A fast switch for a transformer

Abstract

This invention discloses a fast switch for transformers, relating to the field of transformer technology. The invention includes a first conductive component, a second conductive component, an insulating cavity, and a low-melting-point metal component. The first and second conductive components are respectively connected to opposite sides of the insulating cavity. The low-melting-point metal component is located within the insulating cavity, and the connection between the first and second conductive components and the insulating cavity is sealed. Under the action of a short-circuit current, the low-melting-point metal component melts into a liquid metal, and the resistance of the liquid metal is greater than the resistance of the low-melting-point metal component. As a short-circuit protection device in a transformer circuit, the fast switch of this invention, through the cooperation of the low-melting-point metal component and the insulating cavity, allows the resistance between the first and second conductive components to automatically change according to the current in the circuit. This ensures a large resistance is formed when a short-circuit current occurs, while a small resistance is formed during normal use, thereby solving the problem of energy waste during normal circuit operation.

Description

Technical Field

[0001] This invention relates to the field of transformer technology, and specifically provides a fast switch for transformers. Background Technology

[0002] Short-circuit faults are one of the main risks threatening the safety of power transformers during operation. The enormous current generated by a short circuit can cause the transformer winding temperature to rise rapidly in a very short time. If the short-circuit current cannot be effectively limited in time, it will lead to insulation damage or even equipment burnout. The traditional solution to short-circuit problems is to use fuses, which utilize low-melting-point metal wires to melt and provide protection under overload conditions. However, their fatal flaw is that they are disposable and must be replaced after each use, failing to meet the recoverability requirements of modern power systems. Furthermore, with the increasing scale of circuits, the ultra-large current generated by a short circuit has extremely strong electrodynamic forces: pulling, twisting, and tearing transformer windings, busbars, and cables. High-voltage, high-current arcs cannot be extinguished quickly, and forcibly disconnecting the circuit can burn switch contacts, rupture the cabinet, cause insulation breakdown, and even lead to fire and explosion. Therefore, existing technology incorporates short-circuit protection resistors into transformers, serving as dedicated energy-consuming, current-limiting, and arc-stabilizing protection components for fault conditions.

[0003] However, the built-in short-circuit protection resistor will generate a lot of additional energy consumption when the transformer is working, resulting in a lot of wasted electrical energy. Summary of the Invention

[0004] This invention provides a fast switch for transformers to solve the problem of high energy consumption and energy waste caused by the built-in short-circuit protection resistors in transformers.

[0005] The technical solution of the present invention is as follows:

[0006] A fast switch for a transformer includes a first conductive component, a second conductive component, an insulating cavity, and a low-melting-point metal component. The first and second conductive components are connected to opposite sides of the insulating cavity, respectively. The low-melting-point metal component is located inside the insulating cavity, and the connections between the first and second conductive components and the insulating cavity are sealed. Under the influence of a short-circuit current, the low-melting-point metal component melts into a liquid metal, increasing its resistance. In this design, the fast switch operates in two different states depending on the presence of a short-circuit current. Under normal use, the low-melting-point metal component is inside the insulating cavity; in this case, it is a solid conductive component with low resistance, preventing significant energy waste. However, when a short-circuit current exists, the high temperature generated by the current melts the low-melting-point metal component, forming a liquid alloy. Since the resistance of the liquid alloy is higher than that of the original low-melting-point metal component, it acts as a protective resistor in the circuit, reducing the current flow.

[0007] Preferably, the melting point of the low-melting-point metal component is below 200°C. Conventional wires use copper or aluminum conductors. By controlling the melting point of the low-melting-point metal component below 200°C, it can be ensured that the low-melting-point metal component melts before the copper or aluminum conductor fails, thereby ensuring the safety of the circuit.

[0008] Preferably, the low-melting-point metal components are made of bismuth-tin alloy or indium. Bismuth-tin alloy has a melting point of 138°C, and indium has a melting point of 156°C. These components melt quickly when a short-circuit current is present, ensuring efficient and rapid switching.

[0009] To address the slow response speed of low-melting-point metal components under short-circuit current, the fast switch also includes an electromagnetic heating element. This element provides auxiliary rapid heating to the low-melting-point metal components upon the occurrence of a short-circuit current, thereby improving the switch's response speed. In this design, the electromagnetic heating element further enhances the melting rate of the low-melting-point metal components, causing them to melt into molten metal more quickly. This increases the resistance of the fast switch, thus improving its response speed to short-circuit current.

