A power transmission line fault location method and system based on multi-dimensional magnetic field measurement

Abstract

The application discloses a power transmission line fault positioning method and system based on multi-dimensional magnetic field measurement, at least two multi-dimensional magnetic field measuring devices are arranged at different positions of power transmission towers of the same power transmission line; based on the multi-dimensional magnetic field measuring device, the components of the magnetic field intensity in the space x, y and z directions are determined, and the dynamic magnetic field distribution data in the space of the power transmission line is monitored in real time; based on the dynamic magnetic field distribution data, the sensitive direction component is determined; the determined sensitive direction component is subjected to data preprocessing, and the space-time magnetic field intensity matrix is established based on the preprocessed sensitive direction component; based on the space-time magnetic field intensity matrix, the magnetic field intensity time-varying waveform diagram is established, the wave peak of the magnetic field intensity mutation and the time corresponding to the wave peak are determined based on the magnetic field intensity time-varying waveform diagram; and the fault position is determined based on the wave peak and the time corresponding to the wave peak.

Description

Technical Field

[0001] This invention relates to the field of power system transmission line fault location technology, and more specifically, to a method and system for transmission line fault location based on multidimensional magnetic field measurement. Background Technology

[0002] Fault location methods for transmission lines can be categorized into two types based on the installation location of the devices: substation-side and line-side. Substation-side location techniques mainly include impedance location and traveling wave location methods. Impedance location methods determine the fault distance by calculating the ratio of the equivalent impedance at the fault point to the impedance per unit length of the line, based on the power frequency components of the line voltage and current after a fault. Traveling wave location methods utilize the transient traveling wave signal generated at the moment of the fault, capturing the arrival time difference of the traveling wave fronts at both ends of the line and combining this with the wave velocity to calculate the fault location. Line-side location primarily employs the contact-type traveling wave location method, which involves installing traveling wave sensors at key nodes of the line to directly acquire traveling wave waveforms and performing segmented location based on the time difference between the arrival times of the traveling waves received by adjacent sensors.

[0003] The aforementioned methods in the existing technology all have technical limitations. The substation-side impedance location method is significantly affected by line parameter deviations and transition resistance. In long-distance transmission lines, the decrease in impedance-distance linearity leads to increased location errors, and it cannot effectively identify high-resistance grounding faults. The traveling wave location method has stringent requirements for sampling frequency (MHz level) and noise suppression. In complex line topologies, multiple reflections of traveling waves can easily cause wavefront misjudgment. In mountainous lines, the location accuracy deteriorates significantly when the wave velocity is affected by environmental factors. Although the line-side contact traveling wave location method can improve wavefront identification, it requires large-scale deployment of high-precision sensors, resulting in high installation and maintenance costs, poor electromagnetic compatibility, and the sensor power supply module cannot operate when the line-side load is too low. Summary of the Invention

[0004] The present invention provides a method and system for locating transmission line faults based on multidimensional magnetic field measurement, in order to solve the problem of how to locate transmission line faults based on multidimensional magnetic field measurement.

[0005] To address the above problems, this invention provides a method for fault location of transmission lines based on multidimensional magnetic field measurement, the method comprising:

[0006] At least two multidimensional magnetic field measuring devices shall be installed on the transmission towers at different locations along the same transmission line;

[0007] Based on the multidimensional magnetic field measuring device, the components of the magnetic field strength in the three spatial directions (x, y, z) are determined, and the dynamic magnetic field distribution data within the transmission line space is monitored in real time; the sensitive direction component is determined based on the dynamic magnetic field distribution data.

[0008] The determined sensitive direction components are preprocessed, and a spatiotemporal magnetic field strength matrix is ​​established based on the preprocessed sensitive direction components. Based on the spatiotemporal magnetic field strength matrix, a time-varying magnetic field strength waveform is established, and based on the time-varying magnetic field strength waveform, the peaks of abrupt changes in magnetic field strength and the corresponding times are determined.

