A near-overhead power transmission line magnetic shielding non-intrusive magnetic field energy harvesting device

Abstract

This invention discloses a near-overhead power transmission line magnetic shielding non-intrusive magnetic field energy harvesting device, comprising an overhead power transmission line, a lightweight magnetic core, and a cavity; the lightweight magnetic core is placed inside the cavity, and the overhead power transmission line is located above the cavity; the lightweight magnetic core is made of a hollow rectangular thin-walled structure of soft magnetic material with high initial permeability, and is set inside the shell on the side near the overhead power transmission line. The soft magnetic material with high initial permeability efficiently concentrates the power frequency alternating magnetic field around the overhead power transmission line. The shell (9) is a hollow inner cavity structure, which achieves magnetic shielding protection for the internal space. This invention is a high initial permeability composite thin-shell device, which enables the thin shell itself to simultaneously perform magnetic field energy harvesting and internal magnetic shielding.

Description

Technical Field

[0001] This invention belongs to the field of magnetic field energy harvesting and magnetic shielding technology, specifically relating to a near-overhead power transmission line magnetic shielding non-intrusive magnetic field energy harvesting device. Background Technology

[0002] As the core carrier of the power system, the real-time monitoring of the operation status of overhead transmission lines (including parameters such as temperature anomalies, partial discharge, and icing thickness) is a core requirement for the construction and efficient operation and maintenance of smart grids. However, the special environmental conditions of the transmission lines pose dual technical bottlenecks for monitoring equipment, namely power supply mode and magnetic interference protection, which seriously restricts the implementation and application of distributed monitoring systems.

[0003] In terms of power supply, existing solutions have significant drawbacks. These drawbacks mainly include: wired power supply requires the laying of dedicated cables, which is costly to construct and can easily damage the insulation performance of the lines, making it difficult to adapt to complex terrains such as mountains and hills; battery power supply relies on manual replacement at heights, which is risky and costly to maintain, and discarded batteries cause environmental pollution, which is inconsistent with the concept of green environmental protection; non-invasive energy harvesting technologies such as photovoltaics and vibration are significantly limited by environmental factors, and power outages are prone to occur in rainy days and low wind speed scenarios, making it impossible to guarantee the continuous operation of monitoring equipment; magnetic field energy harvesting technology can continuously harvest energy using the alternating magnetic field of transmission lines; In overhead transmission line energy harvesting applications, traditional current transformer (CT) energy harvesting devices have a through-hole intrusion structure, requiring the transmission conductor to pass through the inner ring of the current transformer core to achieve electromagnetic induction energy harvesting. Taking a 10kV overhead transmission line online monitoring project as an example, the installation of traditional CT energy harvesting devices requires prior application for line power outage and dismantling of the original transmission conductors. This not only poses a high risk to power grid operation safety but also incurs high power outage construction and maintenance costs. Furthermore, traditional CTs can only achieve single current induction energy harvesting function, lacking integrated current sensing capabilities. The magnetic shielding design is necessary because the alternating strong magnetic field of 10-100μT generated during the operation of the transmission line will directly cause strong electromagnetic interference to the supporting high-precision sensing, data acquisition and other magnetic field sensitive monitoring equipment. It is necessary to add an independent metal shielding structure and complex anti-interference circuit, which greatly increases the size, weight and high-altitude deployment difficulty of the device. In addition, traditional CT has inherent magnetic saturation defects. When the line is lightly loaded, the induction output power is insufficient and cannot provide stable power supply. When the line is short-circuited or heavily loaded, the magnetic core saturation is prone to burnout of the energy harvesting coil, resulting in extremely poor adaptability to all working conditions.

[0004] Meanwhile, existing products only provide energy harvesting without integrating magnetic shielding, making them unsuitable for monitoring equipment sensitive to magnetic fields. Regarding magnetic interference protection, the alternating magnetic field strength generated during power transmission line operation can reach 10-100 μT, while the magnetic field tolerance threshold of core monitoring components such as Hall effect sensors and fluxgate sensors is typically ≤1 μT. Strong magnetic field interference can lead to distorted monitoring data and abnormal circuit operation, severely affecting monitoring accuracy.

[0005] Existing solutions employ a separate design for the energy harvesting device and the independent shielding box, which not only increases the size of the equipment by more than 50% and the weight by 1-2 times, leading to a surge in high-altitude installation load and costs, but also causes problems such as magnetic field leakage (leakage rate ≥15%) and poor installation coordination. These solutions cannot meet the development needs of miniaturized and integrated monitoring equipment. Therefore, there is an urgent need for a functionally integrated, non-intrusive, lightweight and reliable device for monitoring scenarios near power transmission lines, which can simultaneously solve the problems of power supply stability and magnetic interference protection. Summary of the Invention

[0006] In order to overcome the problems existing in the prior art, the purpose of this invention is to provide a near-overhead power transmission line magnetic shielding non-intrusive magnetic field energy harvesting device. This device is a high initial permeability composite thin shell device, which enables the thin shell itself to simultaneously perform magnetic field energy harvesting and internal magnetic shielding.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A near-overhead power transmission line magnetic shielding non-intrusive magnetic field energy harvesting device, characterized in that it includes an overhead power transmission line 1, a lightweight magnetic core 2, and a cavity 9; The lightweight magnetic core 2 is placed inside the cavity 9, and the overhead power line 1 is located above the cavity 9; The lightweight magnetic core 2 is made of a hollow rectangular thin-walled structure using a soft magnetic material with high initial permeability. It is located inside the shell 9 on the side close to the overhead transmission line 1. The soft magnetic material with high initial permeability efficiently concentrates the power frequency alternating magnetic field around the overhead transmission line 1. The shell 9 is a hollow inner cavity structure, which achieves magnetic shielding protection for the internal space.

[0008] The lightweight magnetic core 2 includes a magnetic core body 21, a copper wire winding 22, an induction winding 3, an energy management circuit 5, an energy storage component 6, a sensing component 7, and a host computer 8. The outer side of the magnetic core 21 is surrounded by a copper wire winding 22. The induction winding 3 is made of insulated enameled copper wire and is uniformly and densely wound on the outer wall of the lightweight magnetic core 2 to form a rectangular spiral structure that matches the shape of the lightweight magnetic core 2. Together with the lightweight magnetic core 2, it constitutes the electromagnetic induction energy harvesting core of the device. The lightweight magnetic core 2 is connected to the energy management circuit 5, and the energy management circuit 5 is connected to the energy storage component 6. The energy management circuit 5 supplies power to the sensing component 7, which is connected to the host computer 8. The lightweight magnetic core 2 is used to shield the sensing component 7.

