Three-component electromagnetic measurement device and method for power transmission tower grounding grid

Abstract

The invention discloses a three-component electromagnetic measurement device and method for a transmission tower grounding grid, and the device comprises an X-direction coil, a Y-direction coil and a Z-direction coil, the normal lines of any two coils are in an orthogonal relation, and the X-direction coil, the Y-direction coil and the Z-direction coil are respectively connected with a signal processing control unit through a preamplifier and a noise filter; and the signal processing control unit is used for collecting magnetic field signals output by the X-direction coil, the Y-direction coil and the Z-direction coil and completing electromagnetic measurement of the grounding grid. The X-direction coil, the Y-direction coil and the Z-direction coil are arranged to collect electromagnetic changes of the grounding grid in different directions respectively, the signal processing control unit is adopted to analyze and calculate the collected data to obtain electromagnetic components of the grounding grid in different directions, and electromagnetic measurement of the grounding grid is completed. The detection accuracy is improved while the detection process of the grounding grid is simplified, and a data basis is provided for analyzing the fault condition of the grounding grid.

Description

Technical Field

[0001] The invention belongs to the technical field of grounding network detection, and in particular relates to a three-component electromagnetic measurement device and method for a transmission tower grounding network. Background Art

[0002] The grounding grid is a mesh structure consisting of multiple metal grounding electrodes buried at a certain depth underground and conductors that connect these grounding electrodes. The grounding grid is widely used in many industries such as electricity, construction, computers, industrial and mining enterprises, communications, etc., playing the role of safety protection and shielding.

[0003] The grounding grid is an important facility for maintaining the safe and reliable operation of the power system. The design, installation and maintenance of the transmission tower grounding grid is the basis for ensuring the safe operation of high-voltage transmission lines and systems. Most transmission lines rely on towers erected in the wild, which are easily struck by lightning and thus endanger the safety and stability of the power grid. The grounding grid can discharge lightning current and fault current when lightning strikes or fails to the equipment, ensuring the stability of the surface potential, thereby ensuring the safe operation of the power system.

[0004] As an independent concealed device buried underground, the construction quality of the transmission tower grounding grid is directly related to the long-term safe and stable operation of the transmission line. During the construction phase, accurate detection of the actual physical state of the grounding grid (including conductor diameter, burial depth, plane position, layout shape, resistance, etc.) is a necessary measure to avoid the decline of construction quality and ensure the safe operation of the grounding grid. During the operation phase, since the grounding grid is in an underground environment for a long time, it is easily affected by moisture, soil pH and other harmful components, resulting in corrosion, fracture and other problems, resulting in poor performance of the grounding grid and poor lightning protection effect, thus threatening the safety of equipment and personal safety.

[0005] In order to ensure the stable operation of the power system, the power inspection department needs to regularly test and evaluate the parameter performance of the transmission tower grounding network, discover problems in advance and take corresponding measures. At present, the grounding network performance evaluation methods include large current analysis method, grounding network node analysis method, electromagnetic field analysis method, electrochemical analysis method, etc., which mainly evaluate the grounding resistance, connectivity, and withstand voltage performance of the grounding network as a whole. These methods have limited diagnostic capabilities for the buried depth, plane position, local corrosion or breakpoints of the grounding network construction. For the construction quality of the grounding network and the diagnosis of fault points in operation, the grounding network condition is mainly judged by the experience of the staff, which is highly subjective and cannot accurately locate the corrosion position of the grounding network, resulting in large-scale excavation during maintenance, which is time-consuming and labor-intensive, and requires power outages. Each power outage for maintenance inevitably brings a lot of economic pressure losses and manpower waste, which brings difficulties to actual operations. How to improve the accuracy and efficiency of grounding network maintenance is a problem that needs to be solved at present. Summary of the invention

[0006] In view of the defects existing in the above-mentioned prior art, the present invention provides a three-component electromagnetic measurement device for a transmission tower grounding network, comprising:

[0007] It includes an X-direction coil, a Y-direction coil, a Z-direction coil and a signal processing control unit, wherein the normals of any two coils among the X-direction coil, the Y-direction coil and the Z-direction coil are in an orthogonal relationship, and the X-direction coil, the Y-direction coil and the Z-direction coil are connected to the signal processing control unit through a preamplifier and a noise filter respectively;

[0008] The X-direction coil, the Y-direction coil and the Z-direction coil are used to detect magnetic fields in different directions in the grounding grid and output magnetic field signals;

[0009] A preamplifier, used for amplifying the magnetic field signal;

[0010] A noise filter is used to filter out noise from magnetic field signals;

[0011] The signal processing control unit is used to collect magnetic field signals and complete electromagnetic measurements of the grounding grid based on the magnetic field signals.

