A nested excitation protection device for interrupting conductors and fuses

Abstract

A nested excitation protection device for interrupting a conductor and a fuse includes a housing, an excitation source, an impact device, a conductor, and a fuse connected in parallel with the conductor. A nested protection device is provided at the pre-break of the fuse below the pre-break of the conductor. The nested protection device at the pre-break of the fuse has a cavity for the broken conductor portion to fall into; the cavity matches the shape of the broken conductor portion. Driven by the impact device, the broken conductor portion pushes the nested protection device to break the fuse. The excitation protection device of the present invention, by providing the nested protection device, can prevent the arc from reigniting at the conductor break while improving arc extinguishing capability.

Description

Technical Field

[0001] The present invention relates to the fields of power control and electric vehicles, and in particular to an excitation protection device for disconnecting a control circuit when a fault occurs. Background Art

[0002] In addition to traditional thermal cutouts, electric vehicle battery pack protection devices now include a new type of protection structure that quickly disconnects the circuit. This protection structure, known as the excitation fuse, is gradually expanding its scope of application. Traditional fuses utilize the thermal accumulation effect of current to melt the current sensing point (narrow neck) of the fuse element over a certain period of time, extinguishing the arc. Excitation fuses, on the other hand, utilize mechanical force to disconnect the conductor within a short period of time, creating a physical break in the circuit.

[0003] The advantages of traditional fuses include their maturity and stability, high breaking capacity, and strong arc extinguishing capability. However, their disadvantages include poor current surge resistance, high heat generation, a long time required to disconnect the circuit at low fault currents, and an inability to provide rapid protection. After the fuse blows, it lacks complete physical isolation, primarily reflected in low insulation resistance values ​​(ranging from 0.1MΩ to 50MΩ). Furthermore, they are relatively heavy and bulky. The advantages of excitation fuses include rapid protection through a quick disconnection opening, excellent current surge resistance, low heat generation, and complete physical isolation after disconnection, with insulation resistance values ​​exceeding 550MΩ. However, their disadvantages are that they rely solely on disconnection openings for disconnection, resulting in a low breaking capacity and weak arc extinguishing capability (relying on air cooling or extrusion to extinguish the arc).

[0004] Taking into account the advantages and disadvantages of fuses and energized fuses, a solution has emerged to improve arc extinguishing and breaking capabilities by connecting a fuse in parallel to the conductor of the energized fuse. On this basis, a more optimal solution has emerged, namely, an energized fuse that sequentially interrupts the conductor and the fuse connected in parallel to the conductor. Under small fault current multiples, this solution mainly uses the interruption of the conductor to open the circuit, and the fuse does not melt, but is simply cut off. Under medium fault current multiples, the conductor is interrupted first, and the current is transferred to the fuse, which begins to melt. During the melting process, the fuse is cut off and the arc extinguishing and breaking capabilities are accelerated. Under large fault current multiples, the conductor is interrupted first, and the current is transferred to the fuse, which quickly and completely melts. Finally, the fuse is interrupted in the absence of current, achieving complete physical isolation.

[0005] The current problems with this excitation fuse are:

[0006] 1. The conductor is exposed to the air before and after disconnection. When the conductor is interrupted under large fault current, if the fuse melts too quickly, arc re-ignition is likely to occur at the conductor break.

[0007] 2. After disconnection, the conductor break lacks protection and is easily contaminated by leaked gunpowder gas or materials burned by the arc, resulting in a decrease in insulation performance.

[0008] 3. The conductor fracture lacks sealing and relies entirely on the air medium to establish insulation. The insulation is greatly affected by the outside world. In high temperature, high humidity, and high altitude areas, it may lead to inability to effectively cooperate with the arc extinguishing melt, resulting in breaking failure. Summary of the Invention

[0009] In order to solve the above technical problems, the present invention provides a nested excitation protection device for interrupting conductors and fuses, which effectively seals and protects the pre-break of the conductor. After the conductor is interrupted, the current flows through the parallel fuse instead. At this time, the nested protection structure on the conductor quickly and effectively seals and protects the conductor break and quickly establishes insulation. Since the conductor break is quickly insulated, a smaller arc-extinguishing fuse can be used and allows for faster melting without the occurrence of excessive overvoltage causing arc reignition at the conductor break. At the same time, the interrupted part of the fuse can also be protected to further enhance the breaking capacity of the fuse.

[0010] In order to solve the above technical problems, the technical solution provided by the present invention is a nested excitation protection device for interrupting conductors and fuses, including a shell, an excitation source, an impact device, a conductor, and a fuse connected in parallel with the conductor, characterized in that a nested protection device is provided at the pre-break of the melt below the pre-break of the conductor, and the nested protection device at the pre-break of the melt is provided with a receiving cavity for the broken part of the conductor to fall into; the receiving cavity matches the shape of the broken part of the conductor; under the drive of the impact device, the broken part of the conductor can push the nested protection device to disconnect the melt.

