Drop-out power protection device

Abstract

The application provides a falling type power protection device, and belongs to the technical field of power, and solves the problem of high operation and maintenance cost caused by the need of replacing fuses on site of the existing falling type power protection device. The falling type power protection device comprises a support structure, upper supports and lower supports arranged at both ends of the support structure, and a liquid metal current limiter arranged side by side with the support structure; the falling type power protection device further comprises a circuit breaking mechanism fixedly connected with the upper supports, one end of the liquid metal current limiter is rotatably connected with the lower supports, and the other end is movably connected with the circuit breaking mechanism.

Description

Technical Field

[0001] This invention belongs to the field of power system technology, and specifically relates to a drop-out protection device. Background Technology

[0002] Drop-out fuses, as protective devices, are widely used in high-voltage power distribution and control systems. Their working principle is that when the current exceeds a specified value, the heat generated by the fuse itself causes the fuse element to melt, and the contact at one end of the fuse tube drops out, thus breaking the circuit and achieving the purpose of circuit breaking protection. However, existing drop-out fuses still require on-site replacement of the fuse wire after it melts, resulting in high maintenance costs. Summary of the Invention

[0003] The present invention aims to at least solve the technical problem that the fuse of the drop-out fuse still needs to be replaced on site after it blows, which results in high operation and maintenance costs, and provides a drop-out power protection device.

[0004] This invention provides a drop-out protection device, which includes a support structure, an upper bracket and a lower bracket disposed at both ends of the support structure, and a liquid metal current limiter disposed alongside the support structure.

[0005] The drop-out power protection device also includes a circuit breaker mechanism fixedly connected to the upper support, one end of the liquid metal current limiter is rotatably connected to the lower support, and the other end is movably connected to the circuit breaker mechanism.

[0006] Optionally, the liquid metal current limiter includes a limiting end cap, an insulating shell, and a fixed electrode; the limiting end cap and the fixed electrode are symmetrically arranged at both ends of the insulating shell and form a sealed cavity with the insulating shell; an insulating partition is vertically arranged inside the sealed cavity, and a flow passage hole is provided in the middle of the insulating partition;

[0007] The liquid metal current limiter also includes a movable electrode, which includes a main body located between the limiting end cap and the insulating partition and a connecting part located outside the sealed cavity; liquid metal is filled between the insulating partition and the main body, and between the insulating partition and the fixed electrode;

[0008] The connecting part is movably connected to the circuit breaker mechanism, and the fixed electrode is rotatably connected to the lower support.

[0009] Optionally, the liquid metal current limiter further includes a reset mechanism, which is disposed between the limiting end cap and the main body of the movable electrode.

[0010] Optionally, the reset mechanism includes a reset spring.

[0011] Optionally, the drop-out protection device further includes a control mechanism, which includes a drive unit fixedly connected to the support structure, a transmission rod fixedly connected to the drive unit, and a transmission frame movably connected to the transmission rod; the transmission frame is also fixedly connected to the liquid metal current limiter and movably connected to the lower support.

[0012] Optionally, the control mechanism is an electromagnetic push-pull rod box, which includes a box body, a permanent magnet disposed inside the box body, an electromagnetic coil wound around the permanent magnet body, and a push-pull rod disposed between the permanent magnet body and the electromagnetic coil; wherein the push-pull rod is fixedly connected to the transmission rod.

[0013] Optionally, the electromagnetic push-pull rod box further includes a limit switch, which is connected to the circuit breaker mechanism in a transmission manner.

[0014] Optionally, the liquid metal current limiter further includes an insulating contact, which is fixedly connected to the connection portion of the movable electrode.

[0015] Optionally, the insulating shell has a cylindrical structure.

[0016] Optionally, the circuit breaker mechanism includes a mechanical switch. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a drop-out power protection device provided in an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of the structure of a liquid metal current limiter provided in an embodiment of the present invention;

[0019] Figure 3 for Figure 2 The cross-sectional view of the liquid metal flow limiter shown is shown.

[0020] Figure 4 for Figure 2 The diagram shows the principle of rapid contraction and arc initiation of liquid metal in the liquid metal current limiter.