[0009] Based on the wave peak and the corresponding time, the fault location is determined.

[0010] Preferably, the multidimensional magnetic field measuring device includes a substrate; the substrate includes two mutually perpendicular substrates or three mutually perpendicular substrates, and a magnetic sensing element parallel to the substrate is disposed on the substrate;

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

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

[0013] Preferably, the magnetically sensitive element includes two sets of anisotropic magnetoresistive sensors and two sets of resistors, which together form a Wheatstone bridge.

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

[0015] The anisotropic magnetoresistive sensor is a permalloy thin film, and the orientation of the permalloy thin film is set so that the easy magnetization axis and the current direction form a 45° angle.

[0016] The anisotropic magnetoresistive sensor measures magnetic flux density with an amplitude 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 under a magnetic field strength of 0.

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

[0019] Preferably, the method further includes restoring the voltage signal output by the Wheatstone bridge to a magnetic field strength signal.

[0020]

[0021] Among them, V out The voltage signal at the output of the Wheatstone bridge after passing through an operational amplifier; V sΔR is the DC power supply voltage at the input terminal of the Wheatstone bridge, typically 12V; ΔR is the change in resistance of the anisotropic magnetoresistive sensor after being affected by an external magnetic field; R is the initial resistance value of the anisotropic magnetoresistive sensor when it is not affected by an external magnetic field; k is the proportionality coefficient between the rate of change of resistance of the anisotropic magnetoresistive sensor and the strength of the applied external magnetic field when it is affected by an external magnetic field, 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 wave peak and the time corresponding to the wave peak includes:

[0023]

[0024] Where x is the distance between two adjacent multidimensional magnetic field measurement transmission line fault location devices, x m The distance between the fault location device that first receives the fault waveform and the fault point is v, the wave velocity is v, 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 multidimensional magnetic field measurement, the system comprising:

[0026] The determination unit is used to install at least two multi-dimensional magnetic field measuring devices on transmission towers at different locations on the same transmission line;

[0027] The monitoring unit is used to determine the components of the magnetic field strength in the three spatial directions (x, y, z) based on the multi-dimensional magnetic field measuring device, and to monitor the dynamic magnetic field distribution data in the space of the transmission line in real time; and to determine the sensitive direction component based on the dynamic magnetic field distribution data.

[0028] Establish a unit for processing multiple horizontal magnetic field intensity components H. X With multiple perpendicular magnetic field strength components H Y Data preprocessing is performed, based on the preprocessed multiple horizontal magnetic field strength components H X With multiple perpendicular magnetic field strength components H Y Establish a spatiotemporal magnetic field intensity matrix; based on the spatiotemporal magnetic field intensity matrix, establish a time-varying waveform diagram of magnetic field intensity; based on the time-varying waveform diagram of magnetic field intensity, determine the peak of the sudden change in magnetic field intensity and the time corresponding to the peak.

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

[0030] Preferably, the multidimensional magnetic field measuring device includes a substrate; the substrate includes two mutually perpendicular substrates or three mutually perpendicular substrates, and a magnetic sensing element parallel to the substrate is disposed on the substrate;

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

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

[0033] Preferably, the magnetically sensitive element includes two sets of anisotropic magnetoresistive sensors and two sets of resistors, which together form a Wheatstone bridge.

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

[0035] The anisotropic magnetoresistive sensor is a permalloy thin film, and the orientation of the permalloy thin film is set so that the easy magnetization axis and the current direction form a 45° angle.

[0036] The anisotropic magnetoresistive sensor measures magnetic flux density with an amplitude 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 under a magnetic field strength of 0.

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

[0039] Preferably, the method further includes restoring the voltage signal output by the Wheatstone bridge to a magnetic field strength signal.