[0009] The two ends of the induction winding 3 are electrically connected to the input end of the energy management circuit 5. Through the principle of electromagnetic induction, the magnetic field energy gathered by the magnetic core is converted into induced alternating current, realizing non-intrusive energy harvesting of the magnetic field of the transmission line. The energy management circuit 5 is a modular printed circuit board (PCB) structure that integrates rectification, filtering, voltage regulation, protection and power control functions. It is set in the hollow magnetic shielding cavity of the lightweight magnetic core 2. Its input end is electrically connected to the induction winding, and its output end is electrically connected to the energy storage component 6 and the sensing component 7, respectively.

[0010] The energy storage component 6 adopts a rectangular modular structure with high cycle life energy storage cells, which is also arranged in the magnetic shielding cavity of the lightweight magnetic core 2. It is electrically connected to the output of the energy management circuit 5, stores the remaining electrical energy, and laterally suppresses the power output fluctuation caused by the load fluctuation of the transmission line. It provides continuous power supply to the device under weak magnetic field conditions, realizing uninterrupted operation under all working conditions. The sensing component 7 is arranged inside the shell and is electrically connected to the energy management circuit 5 and the energy storage component 6. At the same time, it establishes data interaction with the host computer 8 through a communication link, collects monitoring data of the transmission line and the surrounding environment in real time, and is the carrier of the core function of the device. The host computer 8 is deployed on the remote monitoring platform and establishes a two-way communication link with the sensing component 7 to realize remote reception of monitoring data and remote control of device operating parameters.

[0011] The lightweight magnetic core 2 is a hollow cuboid with thin walls and a flat outer wall. The hollow inner cavity forms a closed cavity structure. The lightweight magnetic core 2 is made of a high initial permeability composite material, forming a closed hollow cavity inside, which has both magnetic field guidance and magnetic shielding functions; the induction winding 3 is fixedly wound on the outer surface of the thin shell with insulating glue, and the interior of the lightweight magnetic core 2 is a hollow threshold 23 with a multi-turn copper winding structure; the energy management circuit 5 and the energy storage component 6 are fixed in the internal cavity of the thin shell, and the fixing components are integrated on both sides of the thin shell; The rectifier circuit 51, the overvoltage protection unit 52, the voltage regulator module 53 and the sensing component 7 constitute the fixing component, which is integrated on both sides of the thin shell. The high initial permeability material used in the lightweight magnetic core 2 has a permeability μ0 ≥ 10. 4 H / m, shell thickness is 1.5-3.0 mm, overall dimensions are 120-200 mm×80-120 mm×50-80 mm, and the dimensions of the hollow cavity inside the shell are 100-180 mm×60-100 mm×30-60 mm; The copper wire diameter of the induction winding 3 is 0.1-0.3 mm, the number of turns is 500-1500, and the static resistance of the winding is ≤30 Ω; when the primary current of the transmission line is 100-1000A, the secondary output of the induction winding is 3-15V.

[0012] The energy management circuit 5 includes a rectifier circuit, a voltage regulator module, and an overvoltage protection unit. The rectifier circuit has a rectification efficiency of ≥85%, the voltage regulator module outputs 3.3V, 5V, or 12V DC output with a ripple of 100 mV, and the overvoltage protection unit has a protection threshold of 1.5 times the rated output voltage. Power supply can be automatically restored after the fault is cleared. The rectifier circuit 51, the overvoltage protection unit 52, and the voltage regulator module 53 are arranged sequentially along the power transmission path. Among them, the rectifier circuit 51 serves as the front-end input stage of the entire link. Its input terminal is directly electrically connected to the output terminal of the induction winding and is the power input of the entire energy management module. It is responsible for converting the power frequency alternating induction current output by the induction winding, whose amplitude fluctuates dynamically with the load of the transmission line, into pulsating DC current, providing a basis for the subsequent processing and control of DC power. Its output terminal is directly electrically connected to the input terminal of the overvoltage protection unit to complete the downward transmission of rectified power. The overvoltage protection unit 52, as an intermediate protection stage of the link, is connected in series between the output of the rectifier circuit 51 and the input of the voltage regulator module 53. It is the core safety barrier of the entire circuit. Under normal operating conditions, it can directly transmit the rectified power to the subsequent voltage regulator module with low loss, without affecting the normal power transmission. When extreme conditions such as lightning surges or short circuit faults occur in the transmission line, and instantaneous overvoltage, overcurrent, or surge spikes occur at the rectifier output, it can respond quickly at the nanosecond level. By clamping the voltage, discharging the surge energy, and cutting off the overcurrent loop, it can completely block abnormal power from entering the subsequent circuit, providing front-end protection for the voltage regulator module and load components. Its output is directly electrically connected to the input of the voltage regulator module, providing the voltage regulator module with safe and spike-free input power. As the final output stage of the link, the voltage regulator module 53 receives the safe power output from the overvoltage protection unit 52. It is responsible for converting the DC voltage, which still fluctuates greatly after rectification, into a standard DC voltage with stable amplitude and extremely low ripple. It also provides suitable and stable power supply to the energy storage component and the sensing component through multiple independent output channels. At the same time, the voltage regulator module also establishes linkage with the overvoltage protection unit through a voltage feedback loop. When an abnormal overvoltage occurs at the output, it can trigger the upstream protection in reverse, forming a two-way protection closed loop.

[0013] The first stage provides the input foundation for the next stage, while the next stage extends the functions and provides a safety net for the first stage. The functions complement each other and work together to achieve efficient conversion from AC induced electricity to stable DC electricity and to build a full-link safety protection system. This is the core guarantee for the entire device to achieve stable and uninterrupted power supply.

[0014] The energy management circuit 5 adopts a highly integrated PCB modular structure and is encapsulated in a hollow magnetic shielding cavity of a lightweight thin-shell magnetic core. This completely avoids interference from the strong electromagnetic environment of overhead power lines and ensures the long-term stability of power conversion.