[0012] In a possible implementation, any one of the X-direction coil, the Y-direction coil, and the Z-direction coil specifically includes an AC signal source, a first resistor, a second resistor, a third resistor, a first inductor, a first capacitor, and a second capacitor;

[0013] The AC signal source, the first resistor, the first inductor and the first capacitor are connected in series, the second resistor, the third resistor and the second capacitor are respectively connected in parallel with the first capacitor, and the two common endpoints of the second resistor, the third resistor, the second capacitor and the first capacitor in parallel are connected to the preamplifier.

[0014] In a possible implementation, a level meter is further included, and the level meter is connected to the signal processing control unit;

[0015] A level meter is used to measure the inclination of the three-component electromagnetic measuring device of the transmission tower grounding grid and output an inclination signal;

[0016] The signal processing control unit is used to receive the inclination signal and complete the electromagnetic measurement of the grounding grid in combination with the magnetic field signal.

[0017] In a possible implementation, the signal processing control unit includes a battery and a signal collector, and the battery is connected to the signal collector to provide electrical energy to the signal collector.

[0018] In a possible implementation, the signal collector includes an analog-to-digital converter, a field programmable gate array, a satellite timer, and a memory;

[0019] an analog-to-digital converter, connected to the noise filter, for converting the magnetic field signal into a digital signal;

[0020] A satellite time receiver is connected to the field programmable gate array for time synchronization and outputting time signals;

[0021] A memory, connected to a field programmable gate array, is used to store or read data.

[0022] In a possible implementation, the connection port of the memory includes an Ethernet communication interface, a secure digital memory card interface, and an indicator light interface.

[0023] In one possible implementation, the level is connected to a field programmable gate array;

[0024] The field programmable gate array is used to output magnetic field signals in different directions based on the X-direction coil, the Y-direction coil and the Z-direction coil, and complete the electromagnetic measurement of the ground grid in combination with the coordinate changes of the running time, the running speed and the measurement position, wherein the running time and the measurement position are obtained through a satellite time receiver.

[0025] In a possible implementation, the X-direction electromagnetic component is obtained by combining the running time, running speed and coordinate change of the measurement position with the magnetic field signal output by the X-direction coil, specifically including:

[0026]

[0027] in, is the electromagnetic component generated by the grounding grid in the x direction, is the electromagnetic component generated by the i-th grounding conductor in the grounding grid in the x direction, N is the number of grounding conductors in the grounding grid, μ i0 is the soil magnetic permeability corresponding to the location of the i-th grounding conductor in the grounding grid, I i is the current generated by the i-th grounding conductor in the grounding grid, d i is the distance from the target location to the i-th grounding conductor in the grounding grid, θ i1 is the angle between the target position and the straight line where the first end point of the i-th grounding conductor is located and the i-th grounding conductor, θ i2 Δy is the angle between the target position and the straight line where the second end point of the i-th grounding conductor is located and the i-th grounding conductor, i1 is the coordinate change between the target position and the first end point of the i-th ground conductor on the y-axis, Δy i2 is the coordinate change between the target position and the second end point of the i-th grounding conductor on the y-axis, v is the operating speed of the three-component electromagnetic measurement device of the transmission tower grounding network, Δt i1 Δt is the time taken to run from the target position to the first end point of the i-th grounding conductor. i2It is the time taken to run from the target position to the second end point of the i-th grounding conductor. The target position is the position of the three-component electromagnetic measuring device of the transmission tower grounding network.

[0028] In a possible implementation, the Y-direction electromagnetic component is obtained by combining the running time, running speed and coordinate change of the measurement position with the magnetic field signal output by the Y-direction coil, specifically including:

[0029]

