Power transmission line fault positioning method and system based on multi-dimensional magnetic field measurement

Abstract

The invention discloses a power transmission line fault positioning method and system based on multi-dimensional magnetic field measurement. At least two multi-dimensional magnetic field measurement devices are arranged on power transmission towers at different positions of the same power transmission line; based on the multi-dimensional magnetic field measuring device, determining components of magnetic field intensity in the x, y and z directions of the space, and monitoring dynamic magnetic field distribution data in the space of the power transmission line in real time; determining a sensitive directional component based on the dynamic magnetic field distribution data; performing data preprocessing on the determined sensitive direction component, and establishing a space-time magnetic field intensity matrix based on the preprocessed sensitive direction component; based on the space-time magnetic field intensity matrix, establishing a magnetic field intensity time-varying oscillogram, and based on the magnetic field intensity time-varying oscillogram, determining a wave crest of sudden change of the magnetic field intensity and a moment corresponding to the wave crest; and determining a fault position based on the wave crest and the moment corresponding to the wave crest.

Description

Technical Field

[0001] The present invention relates to the technical field of power system transmission line fault location, and more specifically, to a transmission line fault location method and system based on multi-dimensional magnetic field measurement. Background Art

[0002] Transmission line fault location methods can be divided into two categories based on the device installation location: substation-side and line-side. Substation-side location technologies mainly include impedance location and traveling wave location. The impedance location method is based on the power frequency components of the line voltage and current after the fault, and determines the fault distance by calculating the ratio of the equivalent impedance at the fault point to the impedance per unit length of the line. The traveling wave location method uses the transient traveling wave signal generated at the moment of the fault, and calculates the fault location by capturing the arrival time difference of the traveling wave head at both ends of the line and combining it with the wave velocity. The line side mainly uses the contact traveling wave location method, which directly collects the traveling wave waveform by installing traveling wave sensors at key nodes of the line, and performs segmented location based on the time difference between adjacent sensors receiving the traveling wave.

[0003] All of the above-mentioned existing methods have technical limitations. Substation-side impedance positioning is significantly affected by line parameter deviations and transition resistance. Impedance-distance linearity decreases in long-distance transmission lines, leading to increased positioning errors and inability to effectively identify high-resistance ground faults. Traveling-wave positioning has stringent requirements for sampling frequency (requires MHz levels) and noise suppression. Multiple reflections and refractions of traveling waves in complex line topologies can easily lead to misjudgment of waveheads. Positioning accuracy degrades significantly when wave speeds on mountainous lines are affected by environmental factors. While line-side contact traveling-wave positioning can improve wavehead identification, it requires the large-scale deployment of high-precision sensors, resulting in high installation and maintenance costs, poor electromagnetic compatibility, and inefficiencies in sensor power supply modules when line-side loads are too low. Summary of the Invention

[0004] The technical solution of the present invention provides a transmission line fault location method and system based on multi-dimensional magnetic field measurement to solve the problem of how to locate transmission line faults based on multi-dimensional magnetic field measurement.

[0005] In order to solve the above problems, the present invention provides a method for locating a transmission line fault based on multi-dimensional magnetic field measurement, the method comprising:

[0006] At least two multi-dimensional magnetic field measurement devices are installed on transmission towers at different locations on the same transmission line;

[0007] Based on the multi-dimensional magnetic field measurement device, the components of the magnetic field intensity in the three directions of x, y, and z in space are determined, and the dynamic magnetic field distribution data in the transmission line space is monitored in real time; based on the dynamic magnetic field distribution data, the sensitive direction component is determined;

[0008] Performing data preprocessing on the determined sensitive direction components, establishing a spatiotemporal magnetic field intensity matrix based on the preprocessed sensitive direction components; establishing a magnetic field intensity time-varying waveform diagram based on the spatiotemporal magnetic field intensity matrix, and determining a peak of a sudden change in magnetic field intensity and a time corresponding to the peak based on the magnetic field intensity time-varying waveform diagram;

[0009] The fault location is determined based on the peak and the time corresponding to the peak.

[0010] Preferably, the multi-dimensional magnetic field measuring device comprises a substrate; the substrate comprises two mutually perpendicular substrates or three mutually perpendicular substrates, and a magnetic sensitive element parallel to the substrate is provided on the substrate;

[0011] The two mutually perpendicular substrates are arranged in a plane perpendicular to the power transmission line conductor and are orthogonal to each other;

[0012] The three mutually perpendicular substrates are orthogonal in directions in a three-dimensional space around the transmission line.

[0013] Preferably, the magnetic sensitive element includes two groups of anisotropic magnetoresistive sensors and two groups of resistors, and the two groups of anisotropic magnetoresistive sensors and the two groups of resistors form a Wheatstone bridge.

[0014] Preferably, the anisotropic magnetoresistive sensor further comprises: setting a direction of an easy magnetization axis, wherein the direction of the easy magnetization axis is perpendicular to the direction of the measuring magnetic field;

[0015] The anisotropic magnetoresistive sensor is a Permalloy film, and the direction of the Permalloy film is set so that the easy magnetization axis and the current direction form an angle of 45 degrees;

[0016] The anisotropic magnetoresistive sensor has a measurement amplitude of magnetic induction intensity of not less than ±2mT, a measurement accuracy better than 0.1μT, and an applicable frequency range of not less than 0.1Hz-1MHz.