[0010] A second aspect of this invention addresses the problem of high resistance in low-melting-point metal components, where the resistance increase after melting into molten metal is insufficient. To this end, the fast switch further includes a floating conductive component and a reset assembly. The density of the floating conductive component is lower than that of the molten metal, and its resistance is lower than that of the low-melting-point metal component. The reset assembly is used to reset the floating conductive component before the molten alloy cools. In this solution, because the resistance of the floating conductive component is lower than that of the low-melting-point metal component, its placement reduces the resistance between the first and second conductive components, further reducing energy consumption. After the low-melting-point metal component melts into molten metal, the floating conductive component floats, lowering the molten metal level and creating a smaller cross-sectional area in the current flow direction, further increasing resistance and allowing the molten metal to better stabilize the current. The reset assembly allows the floating conductive component to sink and reset after the molten metal solidifies, ensuring that after the molten metal solidifies into a low-melting-point metal component, the floating conductive component is embedded within it, reducing resistance and ensuring the fast switch can be used repeatedly.

[0011] Preferably, the floating conductive component is a hollow structure, which makes its density lower than that of the molten metal. In this design, the hollow structure facilitates processing, reduces manufacturing costs, and promotes widespread adoption.

[0012] To address the problem of inconvenient reset caused by the floating conductive component being located within an insulating cavity, a reset assembly includes a high-temperature resistant magnet, a reset component, a controller, and a current monitoring element. The high-temperature resistant magnet is positioned at the bottom of the floating conductive component, the reset component is located on the outer surface of the bottom of the insulating cavity, and the current monitoring element monitors the current in the circuit containing the fast switch. The reset component and the current monitoring element are electrically connected to the controller. In this solution, the magnetic field generated by the reset component allows the floating conductive component to be reset without being connected to it, thus solving the problem of difficulty in resetting the floating conductive component.

[0013] The problem arises when a floating conductive component continues to conduct electricity even after it floats. This invention addresses this issue by providing an insulating layer at the bottom of the floating conductive component and a guiding structure between the component and the insulating cavity. This guiding structure constrains the floating conductive component, allowing it only vertical movement. In this solution, the insulating layer reduces the contact area between the molten metal and the floating conductive component, thereby reducing its impact on the resistance of the molten metal. This prevents an overall increase in the resistance of the molten metal as the liquid level drops. Simultaneously, the guiding structure ensures that the floating conductive component only moves vertically, preventing it from shifting angularly towards the first or second conductive component and affecting the resistance.

[0014] To address the issue of a significant increase in resistance caused by the floating conductive component detaching from the low-melting-point metal component, an accelerating lifting component and a resetting component are included. The accelerating lifting component is located at the top of the insulating cavity and uses electromagnetic attraction to accelerate the buoyancy of the floating conductive component. In this solution, the accelerating lifting component can speed up the buoyancy of the floating conductive component, further increasing the resistance increase efficiency between the first and second conductive components, thus enabling a faster response to short-circuit circuits.

[0015] This invention also provides a fast switching control method for transformers, used to control the aforementioned fast switching, employing a current monitoring element to detect the current in the circuit where the fast switch is located, and specifying that the current is lower than a set short-circuit current I. max After a set time T, the reset circuit is activated, generating an electromagnetic force that attracts the floating conductive component. When the current exceeds the short-circuit current I... max Then, the circuit of the acceleration lifting component is turned on, generating an electromagnetic attraction that pulls on the floating conductive component. At the same time, the circuit of the electromagnetic heating component is turned on to begin auxiliary heating of the low-melting-point metal component, accelerating the liquefaction of the low-melting-point metal component. After the low-melting-point metal component melts, the floating conductive component will be raised to the upper limit more quickly by the combined action of buoyancy and lifting force, achieving a high-resistance state.