[0040]

[0041] Among them, V out The voltage signal at the output of the Wheatstone bridge after passing through an operational amplifier; V s ΔR is the DC power supply voltage at the input terminal of the Wheatstone bridge, typically 12V; ΔR is the change in resistance of the anisotropic magnetoresistive sensor after being affected by an external magnetic field; R is the initial resistance value of the anisotropic magnetoresistive sensor when it is not affected by an external magnetic field; k is the proportionality coefficient between the rate of change of resistance of the anisotropic magnetoresistive sensor and the strength of the applied external magnetic field when it is affected by an external magnetic field, 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 wave peak and the time corresponding to the wave peak includes:

[0043]

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

[0045] This invention provides a method and system for fault location of transmission lines based on multidimensional magnetic field measurement. The method includes: installing at least two multidimensional magnetic field measuring devices on transmission towers at different locations along the same transmission line; determining the components of the magnetic field strength in the x, y, and z directions in space based on the multidimensional magnetic field measuring devices, and monitoring the dynamic magnetic field distribution data within the transmission line space in real time; determining sensitive direction components based on the dynamic magnetic field distribution data; performing data preprocessing on the determined sensitive direction components, and establishing a spatiotemporal magnetic field strength matrix based on the preprocessed sensitive direction components; establishing a time-varying waveform diagram of the magnetic field strength based on the spatiotemporal magnetic field strength matrix, and determining the peaks of sudden changes in magnetic field strength and the corresponding times based on the time-varying waveform diagram; and determining the fault location based on the peaks and the corresponding times. This invention provides a method and system for fault location of transmission lines based on multidimensional magnetic field measurement, which greatly improves the accuracy of fault location by capturing vector features from two-dimensional magnetic field data. Attached Figure Description

[0046] Exemplary embodiments of the present invention can be more fully understood by referring to the following figures:

[0047] Figure 1 A flowchart of a transmission line fault location method based on multidimensional magnetic field measurement according to a preferred embodiment of the present invention;

[0048] Figure 2 This is a schematic diagram of the installation of a transmission line fault location device based on multidimensional magnetic field measurement according to a preferred embodiment of the present invention.

[0049] Figure 3 This is a flowchart illustrating the transmission line fault location method based on multidimensional magnetic field measurement according to a preferred embodiment of the present invention.

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

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

[0052] Figure 6 This is a structural diagram of a transmission line fault location system based on multidimensional magnetic field measurement according to a preferred embodiment of the present invention. Detailed Implementation

[0053] Exemplary embodiments of the invention will now be described with reference to the accompanying drawings. However, the invention may be embodied in many different forms and is not limited to the embodiments described herein. These embodiments are provided to fully and completely disclose the invention and to fully convey its scope to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the drawings is not intended to limit the invention. In the drawings, the same units / elements are referred to by the same reference numerals.

[0054] Unless otherwise stated, the terms used herein (including technical terms) have their common meaning as understood by one of ordinary skill in the art. Furthermore, it is understood that terms defined in commonly used dictionaries should be understood to have a meaning consistent with the context of their relevant field, and not to be interpreted as having an idealized or overly formal meaning.

[0055] Figure 1 This is a flowchart of a transmission line fault location method based on multidimensional magnetic field measurement according to a preferred embodiment of the present invention.

[0056] Since existing fault location methods struggle to balance the demands for high precision, adaptability to complex environments, and low cost, this invention provides a low-cost, non-contact fault location plaza that requires no line modifications. It captures the transient magnetic field vector characteristics of faults using a non-contact two-dimensional magnetic field sensor, enabling high-precision fault location in complex terrain.

[0057] like Figure 1 As shown, this invention provides a method for fault location of transmission lines based on multidimensional magnetic field measurement, the method comprising:

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

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

[0060] This invention studies the principle of multidimensional magnetic field measurement, designs the structure of a multidimensional magnetic field measurement device, and obtains the components of magnetic field intensity in the x, y, and z directions in space through orthogonal decomposition, thereby capturing the transient magnetic field vector characteristics around transmission lines.