[0011] Preferably, the nested protection device at the pre-fracture end of the melt comprises two nested protection blocks arranged opposite to each other, and the nested protection blocks are respectively arranged at the pre-fracture end of the melt at intervals; the accommodating cavity is formed between the two nested protection blocks.

[0012] Preferably, an auxiliary arc extinguishing groove is provided at the bottom of the housing below each nested protection block; and the lower end of the nested protection block is located at the opening of the auxiliary arc extinguishing groove.

[0013] Preferably, a ridge is provided at the bottom of the shell, and an auxiliary arc extinguishing structure is mounted on the ridge; the auxiliary arc extinguishing structures located on both sides of the ridge and the side wall of the chamber where the auxiliary arc extinguishing structure is located form the auxiliary arc extinguishing groove.

[0014] Preferably, the nested protection device at the pre-break of the melt comprises two nested protection blocks relatively nested at the upper and lower sides of the pre-break of the melt; the accommodating cavity is provided on the nested protection block close to the conductor side.

[0015] Preferably, at least one arc extinguishing chamber is provided on the nested protection device at the pre-break of the melt, the arc extinguishing chamber is filled with an arc extinguishing medium, and the melt passes through the arc extinguishing chamber.

[0016] Preferably, at least one arc extinguishing chamber is arranged at intervals on the nested protection device on the melt; a vertical groove with an opening facing away from the conductor is provided between the arc extinguishing chambers, or on one side, or on both sides, and a melt nested cutting block is provided in the vertical groove, and a movement gap is retained between the top of the melt nested cutting block and the top of the vertical groove, and the lower end thereof extends out of the nested protection device at the melt pre-break; the melt is located at the top end face of the melt nested cutting block, and disconnection weak points are respectively provided on the melt on both sides of the top end face of the melt nested cutting block.

[0017] Preferably, a nested protection device covering the conductor pre-break is provided at the conductor pre-break.

[0018] Preferably, the nested protection device at the conductor pre-break includes nested protection blocks relatively nested on the upper and lower sides of the conductor pre-break.

[0019] Preferably, the shell includes an upper shell, a lower shell and a bottom cover, the conductor is located between the upper shell and the lower shell, and the bottom cover closes the lower shell; the lower shell on both sides of the nested protection device located at the melt pre-break is respectively provided with a melt arc extinguishing chamber for the melt to pass through, and the melt arc extinguishing chamber is filled with an arc extinguishing medium.

[0020] Preferably, the side wall of the melt arc extinguishing chamber through which the melt passes is provided with an inclined structure; a disconnection weak point is provided on the melt in the arc extinguishing material close to the side of the inclined structure, and when the nested protection device on the melt is pushed downward, the melt is pulled apart at the disconnection weak point.

[0021] Preferably, a through-hole slot for the melt to pass through is provided on the shell wall between the melt arc extinguishing chamber and the conductor, and both ends of the melt are connected in parallel with the conductor after passing through the through-hole slot respectively.

[0022] Preferably, a buffer device is provided on the bottom cover for buffering after the melt is cut off.

[0023] Preferably, the nested protection device and the auxiliary arc extinguishing structure are made of a material that can generate arc extinguishing gas when heated.

[0024] The nested excitation protection device for interrupting conductors and fuses of the present invention, after interrupting the conductor, quickly uses the nested protection device at the conductor to protect the conductor break and establish insulation, thereby preventing the arc from reigniting at the conductor break; the current can only flow through the parallel fuse, and the conductor disconnection part is driven by the impact device to continue to disconnect the fuse, forming at least one mechanical break on the fuse, and the arc extinguishing medium is assisted by the nested protection device at the fuse to further extinguish the arc, thereby improving the breaking capacity and arc extinguishing capacity.

[0025] The nested structure of the conductor and fuse of the present invention allows for the use of smaller-sized fuses in parallel. After the conductor is disconnected, the fuse quickly melts in the arc-extinguishing medium and is mechanically disconnected, forming multiple fractures in the fuse. These multiple fractures, combined with the nested protective device and arc-extinguishing medium at the fuse, extinguish the arc. Overvoltage does not cause arc reignition at the conductor fracture. When using a smaller-sized fuse, its cross-sectional area is smaller, the step current is lower, and the arc-extinguishing pressure required by the fuse-cutting structure is reduced. This makes it easier for the product to achieve normal disconnection, improves arc extinguishing capability, provides rapid protection, and provides excellent insulation performance after disconnection. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a structural diagram of the normal working state of Example 1.

[0027] Figure 2 This is a structural diagram of Example 1 in which a protective device is nested on a conductor to begin establishing insulation after the conductor is interrupted.