[0016] The beneficial effects of this invention are:

[0017] The fast switch of the present invention serves as a short-circuit protection device in a transformer circuit. Through the cooperation of a low-melting-point metal component and an insulating cavity, the resistance between the first and second conductive components can automatically change according to the current in the circuit. This ensures that a large resistance is formed when a short-circuit current occurs, while a small resistance is formed during normal use, thereby solving the problem of energy waste during normal circuit use. Attached Figure Description

[0018] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description of the embodiments 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.

[0019] Figure 1 This is a schematic diagram of the fast switch in Example 1 when the circuit is working normally;

[0020] Figure 2 This is a schematic diagram of the fast switch in Example 1 when a short-circuit current occurs in the circuit;

[0021] Figure 3 This is a schematic diagram of the fast switch in Embodiment 2 when the circuit is working normally;

[0022] Figure 4 This is a schematic diagram of the fast switch in Example 2 when a short-circuit current occurs in the circuit;

[0023] Figure 5 Example 2 is a cross-sectional view of a guide structure from a top view of a floating copper component;

[0024] Figure 6 This is a schematic diagram of the fast switch in Embodiment 2, where the molten metal only contacts the insulating layer when a short-circuit current occurs in the circuit.

[0025] In the above figures, the corresponding reference numerals are as follows:

[0026] 1. First conductive component; 2. Insulating cavity; 3. Second conductive component; 4. Low melting point metal component; 5. Floating copper component; 6. High temperature resistant magnet; 7. Insulating layer; 8. Heat insulation layer; 9. Reset component; 10. Molten metal; 11. Electromagnetic heating component; 12. Accelerating lifting component. Detailed Implementation

[0027] The technical solution of the present invention will be clearly and completely described in conjunction with the accompanying drawings and through specific embodiments of the present invention.

[0028] Example 1:

[0029] like Figure 1As shown in the figure, this embodiment provides a fast switch for a transformer, including a first conductive component 1, a low-melting-point metal component 4, an insulating cavity 2, and a second conductive component 3. The low-melting-point metal component 4 has a melting point below 250°C, and its resistance after melting is greater than its resistance before melting. The low-melting-point metal component 4 is attached to both the first conductive component 1 and the second conductive component 3, forming an electrical connection. The low-melting-point metal component 4 is located inside the insulating cavity 2. The first conductive component 1 and the second conductive component 3 are connected to both ends of the insulating cavity 2, and the connections between the first conductive component 1, the second conductive component 3, and the insulating cavity 2 are sealed. The insulating cavity 2 is a hollow structure supported by an insulator, used to contain the molten low-melting-point alloy, preventing leakage of the molten low-melting-point alloy and ensuring that the low-melting-point alloy can return to its original state after cooling.

[0030] The low-melting-point metal component 4 can be made of bismuth-tin alloy, which has a melting point of 138°C and melts more quickly when exposed to short-circuit current, resulting in higher reaction efficiency. Alternatively, the low-melting-point metal component 4 can be made of metals or alloys with low melting points, such as indium (melting point 156°C), which exhibit increased resistance after melting. When selecting the material for the low-melting-point metal component 4, the maximum allowable short-circuit temperature of copper conductors (250°C) and aluminum conductors (200°C) can be used as references to control the melting point of the low-melting-point metal component 4 to below 200°C.

[0031] like Figure 2 As shown, during operation, if a short-circuit current occurs in the downstream circuit of the transformer, the high temperature caused by the short-circuit current melts the low-melting-point metal component 4. At this time, the first conductive component 1 and the second conductive component 3 are electrically connected through the molten metal 10, and the resistance of the molten metal 10 increases, thus acting as an energy-dissipating, current-limiting, and arc-stabilizing protective element in the transformer circuit. After the molten metal 10 naturally cools and solidifies, it automatically returns to the low-melting-point metal component 4, effectively forming an electrical connection between the first conductive component 1 and the second conductive component 3.

[0032] As an optional implementation, an electromagnetic heating element 11 can be provided on the outside of the insulating cavity 2. This electromagnetic heating element 11 accelerates the melting rate of the low-melting-point metal component 4, thereby improving the response efficiency in the event of a short circuit. The electromagnetic heating element 11 can be an eddy current coil, which has the advantage of rapid heating, meeting the requirement for fast heating. The electromagnetic heating element 11 is equipped with a heating circuit, which includes a current monitoring element and a controller. The current monitoring element is electrically connected to the controller, and the controller is electrically connected to the electromagnetic heating element 11. The current monitored is greater than the short-circuit current I. maxAt this time, the controller starts the electromagnetic heating component 11. The controller is equipped with a timing module. When the electromagnetic heating component 11 is started, the timing module starts timing. When the timing module reaches time t, the controller turns off the electromagnetic heating component 11.