[0061] This invention deploys a multi-dimensional magnetic field measurement device at the first-level crossarm of a transmission tower to monitor the dynamic magnetic field distribution in the vertical plane of the line in real time. It obtains the horizontal magnetic field intensity component Hx and the vertical magnetic field intensity component Hy in this plane.

[0062] Figure 2 In the diagram, 1 represents the transmission tower; 2 represents the enclosure of the multidimensional magnetic field measurement device. The transmission line fault location device based on multidimensional magnetic field measurement is installed at the first-level crossarm of each voltage level tower. The distance between its two-dimensional magnetic field measurement point and the first-level platform is 10-20cm, and the horizontal distance extending beyond the platform is 20-30cm.

[0063] Step 103: Perform data preprocessing on the determined sensitive direction components, and establish a spatiotemporal magnetic field intensity matrix based on the preprocessed sensitive direction components; This invention performs data preprocessing on multi-node magnetic field measurement data to construct a 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, establish a time-varying waveform diagram of magnetic field intensity, and based on the time-varying waveform diagram of magnetic field intensity, determine the peak of the sudden change in magnetic field intensity and the time corresponding to the peak.

[0065] This invention extracts the arrival time difference of traveling waves based on the peak value of the transient waveform of the magnetic field strength during a fault obtained from adjacent sensor nodes, thereby determining the precise location of the fault and achieving accurate fault localization.

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

[0067] Preferably, the multidimensional magnetic field measuring device includes a substrate; the substrate includes two mutually perpendicular substrates or three mutually perpendicular substrates, and a magnetic sensing element parallel to the substrate is disposed on the substrate.

[0068] Two mutually perpendicular substrates are arranged in a plane perpendicular to the power transmission line conductors and are orthogonal to each other.

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

[0070] Preferably, the magnetic sensing element includes two sets of anisotropic magnetoresistive sensors and two sets of resistors, which together form a Wheatstone bridge.

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

[0072] The anisotropic magnetoresistive sensor is a permalloy thin film. By setting the orientation of the permalloy thin film, the easy magnetization axis is made to form a 45° angle with the current direction.

[0073] The anisotropic magnetoresistive sensor measures magnetic flux density with an amplitude of not less than ±2mT, a measurement accuracy better than 0.1μT, and an applicable frequency range of not less than 0.1Hz-1MHz.

[0074] Preferably, the resistance value of the resistor is consistent with the resistance value of the anisotropic magnetoresistive sensor under 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 from the Wheatstone bridge to a magnetic field strength signal.

[0077]

[0078] Among them, V out The voltage signal at the output of the Wheatstone bridge after passing through an operational amplifier; V s ΔR is the DC power supply voltage at the input terminal of the Wheatstone bridge, typically 12V; ΔR is the change in resistance of the anisotropic magnetoresistive sensor after being affected by an external magnetic field; R is the initial resistance value of the anisotropic magnetoresistive sensor when it is not affected by an external magnetic field; k is the proportionality coefficient between the rate of change of resistance of the anisotropic magnetoresistive sensor and the strength of the applied external magnetic field when it is affected by an external magnetic field, 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 multidimensional magnetic field measuring device in this invention is described in detail below:

[0080] The multidimensional magnetic field measuring device comprises three mutually perpendicular substrates, on which magnetically sensitive elements are disposed parallel to the substrates. For example... Figure 4 As shown, a multidimensional magnetic field measurement device structure containing three mutually perpendicular substrates is used as an example.

[0081] Figure 4 The white structure in the middle is the mutually perpendicular substrate mentioned above. The material is generally a non-magnetic, highly insulating material, such as ceramics.

[0082] Figure 4 The structure underlined above represents the magnetic sensing element described above, typically composed of anisotropic magnetoresistive sensors (AMRs). Under specific operating conditions, Hall effect elements, giant magnetoresistive sensors (GMRs), and other similar components may also be used. A single magnetic sensing element can be composed of two AMRs and two resistors forming a Wheatstone bridge, as shown in the diagram. Figure 5 As shown.

