A method, device and system for measuring broadband current in overhead transmission lines

Abstract

This disclosure relates to a method, apparatus, and system for broadband current measurement of overhead transmission lines, belonging to the field of power system technology, and solves the problem of low measurement accuracy in broadband current measurement. The method is applied to a current measurement system comprising a magnetic ring and a first magnetic sensor; wherein the magnetic ring is a non-closed ring structure, and the first magnetic sensor is disposed at a first opening in the non-closed ring shape of the magnetic ring; the first magnetic sensor is a sensor based on the giant magnetoresistance effect; the method includes: connecting a preset power supply voltage to the positive power supply terminal of the overhead transmission line and the grounding terminal of the underground cable; the overhead transmission line being disposed within the magnetic ring; using the first magnetic sensor to detect the magnetic field generated on the overhead transmission line to obtain a first voltage signal; and determining the target current of the overhead transmission line at different frequency components based on the first voltage signal.

Description

Technical Field

[0001] This disclosure relates to the field of power system technology, and in particular to a broadband current measurement method, device and system for overhead transmission lines. Background Technology

[0002] Broadband current measurement of overhead transmission lines provides abundant power grid operation data through comprehensive, multi-frequency capture and analysis of current signals, which helps improve fault diagnosis capabilities, power quality assessment, dynamic characteristic analysis, and equipment condition monitoring. With the development of smart grids and the increasing complexity of power systems, the application of broadband current measurement in modern power systems will become increasingly important. Therefore, improving the measurement accuracy of broadband current measurement has become an urgent problem to be solved. Summary of the Invention

[0003] This invention provides a method, apparatus, and system for measuring broadband current in overhead transmission lines, to at least solve the problem of low measurement accuracy in broadband current measurement in related technologies. The technical solution of this invention is as follows:

[0004] According to a first aspect of the present invention, a broadband current measurement method for an overhead transmission line is provided. The method is applied to a current measurement system, which includes a magnetic ring and a first magnetic sensor. The magnetic ring is a non-closed ring structure, and the first magnetic sensor is disposed at a first opening in the non-closed ring shape of the magnetic ring. The first magnetic sensor is a sensor based on the giant magnetoresistance effect. The method includes: connecting a preset power supply voltage to the positive power supply terminal of the overhead transmission line and the grounding terminal of an underground cable; the overhead transmission line being disposed within the magnetic ring; detecting the magnetic field generated on the overhead transmission line using the first magnetic sensor to obtain a first voltage signal; and determining the target current of the overhead transmission line at different frequency components based on the first voltage signal.

[0005] In one implementation, the current measurement system further includes a second magnetic sensor, which is disposed outside the magnetic ring and opposite to the first magnetic sensor at the first opening. The second magnetic sensor is a sensor based on the giant magnetoresistive effect. The method further includes: using the second magnetic sensor to detect the magnetic field generated on the overhead transmission line to obtain a second voltage signal; and determining the target current based on the first voltage signal and the second voltage signal.

[0006] In another implementation, the first magnetic sensor includes a first GMR chip; the second magnetic sensor includes a second GMR chip; the detection of the magnetic field generated on the overhead transmission line by the first magnetic sensor to obtain a first voltage signal includes: converting the detected first electromagnetic signal into a first voltage signal using the first GMR chip; the detection of the magnetic field generated on the overhead transmission line by the second magnetic sensor to obtain a second voltage signal includes: converting the detected second electromagnetic signal into a second voltage signal using the second GMR chip.

[0007] In another implementation, the current measurement system further includes an analog signal processing module, which is communicatively connected to the first magnetic sensor and the second magnetic sensor; the analog signal processing module is equipped with a signal amplification circuit, a filtering circuit, a linearization processing unit, a temperature compensation circuit, and a zero-point drift suppression unit;

[0008] After converting the detected first electromagnetic signal into a first voltage signal using the first GMR chip, the method further includes: using an analog signal processing module to perform one or more of the following processing on the first voltage signal to obtain a processed first voltage signal: inputting the first voltage signal to a signal amplification circuit and increasing the level of the signal amplification circuit to a preset level to obtain an amplified first voltage signal; and / or using a filtering circuit to filter signals in the first voltage signal that are higher than a preset frequency to obtain a filtered first voltage signal; and / or using a linearization processing unit to convert signals in the first voltage signal that have a non-linear relationship with the first voltage signal into signals that have a linear relationship with the first voltage signal to obtain a linearized first voltage signal; and / or, during the detection of the magnetic field generated on the overhead transmission line by the first magnetic sensor, using a temperature compensation circuit to adjust the ambient temperature during the detection process of the first magnetic sensor so that the ambient temperature is within a first preset temperature range; and / or, when the first magnetic sensor has no input signal, using a zero-point drift suppression unit to adjust the output electromagnetic signal value of the first magnetic sensor to a non-zero preset signal value;

[0009] After converting the detected second electromagnetic signal into a second voltage signal using a second GMR chip, the method further includes:

[0010] The analog signal processing module performs one or more of the following processing on the second voltage signal to obtain the processed second voltage signal: inputting the second voltage signal to a signal amplification circuit and increasing the level of the signal amplification circuit to a preset level to obtain an amplified second voltage signal; and / or, using a filtering circuit to filter the signal in the second voltage signal that is higher than a preset frequency to obtain a filtered second voltage signal; and / or, using a linearization processing unit to convert the signal in the second voltage signal that has a non-linear relationship with the second voltage signal into a signal that has a linear relationship with the second voltage signal to obtain a linearized second voltage signal; and / or, during the process of the second magnetic sensor detecting the magnetic field generated on the overhead transmission line, using a temperature compensation circuit to adjust the ambient temperature during the detection process of the second magnetic sensor so that the ambient temperature is within a second preset temperature range; and / or, when the second magnetic sensor has no input signal, using a zero-point drift suppression unit to adjust the output electromagnetic signal value of the second magnetic sensor to a non-zero preset signal value.

[0011] In another implementation, the current measurement system further includes an MCU processing module, which includes a digital signal processing unit; the MCU processing module is communicatively connected to the analog signal processing module; the method further includes: using the digital signal processing unit to convert the first voltage signal in analog form into the first voltage signal in digital form; and / or, using the digital signal processing unit to convert the second voltage signal in analog form into the second voltage signal in digital form.