[0017] Preferably, the resistance value of the resistor is consistent with the resistance value of the anisotropic magnetoresistive sensor at zero magnetic field strength;

[0018] The input end of the Wheatstone bridge is connected to a DC power supply, and the output end is connected to an operational amplifier.

[0019] Preferably, the method further comprises restoring the voltage signal output by the Wheatstone bridge into a magnetic field strength signal:

[0020]

[0021] Among them, V out is the voltage signal at the output of the Wheatstone bridge after passing through the operational amplifier; V sis the DC power supply voltage at the input end of the Wheatstone bridge, which is generally 12V; ΔR is the change in resistance of the anisotropic magnetoresistive sensor after being affected by the external magnetic field; R is the initial resistance value of the anisotropic magnetoresistive sensor when it is not affected by the external magnetic field; k is the proportional coefficient of the resistance change rate of the anisotropic magnetoresistive sensor when it is affected by the external magnetic field to the applied external magnetic field strength, which can be determined by selecting the working curve of the anisotropic magnetoresistive sensor; H is the amplitude of the external magnetic field strength.

[0022] Preferably, determining the fault location based on the peak and the time corresponding to the peak includes:

[0023]

[0024] Where x is the distance between two adjacent multi-dimensional magnetic field measurement transmission line fault location devices, x m is the distance between the fault location device that first receives the fault waveform and the fault point, v is the wave velocity, and Δt is the time difference between adjacent wave peaks.

[0025] According to another aspect of the present invention, the present invention provides a transmission line fault location system based on multi-dimensional magnetic field measurement, the system comprising:

[0026] a determination unit, configured to set at least two multi-dimensional magnetic field measurement devices on transmission towers at different locations on the same transmission line;

[0027] A monitoring unit is configured to determine the components of the magnetic field intensity in the three spatial directions of x, y, and z based on the multi-dimensional magnetic field measurement device, and monitor the dynamic magnetic field distribution data within the transmission line space in real time; and determine the sensitive direction component based on the dynamic magnetic field distribution data;

[0028] Establish a unit for obtaining multiple horizontal magnetic field intensity components H X With multiple perpendicular magnetic field intensity components H Y Perform data preprocessing based on multiple horizontal magnetic field intensity components H after preprocessing X With multiple perpendicular magnetic field intensity components H Y Establishing a spatiotemporal magnetic field intensity matrix; establishing a magnetic field intensity time-varying waveform diagram based on the spatiotemporal magnetic field intensity matrix; and determining a peak of a sudden change in magnetic field intensity and a time corresponding to the peak based on the magnetic field intensity time-varying waveform diagram;

[0029] The result unit is used to determine the fault location based on the peak and the time corresponding to the peak.

[0030] Preferably, the multi-dimensional magnetic field measuring device comprises a substrate; the substrate comprises two mutually perpendicular substrates or three mutually perpendicular substrates, and a magnetic sensitive element parallel to the substrate is provided on the substrate;

[0031] The two mutually perpendicular substrates are arranged in a plane perpendicular to the power transmission line conductor and are orthogonal to each other;

[0032] The three mutually perpendicular substrates are orthogonal in directions in a three-dimensional space around the transmission line.

[0033] Preferably, the magnetic sensitive element includes two groups of anisotropic magnetoresistive sensors and two groups of resistors, and the two groups of anisotropic magnetoresistive sensors and the two groups of resistors form a Wheatstone bridge.

[0034] Preferably, the anisotropic magnetoresistive sensor further comprises: setting a direction of an easy magnetization axis, wherein the direction of the easy magnetization axis is perpendicular to the direction of the measuring magnetic field;

[0035] The anisotropic magnetoresistive sensor is a Permalloy film, and the direction of the Permalloy film is set so that the easy magnetization axis and the current direction form an angle of 45 degrees;

[0036] The anisotropic magnetoresistive sensor has a measurement amplitude of magnetic induction intensity of not less than ±2mT, a measurement accuracy better than 0.1μT, and an applicable frequency range of not less than 0.1Hz-1MHz.

[0037] Preferably, the resistance value of the resistor is consistent with the resistance value of the anisotropic magnetoresistive sensor at zero magnetic field strength;

[0038] The input end of the Wheatstone bridge is connected to a DC power supply, and the output end is connected to an operational amplifier.

[0039] Preferably, the method further comprises restoring the voltage signal output by the Wheatstone bridge into a magnetic field strength signal:

[0040]

[0041] Among them, V out is the voltage signal at the output of the Wheatstone bridge after passing through the operational amplifier; V s is the DC power supply voltage at the input end of the Wheatstone bridge, which is generally 12V; ΔR is the change in resistance of the anisotropic magnetoresistive sensor after being affected by the external magnetic field; R is the initial resistance value of the anisotropic magnetoresistive sensor when it is not affected by the external magnetic field; k is the proportional coefficient of the resistance change rate of the anisotropic magnetoresistive sensor when it is affected by the external magnetic field to the applied external magnetic field strength, which can be determined by selecting the working curve of the anisotropic magnetoresistive sensor; H is the amplitude of the external magnetic field strength.

