Self-resetting pressure relief device and method for preventing internal arcing faults in a cable branch box

Abstract

The application discloses a kind of self-resetting pressure relief device and method for preventing internal arc fault of cable branch box, belong to cable branch box safety protection field, including cable branch box, the top of the cable branch box is provided with pressure relief mechanism;The pressure relief mechanism includes the rotary lever rotationally connected with the cable branch box, and the outer surface of the rotary lever is fixedly connected with the first semicircle block.By being provided with the pressure relief mechanism consisting of first semicircle block and second semicircle block on the top of cable branch box, recess is opened in the bottom of second semicircle block, so that it is more sensitive to the pressure in the box, when arc fault occurs, it can quickly trigger rotary opening, timely release high-pressure gas in the box, effectively prevent the box from bursting, at the same time, the first semicircle block adopts isosceles trapezoidal section design, and presents the flow state of bottom narrow and wide after rotation, directional guidance is carried out to high-temperature and high-pressure gas, to avoid deformation caused by gas directly impacting second semicircle block.

Description

Technical Field

[0001] This invention relates to the field of safety protection for cable branch boxes, and more specifically, to a self-resetting pressure relief device and method for preventing internal arcing faults in cable branch boxes. Background Technology

[0002] As a key piece of equipment in power distribution network systems, cable distribution boxes are widely used for cable branching and connection in urban power distribution networks, industrial parks, commercial buildings, and residential communities. The cable distribution box contains a large number of cable joints and connectors. When the equipment is affected by factors such as moisture, insulation aging, overvoltage, or external damage, internal arcing may occur. Arcing releases huge energy instantaneously, causing the air inside the box to expand rapidly and generate high-temperature and high-pressure gas several times the atmospheric pressure. If the pressure is not released in time, it may cause the box to burst, the door panel to fly off, or even cause fires and personal injury accidents.

[0003] Existing pressure relief devices automatically close after pressure relief using a spring reset mechanism. However, these devices have the following problems: First, the trigger sensitivity of the pressure relief channel is insufficient, failing to open in time when the pressure inside the chamber reaches a dangerous level, leading to excessive pressure on the chamber. Second, high-temperature and high-pressure gas is directly ejected outwards without necessary guiding and buffering mechanisms, easily causing secondary injuries to surrounding equipment or operators. Third, the opening direction and angle of the pressure relief device are fixed, unable to adapt to the gas discharge direction requirements under different operating conditions. Fourth, existing devices lack a structure to limit chamber deformation, making the chamber prone to permanent deformation under the impact of high-pressure gas.

[0004] Therefore, a self-resetting pressure relief device and method for preventing internal arcing faults in cable branch boxes are proposed. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention aims to provide a self-resetting pressure relief device and method for preventing internal arc faults in cable branch boxes. This is achieved by installing a pressure relief mechanism consisting of a first semicircular block and a second semicircular block at the top of the cable branch box. A groove is formed at the bottom of the second semicircular block to make it more sensitive to the internal pressure. When an arc fault occurs, it can quickly trigger rotation and open, releasing the high-pressure gas inside the box in a timely manner, effectively preventing the box from bursting. Simultaneously, the first semicircular block adopts an isosceles trapezoidal cross-section design, which, after rotation, presents a flow-guiding state that is narrow at the bottom and wide at the top, directionally guiding the high-temperature, high-pressure gas and preventing the gas from directly impacting the second semicircular block and causing deformation.

[0006] To solve the above problems, the present invention adopts the following technical solution.

[0007] A self-resetting pressure relief device for preventing internal arcing faults in a cable branch box includes a cable branch box, and a pressure relief mechanism is provided on the top of the cable branch box.

[0008] The pressure relief mechanism includes a rotating rod rotatably connected to the cable branch box. A first semicircular block is fixedly connected to the outer surface of the rotating rod. The cross-sectional shape of the first semicircular block is an isosceles trapezoid. A second semicircular block is fixedly connected to the wider side of the first semicircular block.