[0030] in, is the electromagnetic component generated by the grounding grid in the y direction, is the electromagnetic component generated by the i-th grounding conductor in the grounding grid in the y direction, N is the number of grounding conductors in the grounding grid, μ i0 is the soil magnetic permeability corresponding to the location of the i-th grounding conductor in the grounding grid, I i is the current generated by the i-th grounding conductor in the grounding grid, d i is the distance from the target location to the i-th grounding conductor in the grounding grid, θ i1 is the angle between the target position and the straight line where the first end point of the i-th grounding conductor is located and the i-th grounding conductor, θ i2 is the angle between the target position and the straight line where the second end point of the i-th grounding conductor is located and the i-th grounding conductor, Δx i1 is the coordinate change between the target position and the first end point of the i-th grounding conductor on the x-axis, Δx i2 is the coordinate change between the target position and the second end point of the i-th grounding conductor on the x-axis, v is the operating speed of the three-component electromagnetic measurement device of the transmission tower grounding network, Δt i1 Δt is the time taken to run from the target position to the first end point of the i-th grounding conductor. i2 It is the time taken to run from the target position to the second end point of the i-th grounding conductor. The target position is the position of the three-component electromagnetic measuring device of the transmission tower grounding network.

[0031] The present invention also discloses a three-component electromagnetic measurement method for a transmission tower grounding network, comprising:

[0032] Set the operating speed and trajectory of the three-component electromagnetic measurement device of the transmission tower grounding network and perform time synchronization;

[0033] Control the operation of the three-component electromagnetic measurement device of the transmission tower grounding network based on the operation time and operation trajectory;

[0034] Combined with the real-time data generated by the X-direction coil, Y-direction coil and Z-direction coil during the operation of the three-component electromagnetic measurement device of the transmission tower grounding network, the electromagnetic components of the transmission tower grounding network in different directions are given.

[0035] The present invention provides a three-component electromagnetic measurement device and method for a transmission tower grounding network, which has at least the following beneficial effects:

[0036] The present invention arranges an X-direction coil, a Y-direction coil and a Z-direction coil to respectively collect electromagnetic changes of a grounding grid in different directions and adopts a signal processing control unit to analyze and calculate the collected data to obtain the electromagnetic components of the grounding grid in different directions, thereby completing the electromagnetic measurement of the grounding grid, simplifying the process of detecting the grounding grid and improving the accuracy of the detection, and providing a data basis for analyzing the fault conditions of the grounding grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 A structural block diagram of a three-component electromagnetic measurement device for a transmission tower grounding network provided by an embodiment of the present invention;

[0038] Figure 2 A structural block diagram of a signal processing control unit provided by an embodiment of the present invention;

[0039] Figure 3 An equivalent circuit diagram of a coil provided in an embodiment of the present invention;

[0040] Figure 4 A schematic diagram of the construction of a grounding grid provided by an embodiment of the present invention;

[0041] Figure 5 A flow chart of a three-component electromagnetic measurement method for a transmission tower grounding grid provided by an embodiment of the present invention.

[0042] Among them, 1. Three-component electromagnetic measuring device of the transmission tower grounding network; 2. X-direction coil; 3. Y-direction coil; 4. Z-direction coil; 5. Level; 6. Battery; 7. Preamplifier; 8. Noise filter; 9. Signal collector; 10. Connection port. DETAILED DESCRIPTION

[0043] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0044] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings, and "multiple" generally includes at least two.

[0045] It should also be noted that the term "includes", "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, so that a commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprising a ..." do not exclude the existence of other identical elements in the commodity or device including the elements.

[0046] With the construction of high-voltage transmission lines and large-scale transformation of urban power grids, the State Grid has put forward strict regulations on the installation and operation and maintenance of grounding devices. In the interpretation of the State Grid's 18 countermeasures, the emphasis is on "preventing grounding grids and overvoltage accidents."

[0047] At present, the inspection and diagnosis of grounding grids mainly rely on the experience of staff, which is highly subjective and cannot accurately locate the corrosion position of the grounding grid, resulting in large-scale excavation during inspection and maintenance, which is time-consuming and labor-intensive, and also requires power outages. The inspection and maintenance of transmission tower grounding grids has problems such as backward means, heavy workload, blind inspection, low efficiency, and high inspection difficulty.

[0048] Therefore, how to accurately evaluate the performance parameters of the grounding device and detect the fault point without power outage or excavation is a problem that needs to be solved at present. The present invention provides a three-component electromagnetic measurement device 1 and method for the grounding network of a transmission tower. Using the device to detect the grounding network can improve the accuracy of the detection, solve the safety hazards of the grounding network, improve the safety and reliability of the power system, effectively prevent the occurrence of power accidents, and ensure the safety of equipment and personnel.