[0042] Preferably, determining the fault location based on the peak and the time corresponding to the peak includes:

[0043]

[0044] Where x is the distance between two adjacent multi-dimensional magnetic field measurement transmission line fault location devices, x m is the distance between the fault location device that first receives the fault waveform and the fault point, v is the wave velocity, and Δt is the time difference between adjacent wave peaks.

[0045] The technical solution of the present invention provides a method and system for locating transmission line faults based on multi-dimensional magnetic field measurement, wherein the method includes: setting at least two multi-dimensional magnetic field measurement devices on transmission towers at different locations on the same transmission line; based on the multi-dimensional magnetic field measurement devices, determining the components of the magnetic field intensity in the three directions of space x, y, and z, and monitoring the dynamic magnetic field distribution data in the transmission line space in real time; determining the sensitive direction component based on the dynamic magnetic field distribution data; performing data preprocessing on the determined sensitive direction component, and establishing a space-time magnetic field intensity matrix based on the preprocessed sensitive direction component; establishing a time-varying waveform diagram of the magnetic field intensity based on the space-time magnetic field intensity matrix, and determining the peak of the sudden change in magnetic field intensity and the corresponding time of the peak based on the time-varying waveform diagram of the magnetic field intensity; and determining the fault location based on the peak and the corresponding time of the peak. The technical solution of the present invention provides a method and system for locating transmission line faults based on multi-dimensional magnetic field measurement, which greatly improves the positioning accuracy by capturing vector features through two-dimensional magnetic field data, and realizes accurate positioning of the fault. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] A more complete understanding of exemplary embodiments of the present invention may be obtained by referring to the following drawings:

[0047] Figure 1 This is a flow chart of a method for locating a power transmission line fault based on multi-dimensional magnetic field measurement according to a preferred embodiment of the present invention;

[0048] Figure 2 Schematic diagram of the installation of a power transmission line fault location device based on multi-dimensional magnetic field measurement according to a preferred embodiment of the present invention;

[0049] Figure 3 A processing flow chart of a transmission line fault location method based on multi-dimensional magnetic field measurement according to a preferred embodiment of the present invention;

[0050] Figure 4 This is a structural diagram of a power transmission line fault location device based on multi-dimensional magnetic field measurement according to a preferred embodiment of the present invention;

[0051] Figure 5 A schematic structural diagram of a magnetic sensitive element in the form of a Wheatstone bridge according to a preferred embodiment of the present invention; and

[0052] Figure 6 2 is a structural diagram of a power transmission line fault location system based on multi-dimensional magnetic field measurement according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0053] Exemplary embodiments of the present invention will now be described with reference to the accompanying drawings. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to provide a thorough and complete disclosure of the present invention and to fully convey the scope of the present invention to those skilled in the art. The terminology used in the exemplary embodiments shown in the accompanying drawings is not intended to limit the present invention. In the accompanying drawings, identical elements are denoted by the same reference numerals.

[0054] Unless otherwise specified, the terms used herein (including technical terms) have the meanings commonly understood by those skilled in the art. In addition, it is understood that terms defined in commonly used dictionaries should be understood to have the same meanings as those in the context of the relevant fields, and should not be understood as idealized or overly formal meanings.

[0055] Figure 1 The figure is a flow chart of a method for locating a power transmission line fault based on multi-dimensional magnetic field measurement according to a preferred embodiment of the present invention.

[0056] Since existing fault location methods are difficult to achieve both high precision, adaptability to complex environments, and low cost, the present invention provides a low-cost, non-contact fault location system that does not require line modification. This system uses a non-contact two-dimensional magnetic field sensor to capture the transient magnetic field vector characteristics of the fault, thereby achieving high-precision positioning of the fault point in complex terrain.

[0057] like Figure 1 As shown, the present invention provides a transmission line fault location method based on multi-dimensional magnetic field measurement, the method comprising:

[0058] Step 101: Install at least two multi-dimensional magnetic field measurement devices on transmission towers at different locations on the same transmission line;

[0059] Step 102: Determine the components of the magnetic field intensity in the three directions x, y, and z in space using a multi-dimensional magnetic field measurement device, and monitor the dynamic magnetic field distribution data within the transmission line space in real time; determine the sensitive direction component based on the dynamic magnetic field distribution data;

[0060] The present invention studies the principle of multi-dimensional magnetic field measurement, designs a multi-dimensional magnetic field measurement device structure, obtains the components of the magnetic field intensity in the x, y, and z directions in space through orthogonal decomposition, and realizes the capture of the transient magnetic field vector characteristics around the transmission line.

[0061] The present invention deploys a multi-dimensional magnetic field measurement device at the first level cross arm of the transmission tower to monitor the dynamic magnetic field distribution in the vertical plane of the line in real time. The horizontal magnetic field intensity component Hx and the vertical magnetic field intensity component Hy in the plane are obtained;

[0062] Figure 2 In the figure, 1 is a transmission tower; 2 is the enclosure housing the multi-dimensional magnetic field measurement device. The transmission line fault location device, based on multi-dimensional magnetic field measurement, is installed on the primary crossarm of each voltage level tower. The two-dimensional magnetic field measurement point is 10-20 cm above the primary platform and extends 20-30 cm horizontally beyond the platform.