[0033] Therefore, the resistance of the low-melting-point metal component 4 is significantly lower than that after melting, which can greatly reduce the resistance of the transformer during normal operation and solve the problem of excessive energy waste during normal operation. Furthermore, the resistance formed after the low-melting-point metal component 4 melts can also act as an energy-dissipating, current-limiting, and arc-stabilizing protection element, ensuring circuit safety. If a short-circuit current occurs again after the molten metal 10 re-solidifies into the low-melting-point metal component 4, the low-melting-point metal component 4 will melt again, still ensuring the safety of the transformer and downstream circuits.

[0034] Both the first conductive component 1 and the second conductive component 3 can be copper contacts.

[0035] It should be noted that in order to ensure that the low-melting-point metal component 4, which connects the first conductive component 1 and the second conductive component 3, can still be formed after the molten metal cools, the insulating cavity 2 needs to be installed horizontally to avoid the low-melting-point metal component 4 not being connected to the first conductive component 1 and the second conductive component 3 after it is formed.

[0036] The controller can be a microcontroller or a PLC. The current monitoring element can be a current transformer (CT). The controller and the current monitoring element can be configured with separate power supplies, such as using a battery.

[0037] Example 2:

[0038] This second embodiment provides a fast switch for a transformer. Unlike the first embodiment, this second embodiment also includes a floating copper component 5.

[0039] like Figure 3 As shown, the floating copper component 5 is located between the first conductive component 1 and the second conductive component 3, and is embedded in the low-melting-point metal component 4. Copper has a higher conductivity than most metals and alloys. By setting the floating copper component 5, the resistance between the first conductive component 1 and the second conductive component 3 can be reduced, further reducing energy waste during normal operation of the transformer.

[0040] The floating copper component 5 adopts a hollow structure, so that the density of the floating copper component 5 is lower than the density of the low melting point metal component 4 after melting. After the low melting point metal component 4 melts, the floating copper component 5 floats up, reducing the contact area between the floating copper component 5 and the molten metal 10, thereby reducing the influence of the floating copper component 5 on the resistance value of the molten metal 10.

[0041] like Figure 4As shown, at the same time, because the floating copper component 5 floats up after the low melting point metal component 4 melts, the liquid level of the molten metal 10 drops after the floating copper component 5 floats up, and the cross-sectional area of ​​the molten metal 10 in the current direction becomes smaller, which further increases the resistance value between the first conductive component 1 and the second conductive component 3.

[0042] Therefore, setting up the floating copper component 5 can not only further reduce the resistance in the circuit under normal circuit conditions, but also reduce the cross-sectional area of ​​the liquid alloy in the current direction by floating, further increasing the resistance between the first conductive component 1 and the second conductive component 3, thus providing better protection for the circuit.

[0043] After the circuit returns to normal operation, a reset assembly is provided for the floating copper component 5 to facilitate its return to its original position. The reset assembly includes a high-temperature resistant magnet 6 disposed at the bottom of the floating copper component 5, a reset component 9 disposed at the bottom of the insulating cavity 2, a current monitoring element for detecting the current in the circuit containing the fast switch, and a controller for controlling the reset component 9 based on the signal from the current monitoring element. The reset component 9 may include an electromagnet. The attraction force generated by the electromagnet acts on the high-temperature resistant magnet 6 at the bottom of the floating copper component 5, causing the high-temperature resistant magnet 6 to move downwards, thus resetting the floating copper component 5.

[0044] It should be noted that if a metal with magnetic attraction is used to replace the floating copper component 5, for example, if an iron component is used to make the floating iron component, then the high-temperature resistant magnet 6 is not necessary. The melting temperature of the low-melting-point metal component 4 of the present invention is below 250°C, which will not cause the iron to lose its magnetic attraction. However, it is preferable to provide the high-temperature resistant magnet 6 to ensure stability.

[0045] High-temperature resistant magnets 6 can be made of AlNiCo, high-temperature NdFeB, etc.