[0009] Furthermore, the combination of the first semicircular block and the second semicircular block seals the top of the cable branch box, and the rotating rod is rotatably connected to the cable branch box via a torsion spring and a bearing.

[0010] The bottom of the second semicircular block is provided with a groove, the front side of the cable branch box is rotatably connected with a flip door, and the top of the cable branch box is provided with a protective mechanism. The protective mechanism includes a top plate that is movably connected to the top of the cable branch box, and the bottom edge of the top plate extends downward to form a first air outlet groove.

[0011] The top of the top plate has a longitudinal groove, and a first movable plate is fixedly connected between the two first air outlet grooves. A second air outlet groove is formed on the surface of the first movable plate.

[0012] A first baffle is fixedly connected to the side of the first movable plate near the cable branch box, and the first movable plate and the first baffle are fixedly connected by a fixing column.

[0013] A second baffle is movably connected between the two first air outlet slots on the front side of the flip door. A second moving plate is provided on the front side of the second baffle and is rotatably connected to the first moving plate. A fixing block is fixedly connected to the left side of the second baffle, and a rotating block is rotatably connected to the left side of the fixing block. A longitudinal groove is provided inside the top plate corresponding to the position of the rotating block.

[0014] The second movable plate has a pop-out block slidably connected inside, and a spring is welded to the left side of the pop-out block. A crossbar is slidably connected to the rear side of the second baffle. A transverse groove is opened inside the second baffle corresponding to the movement trajectory of the crossbar. A connecting block is fixedly connected to the rear side of the crossbar. A movement groove is opened on the surface of the flip door.

[0015] The length of the left end face of the first semicircular block is greater than the length of the right end face of the second semicircular block. Multiple second air outlet slots are provided and are equidistantly distributed along the longitudinal direction of the first moving plate.

[0016] The length of the fixed column is the sum of the thicknesses of the first baffle and the first movable plate. After the first semicircular block rotates, it presents a state that is narrow at the bottom and wide at the top. The first air outlet groove is slidably connected to the edge of the cable branch box.

[0017] A method for a self-resetting pressure relief device for preventing internal arcing faults in a cable branch box includes the following steps:

[0018] S1: Under normal conditions, the first and second semicircular blocks of the pressure relief mechanism remain horizontal under the action of the torsion spring, sealing the top of the cable branch box, protecting the top plate and the first moving plate of the mechanism at the lowest position, and the second vent slot is blocked by the side wall of the cable branch box.

[0019] S2: When an arc fault occurs in the cable branch box, high-temperature and high-pressure gas impacts the bottom of the pressure relief mechanism. The groove at the bottom of the second semicircular block increases the force-bearing area. The first and second semicircular blocks overcome the torsion spring force and rotate clockwise to open, and the high-pressure gas is discharged from the top of the cable branch box.

[0020] S3: The high-pressure gas discharged impacts the top plate, and the top plate slides upward along the top of the cable branch box, driving the first moving plate to rise synchronously. The second gas outlet groove is exposed from the side of the cable branch box, and the gas is discharged from the second gas outlet groove after being buffered by the top plate.

[0021] S4: If it is necessary to adjust the exhaust direction, rotate the fixed column so that the fixed column leaves the first moving plate and extends into the inside of the cable branch box, so that the first moving plate does not drive the first baffle when it moves, and controls the first baffle to block the second exhaust slot to change the exhaust direction.

[0022] S5: After the fault is cleared, the pressure inside the cable branch box returns to normal. The first and second semicircular blocks automatically rotate and reset under the action of the torsion spring, re-sealing the top of the cable branch box. The top plate and the first moving plate descend and reset under the action of gravity.