[0015] The energy storage unit 6 is a micro supercapacitor or a lithium battery. The capacity of the micro supercapacitor is 1-5F, and the capacity of the lithium battery is 500-1000 mAh. It can ensure that the device can continuously supply power for ≥4 hours within the range of ±30% fluctuation of the primary current of the transmission line.

[0016] The lightweight magnetic core 2 is coated with a fluorocarbon coating, with a temperature range of -40℃ to 85℃, a waterproof rating of IP67, and a salt spray corrosion resistance time of ≥1000 hours; when the external magnetic field strength is 10-100μT, the internal magnetic field strength is ≤1μT, and the magnetic field attenuation ratio is ≥90%.

[0017] The beneficial effects of this invention are: This invention employs a lightweight magnetic core structure. The thin-shell is a hollow cuboid with a composite structure, balancing structural strength and lightweight design. The dual function of the thin shell is achieved through a unified structure. The principle of this invention is that high initial permeability materials possess extremely strong magnetic field guiding capabilities. When the device is near a power transmission line, the external alternating magnetic field preferentially flows along the thin shell with higher permeability, forming a closed loop and preventing it from penetrating the shell to enter the interior. This reduces the magnetic field strength inside the shell, achieving efficient magnetic shielding. Simultaneously, the outer surface of the thin shell is fixed with multiple turns of copper induction windings using insulating adhesive. As the alternating magnetic field passes through the thin shell, it cuts magnetic field lines in the windings, generating an induced electromotive force and outputting alternating current, thus completing the magnetic field energy harvesting. The thin-shell structure can both shield the magnetic field and couple the alternating magnetic field to generate an induced electromotive force.

[0018] The thin-shell hollow cavity provides integrated space for monitoring equipment, forming an internal equipment system. A small energy management module and energy storage unit are fixed inside the shell. The energy management module rectifies the AC power output from the winding into DC power and regulates it to 3.3V, 5V or 12V, directly powering the magnetic sensor and data transmission module placed inside the cavity. Excess energy is stored in a miniature supercapacitor or lithium battery to ensure continuous power supply during short-term fluctuations in the primary current of the transmission line, forming a complete system of collection-conversion-storage-power supply. At the same time, the closed thin-shell cavity provides a constant low magnetic interference environment for the sensor and circuit, avoiding the influence of the magnetic field of the transmission line on the monitoring accuracy.

[0019] In terms of reliability and practicality, the design incorporates a non-intrusive installation feature. The thin-shell structure integrates elastic clips and weather-resistant straps on both sides, allowing direct fixation to the crossarms of transmission line towers or conductor supports. Installation requires no disassembly of the transmission line or welding, and can be completed by a single person in 10 minutes. For environmental protection, the thin-shell surface is coated with a fluorocarbon coating, with a temperature resistance range of -40℃ to 85℃ and an IP67 waterproof rating, enabling it to withstand harsh environments such as heavy rain, strong ultraviolet radiation, and salt spray, thus extending its service life. Overvoltage protection modules are installed at both ends of the windings. When a strong magnetic field is generated by a transmission line fault, the circuit is automatically cut off to protect the internal equipment. Power is restored after the fault is cleared, enhancing system safety. This invention, through the functional integration of the thin-shell structure, possesses four core technological advantages: high degree of functional integration, non-intrusive characteristics, stable energy output, and green economy.

[0020] In summary, this invention, through the structural design of a lightweight magnetic core, integrates magnetic field energy harvesting and magnetic shielding functions into a single structure, effectively solving the power supply and magnetic interference problems of near-overhead transmission line monitoring equipment. Its compact structure, lightweight reliability, and convenient installation make it widely applicable to multi-parameter monitoring systems for high-voltage transmission lines, providing key technical support for the intelligent and green upgrading of power systems, and possessing significant technological innovation and large-scale promotion value. Attached Figure Description

[0021] Figure 1 is a schematic diagram of the installation scenario of the device of the present invention.

[0022] Figure 2 is a schematic diagram of the overall structure of the device of the present invention.

[0023] Figure 3 This is a block diagram illustrating the working principle of the device of the present invention.

[0024] Figure 4 This is a schematic diagram of the energy management circuit of the present invention.

[0025] Figure 5 This is a schematic diagram of the energy management circuit of the present invention.

[0026] The attached figures are labeled as follows: 1-Overhead transmission line, 2-Shell, 21-Lightweight magnetic core, 22-Induction winding, 23-Hollow cavity, 5-Energy management circuit, 6-Energy storage component, 7-Sensing component, 8-Host computer, 9-Cavity. Detailed Implementation

[0027] The present invention will now be described in further detail with reference to the accompanying drawings.

