modulus maxima that characterize the line fault (the point in the wavelet transform coefficients that first reaches the preset modulus maxima), a first detection signal representing the detected modulus maxima is generated. The fault traveling wave front recording data and time information corresponding to this first detection signal are sent to the wireless communication device to obtain the arrival time of the first fault traveling wave front. This locates the initial abrupt change position of the fault traveling wave in the line modulus component—the modulus maxima corresponds to the abrupt change time with the strongest signal energy, i.e., the time of the first arrival of the fault traveling wave front. This provides a crucial initial time reference for subsequent clock synchronization and fault location calculation.

[0044] In this embodiment, a power supply unit is also included, which includes a solar panel, a battery, and an energy management circuit, for providing a stable power supply to the fault location system of the entire overhead power distribution network.

[0045] This embodiment provides a non-transitory computer-readable storage medium on which a computer program is stored, which, when executed by a processor, implements the functions of the system as described above.

[0046] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A method for fault location in overhead lines of a power distribution network, characterized in that, include: Acquire several fault traveling wave magnetic field signals; For any fault traveling wave magnetic field signal, the following steps are performed: perform phase mode transformation on the fault traveling wave magnetic field signal and extract the corresponding linear mode component; decompose the linear mode component, determine the mode maximum point, and determine the time corresponding to the mode maximum point as the arrival time of the first fault traveling wave wavefront; synchronize the clock at the arrival time of the first fault traveling wave wavefront to obtain the arrival time of the second fault traveling wave wavefront. Obtain the fault point to be tested and the corresponding fault line parameters; Based on the arrival times of several second fault traveling wave fronts, the arrival times of the first second fault traveling wave fronts corresponding to the fault point under test and the arrival times of the last second fault traveling wave fronts corresponding to the fault point under test are extracted. Based on the arrival times of the second traveling wave front at the beginning and the second traveling wave front at the end, and the parameters of the faulted line, the distance from the fault point to the beginning and the distance from the fault point to the end are calculated to locate the fault in the overhead line of the distribution network.

2. The fault location method for overhead lines in a power distribution network according to claim 1, characterized in that, The acquisition of several fault traveling wave magnetic field signals includes: Several original fault traveling wave magnetic field signals were collected; The original fault traveling wave magnetic field signal is filtered and amplified to obtain several fault traveling wave magnetic field signals.

3. The fault location method for overhead lines in a power distribution network according to claim 1, characterized in that, For any fault traveling wave magnetic field signal, the following steps are performed: Phase-mode transformation is performed on the fault traveling wave magnetic field signal to extract the corresponding linear mode component; including: For any fault traveling wave magnetic field signal, perform the following steps: Based on the fault traveling wave magnetic field signal, the corresponding three-phase current is obtained; The three-phase current is decomposed to extract the ground mode current, the first line mode current, and the second line mode current. The first line-mode current and the second line-mode current constitute the line-mode component.

4. The fault location method for overhead lines in a power distribution network according to claim 1, characterized in that, The process of decomposing the linear mode components, determining the mode maxima, and defining the time corresponding to the mode maxima as the arrival time of the first fault traveling wavefront includes: Multi-scale wavelet decomposition of the linear mode components is performed, and wavelet transform coefficients at several scales are calculated. Based on the wavelet transform coefficients at several scales, the modulus maxima are determined, and the time corresponding to the modulus maxima is determined as the arrival time of the first fault traveling wave front.

5. The fault location method for overhead lines in a power distribution network according to claim 1, characterized in that, The step of synchronizing the arrival time of the first fault traveling wave front with a clock to obtain the arrival time of the second fault traveling wave front includes: Based on a preset second pulse signal and a clock synchronization algorithm, the arrival time of the first fault traveling wave front is synchronized with the clock to obtain the arrival time of the second fault traveling wave front.

6. A fault location system for overhead lines in a power distribution network, characterized in that, It includes a magnetic field signal acquisition unit, a data processing unit, a fault point identification unit, an arrival time extraction unit, and a fault location calculation unit, specifically: The magnetic field signal acquisition unit is used to acquire several fault traveling wave magnetic field signals; The data processing unit is configured to perform the following steps on any fault traveling wave magnetic field signal: perform phase mode transformation on the fault traveling wave magnetic field signal and extract the corresponding line mode component; decompose the line mode component, determine the mode maximum point, and determine the time corresponding to the mode maximum point as the arrival time of the first fault traveling wave wavefront; synchronize the clock at the arrival time of the first fault traveling wave wavefront and obtain the arrival time of the second fault traveling wave wavefront. The fault point identification unit is used to acquire the fault point to be tested and the corresponding fault line parameters; The arrival time extraction unit is used to extract the arrival time of the first second fault traveling wave wave corresponding to the fault point under test and the arrival time of the last second fault traveling wave wave corresponding to the fault point under test, based on the arrival times of several second fault traveling wave wave wave fronts. The fault location calculation unit is used to calculate the distance from the beginning of the fault point and the distance from the end of the fault point based on the arrival time of the second traveling wave front of the first fault, the arrival time of the second traveling wave front of the last fault, and the fault line parameters, so as to realize the fault location of the overhead line of the distribution network.

7. A fault location system for overhead lines in a power distribution network according to claim 6, characterized in that, The magnetic field signal acquisition unit is used to acquire several fault traveling wave magnetic field signals; including: Several original fault traveling wave magnetic field signals were collected; The original fault traveling wave magnetic field signal is filtered and amplified to obtain several fault traveling wave magnetic field signals.

8. A fault location system for overhead lines in a power distribution network according to claim 6, characterized in that, The data processing unit is configured to perform the following steps on any fault traveling wave magnetic field signal: perform phase-mode transformation on the fault traveling wave magnetic field signal and extract the corresponding linear mode component; including: For any fault traveling wave magnetic field signal, perform the following steps: Based on the fault traveling wave magnetic field signal, the corresponding three-phase current is obtained; The three-phase current is decomposed to extract the ground mode current, the first line mode current, and the second line mode current. The first line-mode current and the second line-mode current constitute the line-mode component.

9. A fault location system for overhead lines in a power distribution network according to claim 6, characterized in that, The process of decomposing the linear mode components, determining the mode maxima, and defining the time corresponding to the mode maxima as the arrival time of the first fault traveling wavefront includes: Multi-scale wavelet decomposition of the linear mode components is performed, and wavelet transform coefficients at several scales are calculated. Based on the wavelet transform coefficients at several scales, the modulus maxima are determined, and the time corresponding to the modulus maxima is determined as the arrival time of the first fault traveling wave front.

10. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it performs the functions of the system as described in any one of claims 6 to 9.

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