[0023] S6: When the flip door is opened, the flip door squeezes the second moving plate and the second baffle. The second moving plate and the second baffle rotate synchronously to avoid it. After the flip door is closed, the second moving plate and the second baffle reset, restoring the protection state of the cable branch box.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] This solution involves installing a pressure relief mechanism consisting of a first semicircular block and a second semicircular block at the top of the cable branch box. The bottom of the second semicircular block has a groove to make it more sensitive to the pressure inside the box. When an arc fault occurs, it can be quickly triggered to rotate and open, releasing the high-pressure gas inside the box in a timely manner and effectively preventing the box from bursting. At the same time, the first semicircular block adopts an isosceles trapezoidal cross-section design, which presents a flow guiding state that is narrow at the bottom and wide at the top after rotation, guiding the high-temperature and high-pressure gas in a directional manner and avoiding the gas directly impacting the second semicircular block and causing deformation.

[0026] This solution involves installing a movable top plate and a first movable plate on the top of the cable branch box. When high-pressure gas is discharged, it first impacts the top plate, which then rises and guides the gas to the side through the second vent groove on the first movable plate. This avoids the high-temperature gas from spraying directly upwards and causing damage to the equipment and personnel above, thus providing a good buffering and guiding effect.

[0027] This solution uses a fixed column to adjustably connect the first movable plate and the first baffle. The operator can choose whether the first baffle moves with the first movable plate according to the on-site working conditions, thereby controlling whether the second gas outlet is opened or not, flexibly adjusting the direction and flow of gas discharge to adapt to the requirements of different installation positions and surrounding environments. At the same time, the first movable plate and the first baffle form an external reinforcing structure for the cable branch box, effectively preventing the box from deforming under the impact of high-pressure gas.

[0028] This design incorporates a second movable plate and a second baffle at the flip door. When the flip door is opened, it pushes the second movable plate and the second baffle to rotate synchronously to avoid obstruction, without affecting the normal opening and closing operation of the flip door. After the flip door is closed, the second movable plate and the second baffle reset, together with the first movable plate and the first baffle, to form a complete protective structure for the cable branch box, thus achieving an integrated design of pressure relief function and box structure reinforcement. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the cable branch box of the present invention;

[0030] Figure 2 This is a schematic diagram of the connection structure between the protection mechanism and the cable branch box of the present invention;

[0031] Figure 3 This is a schematic diagram of the pressure relief mechanism of the present invention;

[0032] Figure 4 This is a schematic diagram of the structure of the second baffle of the present invention;

[0033] Figure 5 This is a schematic diagram of the internal structure of the second movable plate of the present invention;

[0034] Figure 6 This is a schematic diagram of the pressure relief mechanism of the present invention;

[0035] Figure 7 This is a bottom view of the pressure relief mechanism of the present invention.

[0036] Explanation of the labels in the diagram:

[0037] 1. Cable branch box; 11. Flip-top door; 111. Moving groove; 2. Protection mechanism; 21. Top plate; 211. First vent groove; 212. Longitudinal groove; 22. First moving plate; 221. Second vent groove; 23. First baffle; 24. Second moving plate; 241. Pop-out block; 242. Spring; 26. Second baffle; 261. Connecting block; 262. Crossbar; 263. Transverse groove; 264. Fixing block; 265. Rotating block; 3. Fixing column; 4. Pressure relief mechanism; 41. First semicircular block; 42. Second semicircular block; 421. Groove; 43. Rotating rod. Detailed Implementation

[0038] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0039] Please see Figures 1 to 7 A self-resetting pressure relief device for preventing internal arcing faults in a cable branch box, comprising a cable branch box 1.