[0021] Figure 5 This is a structural schematic diagram of an electromagnetic push-pull rod box provided as an embodiment of the present invention. Detailed Implementation

[0022] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms "an," "a," or "the," etc., do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms "comprising," "including," etc., mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. The terms "connected," "linked," etc., are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up," "down," "left," "right," etc., are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0024] Existing drop-out fuses use disposable fuses. Excessive current generates Joule heat, causing the fuse to melt and the fuse to trip. In this case, the fuse must be replaced, resulting in high overall maintenance costs. While existing smart drop-out fuses allow for remote control of fuse opening and closing, the fuse still needs to be replaced on-site after it blows, which does not significantly reduce maintenance costs in practice.

[0025] To address at least one of the aforementioned technical problems, embodiments of the present invention provide a drop-out power protection device. The drop-out power protection device provided by the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] Figure 1 This is a schematic diagram of a drop-out power protection device provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the drop-out protection device includes a support structure 1, an upper bracket 11, a lower bracket 12, a liquid metal current limiter 2, and a circuit breaker mechanism 13.

[0027] Specifically, the upper support 11 and the lower support 12 are respectively located at the upper and lower ends of the support structure 1. The circuit breaker mechanism 13 is fixedly connected to the upper support 11. The liquid metal current limiter 2 is arranged side by side with the support structure 1, with one end of the liquid metal current limiter 2 rotatably connected to the lower support 12 and the other end movably connected to the circuit breaker mechanism 13.

[0028] The liquid metal current limiter 2 is rotatably connected to the lower support 12, meaning that the liquid metal current limiter 2 and the lower support 12 are connected in a rotatable manner, that is, after the liquid metal current limiter 2 is connected to the lower support 12, the liquid metal current limiter 2 can rotate relative to the lower support 12. The other end of the liquid metal current limiter 2 is movably connected to the circuit breaker 13, meaning that when the current flowing through the liquid metal current limiter 2 is normal, the liquid metal current limiter 2 is engaged with the circuit breaker 13; when the current flowing through the liquid metal current limiter 2 is excessive, the liquid metal current limiter 2 is disconnected from the circuit breaker 13. Optionally, the movable connection can be a snap-fit ​​connection or an interlocking connection, which is not specifically limited here.

[0029] Optionally, the support structure 1 can be an insulator, which includes a glass fiber resin core rod, an organic material sheath, and sheds. The organic material sheath wraps around the glass fiber resin core rod, and the sheds are disposed on the organic material sheath. Optionally, the insulator is composed of a glass fiber resin core rod or core tube, an organic material sheath, and sheds. The core rod is the load-bearing component of the composite insulator and is also the main part of the internal insulation. The shed sheath is the external insulation part of the composite insulator, and its function is to protect the core rod from external atmospheric attack. This composite insulator is small in size, lightweight, and has high tensile strength, while also avoiding damage caused by bursting.

[0030] The drop-out protection device is connected in series with the circuit through interfaces (not shown in the figure) on the upper bracket 11 and the lower bracket 12. When the current flowing through the liquid metal current limiter 2 in the circuit is within the normal range, the upper end of the liquid metal current limiter 2 is locked with the circuit breaker mechanism 13. When the current flowing through the liquid metal current limiter 2 in the circuit increases abnormally due to short circuit or other reasons, the upper end of the liquid metal current limiter 2 is disconnected from the circuit breaker mechanism 13, and then the liquid metal current limiter 2 drops rapidly from the lower bracket 12 on the side axially away from the support structure 1, thereby disconnecting the circuit and realizing overcurrent and overload protection of the circuit.

[0031] In this embodiment, one end of the liquid metal current limiter 2 is rotatably connected to the lower support 12, and the other end is movably connected to the circuit breaking mechanism 13. When the current flowing through the liquid metal current limiter 2 in the circuit increases abnormally due to short circuit or other reasons, the upper end of the liquid metal current limiter 2 is disconnected from the circuit breaking mechanism 13. Subsequently, the liquid metal current limiter 2 falls rapidly from the side of the lower support away from the support structure 1, thereby disconnecting the circuit and realizing overcurrent and overload protection. Compared with the existing drop-out fuse, since the liquid metal current limiter 2 has a built-in deformable conductor of liquid metal that can be reused, the drop-out power protection device provided in this embodiment does not require on-site replacement of the fuse, thereby significantly reducing the operation and maintenance costs.