[0028] like Figures 1-5As shown, this invention discloses a non-intrusive magnetic field energy harvesting device with near-overhead power transmission line magnetic shielding. All core functional components are encapsulated within a housing. The device is non-intrusive and positioned close to the overhead power line without requiring contact with or modification of the transmission line. The core energy harvesting and magnetic shielding principle of the device is based on a lightweight magnetic core. The lightweight magnetic core 2 is a hollow rectangular thin-walled structure made of soft magnetic material with high initial permeability, located inside the housing near the overhead power line 1. Its high permeability allows for efficient concentration of the power frequency alternating magnetic field around the overhead power line, and the hollow inner cavity structure provides magnetic shielding protection for the internal space. Simultaneously, the lightweight structural design is suitable for high-altitude installation, providing a foundation for the device to simultaneously achieve magnetic shielding and efficient energy harvesting. The induction winding 3 is made of insulated enameled copper wire, uniformly and tightly wound onto the outer wall of the lightweight magnetic core, forming a rectangular spiral structure matching the shape of the lightweight magnetic core 2. Together with the lightweight magnetic core 2, it constitutes the device. The electromagnetic induction energy harvesting core has its two ends of the induction winding 3 electrically connected to the input of the energy management circuit 5. It can convert the magnetic field energy gathered by the magnetic core into induced alternating current through the principle of electromagnetic induction, realizing non-invasive energy harvesting of the magnetic field of the transmission line and completely avoiding the risk of modifying the transmission line by traditional energy harvesting methods. The energy management circuit 5 is a PCB modular structure that integrates rectification, filtering, voltage regulation, protection and power control functions. It is set in the hollow magnetic shielding cavity of the lightweight magnetic core 2. Its input is electrically connected to the induction winding, and its output is electrically connected to the energy storage component 6 and the sensing component 7 respectively. It can convert the unstable alternating current output by the induction winding into stable direct current, and at the same time realize efficient power control and circuit protection, providing a safe and stable power supply for the downstream components. Moreover, thanks to the built-in magnetic shielding design of the magnetic core, it can work stably in the strong electromagnetic environment of the transmission line, ensuring the reliability of the device operation. The energy storage component 6 uses high-cycle-life energy storage cells to form a rectangular modular structure, which is also arranged in the magnetically shielded cavity of the lightweight magnetic core 2. It is electrically connected to the output of the energy management circuit 5, which can store the remaining electrical energy, suppress the power output fluctuation caused by the load fluctuation of the transmission line, and provide continuous power supply to the device under weak magnetic field conditions, so as to achieve uninterrupted operation under all working conditions. The sensing component 7 is arranged inside the shell and is electrically connected to the energy management circuit 5 and the energy storage component 6. At the same time, it establishes data interaction with the host computer 8 through a communication link, which can collect monitoring data of the transmission line and the surrounding environment in real time. It is the carrier of the core function of the device. The host computer 8 is deployed on the remote monitoring platform and establishes a two-way communication link with the sensing component 7, which can realize the remote reception of monitoring data and the remote control of device operating parameters.

[0029] The communication link described here is a dedicated communication channel adapted to high-altitude deployment, strong electromagnetic interference, and long-distance operation and maintenance scenarios of overhead transmission lines. It enables bidirectional, stable, and highly interference-resistant data transmission and command interaction between field-end sensing components and remote host computers. This link adopts a two-tier architecture design: a field-end wireless communication unit and a remote main transmission network. Its core communication unit is integrated within the sensing component, equipped with a low-power, highly interference-resistant industrial-grade wireless communication module. It can flexibly adapt to various communication standards such as LoRa, NB-IoT, and 4G / 5G cellular communication, depending on the actual deployment scenario of the transmission line (suburbs, remote mountainous areas, cross-river / cross-regional lines, etc.), establishing an encrypted communication channel between the sensing component and the host computer. On the one hand, this link can encrypt and transmit in real-time data collected by the sensing component, including overhead transmission line operating status data, surrounding environmental monitoring data, and the device's own power supply operating parameters. The device stably uploads data to a remote host computer, enabling remote online visual monitoring of the transmission line status. It can also receive remote control commands from the host computer, allowing for remote configuration and dynamic adjustment of the sensor's acquisition frequency, acquisition parameter thresholds, and energy management strategy. This eliminates the need for maintenance personnel to climb the towers for on-site operation, significantly reducing the difficulty and safety risks of line maintenance. Furthermore, the power supply for this communication link is directly provided by the device's energy extraction system, eliminating the need for an additional independent power supply unit. Thanks to the device's built-in magnetic shielding design, it can operate stably in environments with alternating strong magnetic fields of 10-100 μT generated by the transmission line, completely avoiding communication interruptions, data loss, and command transmission failures caused by strong electromagnetic interference. This ensures the continuity and reliability of monitoring data transmission, making it a core supporting component for achieving a fully functional closed-loop system and adapting to the needs of unattended, 24 / 7 online monitoring of transmission lines.

[0030] Overall, this device achieves an integrated layered layout of "energy harvesting coupling area - magnetic shielding cavity" in its space. It simultaneously realizes two core functions with a single magnetic core component: efficient energy harvesting through magnetic field convergence and magnetic shielding protection of internal circuits. No additional shielding structure is required, which greatly simplifies the device structure, reduces the overall weight and deployment cost. The non-invasive design does not require any modification to the power transmission line. It has the advantages of high reliability, high integration and maintenance-free long-term operation, which is the key manifestation of the core inventiveness of this invention.