[0040] The top of the cable branch box 1 is equipped with a pressure relief mechanism 4. The pressure relief mechanism 4 includes a rotating rod 43 that is rotatably connected to the cable branch box 1 via a bearing and a torsion spring. A first semicircular block 41 is fixedly connected to the outer surface of the rotating rod 43. The cross-sectional shape of the first semicircular block 41 is an isosceles trapezoid. A second semicircular block 42 is fixedly connected to the wider side of the first semicircular block 41. The combination of the first semicircular block 41 and the second semicircular block 42 seals the top opening of the cable branch box 1. The rotating rod 43 is rotatably connected to the cable branch box 1 via a torsion spring and a bearing, so that the rotating rod 43, along with the first semicircular block 41 and the second semicircular block 42, always keeps the top of the cable branch box 1 sealed, that is, it is in a closed state by default.

[0041] When the cable branch box 1 encounters an arc fault, the internal gas inside the cable branch box 1 expands due to the high temperature generated by the arc, causing a high-pressure situation inside the cable branch box 1. At this time, the high-pressure gas impacts the bottom of the second semicircular block 42 and the first semicircular block 41. The bottom of the second semicircular block 42 is provided with a groove 421, which increases the contact area between the high-pressure gas and the second semicircular block 42, making the impact force on the second semicircular block 42 greater, thus making it easier to trigger the first semicircular block 41 to rotate clockwise with the second semicircular block 42 to open.

[0042] like Figure 3As shown, the length of the left end face of the first semicircular block 41 is greater than the length of the right end face of the second semicircular block 42. After the first semicircular block 41 and the second semicircular block 42 rotate, due to the obstruction of the box wall of the cable branch box 1, the first semicircular block 41 and the second semicircular block 42 cannot continue to rotate. The first semicircular block 41 and the second semicircular block 42 remain in a vertical state, which facilitates the rapid discharge of high temperature and high pressure gas in the cable branch box 1 from the top of the cable branch box 1.

[0043] After the first semicircular block 41 rotates, it becomes narrow at the bottom and wide at the top, which facilitates the guidance of high-temperature and high-pressure gas. The gas is discharged upward and outward along the inclined surface of the first semicircular block 41, preventing the high-temperature and high-pressure gas from directly impacting the second semicircular block 42 and preventing the second semicircular block 42 from deforming under high temperature. The first semicircular block 41 is made of high-temperature resistant material to prevent deformation due to heat, making the device more convenient to use. After the gas in the cable branch box 1 is discharged, the pressure inside the box returns to normal. The first semicircular block 41 and the second semicircular block 42 automatically return to their original closed position under the action of the torsion spring of the rotating rod 43, realizing self-reset.

[0044] The front of the cable branch box 1 is rotatably connected to a flip door 11, which is used to open during routine maintenance and repair. The top of the cable branch box 1 is equipped with a protective mechanism 2.

[0045] The protection mechanism 2 includes a top plate 21 that is movably connected to the top of the cable branch box 1. The bottom edge of the top plate 21 extends downward to form a first vent groove 211. The top plate 21 is slidably connected to the edge of the cable branch box 1 through the first vent groove 211, so that the top plate 21 can slide up and down on the top of the cable branch box 1.

[0046] When the high-pressure gas in the cable branch box 1 is discharged from the pressure relief mechanism 4, the high-temperature gas first impacts the top plate 21 upwards, and the top plate 21 is lifted upwards to prevent the high-temperature gas from being discharged directly to the outside, effectively preventing the high-temperature gas from affecting the staff and other equipment. The top of the top plate 21 is provided with a longitudinal groove 212 to facilitate the discharge of gas from the longitudinal groove 212.

[0047] A first movable plate 22 is fixedly connected between each of the two first vent slots 211. When the top plate 21 moves upward, the top plate 21 moves the first movable plate 22 upward with it. The surface of the first movable plate 22 is provided with a second vent slot 221. When the first movable plate 22 rises to a certain height, the second vent slot 221 is exposed from the side of the cable branch box 1, which facilitates the discharge of gas in the top plate 21 from the second vent slot 221, resulting in better gas discharge. Multiple second vent slots 221 are provided. The top plate 21 is driven to rise to different heights according to the amount of gas discharged from the cable branch box 1, thereby adjusting the rising height of the first movable plate 22 and exposing different numbers of second vent slots 221. This is suitable for working conditions with different gas discharge volumes, making the device more widely applicable.