[0012] In another implementation, the magnetic ring is a three-segment ring structure, which also includes a second opening and a third opening. The segment of the magnetic ring between the second and third openings is an open-close structure used to place overhead transmission lines. The magnetic ring is made of ferrite or nanocrystalline soft magnetic material.

[0013] According to a second aspect of the present invention, a broadband current measuring device for an overhead transmission line is provided, applied to a current measuring system. The current measuring system includes a magnetic ring and a first magnetic sensor. The magnetic ring is a non-closed ring structure, and the first magnetic sensor is disposed at a first opening in a non-closed segment of the magnetic ring. The first magnetic sensor is a sensor based on the giant magnetoresistance effect. The device includes: a power supply unit for connecting a preset power supply voltage to the positive power supply terminal of the overhead transmission line and the grounding terminal of an underground cable; the overhead transmission line is disposed within the magnetic ring; a detection unit for detecting the magnetic field generated on the overhead transmission line using the first magnetic sensor to obtain a first voltage signal; and a determination unit for determining the target current of the overhead transmission line at different frequency components based on the first voltage signal.

[0014] In one implementation, the current measurement system further includes a second magnetic sensor, which is disposed outside the magnetic ring and opposite to the first magnetic sensor at the first opening. The second magnetic sensor is a sensor based on the giant magnetoresistive effect. The detection unit is also used to: detect the magnetic field generated on the overhead transmission line using the second magnetic sensor to obtain a second voltage signal; and determine the target current based on the first voltage signal and the second voltage signal.

[0015] In another implementation, the first magnetic sensor includes a first GMR chip; the second magnetic sensor includes a second GMR chip; the detection unit is specifically used to: use the first GMR chip to convert the detected first electromagnetic signal into a first voltage signal; and use the second GMR chip to convert the detected second electromagnetic signal into a second voltage signal.

[0016] In another implementation, the current measurement system further includes an analog signal processing module, which is communicatively connected to the first magnetic sensor and the second magnetic sensor; the analog signal processing module is equipped with a signal amplification circuit, a filtering circuit, a linearization processing unit, a temperature compensation circuit, and a zero-point drift suppression unit;

[0017] After the first electromagnetic signal detected by the first GMR chip is converted into a first voltage signal, the detection unit is further configured to: perform one or more of the following processing on the first voltage signal using an analog signal processing module to obtain a processed first voltage signal: inputting the first voltage signal to a signal amplification circuit and increasing the level of the signal amplification circuit to a preset level to obtain an amplified first voltage signal; and / or, using a filtering circuit to filter the signal in the first voltage signal that is higher than a preset frequency to obtain a filtered first voltage signal; and / or, using a linearization processing unit to convert the signal in the first voltage signal that has a non-linear relationship with the first voltage signal into a signal that has a linear relationship with the first voltage signal to obtain a linearized first voltage signal; and / or, during the detection of the magnetic field generated on the overhead transmission line by the first magnetic sensor, using a temperature compensation circuit to adjust the ambient temperature during the detection process of the first magnetic sensor so that the ambient temperature is within a first preset temperature range; and / or, when the first magnetic sensor has no input signal, using a zero-point drift suppression unit to adjust the output electromagnetic signal value of the first magnetic sensor to a preset signal value that is not zero;

[0018] After the second electromagnetic signal detected by the second GMR chip is converted into a second voltage signal, the detection unit is further configured to: perform one or more of the following processing on the second voltage signal using an analog signal processing module to obtain a processed second voltage signal: inputting the second voltage signal to a signal amplification circuit and increasing the level of the signal amplification circuit to a preset level to obtain an amplified second voltage signal; and / or, using a filtering circuit to filter signals in the second voltage signal that are higher than a preset frequency to obtain a filtered second voltage signal; and / or, using a linearization processing unit to convert signals in the second voltage signal that have a non-linear relationship with the second voltage signal into signals that have a linear relationship with the second voltage signal to obtain a linearized second voltage signal; and / or, during the detection of the magnetic field generated on the overhead transmission line by the second magnetic sensor, using a temperature compensation circuit to adjust the ambient temperature during the detection process of the second magnetic sensor so that the ambient temperature is within a second preset temperature range; and / or, when the second magnetic sensor has no input signal, using a zero-point drift suppression unit to adjust the output electromagnetic signal value of the second magnetic sensor to a non-zero preset signal value.

[0019] In another implementation, the current measurement system further includes an MCU processing module, which includes a digital signal processing unit; the MCU processing module is communicatively connected to the analog signal processing module; the detection unit is also used to: use the digital signal processing unit to convert the first voltage signal in analog form into the first voltage signal in digital form; and / or, use the digital signal processing unit to convert the second voltage signal in analog form into the second voltage signal in digital form.

[0020] In another implementation, the magnetic ring is a three-segment ring structure, which also includes a second opening and a third opening. The segment of the magnetic ring between the second and third openings is an open-close structure used to place overhead transmission lines. The magnetic ring is made of ferrite or nanocrystalline soft magnetic material.

[0021] According to a third aspect of the present invention, a current measurement system is provided, the current measurement system including a magnetic ring and a first magnetic sensor; wherein the magnetic ring is a non-closed ring structure, the first magnetic sensor is disposed at a first opening of a non-closed ring segment in the magnetic ring, the first magnetic sensor is a sensor based on the giant magnetoresistive effect, and is configured to perform the broadband current measurement method for overhead transmission lines described in the first aspect.

[0022] In one implementation, the current measurement system further includes: a second magnetic sensor disposed outside the magnetic ring and opposite to the first magnetic sensor at the first opening; the second magnetic sensor is a sensor based on the giant magnetoresistive effect (GMR); the first magnetic sensor includes a first GMR chip; the second magnetic sensor includes a second GMR chip; an analog signal processing module communicatively connected to the first and second magnetic sensors; the analog signal processing module includes a signal amplification circuit, a filtering circuit, a linearization processing unit, a temperature compensation circuit, and a zero-point drift suppression unit; and an MCU processing module including a digital signal processing unit; the MCU processing module communicatively connected to the analog signal processing module; the current measurement system is configured to perform a broadband current measurement method for overhead transmission lines as described in the first aspect and any possible implementation thereof.

[0023] In one implementation, the magnetic ring is a three-segment ring structure, and the magnetic ring also includes a second opening and a third opening. The magnetic ring segment between the second opening and the third opening is an open-close structure, used to place overhead transmission lines. The magnetic ring is made of ferrite or nanocrystalline soft magnetic material.

