A high-potential tube power harvesting device

Abstract

This invention discloses a high-potential busbar energy harvesting device, relating to the field of high-voltage power transmission technology. It solves the problem of energy harvesting from a high-potential busbar under conditions of high voltage, high current, electromagnetic environment, and complex metal structure, meeting the power supply needs of high-power loads such as high-voltage bushings and cooling systems near the busbar. It has advantages such as high output power, high reliability, and strong anti-electromagnetic interference capability. The invention includes: a current transformer, a power supply circuit, and a shielding shell. The current transformer includes a magnetic core surrounding the outer wall of the high-voltage busbar and a metal coil wound on the surface of the magnetic core. The power supply circuit includes a primary busbar, a secondary busbar, and a power conversion circuit. The two ends of the metal coil are connected to the primary busbar; the two ends of the power conversion circuit are connected to both the primary and secondary busbars, and the load is connected to the secondary busbar. The current transformer and the power supply circuit are integrated and installed within the shielding shell, and all three are at the same potential. This high-potential busbar energy harvesting device is used for high-voltage power transmission.

Description

Technical Field

[0001] This invention relates to the field of high-voltage power transmission technology, and in particular to a high-potential busbar energy harvesting device. Background Technology

[0002] In ultra-high voltage direct current (UHVDC) or alternating current (AC) transmission projects, UHV transformers and high-voltage bushings are crucial components of the entire transmission and transformation system. High-voltage bushings, in particular, are a vital component of the transformer, constantly subjected to heat generated by various operating load currents. To ensure their operational safety and power supply reliability, active thermal management is necessary. The cooling system is the core of this thermal management, relying on a reliable low-voltage power supply for long-term stable operation. Current technologies utilize ground-based equipment at a low potential, supplying power to the high-potential cooling system within the high-voltage transmission equipment via leads, requiring reliable voltage isolation. This method has low reliability and results in large, expensive equipment. Alternatively, induction energy harvesting devices utilizing high-voltage transmission lines exist; however, these primarily power smaller detection devices. Given the higher power requirements of the cooling system and the complex conditions of high voltage, high current, electromagnetic environment, and metallic environment of the high-voltage busbar, existing induction energy harvesting devices cannot meet these power supply demands. Summary of the Invention

[0003] To address the aforementioned problems, this invention proposes a high-potential busbar energy harvesting device, which has advantages such as high output power, high reliability, no voltage insulation issues, automatic output power adjustment following the busbar current, and strong anti-electromagnetic interference capability.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] This invention provides a high-potential busbar energy harvesting device, comprising: a current transformer, a power supply circuit, and a shielding shell. The current transformer includes a magnetic core and a metal coil. The magnetic core is cylindrical and surrounds the outer wall of the high-voltage busbar, and the metal coil is wound on the surface of the magnetic core. The power supply circuit includes a primary busbar, a secondary busbar, and a power conversion circuit. The two ends of the metal coil are connected to the primary busbar, and the two ends of the power conversion circuit are connected to both the primary and secondary busbars. The load is connected to the secondary busbar. The current transformer and the power supply circuit are integrated and installed inside the shielding shell, and the three are at the same potential.

[0006] The high-potential busbar power extraction device provided in this embodiment of the invention extracts low-voltage alternating current from the high-voltage busbar by utilizing a current transformer composed of a cylindrical magnetic core surrounding the outer wall of the high-voltage busbar and a metal coil surrounding the magnetic core. The two ends of the metal coil are connected to a primary busbar, allowing the electrical energy from the high-voltage busbar to be collected on the primary busbar. Subsequent power conversion circuits can then extract energy from the primary busbar. After conversion by the power conversion circuit, suitable electrical energy for the load is obtained and collected on a secondary busbar, which then supplies power to the load. Furthermore, because the current transformer and power supply circuit are located within a shielded enclosure, and the enclosure, current transformer, and power supply circuit are at the same potential, external environmental factors can be prevented from affecting the device's operation, and electromagnetic radiation can be shielded. Compared to existing technologies, the high-potential busbar power extraction device provided in this embodiment of the invention extracts energy by setting a current transformer on the outer wall of the high-voltage busbar and converts the energy through a power supply circuit to supply power to the load. It has advantages such as high output power, high reliability, small size, easy integration and strong anti-electromagnetic interference capability, and there is no voltage isolation problem of low potential power supply.

