Three-core cable energy harvesting device and monitoring system

Abstract

The present application relates to an energy harvesting device. Regarding the technical problems of high environmental dependency, high operating costs, and low energy harvesting efficiency in existing energy harvesting methods for online monitoring devices, provided are a three-core cable energy harvesting device and monitoring system. An energy harvesting magnetic core is of a hollow cylindrical shape and is used for being sleeved on the outer wall of a three-core cable; three accommodating grooves are formed on the inner wall of the energy harvesting magnetic core, the accommodating grooves extend axially, and the three accommodating grooves are uniformly distributed circumferentially; a boss is formed between every two adjacent accommodating grooves, each single-phase induction coil in a three-phase induction coil set is wound around the corresponding boss, and each single-phase induction coil is located in the accommodating grooves on two sides of the corresponding boss. Compared with existing current transformer energy harvesting methods, the present application employs a completely different energy harvesting principle, which can fully capture spatial magnetic field energy around the three-core cable, enhance the induced potential of the induction coils, and ensure stable energy output, and has high energy harvesting efficiency without dependence on the environment.

Description

A three-core cable power harvesting device and monitoring system Technical Field

[0001] This application pertains to an energy harvesting device, specifically a three-core cable energy harvesting device and a monitoring system. Background Technology

[0002] In recent years, with the acceleration of urbanization and the continuous growth of electricity demand, the scale of urban power grids has developed rapidly. Among them, power cables, with their high efficiency, safety, and aesthetics, have gradually replaced traditional overhead lines and become an indispensable power transmission method in modern cities. However, unlike overhead lines which are directly exposed in the air, power cables are usually laid in underground pipes or enclosed tunnels. Compared to overhead lines, the working environment of power cables is more complex and harsher. Once a fault occurs, it may not only lead to power supply interruption but also cause serious damage to the surrounding environment and facilities. Therefore, real-time monitoring and management of cable operating status has become particularly important. This has made the construction of a cable operating status monitoring system composed of online monitoring equipment a focus of common attention in academia and industry.

[0003] Currently, various methods have been proposed to address the energy supply problem of online monitoring equipment, including solar energy harvesting, laser power supply, and traditional current transformer (CT) power harvesting. However, each technology has its inherent drawbacks, such as high environmental dependence, high operating costs, and low energy harvesting efficiency. Therefore, how to efficiently and stably harvest energy from three-core cables has become a pressing technical challenge that needs to be overcome by those skilled in the art. Summary of the Invention

[0004] This application addresses the technical problems of existing online monitoring equipment energy harvesting methods, such as high environmental dependence, high operating costs, and low energy harvesting efficiency, by providing a three-core cable energy harvesting device and monitoring system.

[0005] To achieve the above objectives, this application adopts the following technical solution:

[0006] In the first aspect, this application proposes a three-core cable energy harvesting device, including an energy harvesting magnetic core and a three-phase induction coil;

[0007] The energy harvesting magnetic core is a hollow column shape, used to be sleeved on the outer wall of the three-core cable; three receiving slots are opened on the inner wall of the energy harvesting magnetic core; the receiving slots extend along the axial direction, the three receiving slots are evenly distributed along the circumference, and a boss is formed between adjacent receiving slots;

[0008] Each single-phase induction coil in the three-phase induction coil is wound on three protrusions, and each single-phase induction coil is located in the receiving slot on both sides of the corresponding protrusion.

[0009] Furthermore, the number of turns in the three-phase induction coils is equal.

[0010] Furthermore, the method for determining the number of turns of a single-phase induction coil includes:

[0011] Obtain the magnetic field strength of the space surrounding the three-core cable;

[0012] Calculate the induced voltage value of one turn of a single-phase induction coil based on the magnetic induction intensity of the space surrounding the three-core cable.

[0013] The number of turns of a single-phase induction coil is determined by combining the induced voltage value of one turn of the single-phase induction coil with the ideal induced voltage value.