[0063] Step 103: Data preprocessing is performed on the determined sensitive directional components, and a spatiotemporal magnetic field intensity matrix is established based on the preprocessed sensitive directional components. The present invention performs data preprocessing on the multi-node magnetic field measurement data to construct the spatiotemporal magnetic field intensity matrix; the multidimensional data stream is transmitted back to the cloud server in real time, and waveform recognition and feature extraction are performed on the spatiotemporal magnetic field intensity matrix on the server side.

[0064] Step 104: Based on the spatiotemporal magnetic field intensity matrix, a magnetic field intensity time-varying waveform diagram is established, and based on the magnetic field intensity time-varying waveform diagram, a peak of a sudden change in magnetic field intensity and a time corresponding to the peak are determined;

[0065] The present invention extracts the arrival time difference of traveling waves based on the sudden change peak value of the transient waveform of the magnetic field intensity obtained by adjacent sensor nodes during the fault, determines the precise position of the fault, and realizes accurate fault location.

[0066] Step 105: Determine the fault location based on the peak and the time corresponding to the peak.

[0067] Preferably, the multi-dimensional magnetic field measuring device comprises a substrate; the substrate comprises two mutually perpendicular substrates or three mutually perpendicular substrates, and a magnetic sensitive element parallel to the substrate is provided on the substrate;

[0068] The two mutually perpendicular substrates are arranged in a plane perpendicular to the transmission line conductor and are orthogonal to each other;

[0069] The three mutually perpendicular substrates are orthogonal in direction in the three-dimensional space around the transmission line.

[0070] Preferably, the magnetic sensitive element includes two groups of anisotropic magnetoresistive sensors and two groups of resistors, and the two groups of anisotropic magnetoresistive sensors and the two groups of resistors form a Wheatstone bridge.

[0071] Preferably, the anisotropic magnetoresistive sensor further comprises: setting a direction of an easy magnetization axis, wherein the direction of the easy magnetization axis is perpendicular to the direction of the measuring magnetic field;

[0072] The anisotropic magnetoresistive sensor is a Permalloy film, which is oriented so that the easy magnetization axis forms a 45° angle with the current direction.

[0073] The anisotropic magnetoresistive sensor has a measurement amplitude of magnetic induction intensity of no less than ±2mT, a measurement accuracy better than 0.1μT, and an applicable frequency range of no less than 0.1Hz-1MHz.

[0074] Preferably, the resistance value of the resistor is consistent with the resistance value of the anisotropic magnetoresistive sensor at zero magnetic field strength;

[0075] The input of the Wheatstone bridge is connected to a 12V DC power supply, and the output is connected to an operational amplifier.

[0076] Preferably, the method further includes restoring the voltage signal output by the Wheatstone bridge into a magnetic field strength signal:

[0077]

[0078] Among them, V out is the voltage signal at the output of the Wheatstone bridge after passing through the operational amplifier; V s is the DC power supply voltage at the input end of the Wheatstone bridge, which is generally 12V; ΔR is the change in resistance of the anisotropic magnetoresistive sensor after being affected by the external magnetic field; R is the initial resistance value of the anisotropic magnetoresistive sensor when it is not affected by the external magnetic field; k is the proportional coefficient of the resistance change rate of the anisotropic magnetoresistive sensor when it is affected by the external magnetic field to the applied external magnetic field strength, which can be determined by selecting the working curve of the anisotropic magnetoresistive sensor; H is the amplitude of the external magnetic field strength.

[0079] The structure of the multi-dimensional magnetic field measurement device in the present invention is specifically described as follows:

[0080] The multi-dimensional magnetic field measuring device comprises three mutually perpendicular substrates, on which magnetic sensitive elements parallel to the substrates are arranged. Figure 4 As shown, a multi-dimensional magnetic field measurement device structure including three mutually perpendicular substrates is taken as an example.

[0081] Figure 4 The white structure in the middle is the mutually perpendicular substrates mentioned above, and the material is generally non-magnetic, high-insulation material such as ceramic.

[0082] Figure 4 The structure with the middle dashed line is the magnetic sensitive element mentioned above, which is generally composed of anisotropic magnetoresistive sensors (AMR). Under certain working conditions, Hall elements, giant magnetoresistive sensors (GMR) and other elements can also be used. A single magnetic sensitive element can be composed of two AMRs and two resistors to form a Wheatstone bridge. The structure is as follows: Figure 5 shown.

[0083] The magnetic film in the AMR sensor is designed to have an easy magnetization axis during manufacturing. When using AMR, by setting the direction of the easy magnetization axis, the sensor can respond only to the target direction component without being affected by other components. Figure 4 In the figure, the direction of the easy magnetization axis is perpendicular to the direction of the measured magnetic field; Figure 4 In the figure, the direction of the sensor's response magnetic field intensity component is marked in the component.

[0084] In the adjacent arms of the Wheatstone bridge, X1 and X2 are composed of two AMRs, and the other two adjacent arms X3 and X4 are composed of resistors. The resistance value is consistent with the resistance of the AMR when there is no magnetic field. The input end of the magnetic sensitive element in the form of a Wheatstone bridge is connected to a 12V DC power supply, and the output end is connected to an operational amplifier, which can amplify the measurement signal to improve accuracy. Among them, the magnetic film in the two AMRs can be selected as a Permalloy film. The direction of the Permalloy is set so that the easy magnetization axis and the current direction are at an angle of 45 degrees, so that the bridge output and the measured magnetic field strength are linearly related. When there is no magnetic field or the measured magnetic field direction is parallel to the easy magnetization axis, the resistance values of X1-X4 are the same and the bridge output is zero; when the measured magnetic field direction is as follows Figure 5 As shown in the figure, when perpendicular to the easy magnetization axis, the bridge output voltage is linearly related to the magnetic field strength, thereby realizing the measurement of the component of the specific magnetic field direction.