[0083] The magnetic thin film in an AMR sensor is designed during manufacturing to have an easy magnetization axis. When using an AMR, by setting the direction of the easy magnetization axis, the sensor can be made to respond only to the target direction component, unaffected by other components. Figure 4 In the middle, the direction of the easy magnetization axis is perpendicular to the direction of the measured magnetic field; Figure 4 In the diagram, the direction of the magnetic field strength component of the sensor response is marked on the component.

[0084] In the adjacent arms of the Wheatstone bridge, X1 and X2 consist of two analog magnetic field sensors (AMRs), while the other two adjacent arms, X3 and X4, consist of resistors with resistance values ​​identical to those of the AMRs when there is no magnetic field. The magnetic sensing elements in the Wheatstone bridge configuration have their input terminals connected to a 12V DC power supply and their output terminals connected to an operational amplifier to amplify the measurement signal and improve accuracy. The magnetic thin film in the two AMRs can be selected as a permalloy thin film. The permalloy's orientation is such that the easy magnetization axis forms a 45° angle with the current direction, resulting in a linear relationship between the bridge output and the measured magnetic field strength. 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 parallel to the easy magnetization axis, the output is zero. Figure 5 As shown, when perpendicular to the easy magnetization axis, the bridge output voltage is linearly related to the magnetic field strength, thus enabling the measurement of specific magnetic field direction components.

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

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

[0087] The multidimensional magnetic field measurement device includes a signal acquisition and processing module, which can acquire the voltage signal output by the Wheatstone bridge-type magnetic sensing element and convert it back into a magnetic field strength signal, as shown in the following formula:

[0088]

[0089] The device operates in the linear region; therefore, parameter k can be found in the magnetic sensing element manual or obtained through testing under rated operating conditions.

[0090] The multidimensional magnetic field measurement device includes a data transmission device that can wirelessly transmit data to a server.

[0091] The multidimensional magnetic field measuring device is encapsulated in an aluminum-magnesium alloy, which can effectively shield electromagnetic interference.

[0092] The multidimensional magnetic field measuring device in this invention is described as follows:

[0093] Considering that the magnetic field strength in the direction parallel to the conductor is ideally zero, and is also extremely small in reality, a two-dimensional component from a multi-dimensional magnetic field measuring device can be used in practical applications. The advantage of this design is that the multi-dimensional magnetic field measuring device can already highlight the transient characteristics of the magnetic field, while significantly reducing the amount of data compared to a three-dimensional device, thus alleviating data processing pressure. The two mutually perpendicular substrates should be positioned in a plane perpendicular to the transmission line conductor and orthogonal to it. In this example, the horizontal and vertical directions are used as examples; other orthogonal decompositions can also be performed in the plane perpendicular to the conductor.

[0094] The data preprocessing includes data cleaning and filtering. The preprocessed data is used to construct a spatiotemporal magnetic field strength matrix, which is transmitted to the cloud server in real time. On the server side, waveform recognition and feature extraction are performed on the spatiotemporal magnetic field strength matrix to identify the time corresponding to the peak of the magnetic field strength when the fault traveling wave arrives.

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

[0096]

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

[0098] This invention calculates the time difference Δt between the arrival times of the magnetic field intensity peaks from adjacent sensor peaks based on the arrival times of fault traveling waves from different directions measured by a multi-dimensional magnetic field measuring device, thereby determining the fault location x. m The basic principle is as follows:

[0099]

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

[0101] This invention provides a method for locating transmission line faults based on multidimensional magnetic field measurement, comprising the following steps:

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

[0103] S2. Deploy a multi-dimensional magnetic field measurement device at the first-level crossarm 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 this plane;

[0104] S3. Perform data preprocessing on multi-node magnetic field measurement data to construct a spatiotemporal magnetic field intensity matrix; transmit the multidimensional 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 transient waveform change peak of the magnetic field strength during the fault obtained from adjacent sensor nodes, extract the arrival time difference of the traveling wave to determine the precise location of the fault and achieve accurate fault location.