[0028] Figure 3 This is a structural schematic diagram of the nested protection device where the conductor disconnected portion and the nested protection device covering the conductor enter the melt in Example 1.

[0029] Figure 4 This is a schematic diagram of the structure in which the conductor and the fuse are both disconnected in Example 1.

[0030] Figure 5 This is a structural diagram of the normal working state of Example 2.

[0031] Figure 6 This is a schematic structural diagram of Example 2 where a protective device is nested on a conductor to begin establishing insulation after the conductor is interrupted.

[0032] Figure 7 This is a structural diagram of the nested protection device where the conductor disconnected portion and the nested protection device covering the conductor enter the melt in Example 2.

[0033] Figure 8 This is a schematic diagram of the structure in which the conductor and the fuse are both disconnected in Example 2.

[0034] Figure 9This is a schematic structural diagram of the location of the primary fracture when the melt is first disconnected in Example 2.

[0035] Figure 10 This is a schematic structural diagram of the location of the secondary fracture when the melt is disconnected for the second time in Example 2. DETAILED DESCRIPTION

[0036] The present invention discloses a nested excitation protection device for interrupting a conductor and a fuse. The device primarily comprises an excitation source, an impact device, a housing, a conductor, and a fuse connected in parallel with the conductor. The nested protection device may be provided on either the conductor or the fuse, or only on the fuse. When there is no parallel fuse and no insulating sheath on the conductor, a nested protection device may be provided in the housing below the conductor. The impact device drives the disconnected portion of the conductor into the nested protection device. The impact device and the nested protection device form an interference fit, completing the insulation seal of the conductor break, thereby interrupting the fault current. When a fuse is connected in parallel and the nested protection device is provided on the fuse, but no insulating sheath is provided on the conductor, the nested protection device on the fuse is located ahead of the disconnected portion of the conductor. The disconnected portion of the conductor and the impact device enter the nested protection device on the fuse together, forming an insulation seal around the conductor break. At this point, the fault current can only flow through the parallel fuse, and the parallel fuse begins to complete the melting and arc extinguishing process. The impact device then continues to drive the nested protection device on the fuse to disconnect the fuse, further enhancing the post-break insulation capability. When nested protection devices are installed on both the conductor and the fuse, the impact device drives the disconnected portion of the conductor with the nested protection device into the nested protection device on the fuse, forming a reliable double-layer seal and establishing insulation. Now, the fault current can only flow through the parallel fuse, which begins to complete the melting and arc extinguishing process. The impact device then continues to drive the nested protection device on the fuse to disconnect the fuse, achieving sequential disconnection of the conductor and fuse, further enhancing post-break insulation.

[0037] The housing can be constructed with an upper and lower housing structure, a left and right housing structure, or other structures. The conductor and the housing are in sealed contact to prevent arcs from flying out of the contact surface during disconnection and damaging external devices, and to prevent external dust and water from entering the housing. The housing is made of insulating material.

[0038] The excitation source is fixed to the housing. This excitation source is a gas generator that generates high-pressure gas upon receiving a specified electrical signal, driving the impact mechanism to displace and sever the conductor. To ensure smooth movement of the impact mechanism, the conductor severance section, and other components within the housing, a cavity is provided within the housing to accommodate these components, the conductor severance section, and the nested protection device.

[0039] A pre-break is provided on the conductor or melt. A nested protection device can be installed at the pre-break of the conductor or melt. The pre-break is the point where the conductor or melt is severed by the impact of the impact device. A weak point is provided on either side of the pre-break. The weak point can be in the form of a V-shaped groove, a U-shaped groove, a reduced cross-section, or a pre-rolled notch, among other structures that reduce strength.

[0040] The melt is bent into a geometric shape for convenient placement within the housing chamber. The melt and impact device are located on either side of the conductor, with the conductor and then the melt positioned in sequence ahead of the impact device. The ends of the melt are electrically connected to the conductor in parallel. This connection can be achieved through bolt crimping, conductive spring connections, welding, or other methods. A narrow neck is also provided on the melt, serving as a pre-melting point. The melt can be mechanically disconnected by the impact device or thermally melted.

[0041] The cavity where the melt neck is located is filled with an arc-extinguishing medium to assist in arc extinguishing. An auxiliary arc-extinguishing structure is provided at the bottom of the housing. The bottom of the housing is sealed by a housing bottom cover.

[0042] The impact device is located between the excitation source and the conductor. The impact device is in sealed contact with the inner chamber of the shell, which realizes the complete separation of the upper and lower chambers of the impact device, can avoid the influence of high-pressure gas on the insulation capacity at the fracture and prevent the fault current from being introduced into the drive circuit. At the same time, the high-pressure gas is independently enclosed between the impact device and the excitation source, which can prevent the impact device from rebounding after moving into place. In order to maintain smooth linear displacement of the impact device, a limiting slide is provided on the chamber where the impact device is located, and the impact device is arranged on opposite sides in the limiting slide to prevent the impact device from rotating in the shell, ensuring that the impact end of the impact device disconnects the pre-fracture of the conductor or melt. The initial position of the impact device is defined by a limiting structure. The material of the impact device is insulating material.