[0048] A first baffle 23 is fixedly connected to the side of the first movable plate 22 near the cable branch box 1. The first baffle 23 is located inside the side wall of the cable branch box 1 and forms a clamping structure with the first movable plate 22 to reinforce the side wall of the cable branch box 1. The first movable plate 22 and the first baffle 23 are fixedly connected by a fixing post 3. The fixing post 3 penetrates the side wall of the cable branch box 1, and the length of the fixing post 3 is the sum of the thicknesses of the first baffle 23 and the first movable plate 22.

[0049] By rotating the fixed column 3, when the fixed column 3 is inside the first movable plate 22 and the first baffle 23, the movement of the first movable plate 22 will move the first baffle 23 together. However, when the fixed column 3 continues to rotate, it leaves the first movable plate 22 and extends into the side wall of the cable branch box 1. At this time, the movement of the first movable plate 22 will not move the first baffle 23. The operator can adjust whether the first baffle 23 follows the movement of the first movable plate 22 as needed, controlling whether the first baffle 23 blocks the second air outlet 221. The direction of the gas ejected from the cable branch box 1 is controlled by the first baffle 23 rising with the first moving plate 22, at which point the second gas outlet 221 opens; when the first baffle 23 does not rise with the first moving plate 22, the second gas outlet 221 is blocked by the first baffle 23, and the gas is discharged from other directions, making the device more convenient to use. Furthermore, the first moving plate 22 and the first baffle 23 form a clamping and reinforcing structure for the cable branch box 1, effectively preventing deformation and bursting of the cable branch box 1 due to gas expansion, thus providing better protection for the cable branch box 1.

[0050] A second baffle 26 is movably connected between the two first air vents 211 on the front side of the flip door 11. A second movable plate 24 is provided on the front side of the second baffle 26 and is rotatably connected to the first movable plate 22. When the flip door 11 is opened, the flip door 11 squeezes the second baffle 26 and the second movable plate 24, causing the second movable plate 24 and the second baffle 26 to rotate synchronously to avoid each other, so as not to affect the rotation of the flip door 11.

[0051] A fixing block 264 is fixedly connected to the left side of the second baffle 26, and a rotating block 265 is rotatably connected to the left side of the fixing block 264. A longitudinal groove 212 is provided inside the top plate 21 corresponding to the position of the rotating block 265, so that the second baffle 26 can slide and rotate in the top plate 21 while carrying the fixing block 264. This does not affect the opening of the flip door 11 and can move with the second moving plate 24, so that the second baffle 26 and the first baffle 23 can play the same role.

[0052] like Figure 5As shown, a pop-out block 241 is slidably connected inside the second movable plate 24. A spring 242 is welded to the left side of the pop-out block 241. The spring 242 causes the pop-out block 241 to be engaged inside the first baffle 23, so that the second movable plate 24 can only rotate when the flip door 11 is squeezed, making the rotation of the second movable plate 24 more controllable and convenient. The right half end face of the pop-out block 241 is an isosceles triangle, which makes it easier for the pop-out block 241 to extend into the first baffle 23, and makes it easier for the pop-out block 241 to leave the first baffle 23 when subjected to a reverse force.

[0053] A crossbar 262 is slidably connected to the rear side of the second baffle 26. A transverse groove 263 is provided inside the second baffle 26 corresponding to the movement trajectory of the crossbar 262, which facilitates the movement of the crossbar 262 inside the transverse groove 263. A connecting block 261 is fixedly connected to the rear side of the crossbar 262, which facilitates the movement of the crossbar 262 with the connecting block 261. A moving groove 111 is provided on the surface of the flip door 11. The moving groove 111 restricts the connecting block 261, so that the connecting block 261 can only move up and down. This controls the second baffle 26 to always be in contact with the second moving plate 24 when the second baffle 26 rotates with the second moving plate 24, making it more convenient for the second moving plate 24 to move up and down with the second baffle 26.