[0024] According to a fourth aspect of the present invention, a computer device is provided, comprising: a processor and a memory for storing processor-executable instructions; wherein the processor is configured to execute the executable instructions to implement the broadband current measurement method for overhead transmission lines as described in the first aspect and any possible implementation thereof.

[0025] According to a fifth aspect of the present invention, a computer-readable storage medium is provided, on which instructions are stored, such that when the instructions in the computer-readable storage medium are executed by a processor of a computer device, an electronic device is enabled to perform the broadband current measurement method for overhead transmission lines as described in the first aspect.

[0026] According to a sixth aspect of the present disclosure, a computer program product is provided, the computer program product including computer instructions, which, when executed on a computer device, cause the computer device to perform the overhead transmission line broadband current measurement method described in the first aspect and any possible implementation thereof.

[0027] The technical solution provided by the embodiments of this application brings at least the following beneficial effects: Given that the giant magnetoresistive effect sensor has advantages such as high sensitivity, wide frequency response, high anti-interference ability, miniaturization, and strong temperature stability in broadband current detection of transmission lines, after the preset power supply voltage is connected to the overhead transmission line and energized, this application uses a first magnetic sensor based on the giant magnetoresistive effect to detect the magnetic field generated by the steady-state current on the overhead transmission line, and obtains a first voltage signal as an analog voltage signal. Based on the fact that the first voltage signal is proportional to the intensity of the measured magnetic field or current, that is, based on the fact that the output voltage will change accordingly with the change of the input signal, the target current on the overhead transmission line at various frequencies can be accurately deduced. Furthermore, in order to reduce the influence of ambient magnetic fields and interfering magnetic fields in steady-state current measurement, the first magnetic sensor is placed in the first opening of the magnetic ring. This allows the first magnetic sensor to generate a magnetic field in the air gap of the magnetic ring to measure the steady-state current of the transmission line. In this way, on the one hand, the sensitivity of the first magnetic sensor to the position of the cable under test can be reduced, so that the magnitude of the magnetic field at the air gap hardly changes with the position of the cable in the ring. On the other hand, it can also amplify the magnetic field of the air gap, increase the measurement accuracy of the first magnetic sensor to the current under test, reduce the interference of external magnetic fields in relative magnitude, and improve the accuracy of current measurement.

[0028] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0029] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure, and are not intended to unduly limit this disclosure.

[0030] Figure 1 This is a schematic diagram of a current measurement system according to an embodiment of the present invention;

[0031] Figure 2 This is a flowchart illustrating a broadband current measurement method for overhead transmission lines according to an embodiment of the present invention;

[0032] Figure 3 This is a block diagram illustrating a broadband current measuring device for an overhead transmission line according to an exemplary embodiment. Detailed Implementation

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0035] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0036] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this disclosure are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this disclosure described herein can be implemented in orders other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0037] This application provides the operational steps of the method described in the embodiments or flowcharts, but based on conventional or non-inventive labor, more or fewer operational steps may be included. The order of steps listed in the embodiments is merely one possible execution order among many steps for the overhead transmission line broadband current measurement method, and does not represent the only possible execution order. This method should be implementable by software and / or hardware.

[0038] Before providing a detailed description of the broadband current measurement method for overhead transmission lines provided in this application embodiment, let's briefly introduce the application scenarios and implementation environment involved in this application embodiment.

[0039] First, a brief introduction to the application scenarios involved in this application will be given.

[0040] Broadband current measurement of overhead transmission lines provides abundant power grid operation data through comprehensive, multi-frequency capture and analysis of current signals, which helps improve fault diagnosis capabilities, power quality assessment, dynamic characteristic analysis, and equipment condition monitoring. With the development of smart grids and the increasing complexity of power systems, the application of broadband current measurement in modern power systems will become increasingly important. Therefore, improving the measurement accuracy of broadband current measurement has become an urgent problem to be solved.

[0041] Research has revealed that existing current sensing technologies have some shortcomings and deficiencies in achieving this goal.

[0042] The first type, electromagnetic current transformers (CTs), are large in size and require a lot of space and metal resources, which is uneconomical in today's resource-scarce world. They are only suitable for AC measurement and cannot measure DC current, making them unsuitable for distributed measurement: due to their large size, they can only be used for measurement in substations and cannot meet the distributed measurement needs of transmission, distribution, and consumption.

[0043] The second type, the Rogowski coil, also cannot measure direct current and has lower accuracy than other types of magnetic sensors.

[0044] The third type, Hall sensors, are greatly affected by ambient temperature, and their accuracy may be affected by changes in ambient temperature, which makes outdoor measurement a significant problem.

[0045] Fourthly, fiber optic current transformers (OFCTs) have a complex structure and require a laser source instead of a voltage or current source, resulting in high cost and low production volume. They are unsuitable for large-scale applications, and their complexity and high cost make large-scale use in smart grids unlikely.

[0046] The aforementioned technical limitations restrict their application in smart grids, particularly in distributed monitoring and online monitoring systems.

[0047] To address the aforementioned issues, this application proposes a broadband current measurement method for overhead transmission lines. This method is based on a magnetic sensor utilizing the giant magnetoresistance effect (GMR) to measure the broadband current of overhead transmission lines, thereby solving the problem of broadband current measurement in overhead transmission lines. This enables efficient and accurate current measurement in transmission lines, thus providing support for the stable operation and intelligent scheduling of transmission lines.

[0048] Secondly, the implementation architecture involved in this application will be briefly introduced below.

[0049] Figure 1 This is a schematic diagram of a current measurement system provided in this disclosure. Figure 1As shown, the current measurement system includes a magnetic ring 10 and a first magnetic sensor 11; wherein, the magnetic ring 10 is an open ring structure, and the first magnetic sensor 11 is disposed at the first opening 101 of the open ring segment in the magnetic ring. The first magnetic sensor 11 is a sensor based on the giant magnetoresistance effect.

[0050] In one embodiment, the current measurement system further includes the following device.

[0051] Firstly, a second magnetic sensor 12 is disposed outside the magnetic ring and opposite to the first magnetic sensor 11 at the first opening 101. The second magnetic sensor 12 is a sensor based on the giant magnetoresistive effect. The first magnetic sensor 11 includes a first GMR chip. The second magnetic sensor 12 includes a second GMR chip.