[0007] Furthermore, an air gap is provided on the magnetic core of the current transformer.

[0008] Furthermore, the outer wall of the high-voltage tube, the inner wall of the magnetic core, and the low-voltage side of the metal coil are connected by conductors.

[0009] Furthermore, the power conversion circuit includes a front-end protection module, a resonant capacitor, a converter module, and a filter module, which are sequentially connected between the primary bus and the secondary bus.

[0010] Furthermore, there are multiple power conversion circuits, which are connected in parallel between the primary bus and the secondary bus.

[0011] Furthermore, switches are installed on the primary busbar and the secondary busbar respectively. When all power conversion circuits are in normal working condition, the switches are closed; when a power conversion circuit is in a fault state, the switches open to isolate the fault, ensuring that other lines are not affected and that the energy harvesting device will not stop working as a whole due to a fault in one place.

[0012] Furthermore, the output power P0 of the energy harvesting device automatically tracks the current change of the high-potential bus I1. When the current I1 in the high-potential bus increases, and the power demand of the load cooling device increases accordingly, the output power P0 of the energy harvesting device increases, which can automatically meet the power demand of the load cooling device. The calculation method of the device output power P0 is as follows:

[0013]

[0014] I1 is the current in the high-potential busbar, R0 is the load resistance referred to the primary side, and X...s R is the reactance of the metal coil after conversion to the primary side. s The resistance of the metal coil is calculated back to the primary side. f is the current frequency in the high-potential tube bus, μ0 is the permeability of free space, μ1 is the relative permeability of the core material, S is the cross-sectional area of ​​the core, and l is the average magnetic path length of the core. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of a high-potential tube power harvesting device provided in an embodiment of the present invention;

[0017] Figure 2 This is a schematic diagram of the electrical principle of a high-potential tube power harvesting device provided in an embodiment of the present invention;

[0018] Figure 3 This is a schematic diagram illustrating a specific implementation of a high-potential tube power harvesting device provided in an embodiment of the present invention.

[0019] 1-High voltage busbar; 2-Current transformer; 21-Magnetic core; 22-Metal coil; 23-Air gap; 24-Conductor; 3-Power supply circuit; 31-Primary busbar; 32-Secondary busbar; 321-Switch; 33-Power conversion circuit; 40-Front-end protection module; 41-Resonant module; 42-Uncontrolled rectifier module; 43-DC voltage regulator module; 44-Three-phase inverter module; 5-Load; 6-Shielding shell. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" 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; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0022] In the description of this invention, "and / or" is merely a way of describing the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0023] The following is a detailed description of a high-potential tube power harvesting device provided by the embodiments of the invention.

[0024] The high-potential tube power harvesting device provided in this embodiment of the invention, such as... Figure 1 As shown, the system includes a current transformer 2, a power supply circuit 3, and a shielding shell 6. The current transformer 2 includes a magnetic core 21 and a metal coil 22. The magnetic core 21 is cylindrical and surrounds the outer wall of the high-voltage tube 1. The metal coil 22 is wound around the surface of the magnetic core 21. Figure 2 As shown, the power supply circuit 3 includes a primary bus 31, a secondary bus 32, and a power conversion circuit 33. The two ends of the metal coil 22 are connected to the primary bus 31, and the two ends of the power conversion circuit 33 are connected to the primary bus 31 and the secondary bus 32. The load 5 is connected to the secondary bus 32. The current transformer 2 and the power supply circuit 3 are integrated and installed in the shielding shell 6, and the three are at the same potential.

[0025] The power extraction device for the high-potential busbar provided in this embodiment of the invention utilizes a current transformer 2, composed of a cylindrical magnetic core 21 disposed on the outer wall of the high-voltage busbar 1 and a metal coil 22 surrounding the magnetic core 21, to induce low-voltage alternating current and extract energy from the high-voltage busbar 1. The two ends of the metal coil 22 are connected to the primary busbar 31, which gathers the electrical energy obtained from the high-voltage busbar 1 onto the primary busbar 31. The subsequent power conversion circuit 33 can then extract energy from the primary busbar 31. After conversion by the power conversion circuit 33, suitable electrical energy for the load 5 is obtained and gathered onto the secondary busbar 32, which then supplies power to the load 5. Furthermore, because the current transformer 2 and the power supply circuit 3 are located within a shielding shell 6, and the shielding shell 6, current transformer 2, and power supply circuit 3 are at the same potential, external environmental factors can be prevented from affecting the operation of the device, and electromagnetic radiation can be shielded. Compared to existing technologies, the high-potential busbar energy harvesting device provided in this embodiment of the invention harvests energy by setting a current transformer 1 on the outer wall of the high-voltage busbar 1, and converts the current through the power supply circuit 3 to supply power to the load 5. It has advantages such as high reliability, small size, easy integration, and strong anti-electromagnetic interference capability, and there is no voltage isolation problem of low-potential power supply.