[0031] By optimizing and determining the structural parameters through electromagnetic simulation, a soft magnetic material with high initial permeability and low loss was selected. Through molding, high-temperature sintering, and precision finishing, a hollow rectangular thin-walled lightweight magnetic core 2 was prepared. The thin-walled structure has uniform wall thickness and a flat outer wall. The hollow inner cavity forms a closed cavity structure. The high permeability thin-walled body not only achieves the convergence and absorption of external magnetic fields, but also forms a natural magnetic shielding space through the hollow inner cavity. At the same time, the thin-walled design significantly reduces the overall weight of the magnetic core, which is suitable for the lightweight requirements of high-altitude and near-line installation. This invention addresses the magnetic field distribution characteristics of 50Hz power frequency overhead transmission lines. First, using ANSYS Maxwell finite element electromagnetic simulation software, with magnetic field focusing efficiency, magnetic shielding effect, and lightweight design as the core optimization objectives, the optimal design parameters for the hollow rectangular thin-shell magnetic core were determined as follows: overall dimensions: length 120 mm-200 mm, width 40 mm-80 mm, height 30 mm-60 mm; hollow inner cavity dimensions: length 110 mm-190 mm, width 30 mm-70 mm, height 20 mm-50 mm; thin-shell wall thickness controlled at 2 mm-5 mm. Simultaneous simulation showed the optimal initial permeability range for the matching material to be 8000-15000 and the saturation magnetic flux density ≥350 mT, ensuring that the magnetic core possesses both excellent magnetic field focusing capability and ≥40 mT magnetic flux density under power frequency magnetic field conditions of 10-100 μT. The internal magnetic shielding efficiency of dB provides a precise parameter benchmark for subsequent fabrication. The material selected is manganese-zinc soft magnetic ferrite powder with high initial permeability and low power frequency loss. The core components of the powder are 52%-54% Fe2O3, 36%-38% MnO, and 8%-12% ZnO, with 0.05%-0.1% Nb2O5 and 0.02%-0.05% CaO as sintering aids and grain inhibitors. The average particle size of the powder is controlled at 0.8 μm-1.2 μm, providing a material basis for the excellent magnetic properties of the magnetic core. The specific fabrication process consists of three core steps, with detailed parameters for each step as follows: The first is the compression molding process, using dry unidirectional compression molding. First, 0.3%-0.5% polyvinyl alcohol binder is added to the powder. After high-speed mixing and uniform mixing, it is placed into a customized alloy steel mold cavity with a 15%-20% sintering shrinkage allowance. The molding pressure is controlled at 80 MPa-120 MPa. MPa, holding pressure for 20 s-40 s, to obtain a uniform density magnetic core green blank. After demolding, the green blank is placed in a constant temperature drying oven at 60℃-80℃ for 4 h-6 h to complete the pre-curing of the binder and the removal of moisture; the second is the high temperature sintering process, which adopts nitrogen-protected pusher-plate tunnel kiln sintering, and nitrogen is introduced throughout the process to control the oxygen partial pressure in the kiln to 0.The temperature is controlled in four stepped zones, ranging from 5% to 2% (using a binder removal and heating zone). The first stage involves heating from room temperature to 400℃-600℃ at a rate of 1℃ / min-2℃ / min, holding for 2-3 hours to completely remove the binder. The second stage involves heating to the sintering zone, heating to the peak sintering temperature of 1280℃-1320℃ at a rate of 3℃ / min-5℃ / min. The third stage involves holding at the peak temperature for 4-6 hours. h, complete the solid-state reaction and grain growth to form a dense spinel crystal phase; the fourth stage is the temperature-controlled cooling zone, where the temperature is first reduced to 900℃ at a rate of 2℃ / min-3℃ / min, and then naturally cooled to room temperature with the furnace. During the cooling process, the oxygen partial pressure is adjusted simultaneously to avoid core oxidation, and finally a sintered core blank with a density ≥95% is obtained; the third is the precision finishing process, which uses a high-precision CNC surface grinder with diamond grinding wheels for wet grinding. First, the six outer surfaces of the core are ground and finished, with dimensional tolerances controlled within ±0.05 mm and surface roughness Ra≤1.6μm, to provide a flat and fitting base for winding. Then, the inner wall of the hollow cavity is precision ground, with the inner cavity dimensional tolerances controlled within ±0.1 mm and the inner wall flatness ≤0.08 mm, to ensure the assembly compatibility of the internal circuit components. After finishing, it is ultrasonically cleaned and dried at 120℃ for 2 hours. h, ultimately yielding a hollow rectangular thin-walled, lightweight magnetic core that meets design requirements.

[0032] After the thin-shell lightweight magnetic core 2 is formed, insulated enameled copper wire is uniformly and densely wound along the length of the outer wall of the thin shell, so that the winding is completely attached to the outer wall of the thin shell, forming an induction winding that matches the thin-shell magnetic core, thus completing the preparation of the energy harvesting core unit. Subsequently, the energy management circuit, energy storage component, and sensing component are sequentially assembled and fixed in the hollow inner cavity of the thin-shell magnetic core, completing the electrical connection and wiring between the induction winding and the energy management circuit, as well as between each functional component, forming a complete functional module. Finally, the functional module is encapsulated in an insulating protective shell, completing the sealed assembly of the device, and establishing a communication link between the sensing component and the host computer, ultimately forming the complete device of this invention that combines magnetic shielding, non-intrusive energy harvesting, lightweight design, and high reliability.

[0033] The lightweight magnetic core 2 is a hollow cuboid structure made of a composite material with high initial permeability, forming a closed hollow cavity inside, which has both magnetic field guidance and magnetic shielding functions; the induction winding 3 is fixedly wound on the outer surface of the thin shell with insulating glue, and its interior is a hollow threshold 23, which is a multi-turn copper winding structure; the energy management circuit and energy storage component are fixed in the inner cavity of the thin shell, and the fixing component is integrated on both sides of the thin shell.

[0034] The high initial permeability material used in the lightweight magnetic core 2 has a permeability μ0 ≥ 10. 4H / m, shell thickness 1.5-3.0mm, overall dimensions 120-200 mm × 80-120 mm × 50-80 mm, internal hollow cavity dimensions 100-180 mm × 60-100 mm × 30-60 mm

[0035] The copper wire diameter of the induction winding 3 is 0.1-0.3 mm, the number of turns is 500-1500, and the static resistance of the winding is ≤30 Ω; when the primary current of the transmission line is 100~1000A, the secondary output of the induction winding is 3-15 V.

[0036] The energy management circuit 5 includes a rectifier circuit, a voltage regulator module, and an overvoltage protection unit. The rectifier circuit has a rectification efficiency of ≥85%. The voltage regulator module can output 3.3 V, 5 V, or 12 V DC output with a ripple of ±100 mV. The overvoltage protection unit has a protection threshold of 1.5 times the rated output voltage and can automatically restore power supply after the fault is cleared.