[0085] AMR sensors can measure magnetic induction intensity within ±2mT, with a measurement accuracy of up to 0.1μT.

[0086] The applicable frequency range of AMR sensors is 0.1Hz-1MHz, which can effectively cover the frequency range of steady-state waveforms and common fault waveforms.

[0087] The multi-dimensional magnetic field measurement device includes a signal acquisition and processing module, which can collect the voltage signal output by the magnetic sensitive element in the form of a Wheatstone bridge and restore it to a magnetic field intensity signal. The formula is as follows:

[0088]

[0089] The device operates in the linear region, so the parameter k can be obtained by referring to the manual of the magnetic sensitive element or by testing under rated working conditions.

[0090] The multi-dimensional magnetic field measuring device comprises a data transmission device, which can transmit the data wirelessly to a server.

[0091] The shell of the multi-dimensional magnetic field measurement device is made of aluminum-magnesium alloy, which can effectively shield electromagnetic interference.

[0092] The multi-dimensional magnetic field measuring device of the present invention is described as follows:

[0093] Considering that the magnetic field intensity in the direction parallel to the conductor is ideally zero, and in reality is also extremely small, the two-dimensional components of the multidimensional magnetic field measurement device can be used in practical applications. The advantage of this design is that the multidimensional magnetic field measurement device can already highlight the transient characteristics of the magnetic field, while significantly reducing the amount of data compared to three-dimensional data, easing data processing pressure. The two mutually perpendicular substrates should be arranged in a plane perpendicular to the transmission line conductor and form an orthogonal relationship. In this example, the horizontal and vertical directions are used as examples, but other orthogonal decompositions can also be performed in the plane perpendicular to the conductor.

[0094] Data preprocessing includes data cleaning and filtering. The preprocessed data is constructed into a space-time magnetic field intensity matrix and transmitted to the cloud server in real time. The space-time magnetic field intensity matrix is subjected to waveform recognition and feature extraction on the server side to identify the moment corresponding to the peak of the magnetic field intensity when the fault traveling wave arrives.

[0095] Preferably, determining the fault location based on the peak and the time corresponding to the peak includes:

[0096]

[0097] Where x is the distance between two adjacent two-dimensional magnetic field measurement transmission line fault location devices, x m is the distance between the fault location device that first receives the fault waveform and the fault point, v is the wave velocity, and Δt is the time difference between adjacent wave peaks.

[0098] The present invention calculates the time difference Δt between the arrival times of the peaks of the magnetic field intensity measured by the multi-dimensional magnetic field measuring device when receiving the fault traveling waves in different directions, thereby determining the fault location x m , the basic principles are as follows:

[0099]

[0100] Where x is the distance between two adjacent two-dimensional magnetic field measurement transmission line fault location devices, x m is the distance between the fault location device that first receives the fault waveform and the fault point, and v is the wave speed.

[0101] The present invention provides a method for locating a transmission line fault based on multi-dimensional magnetic field measurement, comprising the following steps:

[0102] S1. Study the principle of multi-dimensional magnetic field measurement, design the structure of the multi-dimensional magnetic field measurement device, obtain the components of the magnetic field intensity in the x, y, and z directions in space through orthogonal decomposition, and realize the capture of the transient magnetic field vector characteristics around the transmission line;

[0103] S2. Deploy a multi-dimensional magnetic field measurement device at the first-level cross arm of the transmission tower to monitor the dynamic magnetic field distribution in the vertical plane of the line in real time. Obtain the horizontal magnetic field intensity component Hx and the vertical magnetic field intensity component Hy in the plane;

[0104] S3. Preprocess the multi-node magnetic field measurement data to construct a spatiotemporal magnetic field intensity matrix; transmit the multi-dimensional data stream back to the cloud server in real time, and perform waveform recognition and feature extraction on the spatiotemporal magnetic field intensity matrix on the server side;

[0105] S4. Based on the peak value of the transient waveform of the magnetic field intensity obtained by adjacent sensor nodes during the fault, the arrival time difference of the traveling wave is extracted to determine the precise location of the fault and achieve accurate fault location.

[0106] The present invention proposes a transmission line fault location device based on multi-dimensional magnetic field measurement, which includes two mutually perpendicular substrates or three mutually perpendicular substrates, on which magnetic sensitive elements parallel to the substrates are arranged. The two mutually perpendicular substrates should be arranged in a plane perpendicular to the transmission line conductor and form an orthogonal relationship. In this example, the horizontal and vertical directions are taken as examples, and other orthogonal decompositions can also be performed in a plane perpendicular to the conductor; the three mutually perpendicular substrates are orthogonal in direction in space.

[0107] The present invention proposes a transmission line fault location device based on multi-dimensional magnetic field measurement, which performs orthogonal decomposition on the magnetic field intensity components perpendicular to the conductor plane, uses horizontal and vertical directions as directions in the embodiment, and records them as x and y components for measurement.