[0032] In some embodiments, Figure 2This is a schematic diagram of a liquid metal current limiter provided in an embodiment of the present invention. Figure 3 for Figure 2 The cross-sectional view of the liquid metal current limiter shown is shown. Figure 4 for Figure 2 The diagram illustrates the principle of rapid contraction and arc initiation of liquid metal in a liquid metal current limiter. Figures 2-4 As shown, the liquid metal current limiter 2 includes a limiting end cap 21, an insulating shell 22, a fixed electrode 23, and a movable electrode 26.

[0033] Specifically, the limiting end cap 21 and the fixed electrode 23 are symmetrically arranged at both ends of the insulating shell 22, forming a sealed cavity with the insulating shell 22. An insulating partition 24 is vertically arranged inside the sealed cavity, and a flow hole 25 is provided in the middle of the insulating partition 24. The movable electrode 26 includes a main body 261 located between the limiting end cap 21 and the insulating partition 24, and a connecting part 262 located outside the sealed cavity. Liquid metal is filled in the spaces between the insulating partition 24 and the main body 261 of the movable electrode, and between the insulating partition 24 and the fixed electrode 23. Figure 1 As shown, the connecting part 262 is movably connected to the circuit breaker mechanism 13, and the fixed electrode 23 is rotatably connected to the lower support 12. The material of the liquid metal can be selected as needed and is not specifically limited here. Optionally, the material of the liquid metal includes, but is not limited to, gallium indium tin alloys.

[0034] The limiting end cap 21 is used to limit the movement of the movable electrode 26. Its material can be selected as needed and is not specifically limited here. Optionally, the limiting end cap 21 can be made of insulating material. The circuit breaker mechanism 13 can also be selected as needed, for example, it can be a mechanical switch or an electronic switch. Preferably, the circuit breaker mechanism 13 in this embodiment is a mechanical interlock switch.

[0035] The principle of the drop-out protection device in this embodiment is as follows:

[0036] like Figures 1-4 As shown, the drop-out protection device is connected in series with the circuit through interfaces (not shown) on the upper and lower supports. The fixed electrode 23, liquid metal, and movable electrode 26 form a circuit. When the current in the circuit is within the normal range, the three conduct normally. When the current in the circuit increases abnormally due to short circuits or other reasons, the local magnetic field at the flow orifice 25 will increase accordingly, causing the liquid metal at the flow orifice 25 to be subjected to a drop-out. Figure 4The Lorentz force F is shown. When the current increases to a certain extent, the liquid metal at the flow passage 25 undergoes self-contraction under the action of the Lorentz force F, and the effective cross-sectional area of ​​the liquid metal in the flow passage 25 becomes smaller, resulting in an increase in the overall resistance of the liquid metal and producing a current limiting effect. As the current continues to increase and the liquid metal continues to contract, the liquid metal exhibits an arcing phenomenon at the flow passage 25. The Joule heat generated by the current flow and the heat generated at the moment of arcing cause part of the liquid metal at the flow passage 25 to vaporize, generating a certain pressure. This pressure pushes the connection part 262 of the movable electrode 26 to disconnect from the circuit breaking mechanism 13. Subsequently, the liquid metal current limiter 2 falls rapidly from the side of the support 12 away from the support structure 1, thereby disconnecting the circuit and realizing the overcurrent and overload protection of the circuit.

[0037] In this embodiment, when the current increases to a certain extent, the liquid metal at the flow passage 25 undergoes self-contraction under the action of the Lorentz force, and the effective cross-sectional area of ​​the liquid metal in the flow passage 25 becomes smaller, resulting in an increase in the overall resistance of the liquid metal and producing a current limiting effect. As the current continues to increase and the liquid metal continues to contract, part of the liquid metal at the flow passage 25 vaporizes and generates pressure, and the connection part 262 of the active electrode 26 is disconnected from the circuit breaking mechanism 13. Subsequently, the liquid metal current limiter 2 falls rapidly to the side away from the support structure 1, thereby breaking the circuit and achieving complete current interruption, thereby extinguishing the arc. Furthermore, this embodiment adopts a method of limiting current first and then melting, which provides more timely protection for the circuit.

[0038] In some embodiments, such as Figure 3 As shown, the liquid metal current limiter 2 also includes a reset mechanism 28, which is disposed between the limiting end cap 21 and the main body 261 of the movable electrode. The reset mechanism 28 can be an elastic sheet, spring, or the like with a reset function. Preferably, in this embodiment, the reset mechanism 28 is a reset spring.