[0046] A heat insulation layer 8 can be provided between the reset component 9 and the insulating shell. The reset component 9 is fixedly connected to the heat insulation layer 8, and the heat insulation layer 8 is fixedly connected to the insulating shell. The connection method can be welding or connection by fasteners such as bolts.

[0047] The reset component 9 is equipped with a controller and a current monitoring element. The current monitoring element is used to monitor the current in the downstream circuit of the transformer and is electrically connected to the controller. The controller is electrically connected to the reset component 9 and is used to control the start and stop of the reset component 9. When the reset component 9 is activated, the magnetic field generated by the reset component 9 attracts the high-temperature magnet 6, causing the floating copper component 5 to move downward to the bottom of the receiving chamber. After the molten metal 10 re-solidifies, the floating copper component 5 remains embedded in the low-melting-point metal component 4, ensuring that the floating copper component 5 is fully positioned in the circuit and minimizing the resistance between the first conductive component 1 and the second conductive component 3.

[0048] As an optional solution, the controller is equipped with a timing module. The timing module starts timing after the reset component 9 is activated, and the timing duration exceeds the time it takes for the molten metal 10 to naturally solidify into the low-melting-point metal component 4. When the timing module reaches the set duration, the controller shuts off the reset component 9. This setting method eliminates the need for the reset component 9 to remain continuously on, while ensuring that the floating copper component 5 is embedded in the low-melting-point alloy when the molten metal 10 solidifies into the low-melting-point metal component 4.

[0049] As an alternative, the timing module is replaced with a temperature sensor to detect the temperature outside the insulating cavity 2. Since the molten metal 10 is always inside the insulating cavity 2, there is heat exchange between the molten metal 10 and the insulating cavity 2. Therefore, the temperature sensor can determine whether the insulating cavity 2 contains molten metal 10 or the solidified low-melting-point metal component 4 based on its temperature. The solidification temperature of the molten metal 10, or a temperature below that temperature, is set as a threshold. The temperature sensor is electrically connected to the controller. When the temperature detected by the temperature sensor is lower than the set threshold, the controller shuts down the reset component 9, ensuring that the floating copper component 5 is embedded in the solidified low-melting-point metal component 4.

[0050] An insulating layer 7 can be provided at the bottom of the floating copper component 5. When the floating copper component 5 floats on the molten metal 10, the insulating layer 7 occupies a certain volume, which can further reduce the contact area between the floating copper component 5 and the molten metal 10, and reduce the influence of the floating copper component 5 on the resistance of the molten metal 10. Figure 6 As shown, as a further solution, the insulating layer 7 has a certain thickness, so that when the floating copper component 5 floats on the molten metal 10, the molten metal 10 only contacts the insulating layer 7, so that the copper component 5 is not energized after floating, avoiding current from passing through the copper component 5 with low resistance, thereby maximizing the resistance between the first conductive component 1 and the second conductive component 3.

[0051] The top width of the floating copper component 5 is smaller than its bottom width, resulting in a trapezoidal cross-sectional shape parallel to the vertical plane. Because the bottom width of the floating copper component 5 is greater, it will not detach from the low-melting-point metal component 4 after the molten metal 10 solidifies, ensuring the stability of the connection. Furthermore, the greater the bottom width of the floating copper component 5, the greater the depth to which it is immersed in the molten metal 10, resulting in a larger cross-sectional area of ​​copper in the current direction and thus a lower resistance between the first conductive component 1 and the second conductive component 3. Conversely, when the depth of the floating copper component 5 immersed in the molten metal 10 is smaller (because of the insulating layer 7 at the bottom), the smaller the cross-sectional area of ​​copper in the current direction, resulting in a higher resistance between the first conductive component 1 and the second conductive component 3.

[0052] Understandably, the floating copper component 5 can also be replaced with a low-resistance metal such as aluminum.