[0108] The present invention performs waveform recognition and feature extraction on the spatiotemporal magnetic field intensity matrix.

[0109] In S4, the present invention uses the peak time data obtained after processing the space-time magnetic field intensity matrix to solve the time difference between two adjacent groups of multi-dimensional magnetic field measurement devices receiving the fault waveform, and locates the fault based on the time difference.

[0110] The present invention provides a method for locating faults in power transmission lines based on multi-dimensional magnetic field measurement, which has the following beneficial effects: the fault locating method has high positioning accuracy and greatly improves positioning accuracy by capturing vector features through multi-dimensional magnetic field data; at the same time, the required magnetic field measuring device does not need to be installed on the conductor, and the use of a non-contact device is simple to install, which also greatly reduces costs; the fault locating principle is based on magnetic field measurement, which reduces the interference of complex environments on the measuring device, making it able to match complex working conditions; the magnetic field intensity is relatively low during steady-state operation of the three-phase transmission line, but the magnetic field intensity suddenly changes greatly when a fault occurs, and this characteristic also ensures the high measurement accuracy of the device.

[0111] The following examples illustrate the embodiments of the present invention:

[0112] A method for locating a transmission line fault based on multi-dimensional magnetic field measurement mainly comprises the following steps:

[0113] S1. Study the principle of multi-dimensional magnetic field measurement, design the structure of the multi-dimensional magnetic field measurement device, obtain the components of the magnetic field intensity in the x, y, and z directions in space through orthogonal decomposition, and realize the capture of the transient magnetic field vector characteristics around the transmission line;

[0114] S2. Deploy a multi-dimensional magnetic field measurement device at the first-level cross arm of the transmission tower to monitor the dynamic magnetic field distribution in the vertical plane of the line in real time. Obtain the horizontal magnetic field intensity component Hx and the vertical magnetic field intensity component Hy in the plane;

[0115] S3. Preprocess the multi-node magnetic field measurement data to construct a spatiotemporal magnetic field intensity matrix; transmit the multi-dimensional data stream back to the cloud server in real time, and perform waveform recognition and feature extraction on the spatiotemporal magnetic field intensity matrix on the server side;

[0116] S4. Based on the peak value of the transient waveform of the magnetic field intensity obtained by adjacent sensor nodes during the fault, the arrival time difference of the traveling wave is extracted to determine the precise location of the fault and achieve accurate fault location.

[0117] In S1 of the present invention, a multi-dimensional magnetic field measuring device is designed based on anisotropic magnetic sensitive elements, and can be designed as a three-dimensional magnetic field measuring device or a multi-dimensional magnetic field measuring device as needed.

[0118] In the present invention S2, a multi-dimensional magnetic field measuring device is installed at the first-level cross arm of two adjacent 220kV cathead towers to measure the x component Hx and y component Hy of the magnetic field intensity at the installation location;

[0119] In S3 of the present invention, a magnetic field intensity time-varying waveform diagram is drawn on the server side based on the magnetic field intensity time-space matrix transmitted back by two adjacent sensors, and the peak of the sudden change of magnetic field intensity when the fault traveling wave arrives is identified and its time is recorded.

[0120] In S4 of the present invention, the time difference Δt between the arrival times of the peaks of the magnetic field intensity measured by the multi-dimensional magnetic field measuring device when receiving the fault traveling waves in different directions is calculated to determine the fault location x. m ,as follows:

[0121]

[0122] Figure 6 2 is a structural diagram of a power transmission line fault location system based on multi-dimensional magnetic field measurement according to a preferred embodiment of the present invention.

[0123] like Figure 6 As shown, the present invention provides a transmission line fault location system based on multi-dimensional magnetic field measurement, the system comprising:

[0124] A determining unit 601 is configured to set at least two multi-dimensional magnetic field measuring devices on transmission towers at different locations on the same transmission line;

[0125] Monitoring unit 602 is used to determine the components of the magnetic field intensity in the three directions of x, y, and z in space based on the multi-dimensional magnetic field measurement device, and monitor the dynamic magnetic field distribution data in the transmission line space in real time; and determine the sensitive direction component based on the dynamic magnetic field distribution data;

[0126] Establishing unit 603, configured to perform data preprocessing on the determined sensitive direction components, establish a spatiotemporal magnetic field intensity matrix based on the preprocessed sensitive direction components; establish a magnetic field intensity time-varying waveform diagram based on the spatiotemporal magnetic field intensity matrix, and determine a peak of a sudden change in magnetic field intensity and a time corresponding to the peak based on the magnetic field intensity time-varying waveform diagram;

[0127] The result unit 604 is configured to determine the fault location based on the peak and the time corresponding to the peak.

[0128] Preferably, the multi-dimensional magnetic field measuring device comprises a substrate; the substrate comprises two mutually perpendicular substrates or three mutually perpendicular substrates, and a magnetic sensitive element parallel to the substrate is provided on the substrate;

[0129] The two mutually perpendicular substrates are arranged in a plane perpendicular to the transmission line conductor and are orthogonal to each other;

[0130] The three mutually perpendicular substrates are orthogonal in direction in the three-dimensional space around the transmission line.

[0131] Preferably, the magnetic sensitive element includes two groups of anisotropic magnetoresistive sensors and two groups of resistors, and the two groups of anisotropic magnetoresistive sensors and the two groups of resistors form a Wheatstone bridge.