[0014] Furthermore, the energy harvesting core is cylindrical;

[0015] The width of the receiving slot is determined according to the inner diameter of the energy harvesting magnetic core;

[0016] The depth of the receiving slot is determined based on the number of turns of the corresponding single-phase induction coil and the wire diameter.

[0017] Furthermore, the method for determining the axial length of the energy-harvesting magnetic core includes:

[0018] Determine the resistance of the single-phase induction coil and the load resistance;

[0019] Based on the resistance of the single-phase induction coil and the load resistance, determine the relationship between the maximum energy harvesting power of the single-phase induction coil and the axial length of the energy harvesting core.

[0020] Furthermore, the single-phase induction coil is in the shape of an arc, with an inner diameter central angle of 60° and an outer diameter central angle of 120°.

[0021] Furthermore, the energy harvesting core has a split structure, and the various parts of the split structure are spliced ​​together along the circumferential direction to form the overall structure of the energy harvesting core.

[0022] Furthermore, adjacent single-phase induction coils occupy the same volume of space within the accommodating slot.

[0023] Thirdly, this application proposes a three-core cable monitoring system, including monitoring equipment, energy harvesting device, charging circuit and power supply device;

[0024] The energy harvesting device adopts the above-mentioned three-core cable energy harvesting device;

[0025] The three induction coils of the three-core cable power harvesting device are respectively connected to the three phases of the charging circuit input side, and the charging circuit output side is connected to the power supply device and the monitoring equipment.

[0026] Compared with the prior art, this application has the following beneficial effects:

[0027] This application proposes a three-core cable energy harvesting device. Three receiving slots are formed on the inner wall of the energy harvesting magnetic core, with protrusions between adjacent slots. Three-phase induction coils are wound around these protrusions. The energy harvesting magnetic core is designed as a hollow cylinder, allowing it to fit snugly against the surface of the three-core cable, maximizing the contact area and thus effectively capturing the magnetic field energy surrounding the cable. The three receiving slots allow for the design of more turns of induction coils within the same core size, enhancing the magnetic induction intensity in the protrusions and increasing the induced potential of the induction coils. Furthermore, single-phase induction coils are wound around the three protrusions of the energy harvesting magnetic core and cleverly embedded in the receiving slots. By adjusting the volume occupied by each single-phase induction coil in adjacent slots, the induced voltage value of each phase can be controlled, ensuring stable energy output. Therefore, this three-core cable energy harvesting device is environmentally independent and has high energy harvesting efficiency.

[0028] This application also proposes a three-core cable monitoring system, which uses the three-core cable energy harvesting device proposed in this application to output a three-phase AC induced voltage to the charging circuit, and then supplies power to the monitoring equipment through the power supply device, thus possessing all the advantages of the aforementioned three-core cable energy harvesting device. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 is an installation schematic diagram of one embodiment of the three-core cable energy harvesting device of this application.

[0031] Figure 2 is a top view of the energy extraction core in Figure 1.

[0032] Figure 3 is a three-dimensional structural diagram of the energy extraction core in Figure 1.

[0033] Figure 4 is a schematic diagram of a single-phase induction coil.

[0034] Figure 5 is a schematic diagram of one embodiment of the three-core cable monitoring system of this application.

[0035] Figure 6 shows a model of a three-core cable with an infinitely long parallel straight conductor.

[0036] Figure 7 shows the simulated waveform of the induced voltage value of a single-phase induction coil under different bus currents.