[0026] It should be noted that the magnetic core 21 can be made of soft magnetic materials, such as silicon steel sheets and various soft magnetic ferrites. Here, silicon steel sheets are chosen as the material for the magnetic core. The inner diameter of the magnetic core can be 340mm, the outer diameter 400mm, and the height 400mm.

[0027] Meanwhile, the number of turns of the metal coil 22 can be adjusted according to actual needs. Here, as an example, the number of turns of the coil can be selected as 200. In addition, the metal coil can use copper enameled wire, with a diameter of 0.6mm and a resistance per unit length of 0.05Ω / m.

[0028] In some embodiments, such as Figure 1 As shown, an air gap 23 is provided on the magnetic core 21, that is, there is a very narrow gap on the magnetic core 21. By providing the air gap 23, the magnetic flux and magnetic permeability can be reduced, thus avoiding the occurrence of magnetic saturation.

[0029] Optionally, multiple air gaps 23 can be set on the magnetic core 21, and the width of the air gap 23 can be selected as 2mm.

[0030] In some embodiments, such as Figure 1 As shown, the outer wall of the high-voltage tube 1, the inner wall of the magnetic core 21, and the low-voltage side of the metal coil 22 are connected by a conductor 24.

[0031] Since the three components are connected by conductor 24, they are at the same potential, which can prevent discharge from occurring in the gap between the high-voltage tube 1 and the magnetic core 21, protect the circuit, and prevent insulation breakdown.

[0032] In some embodiments, such as Figure 3 As shown, two power conversion circuits 33 are connected between the primary bus 31 and the secondary bus 32. The power conversion circuit includes a front-end protection module 40, a resonant module 41, an uncontrolled rectifier circuit module 42, a DC voltage regulator module 43, and a three-phase inverter module 44.

[0033] The front-end protection module 40 can use a bipolar transient voltage suppressor diode with a breakdown voltage of 400V. When the voltage across the metal coil 22 exceeds the breakdown voltage of the bipolar transient voltage suppressor diode, it conducts, and the voltage across the bipolar transient voltage suppressor diode is maintained at a predetermined safe voltage value, thereby ensuring that downstream circuit components, including subsequent circuits and chips, are protected from damage caused by high voltage surges.

[0034] A resonant module 41 is connected in parallel between the front-end protection module 40 and the uncontrolled rectifier module 42. By setting the resonant module 41 between the front-end protection module 40 and the uncontrolled rectifier module 42, the influence of the self-inductance of the metal coil 22 can be reduced, and the output voltage of the metal coil 22 can be increased. The resonant module 41 can be a resonant capacitor.

[0035] The uncontrolled rectifier module 42 can convert the low-voltage AC power obtained from the current transformer 2 into low-voltage DC power.

[0036] The DC voltage regulator module 43 uses a boost circuit to increase the DC voltage to 400V.

[0037] The three-phase inverter module 44 is connected between the DC voltage regulator module 43 and the secondary bus 32. A pulse-width modulation (PWM) controlled three-phase inverter can be configured to output AC power, which is then fed onto the secondary bus 32 to power the three-phase asynchronous motor of load 5. Alternatively, a suitable converter module can be selected based on the type of load 5.

[0038] The specific process is as follows: first, AC power is converted to DC power through an uncontrolled rectifier circuit, and then the DC power is stabilized at 400V through a boost DC voltage regulator circuit. Finally, the three-phase AC power with a line voltage of 380V is obtained through the PWM-controlled three-phase inverter mentioned above, and then it is collected on the secondary AC bus 32 to supply power to the load 5 three-phase asynchronous motor.

[0039] To ensure the energy harvesting device continues to operate normally under partial fault conditions, two power conversion circuits 33 can be installed, with switches 321 installed on the primary bus 31 and the secondary bus 32. When both power conversion circuits 33 are in normal operating condition, the switches 321 are closed; when one power conversion circuit is in a fault state, the switches 321 open to isolate the fault, ensuring that the non-faulty lines are not affected and the energy harvesting device can still operate stably.