[0049] like Figure 1 As shown, an embodiment of the present invention provides a three-component electromagnetic measurement device 1 for a transmission tower grounding network, comprising an X-direction coil 2, a Y-direction coil 3, a Z-direction coil 4 and a signal processing control unit, wherein the normals of any two coils of the X-direction coil 2, the Y-direction coil 3 and the Z-direction coil 4 are orthogonal, and the X-direction coil 2, the Y-direction coil 3 and the Z-direction coil 4 are connected to the signal processing control unit through a preamplifier 7 and a noise filter 8, respectively. The X-direction coil 2, the Y-direction coil 3 and the Z-direction coil 4 are used to detect magnetic fields in different directions in the grounding network and output magnetic field signals. The preamplifier 7 is used to amplify the magnetic field signal. The noise filter 8 is used to filter out noise from the magnetic field signal. The signal processing control unit is used to collect the magnetic field signal and complete the electromagnetic measurement of the grounding network based on the magnetic field signal.

[0050] The three-component electromagnetic measuring device 1 for the grounding grid of the transmission tower also includes a level 5, which is connected to the signal processing control unit. The level 5 is used to measure the inclination of the three-component electromagnetic measuring device 1 for the grounding grid of the transmission tower and output an inclination signal. The signal processing control unit is used to receive the inclination signal and complete the electromagnetic measurement of the grounding grid in combination with the magnetic field signal.

[0051] Among them, the signal processing control unit includes a battery 6 and a signal collector 9, and the battery 6 is connected to the signal collector 9 to provide power for the signal collector 9. The signal collector 9 includes an analog-to-digital converter (A / D), a field programmable gate array (FPGA), a satellite timer and a memory. The analog-to-digital converter is connected to the noise filter 8 to convert the magnetic field signal into a digital signal. The satellite timer is connected to the field programmable gate array for time synchronization and outputting a time signal. The memory is connected to the field programmable gate array for storing or reading data. In the example provided by the present invention, the above-mentioned memory is a random access memory (RAM). In other embodiments, other memories that can complete the operation of the three-component electromagnetic measurement device 1 of the transmission tower grounding network can be used, and this is not limited. The connection port 10 of the memory includes an Ethernet communication interface, a secure digital disk connector (SD Card Connector) and an indicator light interface. The level 5 is connected to the field programmable gate array. The field programmable gate array is used to output magnetic field signals in different directions based on the X-direction coil 2, the Y-direction coil 3 and the Z-direction coil 4, and complete the electromagnetic measurement of the ground grid in combination with the coordinate changes of the running time, the running speed and the measurement position, wherein the running time and the measurement position are obtained through the satellite time transmitter. A stable clock design is added to the satellite time transmitter, which automatically keeps time after losing the global positioning system (GPS) midway.

[0052] Reference Figure 2When the three-component electromagnetic measuring device 1 of the transmission tower grounding grid is within the range of the grounding grid, the current of the grounding conductor in the grounding grid will have a magnetic field based on the electromagnetic effect. The X-direction coil 2, the Y-direction coil 3 and the Z-direction coil will be affected by the above magnetic field to generate an induced voltage. The input Hx represents the induced voltage generated by the input X-direction coil 2, the input Hy represents the induced voltage generated by the input Y-direction coil 3, and the input Hz represents the induced voltage generated by the input Z-direction coil 4. The induced voltage will pass through the preamplifier 7 and the noise filter 8, and the induced voltage will be impedance matched, filtered and corrected, and the processed signal will be input into the analog-to-digital converter for the next step of processing to obtain a standard signal. The FPGA is provided with logic for analyzing and calculating the electromagnetic components of the grounding grid in all directions according to the standard signal. The FPGA will obtain the standard signal according to actual needs or set parameters to complete the electromagnetic measurement of the grounding grid. The obtained results are then stored in the RAM. The external device can read or view the electromagnetic components of the grounding grid in all directions given by the FPGA through the Ethernet communication interface and / or the secure digital memory card interface. The above-mentioned indicator light interface is used to connect the indicator light, and the change of the indicator light reflects the operating status of the three-component electromagnetic measurement device 1 of the transmission tower grounding network. In a specific example, four light emitting diode (LED) indicator lights are connected through the indicator light interface to realize the overall instrument status indication, which is convenient for status diagnosis. Through the external Ethernet communication interface, the connection operation can be carried out to check the status of the test device in real time, and the external GPS antenna can be connected to facilitate the overall integration with the drone carrying platform. The SD card interface is set to replace the inserted SD card at any time.