[0037] Among them: 1-Three-core cable, 2-Power supply module, 3-Power core, 4-Charging circuit, 5-Single-phase induction coil, 6-Storage slot, 7-Boss, 8-Power supply device, 9-Monitoring equipment. Embodiments of the present invention

[0038] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0039] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0040] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0041] In the description of the embodiments of this application, it should be noted that if terms such as "upper," "lower," "horizontal," or "inner" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of the invention is in use, they are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, terms such as "first" and "second" are only used to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0042] Furthermore, the use of the term "horizontal" does not imply that the component must be absolutely horizontal, but rather that it can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal than "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0043] In the description of the embodiments of this application, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0044] In practical applications, power cables are typically laid in underground pipes or enclosed tunnels. Due to the numerous uncertainties in the underground environment, such as temperature, humidity, soil conditions, moisture infiltration, chemical corrosion, and mechanical stress, the performance and lifespan of power cables can be affected. Therefore, compared to overhead lines, the working environment of power cables is more complex and harsher, making it essential to monitor the reliability and safety of power cable operation through monitoring systems. However, due to the special nature of the working environment, the energy supply problem of the monitoring system has become a major bottleneck restricting its development. This is mainly because the sensor nodes in the monitoring system are usually distributed, and most nodes are located in harsh, difficult-to-maintain underground or tunnel environments, making traditional wired power supply methods impractical.

[0045] Currently used methods all have inherent flaws:

[0046] (1) Solar energy harvesting technology: With its mature technology and extensive application experience, solar energy harvesting technology has become the preferred energy supply solution for many online monitoring systems. However, solar energy harvesting technology is highly dependent on environmental conditions. On sunny days, solar energy harvesting equipment can efficiently convert solar energy into electrical energy, but on cloudy days or at night, the energy density will drop significantly, even less than one-tenth of that on sunny days. In addition, the load-carrying capacity of solar energy harvesting equipment is limited, which cannot meet the operating requirements of some high-energy-consuming equipment. More importantly, as the core component of the solar energy harvesting system, photovoltaic cells also require regular cleaning and maintenance, which increases the operating cost of the system.

[0047] (2) Laser power supply technology: This technology transmits energy from the transmitter to the receiver using a laser beam, providing power to the online monitoring system. However, the energy transmission efficiency of laser power supply technology is not high, with most of the energy dissipated into the air during transmission. This means that to meet the energy requirements of the online monitoring system, it is necessary to increase the laser power or reduce the distance between the transmitter and receiver, which would increase the complexity and cost of the system. In addition, laser power supply technology is also susceptible to environmental factors, such as dust and smoke in the air, which can affect the transmission effect of the laser. Therefore, laser power supply technology is not suitable for situations with a wide distribution of nodes, and it is difficult to apply it to underground pipe gallery environments where three-core cables are located.

[0048] (3) Current transformer energy harvesting technology: Since overhead lines generally use single-core cable designs, the surrounding magnetic field distribution is relatively uniform, making current transformer energy harvesting technology widely used in this field to effectively harvest energy through the principle of electromagnetic induction. However, for three-core cables, the surrounding space contains spatial magnetic fields generated by the three-phase currents, and the superposition of these magnetic fields results in an uneven magnetic field distribution. In traditional current transformer energy harvesting technology, the induction coil is uniformly wound on the surface of the energy harvesting core. The induction coils distributed in different positions will generate induced currents in opposite directions in the uneven magnetic field, thus canceling each other out, resulting in extremely low efficiency in harvesting energy from three-core cables.

[0049] Therefore, how to efficiently and stably harvest energy from three-core cables has become a pressing technical challenge that technical personnel in related fields need to overcome.

[0050] Based on the above, this application proposes a three-core cable energy harvesting device and a monitoring system. The following is a detailed description of this application in conjunction with embodiments and accompanying drawings.

[0051] The three-core cable 1 consists of three electrical conductors. Since the current flowing through the cable is at power frequency, the three-phase currents essentially cancel each other out after combining, making it impossible to directly extract power from the outside of the cable via induction. As an embodiment of the three-core cable power extraction device of this application, it may include a power extraction magnetic core 3 and a three-phase induction coil. This application mainly addresses the difficulty of power extraction from the three-core cable 1 by designing a combined structure of the power extraction magnetic core 3 and the three-phase induction coil, thereby providing a power extraction method with a different principle.