[0037] The energy management circuit 5 adopts a highly integrated PC modular structure, which is encapsulated in a hollow magnetic shielding cavity of a lightweight thin-shell magnetic core. This completely avoids interference from the strong electromagnetic environment of overhead power lines, ensuring the long-term stability of power conversion. The energy management circuit 5 integrates a rectifier circuit, an overvoltage protection unit, and a voltage regulator module along the power transmission path. Each functional unit is integrated through copper foil wiring on the PCB board. The input end of the module is directly electrically connected to the two output ends of the induction winding. The output end is equipped with multiple independent interfaces, which are electrically connected to the energy storage component and the sensing component respectively, forming a complete power conversion, safety protection, and voltage regulation output link. The rectifier circuit adopts a full-bridge rectifier topology, with a Schottky diode with high reverse withstand voltage and low forward voltage drop forming the core unit of the full-bridge rectifier. It is soldered and fixed to the front input area of ​​the PCB. At the same time, a low internal resistance ceramic filter capacitor is connected in parallel at the rectifier output end to form the rectifier circuit unit. This structure can efficiently convert the power frequency alternating induced AC output from the induction winding into smooth pulsating DC, adapting to a wide range of input voltage conditions caused by load fluctuations in overhead transmission lines. The selection of low-loss components can maximize energy extraction efficiency and avoid ineffective energy loss in the rectification stage. The overvoltage protection unit is connected in series between the output of the rectifier circuit and the input of the voltage regulator module, and is soldered and fixed to the middle protection area of ​​the PCB board. The core consists of a transient suppression diode, a varistor, and a resettable fuse forming a composite protection topology. The resettable fuse is connected in series in the main power circuit, and the transient suppression diode and the varistor are connected in parallel between the positive and negative terminals of the circuit, forming a two-stage overvoltage, overcurrent, and surge protection structure. When overhead transmission lines experience short circuits, lightning surges, or other extreme conditions, causing momentary spikes in the output voltage or current of the induction winding, the resettable fuse can quickly trigger overcurrent protection. Transient voltage suppression diodes and varistors provide nanosecond-level response and achieve voltage clamping and surge discharge, preventing high-voltage pulses and large currents from entering the downstream electrical modules, significantly improving the device's anti-interference capability and lifespan under complex power grid conditions. The voltage regulator module uses a wide-input-range switching voltage regulator chip paired with a linear voltage regulator chip to form a two-stage voltage regulation topology. The output area of ​​the PCB is soldered and fixed. The front-stage switching voltage regulator unit is responsible for voltage reduction and pre-regulation over a wide range, while the rear-stage linear voltage regulator unit is responsible for precise voltage regulation and ripple suppression. Simultaneously, multiple stages of capacitors are cascaded at the output of the voltage regulator module to form a low-ripple, high-stability output structure. The module has multiple independent output channels for different loads, respectively matching the charging ports of the energy storage components and the power supply ports of the sensing components. This structure can convert the DC power with large fluctuations after the rectifier circuit into a standard DC voltage with stable amplitude and extremely low ripple. Through multiple independent output channels, it provides suitable charging power to the energy storage components and high-precision stable power supply to the sensing components, adapting to the power demand of different loads and ensuring that the device can achieve stable and continuous power supply under all operating conditions such as light load and heavy load of the transmission line.

[0038] The energy storage unit is a micro supercapacitor or a lithium battery. The capacity of the micro supercapacitor is 1-5 F, and the capacity of the lithium battery is 500-1000 mAh. It can ensure that the device can continuously supply power for ≥4 hours within the range of ±30% fluctuation of the primary current of the transmission line.

[0039] The energy harvesting device is placed directly near the strong magnetic overhead power line, which greatly avoids the difficulties and costs associated with installing closed magnetic cores.

[0040] The lightweight magnetic core 2 is coated with a fluorocarbon coating, with a temperature range of -40℃ to 85℃, a waterproof rating of IP67, and a salt spray corrosion resistance time of ≥1000 hours; when the external magnetic field strength is 10-100 μT, the internal magnetic field strength is ≤1 μT, and the magnetic field attenuation ratio is ≥90%.

[0041] Example 1 The near-overhead power transmission line magnetic shielding-energy harvesting integrated non-intrusive device provided in this embodiment has the following specific parameters for each component: The lightweight magnetic core 2 has a permeability μ0 = 1.2 × 10⁻⁶. 4 Made of nanocrystalline composite material with H / m, the shell is 2.0 mm thick, with overall dimensions of 160 mm × 100 mm × 60 mm. The internal hollow cavity 4 measures 140 mm × 80 mm × 40 mm. The outer surface of the shell is coated with a 60 μm thick fluorocarbon coating to enhance weather resistance and corrosion resistance. The induction winding 3 uses 0.2 mm diameter oxygen-free copper wire, which is fixed to the central area of ​​the outer surface of the shell in a uniform spiral winding manner with a specific size. The total number of turns is 1000, the winding width is 40 mm, and the static resistance of the winding is 20 Ω. Insulated terminals are set at both ends of the winding to avoid conductive contact with the shell. The energy management module 5 integrates a bridge rectifier circuit, a voltage regulator chip, and an overvoltage protection unit. It uses a full-bridge rectifier with a rectification efficiency of 88%, and the regulated output voltage is 3.3 V, 5 V, or 12 V. The power output ripple is ±100 mV, and the overvoltage protection threshold is set to 20 V. The energy storage unit 6 uses multiple 2 F, voltage-resistant 5.5 The V supercapacitor is small in size and fits the installation space of the thin-shell internal cavity 4; the sensing component 7 placed in the hollow cavity 4 can be a Hall temperature sensor or other types of sensor, with a magnetic induction intensity tolerance threshold ≤1 μT and an internal temperature range of -40℃ to 150℃.

[0042] The working process of this invention: The device is distributed and placed near the tower of the 110 kV overhead strong magnetic transmission line 1. During installation, the distance between the control device and the strong magnetic transmission line 1 is 8 cm (6-10 cm) to ensure effective coupling of the magnetic field while avoiding direct contact with the transmission line and thus avoiding safety risks.

[0043] When the high-power magnetic transmission line 1 is operating normally, the 50 Hz alternating current it carries generates an alternating magnetic field of approximately 50 μT. The lightweight magnetic core 2, with its high permeability, guides this magnetic field to form a closed loop along the thin shell, causing the magnetic field strength in the hollow cavity 4 inside the shell to attenuate to 0.8 μT, fully meeting the operating environment requirements of the sensing component 7. Simultaneously, when the alternating magnetic field passes through the thin shell, it electromagnetically couples with the induction winding 3. The winding cuts the magnetic field lines, generating alternating current. This alternating current is transmitted to the energy management module 5, where it is converted to direct current by a bridge rectifier circuit. It is then processed by a voltage regulator chip into stable direct current, directly powering the sensing component 7 and the data transmission module (using a LoRa module for long-distance transmission). Excess energy is stored in the multi-stage supercapacitors of the energy storage unit 6. When the transmission line experiences a short-circuit fault, causing the current to surge to 1.5 kA, the surrounding magnetic field strength increases accordingly to 150 kA. When the output voltage of the induction winding 3 suddenly rises by μT, the overvoltage protection unit in the energy management module 5 is triggered, the transient voltage suppression diode is turned on, and the main power supply circuit is cut off to prevent high voltage from damaging the internal equipment. After the fault is cleared and the primary current of the transmission line returns to normal, the overvoltage protection unit automatically resets within ms and restores normal power supply. The sensing component 7 collects the ambient temperature data around the transmission line in real time and sends it to the background monitoring system through the data transmission module to realize remote real-time monitoring of the sensing parameters.