[0043] Several preferred embodiments are given below and described in detail with reference to the drawings.

[0044] Example 1

[0045] See Figure 1 The housing comprises an upper housing 204 and a lower housing 212 which are sealed and connected to each other. The lower housing 212 is sealed by a bottom cover 214. The housing is made of an insulating material. The upper housing and the lower housing are formed by injection molding, and can also be formed by other molding methods. A cavity is provided in the upper housing and the lower housing, which passes through the upper and lower ends of the upper and lower housings. The conductor 207 is provided between the upper housing and the lower housing, with its two ends located outside the housing and can be connected to an external circuit. The conductor 207 located in the housing passes through the cavity provided in the upper housing and the lower housing.

[0046] In the cavity of the upper shell on one side of the conductor 207, an impact device 203 and an excitation source 201 are arranged in sequence. In this embodiment, the excitation source is an electronic ignition device. The impact device is located between the excitation source and the conductor. The upper end portion in the cavity of the upper shell is set as a step hole structure, and the excitation source is installed at the step hole, and the position is limited by the step hole. A protective cover 202 is pressed on the outer periphery of the upper shell, and the protective cover is pressed on the step on the excitation source. The excitation source is positioned by the protective cover 202 and the limiting step in the cavity of the upper shell. The excitation source can be connected to an external control system, and triggers an action after receiving an excitation electrical signal from the outside, releasing high-pressure gas as the driving force for driving the impact device.

[0047] The impact device 203, in this embodiment, is a piston structure made of an insulating material and formed by injection molding, but can also be formed by other molding methods. The end surface of the impact device 203 near the conductor 207 is configured as an impact end, which cuts the conductor and forms a fracture in the conductor. The upper end surface of the impact device is configured as an arc-shaped concave structure 203a. The purpose of this arc-shaped concave structure is to concentrate the high-pressure gas released by the excitation source and directly act on the upper end surface of the impact device, thereby obtaining maximum driving force. It also reduces the weight of the impact device and saves materials. Several limiting protrusions 203a are spaced apart on the outer circumference of the impact device, and corresponding limiting grooves are provided in the cavity wall of the upper shell. The limiting protrusions 203a are provided in the limiting grooves on the cavity wall to define the initial position of the impact device. The limiting protrusions 203a are shaped as pointed structures inclined diagonally upward. Their purpose is to allow the limiting protrusions 203a to quickly disengage from the limiting grooves when impacted, thereby releasing their restraint on the impact device. When the excitation protection device is in normal operation, i.e., in its initial position, it is necessary to ensure that the impact device does not impact the conductor and affect its normal operation. Therefore, the initial position of the impact device must be limited. However, the limiting protrusion 203a must be able to break when the impact device is impacted by the driving force released by the excitation source, releasing the restraint on the impact device to ensure the impact device can move. The impact device 203 must be in sealed contact with the cavity in which it is located. Therefore, an annular structure is provided on the outer circumference of the impact device, and a sealing ring 203b is disposed within this annular structure. This ensures that the impact device and the cavity in which it is located are in sealed contact at all times during the impact device's movement. To ensure that the impact device maintains sealed contact with the cavity in which it is located during its movement, the sealing ring 203b is preferably located on the upper outer circumference of the impact device. In this embodiment, the impact device 203 is shaped like a T-shaped structure, with its upper end portion in complete sealed contact with the cavity in which it is located, while the cylindrical portion of the T-shaped structure can partially maintain non-contact with the cavity in which it is located, thereby reducing frictional resistance during the movement of the impact device. In order to ensure that the impact device makes linear displacement in the cavity, a limiting groove (not shown) is provided on the cavity walls on both sides of the opposite sides, and a slider is provided at the corresponding position of the impact device. The slider on the impact device is clamped in the limiting groove to ensure the linear displacement of the impact device and prevent rotation in the cavity. At the same time, in order to prevent incorrect installation, the depth or width of the limiting groove and slider on one side can be made different from that on the other side. In order to ensure the linear displacement of the impact device, vertical ridges can also be provided on the cavity walls, and a limiting groove can be provided at one position of the impact device to achieve linear displacement limitation. The end face of the impact end of the impact device is a flat structure.