[0106] This invention proposes a transmission line fault location device based on multidimensional magnetic field measurement, comprising two or three mutually perpendicular base plates. Magnetic sensitive elements parallel to the base plates are disposed on the base plates. The two mutually perpendicular base plates should be arranged in a plane perpendicular to the transmission line conductor and form an orthogonal arrangement. In this example, the horizontal and vertical directions are taken as examples, but other orthogonal decompositions can also be performed in the plane perpendicular to the conductor. The three mutually perpendicular base plates are orthogonal in space.

[0107] This invention proposes a transmission line fault location device based on multidimensional magnetic field measurement. The magnetic field intensity components perpendicular to the conductor plane are orthogonally decomposed, and the horizontal and vertical directions are used as the directions in the embodiment, and are denoted as x and y components for measurement.

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

[0109] In S4, this invention uses the peak time data obtained after processing the spatiotemporal magnetic field strength matrix to solve for the time difference between the fault waveforms received by two adjacent sets of multidimensional magnetic field measuring devices, and then locates the fault based on this time difference.

[0110] This invention provides a fault location method for transmission lines based on multidimensional magnetic field measurement, which has the following advantages: The fault location method has high accuracy, greatly improving accuracy by capturing vector features through multidimensional magnetic field data; simultaneously, the required magnetic field measuring device does not need to be installed on the conductor, and the use of a non-contact device simplifies installation and significantly reduces costs; the fault location principle is based on magnetic field measurement, reducing interference from complex environments on the measuring device, enabling it to adapt to complex operating conditions; the magnetic field strength of a three-phase transmission line is relatively low during steady-state operation, but changes drastically during a fault, a characteristic that also ensures high measurement accuracy of the device.

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

[0112] A method for locating transmission line faults based on multidimensional magnetic field measurement mainly includes the following steps:

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

[0114] S2. Deploy a multi-dimensional magnetic field measurement device at the first-level crossarm 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 this plane;

[0115] S3. Perform data preprocessing on multi-node magnetic field measurement data to construct a spatiotemporal magnetic field intensity matrix; transmit the multidimensional 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 transient waveform change peak of the magnetic field strength during the fault obtained from adjacent sensor nodes, extract the arrival time difference of the traveling wave to determine the precise location of the fault and achieve accurate fault location.

[0117] The present invention S1 designs a multi-dimensional magnetic field measuring device based on anisotropic magnetic sensitive elements, which can be designed as a three-dimensional magnetic field measuring device or a multi-dimensional magnetic field measuring device as needed.

[0118] In S2 of this invention, a multi-dimensional magnetic field measuring device is installed at the first-stage crossarm of two adjacent cat-head towers at 220kV to measure the magnetic field strength x-component Hx and y-component Hy at the installation location.

[0119] In S3 of this invention, based on the spatiotemporal matrix of magnetic field strength returned by two adjacent sensors, a time-varying waveform of magnetic field strength is plotted on the server side, and the peak of the sudden change in magnetic field strength when the fault traveling wave arrives is identified and its time is recorded.

[0120] In S4 of this invention, based on the time corresponding to the peak of the magnetic field strength measured by the multi-dimensional magnetic field measuring device when the fault traveling waves arrive from different directions, the time difference Δt between the peaks of adjacent sensors is calculated to determine the fault location x. m ,as follows:

[0121]

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

[0123] like Figure 6 As shown, this invention provides a transmission line fault location system based on multidimensional magnetic field measurement. The system includes:

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

[0125] The monitoring unit 602 is used to determine the components of the magnetic field strength in the three spatial directions (x, y, z) based on a multi-dimensional magnetic field measuring device, and to monitor the dynamic magnetic field distribution data in the space of the transmission line in real time; and to determine the sensitive direction component based on the dynamic magnetic field distribution data.