[0054] The working process of this device is as follows:

[0055] In normal conditions, the first semicircular block 41 and the second semicircular block 42 of the pressure relief mechanism 4 remain horizontal under the action of the torsion spring, sealing the top of the cable branch box 1. The top plate 21 and the first moving plate 22 of the protection mechanism 2 are in the lowest position, and the second vent 221 is blocked by the side wall of the cable branch box 1.

[0056] When an arc fault occurs in the cable branch box 1, the high-temperature and high-pressure gas rapidly impacts the bottom of the pressure relief mechanism 4. The groove 421 at the bottom of the second semicircular block 42 increases the force-bearing area, causing the first semicircular block 41 and the second semicircular block 42 to rotate clockwise and open rapidly. The high-pressure gas is discharged from the top and impacts the top plate 21, causing it to rise. The first moving plate 22 rises synchronously, and the second vent 221 is exposed. The gas is buffered by the top plate 21 and discharged from the side. At the same time, the first moving plate 22 and the first baffle 23 reinforce the side wall of the box to prevent deformation.

[0057] After the fault is cleared, the pressure inside the box returns to normal. The pressure relief mechanism 4 automatically resets and closes under the action of the torsion spring. The top plate 21 and the first moving plate 22 descend and reset under the action of gravity. If it is necessary to adjust the exhaust direction, the fixed column 3 can be rotated to separate the first baffle 23 from the first moving plate 22, thereby controlling the opening state of the second exhaust slot 221.

[0058] The above description is merely a preferred embodiment of the present invention; however, the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and its improved concepts, should be covered within the scope of protection of the present invention.

Claims

1. A self-resetting pressure relief device for preventing internal arcing faults in a cable branch box, comprising a cable branch box (1), characterized in that: The top of the cable branch box (1) is provided with a pressure relief mechanism (4). The pressure relief mechanism (4) includes a rotating rod (43) rotatably connected to the cable branch box (1). A first semicircular block (41) is fixedly connected to the outer surface of the rotating rod (43). The cross-sectional shape of the first semicircular block (41) is an isosceles trapezoid. A second semicircular block (42) is fixedly connected to the wider side of the first semicircular block (41).

2. The self-resetting pressure relief device for preventing internal arcing faults in a cable branch box according to claim 1, characterized in that: The combination of the first semicircular block (41) and the second semicircular block (42) seals the top of the cable branch box (1), and the rotating rod (43) is rotatably connected to the cable branch box (1) by a torsion spring and a bearing.

3. The self-resetting pressure relief device for preventing internal arcing faults in a cable branch box according to claim 2, characterized in that: The bottom of the second semicircular block (42) is provided with a groove (421). The front side of the cable branch box (1) is rotatably connected with a flip door (11). The top of the cable branch box (1) is provided with a protection mechanism (2). The protection mechanism (2) includes a top plate (21) movably connected to the top of the cable branch box (1). The bottom edge of the top plate (21) extends downward to form a first air outlet groove (211).

4. The self-resetting pressure relief device for preventing internal arcing faults in a cable branch box according to claim 3, characterized in that: The top plate (21) has a longitudinal groove (212) on its top, and a first moving plate (22) is fixedly connected between the two first air outlet grooves (211). A second air outlet groove (221) is provided on the surface of the first moving plate (22).

5. A self-resetting pressure relief device for preventing internal arcing faults in a cable branch box according to claim 4, characterized in that: The first movable plate (22) is fixedly connected to the first baffle (23) on the side near the cable branch box (1), and the first movable plate (22) and the first baffle (23) are fixedly connected by a fixing column (3).