[0048] The conductor 207 is a long strip-shaped plate-like structure made of copper, silver or other conductive metal materials with good electrical conductivity. It can be a straight flat plate structure or a cross-shaped flat plate structure. Two disconnection weak points 207a are spaced apart on the conductor 207 located in the upper and lower shell cavities. The conductor part between the two disconnection weak points forms a pre-break 208, and the impact end of the impact device 203 is directly opposite the pre-break 208 of the conductor. When the pre-break 208 of the conductor is impacted by the impact device, the conductor part at the pre-break of the conductor is completely separated from the conductor 207 under the impact of the impact device to form a conductor disconnection part, and a fracture is formed between the two disconnection weak points of the conductor. In this embodiment, each disconnection weak point 207 is composed of a V-shaped groove correspondingly opened on the upper and lower surfaces of the conductor 207. A nested protection device is provided on the conductor pre-break 208. The conductor nested protection device includes a conductor nested protection block 205 and a conductor nested protection block 206 arranged opposite to each other on the upper and lower surfaces of the conductor pre-break 208. The upper and lower conductor nested protection blocks 205 and 206 are nested relative to each other, enclosing the pre-broken portion of the conductor. The ends of the upper and lower conductor nested protection blocks 205 and 206 are located at the thinnest locations of the conductor's broken edge. Both the upper and lower conductor nested protection blocks 205 and 206 are made of insulating material and conform to the conductor. This structural design ensures that no excess air is trapped between the nested protection device and the pre-broken portion of the conductor. After the pre-broken portion is broken, the nested protection device covers the broken portion of the conductor to the greatest extent possible.

[0049] The lower shell 212 is an integrally formed structure, formed by injection molding or other molding methods. A cavity 212a is provided on the lower shell below the pre-break of the conductor 207. The cavity 212a passes through the upper and lower end surfaces of the lower shell. Cavities 215 are provided on opposite sides of the cavity 212a. The upper end of the cavity 215, which contacts the upper shell and the conductor, is a sealed structure, and the lower end is open. Cavity 212a is a stepped cavity structure, and the width of the cavity above the step is greater than the width of the cavity below the step. The width of the cavity near the conductor is consistent with the width of the nested protective device on the conductor, ensuring that the disconnected portion of the conductor with the nested protective device can enter the cavity below it, and the two ends of the disconnected portion of the conductor are in contact with the cavity wall, which can stretch and squeeze the arc. A symmetrical accommodating groove with an open lower end (not shown) is provided on opposite sides of the cavity below the step to accommodate the nested protective device at the pre-break of the melt. A through-hole groove is provided at the sealed upper end of the cavity 215 for the melt 211 to pass through.

[0050] The melt 211 is made of a conductive material and is a fusible sheet structure. Two groups of disconnection weaknesses are arranged at intervals on the melt, and each group of disconnection weaknesses includes two disconnection weaknesses arranged at intervals, and each group of disconnection weaknesses constitutes a pre-fracture of the melt. A nested protection device is respectively provided at the pre-fracture of each melt. The nested protection device at the melt includes a left nested protection block 209 and a right nested protection block 210, which are respectively assembled in two accommodating grooves below the step of the cavity 212a in the lower shell by interference fit. After assembly, the left nested protection block 209 and the right nested protection block 210 are symmetrically arranged on opposite sides of the cavity 212a, respectively located below the conductor disconnection weakness. The lower ends of the left nested protection block 209 and the right nested protection block 210 extend in a stepped manner toward the center of the cavity 212a, so that their shape is an L-shaped structure. The upper parts of the two symmetrically arranged left nested protection blocks 209 and right nested protection blocks 210 are flush with the inner wall of the cavity 212a in which they are located, and the upper sides form a limiting step-like structure corresponding to the nested protection device at the conductor pre-break and the conductor disconnection part.

[0051] The melt is located at the lower end of the lower shell. It passes through cavity 212a, the left nested protective block 209, the right nested protective block 210, and the open end of cavity 215 located at the lower end of the lower shell. The melt then bends at both ends and enters cavity 215. It then exits through the through-hole slots in cavity 215 and connects in parallel with the conductor located between the upper and lower shells. This connection can be achieved through bolting, welding, or other conductive methods. Once connected in parallel, the melt assumes a spatial geometric structure.