[0052] Both the first magnetic sensor 11 and the second magnetic sensor 12 mentioned above are GMR magnetic sensors. They utilize the giant magnetoresistance effect, which means that when an external magnetic field acts on a magnetic multilayer thin film, its resistance value changes significantly. This effect arises from the different spin states of current-carrying electrons and their different responses to the magnetic field, leading to changes in resistance. GMR magnetic sensors are used to detect magnetic fields generated by current. When current flows through a conductor, it generates a magnetic field around it, which acts on the GMR magnetic sensor, causing its resistance value to change. The resistance change signal output by the GMR magnetic sensor is a relatively weak analog signal, which needs to be converted and amplified by a signal processing circuit to obtain an output signal proportional to the current magnitude. Compared to Hall effect magnetic sensors, GMR magnetic sensors offer higher measurement accuracy, a wider measurement range, faster response, lower power consumption, and stronger anti-interference capabilities.

[0053] Secondly, the analog signal processing module 13 is communicatively connected to the first magnetic sensor 11 and the second magnetic sensor 12.

[0054] The analog signal processing module 13 includes a signal amplification circuit, a filtering circuit, a linearization processing unit, a temperature compensation circuit, and a zero-point drift suppression unit. The specific functions of each of these modules are as follows.

[0055] Signal amplification circuit: Since the signal output by the GMR sensor is usually quite weak, it needs to be amplified to an appropriate level by an amplification circuit for subsequent processing.

[0056] The design of amplifier circuits needs to consider factors such as noise suppression, linearity, and stability to ensure the quality of the amplified signal.

[0057] Filtering current: Filtering circuits are used to remove high-frequency noise and interference from signals, improving the signal-to-noise ratio. Different types of filters can be selected based on the specific application requirements, such as low-pass filters, high-pass filters, or band-pass filters.

[0058] Linearization: Because the output signal of a GMR sensor may have a non-linear relationship with the actual current value, linearization is necessary. Linearization can be achieved through analog circuits or digital signal processing techniques to improve measurement accuracy.

[0059] Temperature compensation circuit: The performance of GMR sensors is significantly affected by temperature, therefore temperature compensation is necessary to eliminate the influence of temperature on the measurement results. Temperature compensation can be achieved by integrating a temperature sensor inside the sensor and adjusting the sensor's gain or offset based on the temperature sensor's output.

[0060] Zero-point drift suppression: Zero-point drift refers to the phenomenon that the output signal of a sensor is not zero when there is no input signal. Various measures can be taken to suppress zero-point drift, such as using high-quality electronic components, optimizing circuit design, and performing regular calibration.

[0061] Optionally, the analog signal processing module 13 also determines EMC (Electromagnetic Compatibility). EMC refers to the ability of an electronic device to function normally in an electromagnetic environment without causing unacceptable electromagnetic interference to other devices in that environment.

[0062] In complex electromagnetic environments, GMR magnetic sensors may be affected by external electromagnetic fields. Therefore, EMC design is necessary to reduce the impact of external interference on sensor performance. EMC design includes various measures such as shielding, grounding, and filtering to ensure stable operation of the sensor in harsh electromagnetic environments.

[0063] Third, the MCU (Microcontroller Unit) processing module 14. The MCU processing module 15 includes a digital signal processing unit; the MCU processing module is communicatively connected to the analog signal processing module.

[0064] In some embodiments, the MCU processing module 14 is also simply referred to as MCU.

[0065] In some embodiments, the first magnetic sensor 11 and the second magnetic sensor 12 are also referred to as GMR magnetic sensors. The magnetic ring, GMR magnetic sensor, analog signal processing module and MCU processing module are collectively referred to as GMR current sensor, that is, the GMR current sensor is composed of magnetic ring, GMR magnetic sensor, analog signal processing module and MCU processing module.

[0066] Both the first and second GMR chips mentioned above are GMR chips. The GMR chip receives the electromagnetic signal generated by the measured current at the air gap of the magnetic core and converts this electromagnetic signal into a voltage signal. The signal processing module amplifies, filters, and zero-adjusts the voltage signal from the GMR chip before outputting the voltage signal. The voltage signal is then converted into a digital signal by an A / D (analog-to-digital) converter for further processing by the MCU.

[0067] The aforementioned MCU, acting as the core processor, receives digital signals from the A / D conversion module. Based on a preset program and algorithm, the MCU processes the received digital signals to obtain the required current value or other relevant information. The MCU can also store, display, or transmit the processed data. The MCU processing module improves measurement accuracy; it can perform precise calculations on the received signals to obtain more accurate current values. Through signal amplification, filtering, and zeroing, errors can be further reduced, improving measurement accuracy. Intelligent functions are also implemented; the MCU can achieve various intelligent functions according to preset programs and algorithms, such as automatic calibration, anomaly detection, and early warning. These functions improve the reliability and stability of the sensor and reduce maintenance costs. The flexibility and programmability of the MCU allow the GMR current sensor to adapt to different application scenarios and needs. By modifying the program or algorithm, the sensor's functionality can be easily upgraded or expanded.

[0068] Optionally, the magnetic ring can be made of ferrite or nanocrystalline soft magnetic material.

[0069] Specifically, the material of the magnetic ring determines its magnetic properties, such as permeability and saturation magnetic flux density, which in turn affect the strength and stability of the magnetic field. Choosing materials with high permeability and saturation magnetic flux density can more effectively concentrate the magnetic field and improve the sensitivity of the sensor.

[0070] When a magnetic ring is in operation, the constantly changing internal magnetic field consumes energy, causing the ring to heat up and increasing the power consumption of the current sensor. Choosing a material with low magnetic loss can reduce the sensor's power consumption and improve energy efficiency. Different materials for magnetic rings have different costs; selecting a cost-effective material can reduce costs while maintaining performance.

[0071] In GMR current sensors, the magnetic ring acts as a concentrating magnetic field. When current flows through a conductor, a magnetic field is generated around the conductor. This magnetic field is concentrated by the magnetic ring and then acts on the GMR sensor chip. The material and shape of the magnetic ring are designed to optimize the concentrating effect of the magnetic field, enabling the sensor to more sensitively detect changes in the magnetic field generated by the current.