[0052] The energy-harvesting magnetic core 3 is a hollow cylindrical shape, used to be sleeved on the outer wall of the three-core cable 1. It should be noted that the specific shape of the energy-harvesting magnetic core 3 should be adapted to the external shape of the three-core cable 1, and should generally be a hollow cylinder. In some special cases, if the external shape of the three-core cable 1 changes, the specific shape of the energy-harvesting magnetic core 3 only needs to be adjusted accordingly. To maximize surface contact, the energy-harvesting magnetic core 3 can be made to contact the surface of the three-core cable 1.

[0053] The inner wall of the energy harvesting core 3 has three receiving slots 6, which extend axially and are evenly distributed circumferentially. A boss 7 is formed between adjacent receiving slots 6. It should be noted that the specific dimensions of the receiving slots 6 and the relative dimensions of the receiving slots 6 and the bosses 7 can be designed according to the required energy harvesting results.

[0054] Each single-phase induction coil 5 in the three-phase induction coil is wound around three protrusions 7, and each single-phase induction coil 5 is located in a receiving slot 6 on both sides of the corresponding protrusion 7. In practical applications, one side of two adjacent single-phase induction coils 5 is accommodated in one receiving slot 6. By controlling the volume occupied by two adjacent single-phase induction coils 5 in one receiving slot 6, the induced voltage value of each phase can be controlled, giving the three-core cable energy harvesting device of this application a wider range of application prospects.

[0055] The energy harvesting method corresponding to the three-core cable energy harvesting device described in this application may include:

[0056] The energy-harvesting magnetic core 3 is fitted outside the three-core cable 1, and the three-phase induction coils are distributed circumferentially outside the three-core cable 1, with the extension direction of the three-phase induction coils parallel to the axis of the three-core cable 1. When three-phase alternating current flows through the three-core cable 1, energy is harvested through the three-phase induction coils. In practical applications, when three-phase power frequency alternating current flows through the three-core cable 1, a constantly changing spatial magnetic field is generated around it. The energy-harvesting magnetic core 3, fitted outside the three-core cable 1, can concentrate the spatial magnetic field around the three-core cable. The three-phase induction coils are wound on the bosses 7 of the magnetic core. The alternating magnetic field passes through the inside of the coils, and through the principle of electromagnetic induction, the three-phase induction coils harvest the energy of the spatial magnetic field around the three-core cable 1 and convert it into electrical energy, thereby outputting a three-phase alternating induced voltage.

[0057] In some embodiments of this application, for ease of installation, the energy harvesting core 3 can adopt a split structure, with each part of the split structure spliced ​​together circumferentially to form the overall structure of the energy harvesting core 3. In practical applications, the split structure can be composed of multiple evenly divided parts or multiple non-uniformly divided parts, which can be adjusted according to usage and processing needs. For example, it can be divided into two evenly divided parts to form two magnetic cores distributed vertically. This makes the installation process simple and quick, allowing installation directly on the surface of the three-core cable 1 without power interruption, improving environmental adaptability and working efficiency. It also greatly facilitates subsequent maintenance. By adjusting the number and specific structure of each part of the split structure, the energy harvesting device can become more flexible and adaptable to more complex environments and scenarios, further enhancing its versatility and practicality. In practical applications, the connection method between the split structures can be a snap-fit ​​connection or any other detachable connection method that ensures a stable and secure connection.