[0052] A bottom cover 214 is installed at the lower end of the lower shell. The contact between bottom cover 214 and the outer surface of the lower shell is assembled using a stepped sleeve to seal the lower shell. Bottom cover 214 also increases the volume of cavities 212a and 215 located below the pre-fractured end of conductor 207; cavities 212a and 215 are not connected. After the bottom cover seals the lower shell, the melt flows through cavities 212a and 215. A ridge is provided on the inner end surface of the bottom cover at the bottom of cavity 212a, with retaining grooves extending into the inner end surface of the bottom cover on either side of the ridge. An auxiliary arc-extinguishing structure 213 is pressed onto the ridge. The bottom of the auxiliary arc-extinguishing structure 213 is interference-fitted into the retaining groove on the inner end surface of the bottom cover, forming an auxiliary arc-extinguishing groove. The bottom of the auxiliary arc-extinguishing structure 213 provides a buffering effect. The auxiliary arc-extinguishing structure 213 is in the shape of a cross, with the auxiliary arc-extinguishing grooves on either side located at the bottom of cavity 212a on either side of the ridge. The lower ends of the left and right nested protective blocks 209 and 210 are located in the auxiliary arc-extinguishing grooves on either side of the auxiliary arc-extinguishing structure. One side of the lower end of each of the left and right nested protective blocks 209 and 210 partially contacts the side of the auxiliary arc-extinguishing structure, while the remaining side surfaces contact the inner wall of cavity 212a. Cavity 215 is filled with arc-extinguishing medium, and the weakest point of the melt is located in cavity 215. This weak point is typically a narrow neck or other structure that increases resistance.

[0053] The working process of this embodiment: Figures 2 to 4 After receiving the excitation electrical signal from the outside, the excitation source 201 is activated, releasing high-pressure gas, driving the impact device 203 to do linear displacement, and the impact end of the impact device 203 impacts the pre-break portion of the conductor 207 covered with the nested protection device, causing the conductor to break from the pre-break portion to form a conductor disconnection portion, such as Figure 2 After the disconnected conductor moves downward a distance of 2 to 3 mm, the nested protection device on the conductor begins to form a first layer of sealing structure, establishing insulation between the conductor fractures. The impact device continues to drive the disconnected conductor portion, covered with the nested protection device, into the cavity 212a of the lower shell, between the left nested protection block 209 and the right nested protection block 210. The disconnected conductor portion is completely covered by the conductor nested protection device and the melt nested protection device, and is completely insulated from the surrounding environment through the combined action. The impact device then continues to drive the disconnected conductor portion and the nested protection device covering it downward, causing the left nested protection block 209 and the right nested protection block 210 to enter the cavities on both sides of the auxiliary arc extinguishing structure, breaking the pre-break of the melt and forming two fractures in the melt. The impact device drives the left nested protection block 209 and the right nested protection block 210 to continue to move with the disconnected conductor portion in the cavities on both sides of the auxiliary arc extinguishing structure, further extinguishing the arc, until the nested protection device covering the disconnected conductor portion abuts the upper end face of the auxiliary arc extinguishing structure above the ridge, and the displacement stops.

[0054] Arc extinguishing principle: When the conductor pre-break is interrupted, the broken part of the conductor with the nested protection device falls into the middle of the nested protection device at the fuse under the drive of the impact device. Due to the combined action of the nested protection device covering the broken part of the conductor and the nested protection device at the fuse, the broken part of the conductor is quickly disconnected from the main circuit and insulation is established, making it difficult for the arc to form and reignite here. At this time, the fault current can only flow through the parallel fuse, and a smaller-sized fuse can be used for faster melting. The overvoltage generated during melting will not cause breakdown and arc reignition between the conductor breaks in the main circuit. The impact device then continues to push the nested protection device at the fuse to displace and disconnect the fuse. The residual arcs at the two breaks formed on the fuse are extinguished under the joint extrusion of the nested protection device at the fuse and the auxiliary arc extinguishing structure.

[0055] Example 2

[0056] The main difference between this embodiment and embodiment 1 is that the structure of the nested protection device at the melt is changed, and the inclination of the contact surface between the lower shell and the upper shell is changed. In embodiment 1, the nested protection device at the melt is set symmetrically on the left and right. In this embodiment 2, the nested protection device at the melt is set up and down. Figure 5 . The nested protection device at the melt includes an upper nested protection block 309 and a lower nested protection block 310 which are relatively nested and located on the upper and lower surfaces of the melt; the melt portion located in the cavity 312a is covered by the upper nested protection block 309 and the lower nested protection block 310. The upper nested protection block 309 is located at the step in the cavity 312a, and has a groove 309a thereon, the inner wall shape of which is consistent with the inner wall shape of the cavity 312a. A vertical groove 309b is provided in the center portion below the upper nested protection block 309, and two small grooves are provided on opposite sides of the vertical groove. The lower nested protection block 310 is a cover-like structure, on which two grooves corresponding to the small grooves on both sides of the vertical groove are provided, and a through-hole groove penetrating the upper and lower end surfaces of the lower nested protection block 310 is provided at the position corresponding to the vertical groove 309b. The upper nested protection block 309 and the lower nested protection block 310 are relatively nested. The vertical grooves 309b and the through-hole grooves of the upper nested protection block and the lower nested protection block form a vertical groove 309b with a deeper depth and the lower end passing through the lower end surface of the lower nested protection block; after the grooves on both sides of the vertical groove 309b are connected, two sealed accommodating cavities 316 are formed on the nested protection device at the melt, and the melt passes through the accommodating cavity 316.

