Ground fault detection system and device for power distribution network

Abstract

The invention relates to a ground fault detection system and device for a power distribution network. The invention relates to the technical field of ground fault detectors. A flame-retardant buffer plate is installed in an inner cavity of the box cover and made of flame-retardant buffer materials, and the area formed between the flame-retardant buffer plate and the interior of the box cover is filled with flame-retardant heat-insulating particles which have a good heat-insulating effect, the heat-insulating capacity of the box cover is improved, and the flame-retardant buffer plate is made of the flame-retardant buffer materials. The grounding fault detection mechanism can also be heated to form fluid to be protected above the detection box when a fire disaster occurs, the fluid can flow to the panel position on the upper surface of the detection box from the leakage hole, so that the panel is packaged, the fluid cannot be burnt, the purpose of isolating the fire disaster is achieved, and the main body of the grounding fault detection mechanism is prevented from being damaged after the fire disaster is eliminated. The fluid is cooled and molded to form a hard protection layer, and the whole protection layer can be uncovered, so that the ground fault detection mechanism which is not damaged is taken out, and the use cost is reduced.

Description

Technical Field

[0001] This invention belongs to the technical field of grounding fault detectors, specifically relating to a grounding fault detector that can take into account buffering, fire prevention and flame retardancy. Background Technology

[0002] With the continuous development of power systems, the safe operation of distribution networks is becoming increasingly important for ensuring social production and daily life. Ground faults are one of the most common types of faults in distribution networks, which can not only cause equipment damage and power outages, but also trigger secondary disasters such as fires, seriously threatening personal and property safety. Therefore, timely and accurate detection and handling of ground faults are crucial for ensuring the safe operation of distribution networks.

[0003] Existing grounding fault detection devices are typically installed in complex outdoor or indoor environments, making them vulnerable to threats such as fires and electrical leaks. In the event of a fire, the outer casing of the detection device may be burned, damaging the internal detection mechanism and rendering it inoperable. Furthermore, the high temperatures generated by a fire may trigger short circuits or malfunctions within the equipment, further exacerbating the damage.

[0004] When a leakage occurs at the wiring points or other locations above the detection box, existing leakage protection measures typically only cut off the power supply and cannot provide timely physical protection for the equipment. Leakage can cause the equipment casing to become electrified, increasing the risk of electric shock and potentially causing a fire.

[0005] Therefore, a ground fault detection system and device for power distribution networks is proposed to solve the above problems. Summary of the Invention

[0006] The purpose of this invention is to provide a grounding fault detection system and device for power distribution networks that is simple in structure and reasonably designed in order to solve the above-mentioned problems.

[0007] The present invention achieves the above objectives through the following technical solutions: A ground fault detection device for power distribution networks includes a detection box and a cover. The cover is detachably mounted on the detection box. A ground fault detection mechanism is installed inside the detection box. A panel is encapsulated on the upper surface of the detection box. The panel has an LED display screen and wiring terminals. The cover has an inner cavity. A flame-retardant buffer plate is installed in the inner cavity. The flame-retardant buffer plate is made of flame-retardant buffer material. The area formed between the flame-retardant buffer plate and the inside of the cover is filled with a flame-retardant medium. Flame retardant media include: the use of flame retardant heat-insulating particles or: Use carbon dioxide and dry extinguishing powder; Among them, the flame-retardant heat-insulating particles are particles made from any one of the following: silicone resin encapsulation material, flame-retardant polycarbonate material, and epoxy resin potting mixture. The carbon dioxide and fire extinguishing dry powder also contain flame-retardant silicone composite particles, which have a smooth film layer on their surface.

[0008] Preferably, the upper and lower surfaces of the flame-retardant buffer plate are respectively provided with an inner groove and a recess, and the inner groove and the recess are quadrilateral grooves; The flame-retardant buffer plate is provided with several through holes running vertically through it.

[0009] Preferably, the detection box is provided with a reserved cavity for installing a communication module, an alarm module, a power management module, and a data storage module.

[0010] Preferably, the flame-retardant buffer plate is provided with injection holes, and an elastic diaphragm is fixedly connected in the injection holes.

[0011] This invention also discloses a ground fault detection system for power distribution networks, including a ground fault detection device for power distribution networks, and further comprising: The device includes a temperature sensor, a leakage current sensor, and an electric heating plate. The electric heating plate is fixedly installed on the inner wall of the box cover and is in contact with flame-retardant and heat-insulating particles. The temperature sensor is installed on the outer surface of the box cover, and the leakage current sensor is installed on the inner surface of the box cover, corresponding to the top of the detection box.