[0044] The core protection of this invention is the integrated structure of a near-overhead power transmission line energy harvesting device that combines magnetic shielding protection and non-intrusive magnetic field energy harvesting. It also protects the spatial relationships, mechanical and electrical connections between the core components of the device, in conjunction with the appendix. Figure 1 Appendix Figure 2 Detailed explanation is as follows: Figure 1 As shown, the entire device is fully sealed by an insulating protective shell 9, and is installed parallel to the overhead power line 1 in a non-invasive and contactless manner. This eliminates the need for the power line to pass through the device or for any disassembly or modification of the power line. This non-invasive installation position is one of the core protective features of this invention. Figure 2As shown, the core innovative structure of the device is a hollow rectangular thin-walled, thin-shell lightweight magnetic core 21. This magnetic core simultaneously constitutes the energy harvesting coupling substrate and the magnetic shielding protection substrate of the device, and is the basic structure for core protection of this invention. The induction winding 22 is made of insulated enameled copper wire and is uniformly and tightly wound and fixed to the outer wall of the lightweight magnetic core 21, forming the core unit of electromagnetic induction energy harvesting of the device together with the magnetic core. This integrated layered structure of "winding on the outer wall to achieve magnetic field energy collection and forming a closed magnetic shielding space in the inner cavity" is the innovative structure for core protection of this invention. The energy management circuit 5, energy storage component, and sensing component are all fixedly installed in the hollow inner cavity 23 of the lightweight magnetic core 21, relying on the high magnetic permeability of the magnetic core to achieve magnetic shielding protection in a strong electromagnetic environment. The insulating protective shell 9 encapsulates all the above core components inside, forming a complete protection and fixing structure. The spatial arrangement of the above components is within the protection scope of this invention. In terms of connection, the electrical connection At the interface level, the two output terminals of the induction winding 22 are directly electrically connected to the input terminal of the energy management circuit 5, and the output terminal of the energy management circuit 5 is electrically connected to the energy storage component and the sensing component respectively, forming a complete electrical link of "induction energy harvesting - rectification and voltage regulation - safety protection - energy storage power supply - sensing load". The sensing component establishes a two-way data interaction connection with the remote host computer through the communication link to realize the uploading of monitoring data and the issuance of remote commands. At the mechanical connection level, the induction winding 22 is mechanically fixed to the outer wall of the lightweight magnetic core 21 by a tight winding. The energy management circuit, energy storage component, and sensing component are fixed in the hollow inner cavity 23 of the magnetic core by slots, bolts or insulating potting. The energy harvesting core unit composed of the magnetic core and the winding is installed inside the insulating protective shell 9 by insulating fasteners to form a stable integrated mechanical structure. The electrical and mechanical connection relationships between the above components are all within the protection scope of this invention.

[0045] The device proposed in this invention is a non-invasive, contactless structure that requires no disassembly or modification of the power transmission line. Installation can be completed simply by laying the device close to the overhead power line, without any power outage. This completely avoids the construction safety risks and power outage costs associated with traditional CT scanners. Furthermore, this device utilizes a thin-shell hollow magnetic core structure with high initial magnetic permeability, achieving both efficient energy harvesting from the external magnetic field and magnetic shielding protection within the internal cavity with a single core component. No additional shielding structure is required, and magnetic field-sensitive components such as energy management circuits, energy storage components, and sensing components can be directly integrated into the shielded cavity of the magnetic core. This perfectly adapts to the power supply requirements of high-precision monitoring equipment in the strong electromagnetic environment of power transmission lines. Moreover, the non-invasive near-field energy harvesting method eliminates the magnetic saturation problem of traditional CT scanners, stably adapting to the energy harvesting needs of power transmission lines under all operating conditions, from light to heavy loads. Compared to traditional CT energy harvesting devices, it offers advantages in ease of installation, operational safety, operating condition adaptability, and high integration, fundamentally solving the core industry pain points of existing energy harvesting products.

Claims

1. A near-overhead power transmission line magnetic shielding non-intrusive magnetic field energy harvesting device, characterized in that, It includes an overhead power line (1), a lightweight magnetic core (2), and a cavity (9); The lightweight magnetic core (2) is placed inside the cavity (9), and the overhead power line (1) is located above the cavity (9); The lightweight magnetic core (2) is made of a hollow rectangular thin-walled structure using a soft magnetic material with high initial permeability. It is placed inside the shell (9) on the side close to the overhead power line (1). The soft magnetic material with high initial permeability efficiently gathers the power frequency alternating magnetic field around the overhead power line (1). The shell (9) is a hollow inner cavity structure, which realizes magnetic shielding protection for the internal space.

2. The near-overhead power transmission line magnetic shielding non-intrusive magnetic field energy harvesting device according to claim 1, characterized in that, The lightweight magnetic core (2) includes a magnetic core body (21), a copper wire winding (22), an induction winding (3), an energy management circuit (5), an energy storage component (6), a sensing component (7), and a host computer (8). The outer side of the magnetic core (21) is surrounded by a copper wire winding (22). The induction winding (3) is made of insulated enameled copper wire and is wrapped in a uniform and dense manner on the outer wall of the lightweight magnetic core (2) to form a rectangular spiral structure that matches the shape of the lightweight magnetic core (2). Together with the lightweight magnetic core (2), it constitutes the electromagnetic induction energy harvesting core of the device. The lightweight magnetic core (2) is connected to the energy management circuit (5), and the energy management circuit (5) is connected to the energy storage component (6). The energy management circuit (5) supplies power to the sensing component (7), which is connected to the host computer (8). The lightweight magnetic core (2) is used to shield the sensing component (7).

3. The near-overhead power transmission line magnetic shielding non-intrusive magnetic field energy harvesting device according to claim 2, characterized in that, The two ends of the induction winding (3) are electrically connected to the input end of the energy management circuit (5). The magnetic field energy gathered by the magnetic core is converted into induced alternating current through the principle of electromagnetic induction, so as to realize non-intrusive energy collection of the magnetic field of the transmission line. The energy management circuit (5) is a PCB modular structure that integrates rectification, filtering, voltage regulation, protection and power control functions. It is set in the hollow magnetic shielding cavity of the lightweight magnetic core (2). Its input end is electrically connected to the induction winding, and its output end is electrically connected to the energy storage component (6) and the sensing component (7) respectively.