[0039] During the complete circuit break, due to the arc suppression inside the liquid metal current limiter 2, the vaporized liquid metal gradually condenses, and the internal pressure gradually decreases. Therefore, under the action of the reset mechanism 28, the movable electrode 26 gradually returns to its initial state, and the movable electrode 26, liquid metal, and fixed electrode 23 are connected again. However, because the liquid metal current limiter 2 is completely disconnected from the circuit breaker mechanism 13, no current flows inside the liquid metal current limiter 2. The circuit can only operate normally after the fault is cleared and the control liquid metal current limiter 2 is reconnected to the circuit breaker mechanism 13.

[0040] In this embodiment, since the liquid metal current limiter 2 is also equipped with a reset mechanism 28, the liquid metal current limiter 2 can be reset and turned on normally after the line fault is cleared, without the need for manual reset, thereby saving labor resources and reducing operation and maintenance costs.

[0041] In some embodiments, such as Figure 1 As shown, the drop-out protection device also includes a control mechanism, which includes a drive unit 31, a transmission rod 32, and a transmission frame 33.

[0042] The drive unit 31 is fixedly connected to the support structure 1. One end of the transmission rod 32 is fixedly connected to the drive unit 31, and the other end is movably connected to the transmission frame 33. The transmission frame 33 is movably connected to the transmission rod 32, and is also fixedly connected to the liquid metal flow limiter 2 and movably connected to the lower support 12.

[0043] During circuit reset, a control signal can be remotely received through the control mechanism, and the transmission rod 32 can be controlled to drag the transmission frame 33 according to the received control signal, so that the liquid metal current limiter 2 moves to the side closer to the support structure 1, thereby realizing the reconnection of the liquid metal current limiter 2 and the circuit breaker mechanism 13 and realizing reset.

[0044] In this embodiment, the control mechanism remotely receives control signals and controls the transmission rod 32 to drag the transmission frame 33 according to the received control signals, thereby resetting the liquid metal current limiter 2 and the circuit breaker mechanism 13. This achieves remote control and unattended operation, greatly reducing maintenance costs.

[0045] The type of control mechanism can be selected as needed and is not specifically limited here. In some embodiments, such as Figure 5 As shown, the control mechanism is an electromagnetic push-pull rod box, which includes a box body (not shown in the figure), a permanent magnet 51 disposed inside the box body, an electromagnetic coil 52 wound around the permanent magnet 51, and a push-pull rod 53 disposed between the permanent magnet 51 and the electromagnetic coil 52. The push-pull rod 53 is fixedly connected to the transmission rod 32.

[0046] During circuit reset, the electromagnetic push-pull rod box receives a control signal. In this embodiment, the control signal is current. The electromagnetic push-pull rod box transmits the received current to the electromagnetic coil 52. Due to the change in the magnetic field inside the box, the push-pull rod 53 moves, thereby driving the transmission rod 32 to drag the transmission frame 33. This causes the liquid metal current limiter 2 to move closer to the support structure 1, thereby reconnecting the liquid metal current limiter 2 with the circuit breaker mechanism 13 and achieving reset.

[0047] In this embodiment, by using an electromagnetic push-pull rod box as a control mechanism, the liquid metal current limiter 2 and the circuit breaker 13 can be automatically reset, realizing remote control and unattended operation, and reducing maintenance costs.

[0048] In alternative implementations, such as Figure 5As shown, the electromagnetic push-pull rod box also includes a limit switch 54, which is connected to the circuit breaker mechanism 13. For example, when the current in the circuit increases abnormally due to a short circuit or other reasons, and when the connection part 262 of the active electrode 26 is just disconnected from the circuit breaker mechanism 13, the circuit breaker mechanism 13 transmits a signal to the limit switch 54 of the electromagnetic push-pull rod box through the transmission structure. As a result, the electromagnetic push-pull rod box drives the push-pull rod 53 to move according to the action of the limit switch 54. The push-pull rod 53 drives the transmission rod 32 to push the transmission frame 33, thereby allowing the liquid metal current limiter 2 to fall more quickly and rapidly, increasing the reaction speed of the drop-out power protection device.