[0057] The lower end surface of the cavity wall 312 a where the melt 311 passes is configured as an inclined surface. Accordingly, the contact point between the bottom cover 314 and the lower end surface of the cavity wall 312 a is also configured as an inclined surface.

[0058] Melt 311 is located at the lower end of the lower shell. It passes through cavity 312a, cavity 315, the inclined surface of the adjacent cavity wall between cavity 312a and cavity 315, the contact surface between the upper and lower nested melt protection blocks 309 and 310, the vertical groove 309b formed by the upper and lower nested melt protection blocks 309 and 310, and the accommodating cavities 316 on either side of the vertical groove. The melt then bends at both ends and enters cavity 315. It then exits through the through-hole slot in cavity 315 and connects in parallel with the conductor located between the upper and lower shells. This connection can be achieved through bolting, welding, or other conductive methods. Once connected in parallel, the melt takes on a spatial geometric structure.

[0059] The bottom cover 314 has grooves corresponding to the cavities 312a and 315 in the lower shell. A snap-fit ​​step is provided on the side end surface of the bottom cover 314. When the bottom cover 314 is positioned at the lower end surface of the lower shell, the snap-fit ​​step on the upper side end surface of the bottom cover 314 intersects with the snap-fit ​​step on the lower shell, sealing the lower shell. Simultaneously, the grooves on the bottom cover seal and lengthen the cavities 312a and 315 in the lower shell. The bottom cover 314 secures the melt 311 between the adjacent inclined surfaces of the cavity walls of the lower shell cavities 312a and 315, facilitating its severance. The melt is bent on one side of the inclined surface of the cavity 315, facilitating the nested protective device in the melt to sever the melt within cavity 312a. A buffer device 313 is provided at the bottom of cavity 312a on the bottom cover 314. In this embodiment, the buffer device is a cushion. Arc extinguishing medium is filled in the accommodating cavity 316 between the upper nested protection block 309 and the lower nested protection block 310 and in the cavity 315. The weak point where the melt is melted is located in the accommodating cavity 316 and / or the cavity 315.

[0060] A nested melt-cutting block 317 is interference-fitted into the vertical groove, with clearance between the upper end of the nested melt-cutting block 317 and the top of the vertical groove. The melt is located at the upper end of the nested melt-cutting block 317. Weak points of disconnection are provided on the melt on both sides of the nested melt-cutting block 317 within the vertical groove.

[0061] The working process of this embodiment 2: see Figures 6 to 8 When the conductor pre-break is broken by the impact device, the broken part of the conductor covered with the nested protection device falls into the groove of the upper nested protection block 309 under the push of the impact device. Under the joint action of the nested protection device covering the broken part of the conductor and the upper nested protection block, the broken part of the conductor is disconnected from the main circuit and moves downward for 2 to 3 mm before quickly establishing insulation. It is difficult for the arc to re-ignite here. The impact device continues to push the upper nested protection block downward and pull the melt. Figure 9The 401 shown is pulled apart, forming a primary cut-off opening of the melt. The primary cut-off opening is located in the cavity 315 and is surrounded by the arc extinguishing medium, which helps extinguish the arc. Afterwards, the impact device drives the conductor disconnection portion and the nested protection device, upper nested protection block, lower nested protection block and nested melt cut-off block 317 covering it to continue to move downward. The nested melt cut-off block 317 stops moving after colliding with the buffer pad 313, pulling apart the melt located in the vertical groove and Figure 10 A secondary melt cutoff is formed at 402 to help improve insulation performance after cutting.

[0062] When the fault current is large, after the conductor is disconnected, a breaking fracture and a melting fracture can be formed on the fuse. The melting fracture of the fuse is formed in a chamber filled with arc extinguishing medium, further improving the arc extinguishing ability.

[0063] The arc extinguishing principle is the same as that of embodiment 1.

[0064] Example 3

[0065] Based on the above-mentioned Examples 1 and 2, the nested protective device on the conductor can be removed. Since the impact device uses insulating material, the impact end face of the impact device covers the pre-break of the conductor when impacting the conductor and drives it into the nested protective device at the pre-break of the melt, which can also achieve insulation and prevent the arc from reigniting.

[0066] The arc extinguishing principle is the same as that of embodiment 1.

[0067] In the above embodiments, a sealing design is adopted between the upper shell, the lower shell and the bottom cover, which can prevent foreign objects from contaminating the fracture and also prevent high-temperature arc from spraying out of the shell and damaging surrounding devices.

[0068] The nested protection device and auxiliary arc-extinguishing structure can be made of materials that generate arc-extinguishing gas when heated, such as rubber, nylon, or other materials that generate gas when heated. During the disconnection process, the nested protection device and auxiliary arc-extinguishing structure generate gas when heated, increasing the gas pressure at the fracture point and compressing the arc, making it easier to extinguish the arc.