[0053] Reference Figure 3 , Figure 3 : is an equivalent circuit diagram of the coil, wherein any one of the X-direction coil 2, the Y-direction coil 3, and the Z-direction coil 4 specifically includes an AC signal source, a first resistor, a second resistor, a third resistor, a first inductor, a first capacitor, and a second capacitor. The AC signal source, the first resistor, the first inductor, and the first capacitor are connected in series, the second resistor, the third resistor, and the second capacitor are respectively connected in parallel with the first capacitor, and two common endpoints of the second resistor, the third resistor, the second capacitor, and the first capacitor in parallel are connected to the preamplifier 7.

[0054] Among them, the voltage v(t) generated by the AC signal source is the induced voltage of the coil, the output u(t) is the induced voltage actually connected to the preamplifier 7, the first inductor L is the inductance of the received coil, r is the internal resistance of the coil, the first capacitor Cr is the distributed capacitance, the second resistor Ra is the input impedance of the preamplifier 7, the second capacitor Ca is the input capacitance of the preamplifier 7, and the third resistor RT is the matching resistor.

[0055] Specifically, for the magnetic field signal output by the X-direction coil 2, the X-direction electromagnetic component is obtained by combining the running time, running speed and coordinate change of the measurement position, which specifically includes:

[0056]

[0057] in, is the electromagnetic component generated by the grounding grid in the x direction, is the electromagnetic component generated by the i-th grounding conductor in the grounding grid in the x direction, N is the number of grounding conductors in the grounding grid, μ i0 is the soil magnetic permeability corresponding to the location of the i-th grounding conductor in the grounding grid, I i is the current generated by the i-th grounding conductor in the grounding grid, d i is the distance from the target location to the i-th grounding conductor in the grounding grid, θ i1 is the angle between the target position and the straight line where the first end point of the i-th grounding conductor is located and the i-th grounding conductor, θ i2 Δy is the angle between the target position and the straight line where the second end point of the i-th grounding conductor is located and the i-th grounding conductor, i1 is the coordinate change between the target position and the first end point of the i-th ground conductor on the y-axis, Δy i2 is the coordinate change between the target position and the second end point of the i-th grounding conductor on the y-axis, v is the operating speed of the three-component electromagnetic measurement device 1 of the transmission tower grounding network, Δt i1 Δt is the time taken to run from the target position to the first end point of the i-th grounding conductor. i2 It is the time taken to run from the target position to the second end point of the i-th grounding conductor, and the target position is the position of the three-component electromagnetic measuring device 1 of the transmission tower grounding network.

[0058] It is understandable that the magnitude of the current generated by the grounding conductor in the grounding grid will affect the magnitude of the magnetic field strength generated. The magnetic field strength will also affect the induced voltage generated by the X-direction coil 2, the Y-direction coil 3 and the Z-direction coil 4, so the current generated by the grounding conductor in the grounding grid can be determined by the induced voltage generated by each coil. Soil magnetic permeability refers to the soil's ability to conduct magnetic fields. The operating speed of the three-component electromagnetic measurement device 1 for the transmission tower grounding grid is set according to actual needs, Δt i1 and Δt i2 It is obtained through a satellite timer. The grounding grid needs to be designed according to the actual situation of the construction site, so the structure of the grounding grid is known. According to the actual measurement requirements, the running track of the three-component electromagnetic measurement device 1 of the transmission tower grounding grid is set, and the obtained parameters are substituted into the formula to obtain the components of the grounding grid in different directions. It should be understood that due to the different running tracks and / or three-dimensional coordinate systems, cosθ i1 and cosθi2 The calculation method is slightly different. The same is true for the electromagnetic component in the Y direction and the electromagnetic component in the Z direction.

[0059] Specifically, for the magnetic field signal output by the Y-direction coil 3, the Y-direction electromagnetic component is obtained by combining the running time, running speed and coordinate change of the measurement position, which specifically includes:

[0060]

[0061] in, is the electromagnetic component generated by the grounding grid in the y direction, is the electromagnetic component generated by the i-th grounding conductor in the grounding grid in the y direction, N is the number of grounding conductors in the grounding grid, μ i0 is the soil magnetic permeability corresponding to the location of the i-th grounding conductor in the grounding grid, I i is the current generated by the i-th grounding conductor in the grounding grid, d i is the distance from the target location to the i-th grounding conductor in the grounding grid, θ i1 is the angle between the target position and the straight line where the first end point of the i-th grounding conductor is located and the i-th grounding conductor, θ i2 is the angle between the target position and the straight line where the second end point of the i-th grounding conductor is located and the i-th grounding conductor, Δx i1 is the coordinate change between the target position and the first end point of the i-th grounding conductor on the x-axis, Δx i2 is the coordinate change between the target position and the second end point of the i-th grounding conductor on the x-axis, v is the operating speed of the three-component electromagnetic measurement device 1 of the transmission tower grounding network, Δt i1 Δt is the time taken to run from the target position to the first end point of the i-th grounding conductor. i2 It is the time taken to run from the target position to the second end point of the i-th grounding conductor, and the target position is the position of the three-component electromagnetic measuring device 1 of the transmission tower grounding network.