[0049] In some embodiments, such as Figure 2 and Figure 3 As shown, in order to prevent leakage of current at the connection portion 262 of the active electrode 26, the liquid metal current limiter 2 also includes an insulating contact 27, which is fixedly connected to the connection portion 262 of the active electrode 26.

[0050] In some embodiments, such as Figures 2-3 As shown, the movable electrode 26 is made of a highly conductive material and designed as a cylindrical piston structure, forming a seal with the interior of the insulating shell 22. However, it can move axially relative to the insulating shell 22 for conducting electricity and moving the insulating contact 27. A through hole 262 is provided on the connecting part of the movable electrode 26 for connecting an external conductive terminal. The fixed electrode 23 is also made of a highly conductive material and is tightly connected to the end of the insulating shell 22, forming a good seal. The fixed electrode 23 also has a through hole for connecting an external conductive terminal. The shape of the insulating shell 22 can be selected according to the situation and is not specifically limited here. Preferably, the insulating shell 22 is cylindrical. The limiting end cap 21 and the insulating shell 22, as well as the fixed electrode 23 and the insulating shell 22, are connected by fastening bolts.

[0051] In this embodiment, since the liquid metal flow limiter 2 adopts the form of a cylindrical cylinder, it has the advantages of good sealing performance, high reliability, small size, and can be installed and placed in any direction.

[0052] In some embodiments, such as Figure 2 As shown, the flow passage 25 can be circular, elliptical, triangular, rectangular, or square.

[0053] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A drop-out protection device, characterized in that, The device includes a support structure, an upper bracket and a lower bracket disposed at both ends of the support structure, and a liquid metal flow limiter disposed alongside the support structure; The drop-out power protection device also includes a circuit breaker mechanism fixedly connected to the upper support. One end of the liquid metal current limiter is rotatably connected to the lower support, and the other end is movably connected to the circuit breaker mechanism. The liquid metal current limiter includes a limiting end cap, an insulating shell, and a fixed electrode. The limiting end cap and the fixed electrode are symmetrically arranged at both ends of the insulating shell and form a sealed cavity with the insulating shell. An insulating partition is vertically arranged inside the sealed cavity, and a flow hole is provided in the middle of the insulating partition. The liquid metal current limiter further includes a movable electrode, which includes a main body located between the limiting end cap and the insulating partition and a connecting part located outside the sealed cavity; liquid metal is filled between the insulating partition and the main body, and liquid metal is filled between the insulating partition and the fixed electrode; wherein, the connecting part is movably connected to the circuit breaker mechanism, and the fixed electrode is rotatably connected to the lower support. The drop-out power protection device also includes a control mechanism for reconnecting the liquid metal current limiter to the circuit breaker mechanism to achieve a reset. The control mechanism includes a limit switch; the limit switch is connected to the circuit breaker mechanism, causing the liquid metal current limiter to fall rapidly to the side away from the support structure, so as to realize the rapid arc extinguishing of the drop-out power protection device.

2. The drop-out protection device according to claim 1, characterized in that, The liquid metal current limiter also includes a reset mechanism, which is disposed between the limiting end cap and the main body of the movable electrode.

3. The drop-out protection device according to claim 2, characterized in that, The reset mechanism includes a reset spring.

4. The drop-out protection device according to claim 1, characterized in that, The control mechanism includes a drive unit fixedly connected to the support structure, a transmission rod fixedly connected to the drive unit, and a transmission frame movably connected to the transmission rod; the transmission frame is also fixedly connected to the liquid metal flow limiter and movably connected to the lower support.

5. The drop-out protection device according to claim 4, characterized in that, The control mechanism is an electromagnetic push-pull rod box, which includes a box body, a permanent magnet disposed inside the box body, an electromagnetic coil wound around the permanent magnet body, and a push-pull rod disposed between the permanent magnet body and the electromagnetic coil body; wherein, the push-pull rod is fixedly connected to the transmission rod.

6. The drop-out protection device according to claim 1, characterized in that, The liquid metal current limiter also includes an insulating contact, which is fixedly connected to the connection portion of the movable electrode.

7. The drop-out protection device according to claim 1, characterized in that, The insulating outer shell has a cylindrical structure.

8. The drop-out protection device according to claim 1, characterized in that, The circuit breaker mechanism includes a mechanical switch.

Images