[0072] Thus, the functions of a magnetic ring include: enhancing magnetic field strength, as it concentrates the magnetic field around the conductor, thereby increasing the magnetic field strength and improving the sensitivity of the GMR sensor to changes in the magnetic field; improving measurement accuracy, as optimized design of the magnetic ring can reduce interference from the external environment, thus improving measurement accuracy; and protecting the sensor, as the magnetic ring also protects the sensor from direct exposure to harsh environments, extending the sensor's lifespan.

[0073] In one embodiment, the magnetic ring 10 has a three-segment ring structure. The magnetic ring 10 also includes a second opening 102 and a third opening 103. The magnetic ring segment between the second opening 102 and the third opening 103 has an openable and closing structure for placing overhead transmission lines.

[0074] In this embodiment, the magnetic ring 10 adopts a three-segment design, as shown in Figure 1. The three-segment design means that the annular magnetic ring is divided into three segments. The semi-circular openings (i.e., the second opening 102 and the third opening 103) are designed for an openable structure, facilitating the installation of overhead power lines using the second opening 102 and the third opening 103. The opening in the middle, the first opening 101, is for convenient placement of the first magnetic sensor 11.

[0075] The aforementioned GMR magnetic sensor is constructed from thin films of various ferromagnetic, non-ferromagnetic, and metal oxide materials using magnetron sputtering technology. The magnetoresistance of this structure varies with the magnitude of the external magnetic field along the sensing axis. Based on this characteristic, tunneling magnetoresistors with opposite directions along the sensing axis are internally wired to form a Wheatstone bridge structure. When the external magnetic field increases in the positive direction of the sensing axis, the resistance of the tunneling magnetoresistors decreases; when the external magnetic field increases in the negative direction of the sensing axis, the resistance of the tunneling magnetoresistors increases. Furthermore, the increase and decrease in resistance are linearly related to the decrease and increase in the external magnetic field within the measurement range.

[0076] In some implementations, when an appropriate power supply voltage is applied across VCC and GND, a differential output voltage that linearly varies with the magnitude of the external magnetic field can be obtained at the VO+ and VO- terminals. In practical applications, the magnetic field generated by the current flowing through the transmission line is usually not an ideal magnetic field. The magnetic field at the GMR location is easily affected by the magnetic field generated by the surrounding current and the spatial electromagnetic field, affecting the measurement accuracy of the cable current under test. To reduce the influence of the ambient magnetic field and interfering magnetic field in steady-state current measurement, a magnetic field measurement of the steady-state current of the transmission line is generated within the air gap of a magnetic collecting ring made of ferrite material. Placing the GMR chip for steady-state current measurement in the center of the air gap reduces the sensitivity of the GMR magnetic sensor to the position of the cable under test, making the magnetic field magnitude at the air gap almost unaffected by changes in the cable position within the ring. It also amplifies the air gap magnetic field, increasing the measurement accuracy of the GMR sensor for the current under test, while relatively reducing interference from the external magnetic field and improving measurement accuracy.

[0077] The broadband current measurement method for overhead transmission lines provided in this application can be applied to the aforementioned methods. Figure 1 The current measurement system in the implementation architecture is shown. For ease of understanding, the broadband current measurement method for overhead transmission lines provided in this application will be described in detail below with reference to the accompanying drawings. Figure 2 This is a flowchart illustrating a broadband current measurement method for overhead transmission lines provided in an embodiment of this application. Figure 2 As shown, the broadband current measurement method for overhead transmission lines includes the following steps.

[0078] S21, connect the preset power supply voltage to the positive power supply terminal of the overhead transmission line and the grounding terminal of the underground cable.

[0079] The overhead transmission line is set in the magnetic ring.

[0080] S22, the first magnetic sensor is used to detect the magnetic field generated on the overhead transmission line to obtain the first voltage signal.

[0081] S23, Based on the first voltage signal, determine the target current of the overhead transmission line under different frequency components.

[0082] Through the above implementation methods, given that the giant magnetoresistive effect magnetic sensor has advantages such as high sensitivity, wide frequency response, high anti-interference capability, miniaturization, and strong temperature stability in broadband current detection of transmission lines, this application, after connecting the preset power supply voltage to the overhead transmission line and energizing it, uses a first magnetic sensor based on the giant magnetoresistive effect to detect the magnetic field generated by the steady-state current on the overhead transmission line, obtaining a first voltage signal as an analog voltage signal. Based on the fact that the first voltage signal is linearly proportional to the strength of the measured magnetic field or current, that is, based on the fact that the output voltage will change accordingly with the change of the input signal, the target current on the overhead transmission line at various frequencies can be accurately deduced.

[0083] Meanwhile, in order to reduce the influence of ambient magnetic fields and interfering magnetic fields in steady-state current measurement, the first magnetic sensor is set in the first opening of the magnetic ring. This allows the first magnetic sensor to generate a magnetic field in the air gap of the magnetic ring to measure the steady-state current of the transmission line. In this way, on the one hand, the sensitivity of the first magnetic sensor to the position of the cable under test can be reduced, so that the magnitude of the magnetic field at the air gap hardly changes with the position of the cable in the ring. On the other hand, it can also amplify the magnetic field of the air gap, increase the measurement accuracy of the first magnetic sensor to the current under test, reduce the interference of external magnetic fields in relative magnitude, and improve the accuracy of current measurement.

[0084] In the above embodiments, a magnetic sensor based on the giant magnetoresistive effect (GMR) is used to measure the broadband current of overhead transmission lines, thereby solving the problem of broadband current measurement in overhead transmission lines. This enables efficient and accurate current measurement in transmission lines, thus providing support for the stable operation and intelligent scheduling of transmission lines.

[0085] In one implementation, a second magnetic sensor is used to detect the magnetic field generated on the overhead transmission line to obtain a second voltage signal, and the target current is determined based on the first voltage signal and the second voltage signal.

[0086] The bandwidth of the second magnetic sensor is higher than that of the first magnetic sensor.

[0087] One specific method to enhance current bandwidth is to transfer the rapidly changing current component to a broadband current sensor, which is determined by the transfer function of the combination of the first and second magnetic sensors. The sensor transfer function H of the combination of the first and second magnetic sensors is... GMR (s) is the Laplace transform of the combined output voltage signal of the first and second magnetic sensors, U. GMR Both I(s) and the Laplace transform of the input current signal are given by the following formula (1).