[0062] Specifically, for the magnetic field signal output by the Z-direction coil 4, the Z-direction electromagnetic component is obtained by combining the running time, running speed and coordinate change of the measurement position, which specifically includes:

[0063]

[0064] in, is the electromagnetic component generated by the grounding grid in the z direction, is the electromagnetic component generated by the i-th grounding conductor in the grounding grid in the z direction, N is the number of grounding conductors in the grounding grid, μ i0 is the soil magnetic permeability corresponding to the location of the i-th grounding conductor in the grounding grid, I iis the current generated by the i-th grounding conductor in the grounding grid, d i is the distance from the target location to the i-th grounding conductor in the grounding grid, θ i1 is the angle between the target position and the straight line where the first end point of the i-th grounding conductor is located and the i-th grounding conductor, θ i2 is the angle between the target position and the straight line where the second end point of the i-th grounding conductor is located and the i-th grounding conductor, Δx i1 is the coordinate change between the target position and the first end point of the i-th grounding conductor on the x-axis, Δx i2 is the coordinate change between the target position and the second end point of the i-th grounding conductor on the x-axis, v is the operating speed of the three-component electromagnetic measurement device 1 of the transmission tower grounding network, Δt i1 Δt is the time taken to run from the target position to the first end point of the i-th grounding conductor. i2 It is the time taken to run from the target position to the second end point of the i-th grounding conductor, and the target position is the position of the three-component electromagnetic measuring device 1 of the transmission tower grounding network.

[0065] In a specific embodiment, referring to Figure 4 Before using the three-component electromagnetic measurement device 1 of the transmission tower grounding network to perform electromagnetic measurement of the grounding network, it is necessary to use a satellite timer to keep the transmission time and the reception time synchronized with the transmitter, that is, after the three-component electromagnetic measurement device 1 of the transmission tower grounding network is started, the field programmable gate array will first send a time synchronization instruction to the satellite timer. After receiving the time synchronization instruction, the satellite timer will perform time synchronization and return synchronization completion information. After receiving the synchronization completion information, the field programmable gate array will control the operation of the three-component electromagnetic measurement device 1 of the transmission tower grounding network according to actual needs.

[0066] In the process of using the three-component electromagnetic measurement device 1 of the transmission tower grounding network to perform electromagnetic measurement of the grounding network, it is necessary to use an unmanned aerial vehicle or a manually suspended measuring device, and perform mobile measurement at a preset moving speed within a preset grounding network range. During the mobile measurement process, real-time data, real-time spatial coordinates and moving trajectory of the three component magnetic fields in the X direction, Y direction and Z direction can be obtained. In a specific example, the moving speed of the three-component electromagnetic measurement device 1 of the transmission tower grounding network does not exceed 3 meters / second.

[0067] The three-component electromagnetic measuring device 1 of the transmission tower grounding network is a receiving device, and the long wire emission source is a part of the grounding conductor in the grounding network. The grounding conductor includes the grounding electrode in the grounding network and the conductor connecting the grounding electrodes to each other. The measuring point is the position where the three-component electromagnetic measuring device 1 of the transmission tower grounding network needs to measure electromagnetic components in different directions.

[0068] The present invention improves the accuracy of electromagnetic exploration and reduces safety hazards caused by corrosion and breakage of the grounding grid by analyzing and interpreting the electromagnetic components in three directions. It adopts a combined control method of ARM and FPGA, with FPGA performing real-time acquisition and ARM performing later storage and transmission, effectively improving the performance of the device. The satellite timer can give each sampling point an accurate timestamp, with a deviation from the absolute time of less than 30 nanoseconds, ensuring the accuracy of data transmission.