4. The near-overhead power transmission line magnetic shielding non-intrusive magnetic field energy harvesting device according to claim 3, characterized in that, The energy storage component (6) is constructed with a rectangular modular structure using energy storage cells with high cycle life. It is also arranged in the magnetic shielding cavity of the lightweight magnetic core (2) and electrically connected to the output end of the energy management circuit (5). It stores the remaining electrical energy, suppresses the power fluctuation caused by the load fluctuation of the transmission line laterally, and continuously supplies power to the device under weak magnetic field conditions, so as to achieve uninterrupted operation under all working conditions. The sensing component (7) is arranged inside the shell and electrically connected to the energy management circuit (5) and the energy storage component (6). At the same time, it establishes data interaction with the host computer (8) through the communication link to collect monitoring data of the transmission line and the surrounding environment in real time. The host computer (8) is deployed on the remote monitoring platform and establishes a two-way communication link with the sensing component (7) to realize the remote reception of monitoring data and the remote control of device operating parameters.

5. The near-overhead power transmission line magnetic shielding non-intrusive magnetic field energy harvesting device according to claim 1, characterized in that, The lightweight magnetic core (2) is a hollow rectangular box with thin walls and a flat outer wall. The hollow inner cavity forms a closed cavity structure. The lightweight magnetic core (2) is made of a high initial permeability composite material, forming a closed hollow cavity inside, which has both magnetic field guidance and magnetic shielding functions; the induction winding (3) is fixedly wound on the outer surface of the thin shell with insulating glue, and the interior of the lightweight magnetic core (2) is a hollow threshold (23) with a multi-turn copper winding structure; the energy management circuit (5) and the energy storage component (6) are fixed in the inner cavity of the thin shell; The rectifier circuit (51), overvoltage protection unit (52), voltage regulator module (53) and sensing component (7) constitute the fixed component, which is integrated on both sides of the thin shell; The permeability μ0 of the high initial permeability material used in the lightweight magnetic core (2) is ≥10. 4 H / m, shell thickness is 1.5-3.0mm, overall dimensions are 120-200 mm×80-120 mm×50-80 mm, and the dimensions of the hollow cavity inside the shell are 100-180 mm×60-100 mm×30-60 mm; The copper wire diameter of the induction winding (3) is 0.1-0.3 mm, the number of turns is 500-1500, and the static resistance of the winding is ≤30Ω; when the primary current of the transmission line is 100-1000 A, the secondary output of the induction winding is 3-15 V.

6. The near-overhead power transmission line magnetic shielding non-intrusive magnetic field energy harvesting device according to claim 1, characterized in that, The energy management circuit (5) includes a rectifier circuit (51), an overvoltage protection unit (52), and a voltage regulator module (53). The rectifier circuit (51) has a rectification efficiency of ≥85%, and the voltage regulator module (53) outputs 3.3 V, 5 V, or 12 V DC output with a ripple of 100 mV. The overvoltage protection unit (52) has a protection threshold of 1.5 times the rated output voltage and can automatically restore power supply after the fault is cleared. The rectifier circuit (51), overvoltage protection unit (52), and voltage regulator module (53) are arranged sequentially along the power transmission path; Among them, the rectifier circuit (51) serves as the front-end input stage of the entire link. Its input end is directly connected to the output end of the induction winding. It is the power input of the entire energy management module and is responsible for converting the power frequency alternating induction power output by the induction winding, whose amplitude fluctuates dynamically with the load of the transmission line, into pulsating DC power. Its output end is directly connected to the input end of the overvoltage protection unit to complete the downward transmission of rectified power. The overvoltage protection unit (52) serves as an intermediate protection stage in the link. It is connected in series between the output of the rectifier circuit (51) and the input of the voltage regulator module (53). Under normal operating conditions, it can transmit the rectified power directly to the downstream voltage regulator module with low loss, without affecting the normal power transmission. When the transmission line experiences extreme conditions such as lightning surges or short circuit faults, and instantaneous overvoltage, overcurrent, or surge spikes occur at the rectifier output, it responds quickly at the nanosecond level. By clamping the voltage, discharging the surge energy, and cutting off the overcurrent loop, it completely blocks the abnormal power from entering the downstream circuit, providing front-end protection for the voltage regulator module and load components. Its output is directly electrically connected to the input of the voltage regulator module, providing safe and spike-free input power for the voltage regulator module. The voltage regulator module (53) serves as the end output stage of the link. It receives the safe power output from the overvoltage protection unit (52) and is responsible for converting the DC voltage, which still fluctuates greatly after rectification, into a standard DC voltage with stable amplitude and extremely low ripple. It also provides a stable power supply to the energy storage component and the sensing component through multiple independent output channels. At the same time, the voltage regulator module also establishes a linkage with the overvoltage protection unit through a voltage feedback loop. When an abnormal overvoltage occurs at the output end, it can trigger the front-end protection in reverse to form a two-way protection closed loop.

7. The near-overhead power transmission line magnetic shielding non-intrusive magnetic field energy harvesting device according to claim 6, characterized in that, The energy management circuit (5) adopts a highly integrated PCB modular integrated structure and is encapsulated in a hollow magnetic shielding cavity of a lightweight thin-shell magnetic core. This can completely avoid the interference of the strong electromagnetic environment of overhead power lines on the circuit and ensure the long-term stability of power conversion.

8. A near-overhead power transmission line magnetic shielding non-intrusive magnetic field energy harvesting device according to claim 7, characterized in that, The energy storage unit (6) is a micro supercapacitor or a lithium battery. The capacity of the micro supercapacitor is 1-5 F, and the capacity of the lithium battery is 500-1000 mAh. It can ensure that the device can continuously supply power for ≥4 hours within the range of ±30% fluctuation of the primary current of the transmission line.

9. A near-overhead power transmission line magnetic shielding non-intrusive magnetic field energy harvesting device according to claim 1, characterized in that, The lightweight magnetic core (2) is coated with a fluorocarbon coating, with a temperature range of -40℃ to 85℃, a waterproof rating of IP67, and a salt spray corrosion resistance time of ≥1000 hours; when the external magnetic field strength is 10~100 μT, the internal magnetic field strength is ≤1 μT, and the magnetic field attenuation ratio is ≥90%.

Images