6. The self-resetting pressure relief device for preventing internal arcing faults in a cable branch box according to claim 5, characterized in that: A second baffle (26) is movably connected between the two first air outlet slots (211) on the front side of the flip door (11). A second moving plate (24) is provided on the front side of the second baffle (26) and is rotatably connected to the first moving plate (22). A fixing block (264) is fixedly connected to the left side of the second baffle (26). A rotating block (265) is rotatably connected to the left side of the fixing block (264). A longitudinal groove (212) is provided inside the top plate (21) corresponding to the position of the rotating block (265).

7. A self-resetting pressure relief device for preventing internal arcing faults in a cable branch box according to claim 6, characterized in that: The second movable plate (24) has a pop-out block (241) slidably connected inside. A spring (242) is welded to the left side of the pop-out block (241). A crossbar (262) is slidably connected to the rear side of the second baffle (26). A transverse groove (263) is opened inside the second baffle (26) corresponding to the movement trajectory of the crossbar (262). A connecting block (261) is fixedly connected to the rear side of the crossbar (262). A moving groove (111) is opened on the surface of the flip door (11).

8. The self-resetting pressure relief device for preventing internal arcing faults in a cable branch box according to claim 7, characterized in that: The length of the left end face of the first semicircular block (41) is greater than the length of the right end face of the second semicircular block (42). Multiple second air outlet grooves (221) are provided and are distributed equidistantly along the longitudinal direction of the first moving plate (22).

9. A self-resetting pressure relief device for preventing internal arcing faults in a cable branch box according to claim 8, characterized in that: The length of the fixed column (3) is the sum of the thicknesses of the first baffle (23) and the first movable plate (22). The first semicircular block (41) rotates to a state where it is narrow at the bottom and wide at the top. The first air outlet groove (211) is slidably connected to the edge of the cable branch box (1).

10. A method for a self-resetting pressure relief device for preventing internal arcing faults in a cable branch box as described in any one of claims 1-9, characterized in that: Includes the following steps: S1: In normal condition, the first semicircular block (41) and the second semicircular block (42) of the pressure relief mechanism (4) remain horizontal under the action of the torsion spring, sealing the top of the cable branch box (1), the top plate (21) and the first moving plate (22) of the protection mechanism (2) are in the lowest position, and the second vent slot (221) is blocked by the side wall of the cable branch box (1); S2: When an arc fault occurs in the cable branch box (1), the high temperature and high pressure gas impacts the bottom of the pressure relief mechanism (4). The groove (421) at the bottom of the second semicircular block (42) increases the force-bearing area. The first semicircular block (41) and the second semicircular block (42) overcome the torsion spring force and rotate clockwise to open. The high pressure gas is discharged from the top of the cable branch box (1). S3: The high-pressure gas discharged impacts the top plate (21), the top plate (21) slides upward along the top of the cable branch box (1), driving the first moving plate (22) to rise synchronously, the second gas outlet groove (221) is exposed from the side of the cable branch box (1), and the gas is discharged from the second gas outlet groove (221) after being buffered by the top plate (21). S4: If it is necessary to adjust the exhaust direction, rotate the fixed column (3) so that the fixed column (3) leaves the first moving plate (22) and extends into the inside of the cable branch box (1) so that the first moving plate (22) does not drive the first baffle (23) when it moves, and controls the first baffle (23) to block the second exhaust groove (221) to change the exhaust direction. S5: After the fault is cleared, the pressure inside the cable branch box (1) returns to normal. The first semicircular block (41) and the second semicircular block (42) automatically rotate and reset under the action of the torsion spring, re-sealing the top of the cable branch box (1). The top plate (21) and the first moving plate (22) descend and reset under the action of gravity. S6: When the flip door (11) is opened, the flip door (11) squeezes the second moving plate (24) and the second baffle (26). The second moving plate (24) and the second baffle (26) rotate synchronously to avoid each other. After the flip door (11) is closed, the second moving plate (24) and the second baffle (26) reset and restore the protection state of the cable branch box (1).

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