[0088]

[0089] Among them, T GMR K is the time constant. GMR The gain and time constant can be determined from the technical datasheet of the GMR chip.

[0090] Furthermore, to increase bandwidth, an RC low-pass filter is introduced to ensure a linear relationship between input and output, using the formula (2). The transfer function of the RC low-pass filter is H. RC (s).

[0091]

[0092] Among them, the Laplace transform U of the output voltage signal of the RC low-pass filter RC (s), K RC The gain constant is given, and the cutoff frequency of the RC filter is given.

[0093] For different bandwidth ranges, bandwidth f can be determined using time-domain analysis. BW The calculation is shown in the following formula (3).

[0094]

[0095] Where 0.35 is an empirical value, t rise and t fall The rise and fall times are typically measured between 10% and 90% of the set value.

[0096] In this embodiment, the signals detected by the first sensor inside the magnetic ring and the second sensor outside the magnetic ring are combined, thereby improving the frequency band range and enhancing the current bandwidth.

[0097] Optionally, the first magnetic sensor includes a first GMR chip; the second magnetic sensor includes a second GMR chip.

[0098] Based on this, the specific process of obtaining the first voltage signal in S22 above is as follows: the first GMR chip is used to convert the detected first electromagnetic signal into a first voltage signal.

[0099] The specific process for obtaining the second voltage signal is as follows: The detected second electromagnetic signal is converted into a second voltage signal using a second GMR chip.

[0100] In one embodiment, after the first electromagnetic signal detected by the first GMR chip is converted into a first voltage signal, the first voltage signal is processed by an analog signal processing module to obtain the processed first voltage signal.

[0101] Firstly, the first voltage signal is input to the signal amplification circuit, and the level of the signal amplification circuit is increased to a preset level to obtain the amplified first voltage signal.

[0102] Secondly, a filtering circuit is used to filter the signal in the first voltage signal that is higher than the preset frequency, so as to obtain the filtered first voltage signal.

[0103] Third, a linearization processing unit is used to convert the signal in the first voltage signal that has a non-linear relationship with the first voltage signal into a signal that has a linear relationship with the first voltage signal, so as to obtain the first voltage signal after linearization processing.

[0104] Fourth, during the process of the first magnetic sensor detecting the magnetic field generated on the overhead transmission line, a temperature compensation circuit is used to adjust the ambient temperature during the detection process of the first magnetic sensor so that the ambient temperature is within the first preset temperature range.

[0105] Fifth, when the first magnetic sensor has no input signal, a zero-point drift suppression unit is used to adjust the output electromagnetic signal value of the first magnetic sensor to a preset signal value that is not zero.

[0106] Through the above implementation method, the first voltage signal is optimized to determine the target current more accurately based on the processed first voltage signal.

[0107] In another embodiment, after the detected second electromagnetic signal is converted into a second voltage signal using a second GMR chip, an analog signal processing module is used to perform one or more of the following processing on the second voltage signal to obtain the processed second voltage signal.

[0108] First, the second voltage signal is input to the signal amplification circuit, and the level of the signal amplification circuit is increased to a preset level to obtain the amplified second voltage signal.

[0109] Secondly, a filtering circuit is used to filter the signal in the second voltage signal that is higher than the preset frequency, so as to obtain the filtered second voltage signal.

[0110] Third, a linearization processing unit is used to convert the signal in the second voltage signal that has a nonlinear relationship with the second voltage signal into a signal that has a linear relationship with the second voltage signal, so as to obtain the second voltage signal after linearization processing.

[0111] Fourth, during the process of the second magnetic sensor detecting the magnetic field generated on the overhead transmission line, a temperature compensation circuit is used to adjust the ambient temperature during the detection process of the second magnetic sensor so that the ambient temperature is within the second preset temperature range.

[0112] Fifth, when there is no input signal, the second magnetic sensor employs a zero-point drift suppression unit to adjust the output electromagnetic signal value of the second magnetic sensor to a preset signal value that is not zero.

[0113] Through the above implementation method, the second voltage signal is optimized to determine the target current more accurately based on the processed first voltage signal and the processed second voltage signal.

[0114] As one implementation method, a digital signal processing unit is used to convert the first voltage signal in analog form into a first voltage signal in digital form.

[0115] Through the above implementation method, the representation of the first voltage signal is transformed so as to more accurately characterize the target current based on the transformed first voltage signal.

[0116] As another implementation, a digital signal processing unit is used to convert the second voltage signal in analog form into a second voltage signal in digital form.

[0117] Through the above implementation method, the representation of the second voltage signal is converted so as to more accurately characterize the target current based on the converted first voltage signal and the converted second voltage signal.

[0118] To achieve the above functions, the overhead transmission line broadband current measurement device includes corresponding hardware structures and / or software modules for performing each function. Those skilled in the art will readily recognize that, based on the algorithmic steps of the examples described in conjunction with the embodiments disclosed herein, this application can be implemented in hardware or a combination of hardware and computer software. Whether a function is implemented in hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0119] This disclosure also provides an embodiment such as Figure 3 The diagram illustrates a broadband current measuring device for overhead transmission lines, applied to a current measuring system. The current measuring system includes a magnetic ring and a first magnetic sensor. The magnetic ring is a non-closed ring structure, and the first magnetic sensor is located at the first opening of the non-closed ring segment within the magnetic ring. The first magnetic sensor is a sensor based on the giant magnetoresistance effect. The device includes a power supply unit 301, a detection unit 302, and a determination unit 303.

[0120] The power supply unit 301 is used to connect the preset power supply voltage to the positive power supply terminal of the overhead transmission line and the grounding terminal of the underground cable; the overhead transmission line is set in the magnetic ring.

[0121] The detection unit 302 is used to detect the magnetic field generated on the overhead transmission line using a first magnetic sensor to obtain a first voltage signal.

[0122] The determining unit 303 is used to determine the target current of the overhead transmission line under different frequency components based on the first voltage signal.

[0123] In one embodiment, the current measurement system further includes a second magnetic sensor, which is disposed outside the magnetic ring and opposite to the first magnetic sensor at the first opening. The second magnetic sensor is a sensor based on the giant magnetoresistance effect. The detection unit 302 is also used to: use the second magnetic sensor to detect the magnetic field generated on the overhead transmission line to obtain a second voltage signal; and determine the target current based on the first voltage signal and the second voltage signal.