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

[0127] Result unit 604 is used to determine the fault location based on the peak and the time corresponding to the peak.

[0128] Preferably, the multidimensional magnetic field measuring device includes a substrate; the substrate includes two mutually perpendicular substrates or three mutually perpendicular substrates, and a magnetic sensing element parallel to the substrate is disposed on the substrate.

[0129] Two mutually perpendicular substrates are arranged in a plane perpendicular to the power transmission line conductors and are orthogonal to each other.

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

[0131] Preferably, the magnetic sensing element includes two sets of anisotropic magnetoresistive sensors and two sets of resistors, which together form a Wheatstone bridge.

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

[0133] The anisotropic magnetoresistive sensor is a permalloy thin film. By setting the orientation of the permalloy thin film, the easy magnetization axis is made to form a 45° angle with the current direction.

[0134] The anisotropic magnetoresistive sensor measures magnetic flux density with an amplitude of not less than ±2mT, a measurement accuracy better than 0.1μT, and an applicable frequency range of not 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 from the Wheatstone bridge to a magnetic field strength signal.

[0138]

[0139] Among them, V out The voltage signal at the output of the Wheatstone bridge after passing through an operational amplifier; V s ΔR is the DC power supply voltage at the input terminal of the Wheatstone bridge, typically 12V; ΔR is the change in resistance of the anisotropic magnetoresistive sensor after being affected by an external magnetic field; R is the initial resistance value of the anisotropic magnetoresistive sensor when it is not affected by an external magnetic field; k is the proportionality coefficient between the rate of change of resistance of the anisotropic magnetoresistive sensor and the strength of the applied external magnetic field when it is affected by an external magnetic field, 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 wave crest and the corresponding time includes:

[0141]

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

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

[0144] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can 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 can be implemented using various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0145] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations 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, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0146] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0147] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0148] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0149] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

[0150] The invention has been described with reference to a few embodiments. However, as will be known to those skilled in the art, and as defined in the appended claims, other embodiments besides those disclosed above fall equivalently within the scope of the invention.

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

Claims

1. A method for fault location of transmission lines based on multidimensional magnetic field measurement, the method comprising: At least two multidimensional magnetic field measuring devices shall be installed on the transmission towers at different locations along the same transmission line; The multidimensional magnetic field measuring device includes a substrate; the substrate includes three mutually perpendicular substrates, and a magnetic sensing element parallel to the substrate is disposed on the substrate; the three mutually perpendicular substrates are orthogonal in the actual three-dimensional space around the transmission line; the magnetic sensing element includes two sets of anisotropic magnetoresistive sensors and two sets of resistors, and the two sets of anisotropic magnetoresistive sensors and two sets of resistors form a Wheatstone bridge. The anisotropic magnetoresistive sensor further includes: setting the easy magnetization axis direction, which is perpendicular to the direction of the measured magnetic field; the anisotropic magnetoresistive sensor is a permalloy thin film, and the orientation of the permalloy thin film is set so that the easy magnetization axis forms a 45° angle with the current direction; and restoring the voltage signal output by the Wheatstone bridge to a magnetic field strength signal. in, The voltage signal after the Wheatstone bridge output is amplified by an operational amplifier. The DC power supply voltage at the input terminal of the Wheatstone bridge; This refers to the change in resistance of an anisotropic magnetoresistive sensor after it is affected by an external magnetic field. is the initial resistance value of the anisotropic magnetoresistive sensor when it is not affected by an external magnetic field; k is the proportionality coefficient of the resistance change rate of the anisotropic magnetoresistive sensor when it is affected by an external magnetic field to the strength of the applied external magnetic field, which can be determined by selecting the working curve of the anisotropic magnetoresistive sensor. H The amplitude of the external magnetic field strength; Based on the multidimensional magnetic field measuring device, the components of the magnetic field strength in the three spatial directions (x, y, z) are determined, and the dynamic magnetic field distribution data within the transmission line space is monitored in real time; the sensitive direction component is determined based on the dynamic magnetic field distribution data. The determined sensitive direction components are preprocessed, and a spatiotemporal magnetic field strength matrix is ​​established based on the preprocessed sensitive direction components. Based on the spatiotemporal magnetic field strength matrix, a time-varying waveform diagram of magnetic field strength is established. Based on the time-varying waveform diagram of magnetic field strength, the peak of the sudden change in magnetic field strength and the time corresponding to the peak are determined. Based on the wave peaks and the corresponding times, the fault location is determined, including: in, The distance between two adjacent multidimensional magnetic field measurement devices for fault location of transmission lines. The distance between the fault location device that first receives the fault waveform and the fault point. For wave speed, The time difference between adjacent wave peaks.