[0053] like Figure 5 As shown, a guide structure is also provided inside the insulating cavity 2 to constrain the movement direction of the floating copper component 5. The guide structure can be a protrusion on the side wall of the insulating cavity 2. The side of the floating copper component 5 has a vertical groove, and the protrusion engages in the groove, allowing the floating copper component 5 to move only in the vertical direction. The protrusion can be the end of a screw, and the side wall of the insulating cavity 2 has a threaded hole. During installation, the floating copper component 5 is installed with both ends connected to the low-melting-point metal component 4. The floating copper component 5 is inserted into the insulating cavity 2 from the end. When the groove of the floating copper component 5 corresponds to the threaded hole, the screw is screwed in, so that the end of the screw engages in the groove. After the screw is fixed, welding is performed to form a seal between the screw and the threaded hole. Finally, the first conductive component 1 and the second conductive component 3 are fixed to both ends of the insulating cavity 2, ensuring that the first conductive component 1 and the second conductive component 3 are electrically connected to the low-melting-point metal component 4. The guiding structure forms a mechanical fit between the floating copper component 5 and the insulating cavity 2, ensuring that the floating copper component 5 can only move up and down, and that the floating copper component 5 cannot approach the first conductive component 1 or the second conductive component 3.

[0054] As an optional technical solution, the outer side wall of the top of the insulating cavity 2 is also provided with an acceleration and lifting component 12, which is used to provide an upward force for the floating copper component 5, thereby accelerating the upward speed of the floating copper component 5.

[0055] The accelerating lifting component 12 can be an electromagnet. When energized, the electromagnet applies an upward magnetic force to the floating copper component 5, thus accelerating its upward movement. This increased upward movement allows for a faster increase in the resistance of the rapid switching mechanism. Furthermore, the accelerating lifting component 12 also prevents the floating copper component 5 from relying on the buoyancy of the molten metal, reducing the volume of the low-melting-point metal component 4. This results in less molten metal remaining after melting, and a higher resistance between the first conductive component 1 and the second conductive component 3.

[0056] The accelerating lifting component 12 can also be a permanent magnet. In this case, the magnetic force generated by the reset component 9 is greater than the sum of the magnetic force of the permanent magnet and the buoyancy of the floating copper component 5, ensuring that the reset component 9 can sink the floating copper component 5 when it is working.

[0057] As an optional implementation, a heat insulation layer 8 may also be provided between the accelerating lifting component 12 and the insulating cavity 2.

[0058] In one embodiment, when both the accelerating lifting component 12 and the resetting component 9 are provided, the guide structure may not be required. In this case, by placing both the accelerating lifting component 12 and the resetting component 9 at the center of the length of the insulating cavity, the floating copper component 5 can be kept in a centered position by using magnetic force applied to the high-temperature resistant magnet 6.

[0059] When the acceleration lifting component 12 and the reset component are provided, the electromagnetic heating component 11 is respectively provided at both ends of the insulating cavity 2, while the acceleration lifting component 12 and the reset component 9 are provided in the middle of the insulating cavity 2.

[0060] Example 3:

[0061] This embodiment three provides a transformer circuit, which is equipped with the fast switch described in embodiment one or embodiment two.

[0062] The quick-connect switch is located in the circuit at the transformer output terminal or inside the transformer. The circuit containing the quick-connect switch includes a current monitoring element and a controller. The current monitoring element monitors the current in the circuit, while the controller controls the electromagnetic heating component 11, the reset component 9, and the acceleration lifting component 12 based on the signal from the current monitoring element. Electrical appliances are also connected to this circuit.

[0063] This third embodiment also provides a control method for fast switching of a transformer. After setting a current monitoring element in the circuit where the fast switch is located, if the current monitored by the current monitoring element is greater than the short-circuit current I... max At this time, the reset component 9 does not work, while the acceleration and lifting component 12 can remain in operation. When the current in the circuit containing the fast switch exceeds the short-circuit current I... maxAt that time, the current monitoring element detected a current greater than the short-circuit current I. max If the accelerating lifting component 12 is an electromagnet, the current in the accelerating lifting component 12 can be increased, thereby increasing the magnetic force of the accelerating lifting component 12 and accelerating the upward speed of the floating copper component 5. Meanwhile, when the current monitoring element detects a current less than the short-circuit current I... max After a set time T, the reset component 9 is energized. At this time, the acceleration lifting component 12 can be de-energized or the current can be restored to the level where the short-circuit current I occurs. max Previously, the reset component 9 would continue to work for a period of time (T1) and then stop working.