[0012] As a further optimization of the present invention, it also includes: Communication module, alarm module, power management module, and data storage module; The communication module, alarm module, power management module, and data storage module are installed inside the reserved cavity in the detection box; The communication module uses a 4G / 5G wireless communication module or an RS485 wired communication module. The data storage module uses a large-capacity memory to store historical detection data and fault records.

[0013] As a further optimization of the present invention, the alarm module uses an audible and visual alarm device; The sound and light alarm device is positioned on the bottom surface of the panel, and the panel has a transparent glass plate area and a sound hole. The glass plate area allows light to pass through the sound and light alarm device, and the sound hole allows sound to pass through the sound and light alarm device.

[0014] As a further optimization of the present invention, the power management module uses a DC battery and is equipped with a solar charging panel and an external power interface. The solar charging panel is installed on the upper surface of the box cover, the DC battery is installed in the reserved cavity, and the DC battery and the solar charging panel are connected by wires. The wires are pre-embedded, and the reserved cavity is also equipped with a solar energy conversion device that converts solar energy into electrical energy.

[0015] As a further optimization of the present invention, the flame-retardant buffer plate and flame-retardant heat-insulating particles are disposed inside the detection box to protect the periphery of the grounding fault detection mechanism.

[0016] As a further optimization of the present invention, the temperature sensor, the leakage current sensor and the electric heating plate are connected by a controller; When a fire occurs outside the testing chamber, the temperature will rise. When the temperature sensor detects that the temperature outside the testing chamber is too high, the controller will activate the electric heating plate. The power management module in the inner slot will supply power to the electric heating plate. The electric heating plate will fully heat and melt all the flame-retardant and heat-insulating particles, so that the protective film formed can completely cover the upper surface of the testing chamber to protect it. When there is a leakage at the wiring position or other location above the testing box, the leakage sensor detects the leakage and controls the electric heating plate to start through the controller. The electric heating plate heats the flame-retardant and heat-insulating particles, which then flow as a fluid onto the upper surface of the testing box. When the fluid solidifies, it forms a protective layer.

[0017] The beneficial effects of this invention are as follows: The flame-retardant and heat-insulating particles in this invention not only have a good heat insulation effect and increase the heat insulation capacity of the box cover, but also can be heated to form a fluid in the event of a fire, which can then protect the top of the detection box. The fluid can flow from the leak hole to the panel on the upper surface of the detection box, thereby sealing the panel. The fluid is non-flammable, thus isolating the fire and preventing damage to the main body of the grounding fault detection mechanism. After the fire is extinguished, the fluid cools and solidifies to form a hard protective layer. The entire protective layer can be peeled off, allowing the undamaged grounding fault detection mechanism to be removed, thereby reducing the cost of use.

[0018] In this invention, the flame-retardant buffer plate can be used for both buffering and fluid gathering, making it easier for the fluid to bond together after cooling and solidification, and allowing the protective layer to be peeled off sequentially.

[0019] When there is a leakage at the wiring position or other locations above the detection box, the leakage sensor can detect the leakage and then control the electric heating plate to start. The electric heating plate heats the flame-retardant and heat-insulating particles, which then flow into the upper surface of the detection box. When the fluid solidifies, it forms a protective layer. This protective layer is not only insulating but also provides flame-retardant protection, allowing the leakage to be resolved in a timely manner.

[0020] The reserved cavity can be used to install communication modules, alarm modules, power management modules, and data storage modules, allowing users to flexibly select and install the corresponding modules according to their actual needs, making this grounding fault detection mechanism suitable for more outdoor and indoor scenarios.

[0021] Once the flame-retardant and heat-insulating particles form a protective layer and solidify, when the protective layer is manually peeled off after the fire is extinguished, not only can the protective layer attached to the upper surface of the testing box be peeled off, but also the encapsulation structure solidified under the protective layer can be peeled off. Peeling off the encapsulation structure can also clean the gaps in the structure or the electrical connection points, especially removing dust from the gaps in the structure or the electrical connection points. During use, this can significantly reduce the operating temperature of the device and help extend the service life of the device.

[0022] When fire extinguishing dry powder and carbon dioxide combine, they act on the surface of the testing chamber, providing excellent flame retardancy and insulation, and are non-toxic and harmless.