[0069] Before the three-component electromagnetic measurement device 1 of the transmission tower grounding network is put into use, a noise test is performed on it. The test process specifically includes: placing the test device in a magnetic shielding barrel, connecting the signal output by the test device to the analog input terminal of the data acquisition device through an analog data line, and testing the peak-to-peak value (pp value) of the background noise of the above test device. The sampling rate is 96K, that is, 96,000 points are sampled per second. The result shows that the peak-to-peak value of the noise is 0.3 microvolts (1-10KHz), so the background noise frequency band of the test device is a flat area in the range of 1Hz-10KHz, and the peak noise is less than 0.3 microvolts.

[0070] Before the three-component electromagnetic measuring device 1 of the transmission tower grounding network is put into use, a sensitivity test is performed on it. The sensitivity test process specifically includes: placing the test device in a calibration solenoid, exciting signals of different frequencies through the solenoid, and measuring the response of the test device at different frequencies. The test results are shown in Table 1.

[0071] Table 1 Sensitivity test results of the test device

[0072] Serial number Test content Technical index requirements Test Results 1 Test device noise Less than 3nV / Hz 0.3uVpp, better than 3nV / Hz 2 Test device sensitivity Better than 0.15mv / nT·Hz Better than 0.15mv / nT·Hz

[0073] Reference Figure 5 The embodiment of the present invention provides a three-component electromagnetic measurement method of a transmission tower grounding network, comprising:

[0074] Setting the running speed and running trajectory of the three-component electromagnetic measuring device 1 of the transmission tower grounding network and performing time synchronization;

[0075] Based on the operation time and operation trajectory, the operation of the three-component electromagnetic measurement device 1 of the transmission tower grounding network is controlled;

[0076] Combined with the real-time data generated by the X-direction coil 2, the Y-direction coil 3 and the Z-direction coil 4 during the operation of the three-component electromagnetic measurement device 1 of the transmission tower grounding network, the electromagnetic components of the transmission tower grounding network in different directions are given.

[0077] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working process described can refer to the corresponding process in the aforementioned device embodiment, and will not be repeated here.

[0078] Although preferred embodiments of the present invention have been described, additional changes and modifications may be made to these embodiments by those skilled in the art once the basic inventive concepts are known. 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. 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 these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A three-component electromagnetic measurement device for a transmission tower grounding grid, characterized in that: It includes an X-direction coil, a Y-direction coil, a Z-direction coil and a signal processing control unit, wherein the normals of any two coils among the X-direction coil, the Y-direction coil and the Z-direction coil are in an orthogonal relationship, and the X-direction coil, the Y-direction coil and the Z-direction coil are connected to the signal processing control unit through a preamplifier and a noise filter respectively; The X-direction coil, the Y-direction coil and the Z-direction coil are used to detect magnetic fields in different directions in the grounding grid and output magnetic field signals; A preamplifier, used for amplifying the magnetic field signal; A noise filter is used to filter out noise from magnetic field signals; The signal processing control unit is used to collect magnetic field signals and complete electromagnetic measurements of the grounding grid based on the magnetic field signals.

2. The three-component electromagnetic measurement device for the transmission tower grounding grid according to claim 1, characterized in that: Any one of the X-direction coil, the Y-direction coil, and the Z-direction coil specifically includes an AC signal source, a first resistor, a second resistor, a third resistor, a first inductor, a first capacitor, and a second capacitor; The AC signal source, the first resistor, the first inductor and the first capacitor are connected in series, the second resistor, the third resistor and the second capacitor are respectively connected in parallel with the first capacitor, and the two common endpoints of the second resistor, the third resistor, the second capacitor and the first capacitor in parallel are connected to the preamplifier.

3. The three-component electromagnetic measurement device for the transmission tower grounding grid according to claim 1, characterized in that: Also included is a level meter connected to the signal processing control unit; A level meter is used to measure the inclination of the three-component electromagnetic measuring device of the transmission tower grounding grid and output an inclination signal; The signal processing control unit is used to receive the inclination signal and complete the electromagnetic measurement of the grounding grid in combination with the magnetic field signal.

4. The three-component electromagnetic measurement device for the transmission tower grounding grid according to claim 3, characterized in that: The signal processing control unit comprises a battery and a signal collector. The battery is connected to the signal collector to provide electrical energy to the signal collector.

5. The three-component electromagnetic measurement device for the transmission tower grounding grid according to claim 4, characterized in that: The signal collector includes an analog-to-digital converter, a field programmable gate array, a satellite timer and a memory; an analog-to-digital converter, connected to the noise filter, for converting the magnetic field signal into a digital signal; A satellite time receiver is connected to the field programmable gate array for time synchronization and outputting time signals; A memory, connected to a field programmable gate array, is used to store or read data.