[0058] Specifically, an example will be used to illustrate the three-core cable power harvesting device of this application. Figure 1 shows an installation schematic diagram of one embodiment of the three-core cable power harvesting device of this application. Figure 2 shows a top view of the power harvesting magnetic core 3. Figure 3 shows a three-dimensional structural diagram of the power harvesting magnetic core 3. The three-core cable power harvesting device is sleeved on the outside of the three-core cable 1. The power harvesting magnetic core 3 has a split structure, with one receiving groove 6 on the inner wall of the upper half and two receiving grooves 6 on the inner wall of the lower half. Three receiving grooves 6 are evenly arranged circumferentially on the inner wall of the power harvesting magnetic core 3, and each receiving groove 6 extends along the axial direction of the power harvesting magnetic core 3 and penetrates both ends of the axial direction of the power harvesting magnetic core 3. Figure 4 shows a structural schematic diagram of the single-phase induction coil 5. The single-phase induction coil 5 is arc-shaped, with an inner diameter central angle of 60° and an outer diameter central angle of 120°. Correspondingly, the spatial outline of the storage slot 6 is also arc-shaped, with a central angle of 60° for each slot. The three storage slots 6 are rotationally symmetrical about the center of the axial section of the energy harvesting core 3, with a rotation angle of 120°. This ensures that the number of turns of the induction coil is maximized while keeping the size of the energy harvesting core 3 constant, thereby enhancing the induced electromotive force of the induction coil. The three-phase induction coils are wound on the three protrusions 7 on the inner wall of the energy harvesting core 3, and are positioned to harvest energy along the circumferential direction of the surface of the three-core cable 1. The two sides of the induction coils are embedded in the storage slots 6, and one side of the single-phase induction coil 5 is embedded in the storage slot 6, occupying half the volume of the storage slot 6. Each storage slot 6 contains two-phase induction coils. The energy harvesting core 3 and the three-phase induction coils together form the energy harvesting power module 2.

[0059] Accordingly, this application also proposes a three-core cable monitoring system. Figure 5 shows a schematic diagram of one embodiment of the three-core cable monitoring system of this application. It may include a monitoring device 9, an energy harvesting device, a charging circuit 4, and a power supply device 8. The energy harvesting device is the three-core cable energy harvesting device proposed in this application. The three induction coils of the three-core cable energy harvesting device are respectively connected to the three phases of the input side of the charging circuit 4 (phase A, phase B, and phase C in Figure 5), and the output side of the charging circuit 4 is connected to the power supply device 8 and the monitoring device 9. The energy harvesting magnetic core 3 is fitted onto the surface of the three-core cable 1. The three-phase induction coils collect energy along the circumferential direction of the surface of the three-core cable 1. The three-core cable energy harvesting device outputs a three-phase AC induced voltage, which supplies energy to the power supply device 8 and the monitoring device 9 through the charging circuit 4. Utilizing the principle of electromagnetic induction, the energy harvesting magnetic core 3 is fitted onto the surface of the three-core cable 1. Through the ingenious arrangement of the internal storage groove 6, the boss 7, and the induction coils of the energy harvesting magnetic core 3, efficient and stable energy harvesting is achieved.

[0060] This application's three-core cable monitoring system, combined with the aforementioned example of a three-core cable energy harvesting device, maximizes the contact area with the three-core cable 1 by setting the energy harvesting magnetic core 3 as a hollow cylinder, thereby fully capturing the spatial magnetic field energy around the three-core cable 1. The arrangement of the grooves and protrusions 7 allows the energy harvesting magnetic core 3 to efficiently concentrate magnetism, enhancing the magnetic induction intensity in the protrusions 7, and thus increasing the induced electromotive force of the induction coil. In addition, the two sides of the induction coil are cleverly distributed in half the volume of two adjacent grooves, keeping the output induced voltage value consistent, which not only simplifies the topology of the charging circuit 4 but also ensures stable energy output.

[0061] In practical applications, in some embodiments of the three-core cable monitoring system of this application, the power supply device 8 can directly use a battery, or it can use other power supply devices to achieve energy storage and power supply. Additionally, it should be noted that the charging circuit 4 and the monitoring device 9 can adopt existing related structures, which will not be elaborated here.