Claims

1. A nested excitation protection device for interrupting a conductor and a melt, comprising a housing, an excitation source, an impact device, a conductor, and a melt connected in parallel with the conductor, characterized in that: A nesting protection device is provided at the pre-break end of the fuse below the pre-break end of the conductor, and a receiving cavity is provided on the nesting protection device at the pre-break end of the fuse for the broken part of the conductor to fall into; The shape of the accommodating cavity matches that of the conductor disconnecting portion; when driven by the impact device, the conductor disconnecting portion can push the nested protection device to disconnect the melt.

2. The nested excitation protection device for interrupting conductors and fuses according to claim 1, characterized in that: The nested protection device at the pre-fracture end of the melt comprises two nested protection blocks arranged opposite to each other. The nested protection blocks are respectively arranged at intervals at the pre-fracture end of the melt; the accommodating cavity is formed between the two nested protection blocks.

3. The nested excitation protection device for interrupting conductors and fuses according to claim 2, characterized in that: An auxiliary arc extinguishing groove is provided at the bottom of the shell below each nested protection block; the lower end of the nested protection block is located at the opening of the auxiliary arc extinguishing groove.

4. The nested excitation protection device for interrupting conductors and fuses according to claim 3, characterized in that: A ridge is provided at the bottom of the shell, and an auxiliary arc extinguishing structure is set on the ridge; the auxiliary arc extinguishing structures located on both sides of the ridge and the side wall of the chamber where the auxiliary arc extinguishing structure is located form the auxiliary arc extinguishing groove.

5. The nested excitation protection device for interrupting conductors and fuses according to claim 1, characterized in that: The nested protection device at the pre-break of the melt comprises two nested protection blocks relatively nested at the upper and lower sides of the pre-break of the melt; the accommodating cavity is provided on the nested protection block close to the conductor side.

6. The nested excitation protection device for interrupting conductors and fuses according to claim 5, characterized in that: At least one arc extinguishing chamber is provided on the nested protection device at the pre-break of the melt. The arc extinguishing chamber is filled with an arc extinguishing medium, and the melt passes through the arc extinguishing chamber.

7. The nested excitation protection device for interrupting conductors and fuses according to claim 6, characterized in that: At least one arc extinguishing chamber is arranged at intervals on the nested protection device on the melt; a vertical groove with an opening facing away from the conductor is provided between, on one side, or on both sides of the arc extinguishing chamber, and a melt nested cutting block is provided in the vertical groove, a movement gap is retained between the top of the melt nested cutting block and the top of the vertical groove, and the lower end thereof extends out of the nested protection device at the melt pre-fracture; The melt is located at the top end surface of the melt nesting cutting block, and the melt on both sides of the top end surface of the melt nesting cutting block is respectively provided with a breaking weak point.

8. The nested excitation protection device for interrupting conductors and fuses according to any one of claims 1 to 7, characterized in that: A nested protection device covering the conductor pre-broken end is provided at the conductor pre-broken end.

9. The nested excitation protection device for interrupting conductors and fuses according to claim 8, characterized in that: The nested protection device at the conductor pre-break includes nested protection blocks relatively nested and arranged on the upper and lower sides of the conductor pre-break.

10. The nested excitation protection device for interrupting conductors and fuses according to any one of claims 1 to 7 and 9, characterized in that: The shell includes an upper shell, a lower shell and a bottom cover, the conductor is located between the upper shell and the lower shell, and the bottom cover closes the lower shell; the lower shell on both sides of the nested protection device located at the melt pre-break are respectively provided with melt arc extinguishing chambers for the melt to pass through, and the melt arc extinguishing chambers are filled with arc extinguishing medium.

11. The nested excitation protection device for interrupting conductors and fuses according to claim 10, characterized in that: The side wall of the melt arc extinguishing chamber through which the melt passes is provided with an inclined structure; a disconnection weak point is provided on the melt in the arc extinguishing material close to the side of the inclined structure, and when the nested protection device on the melt is pushed downward, the melt is pulled apart at the disconnection weak point.

12. The nested excitation protection device for interrupting conductors and fuses according to claim 10, characterized in that: A through-hole slot for the melt to pass through is provided on the shell wall between the melt arc extinguishing chamber and the conductor. Both ends of the melt pass through the through-hole slots respectively and are connected in parallel with the conductor.

13. The nested excitation protection device for interrupting conductors and fuses according to claim 10, characterized in that: A buffer device is provided on the bottom cover for buffering after the melt is cut off.

14. The nested excitation protection device for interrupting conductors and fuses according to any one of claims 1 to 7, 9, 11 to 13, characterized in that: The nested protection device and the auxiliary arc extinguishing structure are made of materials that can generate arc extinguishing gas when heated.

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