[0064] It should be noted that the molten metal will not solidify within time T, but will solidify at the end of time T1. Time T and time T1 are determined based on the material and mass of the low-melting-point metal component 4.

[0065] As an optional solution, the electromagnetic heating component 11 and the accelerating lifting component 12 are energized simultaneously, with the energizing time of the electromagnetic heating component 11 being slightly shorter than that of the accelerating lifting component 12. That is, the accelerating lifting component 12 stops operating after a certain period of time following the cessation of operation of the electromagnetic heating component 11. During this period of cessation, the low-temperature metal component 4 has melted into molten metal 10, and the accelerating lifting component 12 has already completed the task of accelerating the floating copper component 5 to float. Therefore, by setting the time interval for stopping operation 12, while ensuring the formation of molten metal 10, it is possible to ensure that the accelerating lifting component 12 completes the task of accelerating the floating copper component 5 to float.

[0066] It should be noted that the molten metal will not solidify within time T, but will solidify at the end of time T1. Time T and time T1 are determined based on the material and mass of the low-melting-point metal component 4.

Claims

1. A fast switch for a transformer, characterized in that, It includes a first conductive component, a second conductive component, an insulating cavity, and a low-melting-point metal component. The first and second conductive components are respectively connected to the two sides of the insulating cavity. The low-melting-point metal component is located inside the insulating cavity. The connection between the first and second conductive components and the insulating cavity is sealed. The low-melting-point metal component melts into liquid metal under the action of short-circuit current. After the low-melting-point metal component melts into liquid metal, its resistance increases.

2. A fast switch for a transformer according to claim 1, characterized in that, Low-melting-point metal parts have a melting point below 200°C.

3. A fast switch for a transformer according to claim 2, characterized in that, Low-melting-point metal components are made of bismuth-tin alloys or indium.

4. A fast switch for a transformer according to claim 2, characterized in that, It also includes an electromagnetic heating element for auxiliary rapid heating of low-melting-point metal parts, thereby improving the response speed of rapid switching.

5. A fast switch for a transformer according to claim 2, characterized in that, The fast switch also includes a floating conductive component and a reset assembly. The density of the floating conductive component is lower than that of the molten metal, and the resistance of the floating conductive component is lower than that of the low-melting-point metal component. The reset assembly is used to reset the floating conductive component before the liquid alloy cools down.

6. A fast switch for a transformer according to claim 5, characterized in that, The floating conductive component has a hollow structure, which makes its density lower than that of the molten metal.

7. A fast switch for a transformer according to claim 6, characterized in that, The reset assembly includes a high-temperature resistant magnet, a reset component, a controller, and a current monitoring element. The high-temperature resistant magnet is located at the bottom of the floating conductive component, the reset component is located on the outer side of the bottom of the insulating cavity, and the current monitoring element is used to monitor the current in the circuit where the fast switch is located. The reset component and the current monitoring element are electrically connected to the controller.

8. A fast switch for a transformer according to claim 7, characterized in that, An insulating layer is provided at the bottom of the floating conductive component, and a guide structure is provided between the floating conductive component and the insulating cavity. The guide structure is used to constrain the floating conductive component, so that the floating conductive component only has the degree of freedom to move up and down.

9. A fast switch for a transformer according to claim 7, characterized in that, It also includes an acceleration lifting component and a reset component. The acceleration lifting component is located at the top of the insulating cavity and accelerates the floating speed of the floating conductive component through electromagnetic attraction.

10. A fast switching control method for a transformer, characterized in that, For controlling the fast switch as described in any one of claims 1-9, a current monitoring element is used to detect the current in the circuit where the fast switch is located, and the current is lower than a set short-circuit current I. max After a set time T, the reset circuit is activated, generating an electromagnetic force that attracts the floating conductive component. When the current exceeds the short-circuit current I... max Then, the circuit of the acceleration lifting component is turned on, generating an electromagnetic attraction that pulls on the floating conductive component. At the same time, the circuit of the electromagnetic heating component is turned on to begin auxiliary heating of the low-melting-point metal component, accelerating the liquefaction of the low-melting-point metal component. After the low-melting-point metal component melts, the floating conductive component will be raised to the upper limit more quickly by the combined action of buoyancy and lifting force, achieving a high-resistance state.

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