[0062] It should be noted that, in order to achieve better energy harvesting performance, the specific parameters of the capacitor slot 6, the energy harvesting core 3, and the coil can be designed:

[0063] As an example, the energy-harvesting magnetic core 3 is made of silicon steel, and the induction coil is made of copper wire. The number of turns of the single-phase induction coil 5 wound on each boss 7 is equal. Therefore, the number of turns of the single-phase induction coil... This can be determined using the following methods:

[0064] (1) Calculate the magnetic induction intensity and distribution in the space around the three-core cable 1.

[0065] Figure 6 shows a model of a three-core cable 1 with parallel, infinitely long straight conductors. It is assumed that the center point of the three-core cable 1 is located at the origin, and the radius of each phase cable is... Take any point outside the cable The coordinates are set to . , , The magnetic field strength generated around each phase of a three-phase infinitely long parallel straight conductor is:

[0066]

[0067] in, air permeability, Relative permeability The current amplitude on each phase conductor, for Click Distance between the centers of the phase cables for Click Distance between the centers of the phase cables for Click Distance between the centers of the phase cables For electrical angle, For time, The phase angle, for Phase magnetic field unit vector, for Phase magnetic field unit vector, for Phase magnetic field unit vector, for The magnetic field strength generated by an infinitely long parallel straight conductor. for The magnetic field strength generated by an infinitely long parallel straight conductor. for The magnetic field strength generated around an infinitely long parallel straight conductor.

[0068] in:

[0069]

[0070] in, The radius of each phase cable.

[0071] Substituting equation (1-1) into equation (1-2), and considering the three-phase cable... The magnetic fields generated at each point are summed and simultaneously decomposed onto the coordinate axes. direction and The direction is used to obtain the magnetic induction intensity of the space surrounding the three-core cable 1. for:

[0072]

[0073] in:

[0074]

[0075] in, for Unit vector along the axis for Unit vector along the axis.

[0076] (2) Calculate the induced voltage value of one turn of the single-phase induction coil 5. .

[0077]

[0078] in, To determine the axial length of the energy extraction core 3, To extract the inner diameter of the energy core 3, The groove depth of the receiving slot 6.

[0079] (3) Based on the ideal induced voltage value Calculate the number of turns of single-phase induction coil 5. .

[0080]

[0081] Axial length of energy harvesting core 3 The maximum energy extraction power of the expected single-phase induction coil 5 can be achieved. Sure:

[0082] (1) Calculate the resistance of single-phase induction coil 5. .

[0083]

[0084] in, This is the length of the short side of the single-phase induction coil 5. The resistivity of copper, The wire diameter is for the single-phase induction coil 5.

[0085] (2) Calculate the load resistance .

[0086] According to the maximum power transfer theorem in circuit theory, the power supply output power is maximized when the load impedance equals the internal impedance. Therefore:

[0087]

[0088] (3) Calculate the axial length of the energy harvesting core 3 and the maximum energy harvesting power of the single-phase induction coil 5. The relationship between them.

[0089]

[0090] in, This represents the induced voltage value of a single-phase induction coil.

[0091] Based on the above relationship, a suitable axial length of the energy harvesting core 3 can be designed, and the axial length of the energy harvesting core 3 and the number of turns of the single-phase induction coil can be solved together. As an optimal design solution, it can be used in... While meeting the requirements, the axial length of the energy harvesting core 3 should be minimized.

[0092] It should be noted that the specific structure of the energy harvesting device in this application can be further optimized by modifying the structure of the receiving tank 6.

[0093] Width of the opening of each receiving slot 6 for:

[0094]

[0095] Depth of each accommodating slot 6 for:

[0096]

[0097] In addition, the core thickness at boss 7 It could be:

[0098]

[0099] The structure with optimal energy harvesting performance can be obtained under the above parameter design. Appropriate adjustments can be made in practical applications.