6. The three-component electromagnetic measurement device for the transmission tower grounding grid according to claim 5, characterized in that: The connection ports of the memory include an Ethernet communication port, a secure digital memory card port and an indicator light port.

7. The three-component electromagnetic measurement device for the transmission tower grounding grid according to claim 5, characterized in that: The level is connected to the field programmable gate array; The field programmable gate array is used to output magnetic field signals in different directions based on the X-direction coil, the Y-direction coil and the Z-direction coil, and complete the electromagnetic measurement of the ground grid in combination with the coordinate changes of the running time, the running speed and the measurement position, wherein the running time and the measurement position are obtained through a satellite time receiver.

8. The three-component electromagnetic measurement device for the transmission tower grounding grid according to claim 7, characterized in that: For the magnetic field signal output by the X-direction coil, the X-direction electromagnetic component is obtained by combining the running time, running speed and coordinate changes of the measurement position, including: in, is the electromagnetic component generated by the grounding grid in the x direction, is the electromagnetic component generated by the i-th grounding conductor in the grounding grid in the x direction, N is the number of grounding conductors in the grounding grid, μ i0 is the soil magnetic permeability corresponding to the location of the i-th grounding conductor in the grounding grid, I i is the current generated by the i-th grounding conductor in the grounding grid, d i is the distance from the target location to the i-th grounding conductor in the grounding grid, θ i1 is the angle between the target position and the straight line where the first end point of the i-th grounding conductor is located and the i-th grounding conductor, θ i2 Δy is the angle between the target position and the straight line where the second end point of the i-th grounding conductor is located and the i-th grounding conductor, i1 is the coordinate change between the target position and the first end point of the i-th ground conductor on the y-axis, Δy i2 is the coordinate change between the target position and the second end point of the i-th grounding conductor on the y-axis, v is the operating speed of the three-component electromagnetic measurement device of the transmission tower grounding network, Δt i1 Δt is the time taken to run from the target position to the first end point of the i-th grounding conductor. i2 It is the time taken to run from the target position to the second end point of the i-th grounding conductor. The target position is the position of the three-component electromagnetic measuring device of the transmission tower grounding network.

9. The three-component electromagnetic measurement device for the transmission tower grounding grid according to claim 7, characterized in that: For the magnetic field signal output by the Y-direction coil, the Y-direction electromagnetic component is obtained by combining the running time, running speed and coordinate changes of the measurement position, including: in, is the electromagnetic component generated by the grounding grid in the y direction, is the electromagnetic component generated by the i-th grounding conductor in the grounding grid in the y direction, N is the number of grounding conductors in the grounding grid, μ i0 is the soil magnetic permeability corresponding to the location of the i-th grounding conductor in the grounding grid, I i is the current generated by the i-th grounding conductor in the grounding grid, d i is the distance from the target location to the i-th grounding conductor in the grounding grid, θ i1 is the angle between the target position and the straight line where the first end point of the i-th grounding conductor is located and the i-th grounding conductor, θ i2 is the angle between the target position and the straight line where the second end point of the i-th grounding conductor is located and the i-th grounding conductor, Δx i1 is the coordinate change between the target position and the first end point of the i-th grounding conductor on the x-axis, Δx i2 is the coordinate change between the target position and the second end point of the i-th grounding conductor on the x-axis, v is the operating speed of the three-component electromagnetic measurement device of the transmission tower grounding network, Δt i1 Δt is the time taken to run from the target position to the first end point of the i-th grounding conductor. i2 It is the time taken to run from the target position to the second end point of the i-th grounding conductor. The target position is the position of the three-component electromagnetic measuring device of the transmission tower grounding network.

10. A three-component electromagnetic measurement method for a transmission tower grounding grid, characterized in that: A three-component electromagnetic measurement device for a transmission tower grounding network as claimed in any one of claims 1 to 9, comprising: Set the operating speed and trajectory of the three-component electromagnetic measurement device of the transmission tower grounding network and perform time synchronization; Control the operation of the three-component electromagnetic measurement device of the transmission tower grounding network based on the operation time and operation trajectory; Combined with the real-time data generated by the X-direction coil, Y-direction coil and Z-direction coil during the operation of the three-component electromagnetic measurement device of the transmission tower grounding network, the electromagnetic components of the transmission tower grounding network in different directions are given.

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