[0132] Preferably, the anisotropic magnetoresistive sensor further comprises: setting a direction of an easy magnetization axis, wherein the direction of the easy magnetization axis is perpendicular to the direction of the measuring magnetic field;

[0133] The anisotropic magnetoresistive sensor is a Permalloy film, which is oriented so that the easy magnetization axis forms a 45° angle with the current direction.

[0134] The anisotropic magnetoresistive sensor has a measurement amplitude of magnetic induction intensity of no less than ±2mT, a measurement accuracy better than 0.1μT, and an applicable frequency range of no less than 0.1Hz-1MHz.

[0135] Preferably, the resistance value of the resistor is consistent with the resistance value of the anisotropic magnetoresistive sensor;

[0136] The input of the Wheatstone bridge is connected to a DC power supply, and the output is connected to an operational amplifier.

[0137] Preferably, the method further includes restoring the voltage signal output by the Wheatstone bridge into a magnetic field strength signal:

[0138]

[0139] Among them, V out is the voltage signal at the output of the Wheatstone bridge after passing through the operational amplifier; V s is the DC power supply voltage at the input end of the Wheatstone bridge, which is generally 12V; ΔR is the change in resistance of the anisotropic magnetoresistive sensor after being affected by the external magnetic field; R is the initial resistance value of the anisotropic magnetoresistive sensor when it is not affected by the external magnetic field; k is the proportional coefficient of the resistance change rate of the anisotropic magnetoresistive sensor when it is affected by the external magnetic field to the applied external magnetic field strength, which can be determined by selecting the working curve of the anisotropic magnetoresistive sensor; H is the amplitude of the external magnetic field strength.

[0140] Preferably, determining the fault location based on the peak and the time corresponding to the peak includes:

[0141]

[0142] Where x is the distance between two adjacent multi-dimensional magnetic field measurement transmission line fault location devices, x m is the distance between the fault location device that first receives the fault waveform and the fault point, v is the wave velocity, and Δt is the time difference between adjacent wave peaks.

[0143] A transmission line fault location system based on multi-dimensional magnetic field measurement in a preferred embodiment of the present invention corresponds to a transmission line fault location method based on multi-dimensional magnetic field measurement in another preferred embodiment of the present invention, and will not be described in detail here.

[0144] It will be understood by those skilled in the art that the embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of the present invention may be implemented in various computer languages, for example, the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0145] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowcharts and / or block diagrams, as well as combinations of processes and / or blocks in the flowcharts and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowcharts and / or block diagrams. Figure 1a process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0146] These computer program instructions may also be stored in a computer readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 a process or multiple processes and / or boxes Figure 1 The function specified in one or more boxes.

[0147] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing the instructions executed on the computer or other programmable device for implementing the process. Figure 1 a process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0148] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0149] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

[0150] The invention has been described above with reference to a few embodiments. However, it is readily apparent to a person skilled in the art that other embodiments than the ones disclosed above are equally within the scope of the invention, as defined by the appended patent claims.

[0151] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a / / the [means, component, etc.]" are to be interpreted openly as referring to at least one instance of a means, component, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not necessarily need to be performed in the exact order disclosed, unless explicitly stated otherwise.

Claims

1. A method for locating a transmission line fault based on multi-dimensional magnetic field measurement, the method comprising: At least two multi-dimensional magnetic field measurement devices are installed on transmission towers at different locations on the same transmission line; Based on the multi-dimensional magnetic field measurement device, the components of the magnetic field intensity in the three directions of x, y, and z in space are determined, and the dynamic magnetic field distribution data in the transmission line space is monitored in real time; determining a sensitive directional component based on the dynamic magnetic field distribution data; performing data preprocessing on the determined sensitive directional components, and establishing a spatiotemporal magnetic field intensity matrix based on the preprocessed sensitive directional components; Based on the spatiotemporal magnetic field intensity matrix, a magnetic field intensity time-varying waveform diagram is established, and based on the magnetic field intensity time-varying waveform diagram, a peak of a sudden change in magnetic field intensity and a time corresponding to the peak are determined; The fault location is determined based on the peak and the time corresponding to the peak.

2. The method according to claim 1, wherein the multi-dimensional magnetic field measurement device comprises a substrate; the substrate comprises two mutually perpendicular substrates or three mutually perpendicular substrates, and a magnetic sensitive element parallel to the substrate is provided on the substrate; The two mutually perpendicular substrates are arranged in a plane perpendicular to the power transmission line conductor and are orthogonal to each other; The three mutually perpendicular substrates are orthogonal in directions in a three-dimensional space around the transmission line. 3 . The method according to claim 2 , wherein the magnetic sensitive element comprises two groups of anisotropic magnetoresistive sensors and two groups of resistors, and the two groups of anisotropic magnetoresistive sensors and the two groups of resistors form a Wheatstone bridge.

4. The method according to claim 3, wherein the anisotropic magnetoresistive sensor further comprises: Setting the direction of the easy magnetization axis, wherein the direction of the easy magnetization axis is perpendicular to the direction of the measured magnetic field; The anisotropic magnetoresistive sensor is a Permalloy film, and the direction of the Permalloy film is set so that the easy magnetization axis and the current direction form an angle of 45 degrees; The anisotropic magnetoresistive sensor has a measurement amplitude of magnetic induction intensity of not less than ±2mT, a measurement accuracy better than 0.1μT, and an applicable frequency range of not less than 0.1Hz-1MHz.