[0124] In another embodiment, the first magnetic sensor includes a first GMR chip; the second magnetic sensor includes a second GMR chip; the detection unit 302 is specifically used to: use the first GMR chip to convert the detected first electromagnetic signal into a first voltage signal; and use the second GMR chip to convert the detected second electromagnetic signal into a second voltage signal.

[0125] In another embodiment, the current measurement system further includes an analog signal processing module, which is communicatively connected to the first magnetic sensor and the second magnetic sensor; the analog signal processing module is provided with a signal amplification circuit, a filtering circuit, a linearization processing unit, a temperature compensation circuit, and a zero-point drift suppression unit;

[0126] After the first electromagnetic signal detected by the first GMR chip is converted into a first voltage signal, the detection unit 302 is further configured to: perform one or more of the following processing on the first voltage signal using an analog signal processing module to obtain a processed first voltage signal: inputting the first voltage signal to a signal amplification circuit and increasing the level of the signal amplification circuit to a preset level to obtain an amplified first voltage signal; and / or, using a filtering circuit to filter the signal in the first voltage signal that is higher than a preset frequency to obtain a filtered first voltage signal; and / or, using a linearization processing unit to convert the signal in the first voltage signal that has a non-linear relationship with the first voltage signal into a signal that has a linear relationship with the first voltage signal to obtain a linearized first voltage signal; and / or, during the detection of the magnetic field generated on the overhead transmission line by the first magnetic sensor, using a temperature compensation circuit to adjust the ambient temperature during the detection process of the first magnetic sensor so that the ambient temperature is within a first preset temperature range; and / or, when the first magnetic sensor has no input signal, using a zero-point drift suppression unit to adjust the output electromagnetic signal value of the first magnetic sensor to a preset signal value that is not zero;

[0127] After the second electromagnetic signal detected by the second GMR chip is converted into a second voltage signal, the detection unit 302 is further configured to: perform one or more of the following processing on the second voltage signal using an analog signal processing module to obtain a processed second voltage signal: inputting the second voltage signal to a signal amplification circuit and increasing the level of the signal amplification circuit to a preset level to obtain an amplified second voltage signal; and / or, using a filtering circuit to filter the signal in the second voltage signal that is higher than a preset frequency to obtain a filtered second voltage signal; and / or, using a linearization processing unit to convert the signal in the second voltage signal that has a non-linear relationship with the second voltage signal into a signal that has a linear relationship with the second voltage signal to obtain a linearized second voltage signal; and / or, during the process of the second magnetic sensor detecting the magnetic field generated on the overhead transmission line, using a temperature compensation circuit to adjust the ambient temperature during the detection process of the second magnetic sensor so that the ambient temperature is within a second preset temperature range; and / or, when the second magnetic sensor has no input signal, using a zero-point drift suppression unit to adjust the output electromagnetic signal value of the second magnetic sensor to a preset signal value that is not zero.

[0128] In another embodiment, the current measurement system further includes an MCU processing module, which includes a digital signal processing unit; the MCU processing module is communicatively connected to the analog signal processing module; the detection unit 302 is further configured to: use the digital signal processing unit to convert the first voltage signal in analog form into a first voltage signal in digital form; and / or, use the digital signal processing unit to convert the second voltage signal in analog form into a second voltage signal in digital form.

[0129] In another embodiment, the magnetic ring has a three-segment ring structure, and the magnetic ring also includes a second opening and a third opening. The magnetic ring segment between the second opening and the third opening has an open and close structure for placing overhead transmission lines. The magnetic ring is made of ferrite or nanocrystalline soft magnetic material.

[0130] Regarding the apparatus in the above embodiments, the specific manner in which each unit module performs its operations has been described in detail in the embodiments related to the method, and will not be elaborated upon here.

[0131] This application also provides a computer-readable storage medium. When the instructions in the computer-readable storage medium are executed by the processor of an overhead transmission line broadband current measuring device or electronic device, the overhead transmission line broadband current measuring device or electronic device is able to perform the overhead transmission line broadband current measuring method as described in any of the above possible embodiments. And it can achieve the same technical effect; to avoid repetition, it will not be described again here.

[0132] This application also provides a computer program product, including a computer program or instructions, which are executed by a processor as described in any of the possible embodiments above for a broadband current measurement method for overhead transmission lines. This achieves the same technical effect, and to avoid repetition, it will not be described again here.

[0133] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0134] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. A broadband current measurement method for overhead transmission lines, characterized in that, An application is made in a current measurement system, the current measurement system including a magnetic ring and a first magnetic sensor; wherein, the magnetic ring is a non-closed ring structure, and the first magnetic sensor is disposed at a first opening in the non-closed ring shape of the magnetic ring, so that the magnitude of the magnetic field at the first opening does not change substantially with the position of the overhead transmission line within the magnetic ring, and the magnetic ring amplifies the magnetic field at the first opening; the magnetic ring is a three-segment ring structure, the magnetic ring also including a second opening and a third opening, the segment of the magnetic ring between the second opening and the third opening is an open-close structure, used to place the overhead transmission line; the magnetic ring is made of ferrite or nanocrystalline soft magnetic material; the first magnetic sensor is a sensor based on the giant magnetoresistance effect; the current measurement system also includes a second magnetic sensor, the second magnetic sensor is disposed outside the magnetic ring and opposite to the first magnetic sensor at the first opening, the second magnetic sensor is a sensor based on the giant magnetoresistance effect; the method includes: A preset power supply voltage is connected to the positive power supply terminal of the overhead transmission line and the grounding terminal of the underground cable; the overhead transmission line is installed in the magnetic ring; The first magnetic sensor is used to detect the magnetic field generated on the overhead transmission line to obtain a first voltage signal; the second magnetic sensor is used to detect the magnetic field generated on the overhead transmission line to obtain a second voltage signal. Based on the first voltage signal and the second voltage signal, the target current of the overhead transmission line under different frequency components is determined.

2. The method according to claim 1, characterized in that, The first magnetic sensor includes a first GMR chip; the second magnetic sensor includes a second GMR chip. The step of using the first magnetic sensor to detect the magnetic field generated on the overhead transmission line and obtain a first voltage signal includes: using the first GMR chip to convert the detected first electromagnetic signal into the first voltage signal; The step of using the second magnetic sensor to detect the magnetic field generated on the overhead transmission line and obtain a second voltage signal includes: using the second GMR chip to convert the detected second electromagnetic signal into the second voltage signal.