[0023] The fire extinguishing dry powder is adhered to the surface of the test chamber by flame-retardant silicone composite particles, which can still protect the electrical components inside the test chamber even if the lid is damaged, providing strong protection. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the detection box structure of the present invention; Figure 2 This is a schematic diagram of the grounding fault detection device for power distribution networks according to the present invention; Figure 3 This is a front view of the grounding fault detection device for power distribution networks according to the present invention; Figure 4 This is a schematic diagram of the box cover structure in Embodiment 1 of the present invention; Figure 5 This is the invention Figure 4 Enlarged schematic diagram of the structure at point A in the middle; Figure 6 This is a schematic diagram of the internal structure of the detection box of the present invention; Figure 7 This is a diagram of the grounding fault detection system for power distribution networks according to the present invention; Figure 8 This is a schematic diagram of the box cover structure in Embodiment 2 of the present invention; Figure 9 This is a schematic diagram of the automatic sealing mechanism of the present invention; Figure 10 This is the invention Figure 9 Enlarged schematic diagram of the structure at point B; Figure 11 This is a schematic diagram of the structure of the detection box and the box cover of the present invention when separated.

[0025] In the diagram: 1. Detection box; 2. Box cover; 3. Box cover inner cavity; 4. LED display screen; 5. Wiring terminal; 6. Flame-retardant buffer plate; 7. Groove; 8. Flame-retardant heat insulation particles; 9. Temperature sensor; 10. Leakage sensor; 11. Electric heating plate; 12. Leakage hole; 13. Inner groove; 14. Outer protection zone; 15. Reserved cavity; 16. Spray hole; 17. Elastic diaphragm; 18. Automatic sealing mechanism; 19. First sealing groove; 20. Second sealing groove; 21. Air cavity; 22. Rubber sealing airbag; 23. First connecting rod; 24. First magnetic plate; 25. Second magnetic plate; 26. Upper connecting plate; 27. Second connecting rod; 28. Piston plate; 29. ​​Hose; 30. Spring; 31. Chamfer. Detailed Implementation

[0026] The present application will now be described in further detail with reference to the accompanying drawings. It should be noted that the following specific embodiments are only used to further illustrate the present application and should not be construed as limiting the scope of protection of the present application. Those skilled in the art can make some non-essential improvements and adjustments to the present application based on the above application content.

[0027] Example 1: like Figures 1 to 2 As shown, a grounding fault detection device for power distribution networks includes a detection box 1 and a box cover 2. The detection box 1 is made of a robust outer shell material and has good waterproof and dustproof performance, making it suitable for complex outdoor environments. The box cover 2 is an openable design and is connected to the detection box 1 by a hinge, which facilitates the installation, debugging and maintenance of the equipment.

[0028] The ground fault detection mechanism is located inside the detection box 1. Common detection modules in existing technologies can be selected according to actual needs, such as detection modules based on zero-sequence current method, zero-sequence voltage method or transient signal analysis method, to meet the detection needs of different application scenarios. A panel suitable for the ground fault detection mechanism is encapsulated on the upper surface of the detection box 1. The panel has an LED display screen 4 and a wiring terminal 5.

[0029] The LED display screen 4 is used to display the operating status, detection data, and fault alarm information of the ground fault detection mechanism in real time, so that users can intuitively understand the operation of the equipment. The LED display screen 4 is also equipped with buttons, which users can use to adjust the parameters in the ground fault detection mechanism, such as setting alarm thresholds and selecting detection modes, so as to achieve flexible configuration of the equipment.

[0030] Terminal 5 is used to connect the grounding wire and the detection signal line of the power distribution network, ensuring that the grounding fault detection mechanism can accurately collect the grounding fault signal of the power distribution network. Terminal 5 adopts an anti-loosening design to ensure a firm and reliable connection and avoid abnormal detection data due to poor contact.

[0031] refer to Figure 6 and Figure 7As shown, in another embodiment, the present invention also provides a reserved cavity 15 in the detection box 1, which can be used to install a communication module, an alarm module, a power management module and a data storage module.

[0032] The communication module can use a 4G / 5G wireless communication module or an RS485 wired communication module to transmit the detection data to the background monitoring system in real time, enabling remote monitoring and data analysis.

[0033] The alarm module can be configured with an audible and visual alarm device. When a grounding fault is detected, an audible and visual alarm signal will be issued immediately to remind on-site personnel to handle the situation in a timely manner. However, it should be noted that if the audible and visual alarm device is installed at the reserved cavity 15 position, the audible and visual alarm device needs to be installed in a position that is attached to the bottom surface of the panel, and the panel needs to have a transparent glass plate area and a sound hole to enable the audible and visual alarm device to work properly.