5. The method according to claim 3, wherein the resistance value of the resistor is consistent with the resistance value of the anisotropic magnetoresistive sensor at zero magnetic field strength; The input end of the Wheatstone bridge is connected to a DC power supply, and the output end is connected to an operational amplifier.

6. The method according to claim 5 , further comprising converting the voltage signal output by the Wheatstone bridge into a magnetic field strength signal: in, V out is the voltage signal at the output of the Wheatstone bridge after passing through the operational amplifier; V s is the DC power supply voltage at the input end of the Wheatstone bridge, which is generally 12V; ΔR is the change in resistance of the anisotropic magnetoresistive sensor after being affected by the external magnetic field; R is the initial resistance value of the anisotropic magnetoresistive sensor when it is not affected by the external magnetic field; k is the proportional coefficient of the resistance change rate of the anisotropic magnetoresistive sensor when it is affected by the external magnetic field to the applied external magnetic field strength, which can be determined by selecting the working curve of the anisotropic magnetoresistive sensor; H is the amplitude of the external magnetic field strength.

7. The method according to claim 1, wherein determining the fault location based on the peak and the time corresponding to the peak comprises: Where x is the distance between two adjacent multi-dimensional magnetic field measurement transmission line fault location devices, x m is the distance between the fault location device that first receives the fault waveform and the fault point, v is the wave velocity, and Δt is the time difference between adjacent wave peaks.

8. A transmission line fault location system based on multi-dimensional magnetic field measurement, the system comprising: a determination unit, configured to set at least two multi-dimensional magnetic field measurement devices on transmission towers at different locations on the same transmission line; A monitoring unit, configured to determine the components of the magnetic field intensity in the three spatial directions of x, y, and z based on the multi-dimensional magnetic field measurement device, and to monitor the dynamic magnetic field distribution data within the transmission line space in real time; determining a sensitive directional component based on the dynamic magnetic field distribution data; An establishing unit, configured to perform data preprocessing on the determined sensitive directional components, and establish a spatiotemporal magnetic field intensity matrix based on the preprocessed sensitive directional components; Based on the spatiotemporal magnetic field intensity matrix, a magnetic field intensity time-varying waveform diagram is established, and based on the magnetic field intensity time-varying waveform diagram, a peak of a sudden change in magnetic field intensity and a time corresponding to the peak are determined; The result unit is used to determine the fault location based on the peak and the time corresponding to the peak.

9. The system according to claim 8, wherein the multi-dimensional magnetic field measurement device comprises a substrate; the substrate comprises two mutually perpendicular substrates or three mutually perpendicular substrates, and a magnetic sensitive element is provided on the substrate parallel to the substrate; The two mutually perpendicular substrates are arranged in a plane perpendicular to the power transmission line conductor and are orthogonal to each other; The three mutually perpendicular substrates are orthogonal in directions in a three-dimensional space around the transmission line. 10 . The system according to claim 9 , wherein the magnetic sensitive element comprises two groups of anisotropic magnetoresistive sensors and two groups of resistors, and the two groups of anisotropic magnetoresistive sensors and the two groups of resistors form a Wheatstone bridge.

11. The system of claim 10, wherein the anisotropic magnetoresistive sensor further comprises: Setting the direction of the easy magnetization axis, wherein the direction of the easy magnetization axis is perpendicular to the direction of the measured magnetic field; The anisotropic magnetoresistive sensor is a Permalloy film, and the direction of the Permalloy film is set so that the easy magnetization axis and the current direction form an angle of 45 degrees; The anisotropic magnetoresistive sensor has a measurement amplitude of magnetic induction intensity of not less than ±2mT, a measurement accuracy better than 0.1μT, and an applicable frequency range of not less than 0.1Hz-1MHz.

12. The system according to claim 10, wherein the resistance value of the resistor is consistent with the resistance value of the anisotropic magnetoresistive sensor at zero magnetic field strength; The input end of the Wheatstone bridge is connected to a DC power supply, and the output end is connected to an operational amplifier.

13. The system according to claim 12, further comprising converting the voltage signal output by the Wheatstone bridge into a magnetic field strength signal: in, V out is the voltage signal at the output of the Wheatstone bridge after passing through the operational amplifier; V s is the DC power supply voltage at the input end of the Wheatstone bridge, which is generally 12V; ΔR is the change in resistance of the anisotropic magnetoresistive sensor after being affected by the external magnetic field; R is the initial resistance value of the anisotropic magnetoresistive sensor when it is not affected by the external magnetic field; k is the proportional coefficient of the resistance change rate of the anisotropic magnetoresistive sensor when it is affected by the external magnetic field to the applied external magnetic field strength, which can be determined by selecting the working curve of the anisotropic magnetoresistive sensor; H is the amplitude of the external magnetic field strength.

14. The system according to claim 8, wherein determining the fault location based on the peak and the time corresponding to the peak comprises: Where x is the distance between two adjacent multi-dimensional magnetic field measurement transmission line fault location devices, x m is the distance between the fault location device that first receives the fault waveform and the fault point, v is the wave velocity, and Δt is the time difference between adjacent wave peaks.

Images