[0100] To verify the energy extraction effect of this application, the induced voltage value of the single-phase induction coil 5 was simulated using different bus currents, as shown in Figure 7, which displays the simulated waveform of the induced voltage value of the single-phase induction coil 5 under different bus currents. A common YJV22-10kv-3*240 type three-core cable 1 was used as the simulation object, and the number of turns of the single-phase induction coil 5 was determined. 300 turns, copper wire diameter The length of the energy-harvesting core is 0.8mm. The length is 25cm. With effective bus current values ​​of 50A, 100A, and 150A, the peak induced voltage of the single-phase induction coil 5 is 1.2V, 2.52V, and 3.75V, respectively; the corresponding maximum power is 43mW, 180mW, and 402mW, respectively; the total power of the three-phase induction coils is 129mW, 540mW, and 1.2W, respectively. It can be seen that when the bus current reaches 100A or more, the output power of the energy harvesting device proposed in this application can meet the power supply requirements of the online monitoring equipment 9 (temperature measurement, ultrasonic partial discharge, etc.) and the microprocessor chip.

[0101] The above are merely preferred embodiments of this application and are not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A three-core cable power taking device, comprising a power taking magnetic core (3) and a three-phase induction coil; characterized in that: the power taking magnetic core (3) is in a hollow columnar shape, used for being sleeved on the outer wall of a three-core cable (1); three accommodating grooves (6) are formed on the inner wall of the power taking magnetic core (3); the accommodating grooves (6) extend in the axial direction, and the three accommodating grooves (6) are uniformly distributed in the circumferential direction, and a boss (7) is formed between adjacent accommodating grooves (6); each single-phase induction coil (5) in the three-phase induction coil is wound on the three bosses (7) respectively, and each single-phase induction coil (5) is located in the accommodating grooves (6) on both sides of the corresponding boss (7).

2. A three-core cable power extractor device according to claim 1, characterized in that, The number of turns of the three-phase induction coil is equal.

3. A three-core cable power extractor device according to claim 2, wherein, A method for determining the number of turns of the single-phase induction coil (5) comprises: obtaining the spatial magnetic induction intensity around the three-core cable (1); calculating the induced voltage value of one turn of the single-phase induction coil (5) according to the spatial magnetic induction intensity around the three-core cable (1); determining the number of turns of the single-phase induction coil (5) in combination with the induced voltage value of one turn of the single-phase induction coil (5) and the ideal induced voltage value.

4. The power taking device of a three-core cable according to any one of claims 1 to 3, characterized in that, The power taking magnetic core (3) is in a cylindrical shape; The width of the opening of the accommodating groove (6) is determined according to the inner diameter of the power taking magnetic core (3); The depth of the accommodating groove (6) is determined according to the number of turns of the corresponding single-phase induction coil (5) and the wire diameter.

5. A three-core cable power extractor device according to claim 4, wherein, A method for determining the axial length of the power taking magnetic core (3) comprises: determining the resistance of the single-phase induction coil (5) and the load resistance; determining the relationship between the maximum power taking power of the single-phase induction coil (5) and the axial length of the power taking magnetic core (3) according to the resistance of the single-phase induction coil (5) and the load resistance.

6. A three-core cable power extractor device according to claim 5, wherein, The single-phase induction coil (5) is in an arc shape, the inner diameter has a central angle of 60°, and the outer diameter has a central angle of 120°.

7. A three-core cable power extractor device according to claim 6, wherein, The power taking magnetic core (3) is in a split structure, and each part of the split structure is spliced in the circumferential direction to form the overall structure of the power taking magnetic core (3).

8. A three-core cable power extractor device according to claim 7, wherein, The space volumes occupied by adjacent single-phase induction coils (5) in the accommodating grooves (6) are equal.

9. A three-core cable monitoring system, comprising a monitoring device (9), a power taking device, a charging circuit (4) and a power supply device (8); characterized in that: the power taking device adopts the three-core cable power taking device according to any one of claims 1 to 8; the three induction coils of the three-core cable power taking device are connected to the three-phase input side of the charging circuit (4) respectively, and the output side of the charging circuit (4) is connected to the power supply device (8) and the monitoring device (9).

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