2. The method according to claim 1, wherein the resistance value of the resistor is consistent with the resistance value of the anisotropic magnetoresistive sensor under a magnetic field strength of 0; The input of the Wheatstone bridge is connected to a DC power supply, and the output is connected to an operational amplifier.

3. A transmission line fault location system based on multidimensional magnetic field measurement, the system comprising: The determination unit is used to install at least two multi-dimensional magnetic field measuring devices on transmission towers at different locations on the same transmission line; The multidimensional magnetic field measuring device includes a substrate; the substrate includes three mutually perpendicular substrates, and a magnetic sensing element parallel to the substrate is disposed on the substrate; the three mutually perpendicular substrates are orthogonal in the actual three-dimensional space around the transmission line; the magnetic sensing element includes two sets of anisotropic magnetoresistive sensors and two sets of resistors, and the two sets of anisotropic magnetoresistive sensors and two sets of resistors form a Wheatstone bridge. The anisotropic magnetoresistive sensor further includes: setting the easy magnetization axis direction, which is perpendicular to the direction of the measured magnetic field; the anisotropic magnetoresistive sensor is a permalloy thin film, and the orientation of the permalloy thin film is set so that the easy magnetization axis forms a 45° angle with the current direction; and restoring the voltage signal output by the Wheatstone bridge to a magnetic field strength signal. in, The voltage signal after the Wheatstone bridge output is amplified by an operational amplifier. The DC power supply voltage at the input terminal of the Wheatstone bridge; This refers to the change in resistance of an anisotropic magnetoresistive sensor after it is affected by an external magnetic field. is the initial resistance value of the anisotropic magnetoresistive sensor when it is not affected by an external magnetic field; k is the proportionality coefficient of the resistance change rate of the anisotropic magnetoresistive sensor when it is affected by an external magnetic field to the strength of the applied external magnetic field, which can be determined by selecting the working curve of the anisotropic magnetoresistive sensor. H The amplitude of the external magnetic field strength; The monitoring unit is used to determine the components of the magnetic field strength in the three spatial directions (x, y, z) based on the multi-dimensional magnetic field measuring device, and to monitor the dynamic magnetic field distribution data in the space of the transmission line in real time; and to determine the sensitive direction component based on the dynamic magnetic field distribution data. A data preprocessing unit is used to preprocess the determined sensitive direction components, establish a spatiotemporal magnetic field strength matrix based on the preprocessed sensitive direction components, establish a time-varying magnetic field strength waveform based on the spatiotemporal magnetic field strength matrix, and determine the peak of the magnetic field strength change and the time corresponding to the peak based on the time-varying magnetic field strength waveform. The result unit, used to determine the fault location based on the wave peak and the time corresponding to the wave peak, includes: in, The distance between two adjacent multidimensional magnetic field measurement devices for fault location of transmission lines. The distance between the fault location device that first receives the fault waveform and the fault point. For wave speed, The time difference between adjacent wave peaks.

4. In the system according to claim 3, the resistance value of the resistor is consistent with the resistance value of the anisotropic magnetoresistive sensor under a magnetic field strength of 0. The input of the Wheatstone bridge is connected to a DC power supply, and the output is connected to an operational amplifier.

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