[0040] Furthermore, as mentioned above, when the energy harvesting device of the aforementioned high-voltage busbar is used in high-voltage transmission equipment, it can supply power to the air supply device, thereby providing air cooling for the high-voltage bushing. Simultaneously, according to the principle of electromagnetic induction, the current induced in the metal coil 22 will change according to the current in the high-voltage busbar 1. Specifically, the calculation method for the output power P0 of the metal coil is as follows:

[0041]

[0042] In the formula, I1 is the current in the high-voltage bus, R0 is the load resistance referred to the primary side, and R s The resistance of the metal coil is calculated back to the primary side. f is the current frequency in the high-potential tube bus, μ0 is the permeability of free space, μ1 is the relative permeability of the core material, S is the cross-sectional area of ​​the core, and l is the average magnetic path length of the core.

[0043] This shows that the AC voltage output by the metal coil 22 automatically tracks the current change of the high-voltage busbar 1. When the current in the high-voltage busbar 1 increases, the cooling demand inside the high-voltage bushing also increases, and the output voltage of the metal coil 22 increases, correspondingly increasing the output power of the air supply device to automatically meet the cooling demand. Specifically, the relationship between the power of the load 5 after conversion by the power supply circuit 3 and the current in the high-voltage busbar 1 is as follows: When the current in the high-voltage busbar 1 is 3000A, the output power is 400W; when the current in the high-voltage busbar 1 is 5000A, the output power is 1000W; under extreme conditions, when the current in the high-voltage busbar 1 is 6376A, the output power is 1500W.

[0044] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A high-potential tube power harvesting device, characterized in that, include: A current transformer, comprising a magnetic core and a metal coil, wherein the magnetic core is cylindrical and surrounds the outer wall of a high-voltage tube, the metal coil is wound on the surface of the magnetic core, and an air gap is provided on the magnetic core; The power supply circuit includes a primary bus, a secondary bus, and a power conversion circuit; both ends of the metal coil are connected to the primary bus; both ends of the power conversion circuit are connected to the primary bus and the secondary bus; the load is connected to the secondary bus. The shielding shell integrates the current transformer and the power supply circuit within it; the shielding shell, the current transformer, and the power supply circuit are at the same potential. The outer wall of the high-voltage tube, the inner wall of the magnetic core, and the low-voltage side of the metal coil are connected by a conductor, and the three are at the same potential.

2. The energy harvesting device for the high-potential tube according to claim 1, characterized in that, The metal coil is one or more, and the metal coil is connected to the primary bus.

3. The energy harvesting device for the high-potential tube according to claim 1, characterized in that, The power conversion circuit includes a front-end protection module, a resonant capacitor, a converter module, and a filter module, which are connected sequentially between the primary bus and the secondary bus.

4. The energy harvesting device for the high-potential tube according to claim 1, characterized in that, The power conversion circuits are multiple, and these multiple power conversion circuits are connected in parallel between the primary bus and the secondary bus, serving as backups for each other.

5. The energy harvesting device for the high-potential tube according to claim 1, characterized in that, Each of the primary busbars and the secondary busbars is equipped with a sectionalizing switch. When all the power conversion circuits are in normal working condition, the switch is closed. When a power conversion circuit is in a fault condition, the switch is opened to isolate the fault, and other lines are not affected.

6. The energy harvesting device for the high-potential tube according to claim 1, characterized in that, The energy harvesting device outputs power P 0 Automatically tracks the high-potential tube motherboard I The current change of 1, when the current in the high-potential tube bus... I When the load cooling device's power demand increases, the power output of the energy harvesting device also increases. P The power requirement of the load cooling device is automatically met by a 0 increase, and the output power of the device is [not specified]. P The calculation method for 0 is as follows: ； I 1 represents the current in the high-potential busbar. R 0 represents the load resistance after being referred back to the primary side. X s This is the reactance of the metal coil after conversion to the primary side. R s The resistance of the metal coil after conversion to the original side, f The frequency of the current in the high-potential busbar. μ 0 is the permeability of free space. μ 1 represents the relative permeability of the core material. S The cross-sectional area of ​​the iron core is... l This represents the average magnetic circuit length of the iron core.

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