3. The method according to claim 2, characterized in that, The current measurement system further includes an analog signal processing module, which is communicatively connected to the first magnetic sensor and the second magnetic sensor; the analog signal processing module is provided with a signal amplification circuit, a filtering circuit, a linearization processing unit, a temperature compensation circuit, and a zero-point drift suppression unit. After the first electromagnetic signal detected by the first GMR chip is converted into the first voltage signal, the method further includes: The analog signal processing module performs one or more of the following processing steps on the first voltage signal to obtain the processed first voltage signal: The first voltage signal is input to the signal amplification circuit, and the level of the signal amplification circuit is increased to a preset level to obtain the amplified first voltage signal; And / or, the filtering circuit is used to filter the signal in the first voltage signal that is higher than the preset frequency to obtain the first voltage signal after filtering. And / or, a linearization processing unit is used to convert the signal in the first voltage signal that has a non-linear relationship with the first voltage signal into a signal that has a linear relationship with the first voltage signal, so as to obtain the first voltage signal after linearization processing; And / or, during the process of the first magnetic sensor detecting the magnetic field generated on the overhead transmission line, the temperature compensation circuit is used to adjust the ambient temperature during the detection process of the first magnetic sensor so that the ambient temperature is within a first preset temperature range. And / or, when the first magnetic sensor has no input signal, a zero-point drift suppression unit is used to adjust the output electromagnetic signal value of the first magnetic sensor to a preset signal value that is not zero; After the second electromagnetic signal detected by the second GMR chip is converted into the second voltage signal, the method further includes: The analog signal processing module performs one or more of the following processing steps on the second voltage signal to obtain the processed second voltage signal: The second voltage signal is input to the signal amplification circuit, and the level of the signal amplification circuit is increased to a preset level to obtain the amplified second voltage signal; And / or, the filtering circuit is used to filter the signal in the second voltage signal that is higher than the preset frequency to obtain the filtered second voltage signal; And / or, a linearization processing unit is used to convert the signal in the second voltage signal that has a non-linear relationship with the second voltage signal into a signal that has a linear relationship with the second voltage signal, so as to obtain the second voltage signal after linearization processing; And / or, during the process of the second magnetic sensor detecting the magnetic field generated on the overhead transmission line, the temperature compensation circuit is used to adjust the ambient temperature during the detection process of the second magnetic sensor so that the ambient temperature is within a second preset temperature range; And / or, when the second magnetic sensor has no input signal, a zero-point drift suppression unit is used to adjust the output electromagnetic signal value of the second magnetic sensor to a preset signal value that is not zero.

4. The method according to claim 3, characterized in that, The current measurement system further includes an MCU processing module, which includes a digital signal processing unit; the MCU processing module is communicatively connected to the analog signal processing module; the method further includes: The digital signal processing unit is used to convert the first voltage signal in analog form into the first voltage signal in digital form. And / or, using the digital signal processing unit, the second voltage signal in analog form is converted into the second voltage signal in digital form.

5. A broadband current measuring device for overhead transmission lines, characterized in that, An application is made in a current measurement system, the current measurement system including a magnetic ring and a first magnetic sensor; wherein, the magnetic ring is an open ring structure, the first magnetic sensor is disposed at a first opening of the open ring segment of the magnetic ring, so that the magnitude of the magnetic field at the first opening does not change substantially with the position of the overhead transmission line within the magnetic ring, and the magnetic ring amplifies the magnetic field at the first opening; the magnetic ring is a three-segment ring structure, the magnetic ring also includes a second opening and a third opening, the segment of the magnetic ring between the second opening and the third opening is an open-close structure, used to place the overhead transmission line; the magnetic ring is made of ferrite or nanocrystalline soft magnetic material; the first magnetic sensor is a sensor based on the giant magnetoresistance effect; the current measurement system also includes a second magnetic sensor, the second magnetic sensor is disposed outside the magnetic ring and opposite to the first magnetic sensor at the first opening, the second magnetic sensor is a sensor based on the giant magnetoresistance effect; the device includes: A power supply unit is used to connect a preset power supply voltage to the positive power supply terminal of the overhead transmission line and the grounding terminal of the underground cable; the overhead transmission line is installed in the magnetic ring; The detection unit is used to detect the magnetic field generated on the overhead transmission line using the first magnetic sensor to obtain a first voltage signal; and to detect the magnetic field generated on the overhead transmission line using the second magnetic sensor to obtain a second voltage signal. Define the unit. Based on the first voltage signal and the second voltage signal, the target current of the overhead transmission line under different frequency components is determined.

6. A current measurement system, characterized in that, The current measurement system includes a magnetic ring and a first magnetic sensor; wherein the magnetic ring is an open ring structure, and the first magnetic sensor is disposed at the first opening of the open ring segment of the magnetic ring. The first magnetic sensor is a sensor based on the giant magnetoresistance effect, so that the magnitude of the magnetic field at the first opening does not change substantially with the position of the overhead transmission line within the magnetic ring, and the magnetic ring amplifies the magnetic field at the first opening; the magnetic ring is a three-segment ring structure, and the magnetic ring also includes a second opening and a third opening. The segment of the magnetic ring between the second opening and the third opening is an open-close structure for placing the overhead transmission line; the magnetic ring is made of ferrite or nanocrystalline soft magnetic material; the current measurement system also includes a second magnetic sensor, which is disposed outside the magnetic ring and opposite to the first magnetic sensor at the first opening. The second magnetic sensor is a sensor based on the giant magnetoresistance effect; the current measurement system is configured to perform the broadband current measurement method for overhead transmission lines as described in claim 1.

7. The system according to claim 6, characterized in that, The current measurement system also includes: The first magnetic sensor includes a first GMR chip; the second magnetic sensor includes a second GMR chip. An analog signal processing module is communicatively connected to the first magnetic sensor and the second magnetic sensor; the analog signal processing module includes a signal amplification circuit, a filtering circuit, a linearization processing unit, a temperature compensation circuit, and a zero-point drift suppression unit. An MCU processing module, comprising a digital signal processing unit; the MCU processing module is communicatively connected to the analog signal processing module. The current measurement system is configured to perform the broadband current measurement method for overhead transmission lines as described in any one of claims 1 to 4.

Images