[0034] The power management module can use a high-performance DC battery and is equipped with a solar charging panel and an external power interface to ensure that the device can operate stably for a long time without mains power. It should be noted that when equipped with a solar charging panel, the solar charging panel can be installed on the upper surface of the cover 2, and the DC battery is installed in the reserved cavity 15. The DC battery and the solar charging panel are connected by wires, which are pre-embedded in appropriate positions. The reserved cavity 15 is also equipped with a solar energy conversion device that converts solar energy into electrical energy. This is a conventional design and will not be described in detail here.

[0035] Based on the fact that the present invention includes a reserved cavity 15, suitable modules can be selectively installed in the reserved cavity 15, making the grounding fault detection mechanism applicable to more outdoor and indoor scenarios.

[0036] The data storage module can use a large-capacity storage device to store historical test data and fault records, allowing users to easily access and analyze them at any time.

[0037] In actual implementation, the ground fault detection mechanism can be connected to the controller, which in turn is connected to the alarm module, power management module, data storage module, and communication module. The controller uses common existing control chips to realize the corresponding alarm, power supply, data storage, and communication functions of the ground fault detection mechanism.

[0038] refer to Figure 1 and Figure 2 As shown in the figure, the present invention has a box cover cavity 3 inside the box cover 2, and a flame-retardant buffer plate 6 is installed in the box cover cavity 3. The flame-retardant buffer plate 6 is made of flame-retardant buffer material, such as flame-retardant rubber, and can be used to protect the top of the grounding fault detection mechanism to achieve the purpose of buffer protection.

[0039] refer to Figures 2 to 5As shown, inner grooves 13 and grooves 7 are respectively provided on the upper and lower surfaces of the flame-retardant buffer plate 6. The inner grooves 13 and grooves 7 are quadrilateral grooves, which increase the buffering and protective effect of the flame-retardant buffer plate 6. Multiple inner grooves 13 and grooves 7 are provided. The area formed between the flame-retardant buffer plate 6 and the inside of the box cover 2 is filled with flame-retardant and heat-insulating particles 8. The flame-retardant and heat-insulating particles 8 can be made of materials such as silicone resin encapsulation material, flame-retardant polycarbonate material, and epoxy resin potting mixture.

[0040] These particles not only have good heat insulation properties, increasing the heat insulation capacity of the cover 2, but can also be heated to form a fluid in the event of a fire, thus protecting the area above the detection box 1.

[0041] Specifically, in the event of a fire, the fire usually burns the cover 2 first, and then affects the flame-retardant and heat-insulating particles 8 inside the cover 2. The flame-retardant and heat-insulating particles 8 melt and form a fluid when heated. The flame-retardant buffer plate 6 is provided with several vertically penetrating holes 12. The fluid can flow from the holes 12 to the panel on the upper surface of the detection box 1, thereby sealing the panel. The fluid is non-combustible, which serves to isolate the fire, avoid damage to the main body of the grounding fault detection mechanism, and reduce the cost of use.

[0042] Once the fire is extinguished, the fluid cooling process forms a hard protective layer that can be peeled off to remove the undamaged grounding fault detection mechanism.

[0043] In this invention, the flame-retardant buffer plate 6 can be used for buffering on the one hand, and for gathering the fluid on the other hand, so that the fluid can be easily bonded into a whole after cooling and forming, and the protective layer can be peeled off sequentially.

[0044] It should also be noted that the flame-retardant buffer plate 6 and flame-retardant heat-insulating particles 8 in this invention can also be set inside the detection box 1 to form an outer protection zone 14, which is used to protect the periphery of the grounding fault detection mechanism.

[0045] Furthermore, the present invention also provides a protection system suitable for a ground fault detection mechanism, including: a temperature sensor 9, a leakage current sensor 10, and an electric heating plate 11. The electric heating plate 11 is fixedly installed on the inner wall of the box cover 2 and is in contact with the flame-retardant and heat-insulating particles 8. The temperature sensor 9 is installed on the outer surface of the box cover 2, and the leakage current sensor 10 is installed on the inner surface of the box cover 2 and corresponds to the top of the detection box 1.

[0046] When a fire occurs outside the testing box 1, the temperature will rise. If the fire does not fully heat and melt all the flame-retardant and heat-insulating particles 8, the protective layer formed by the fluid on the upper surface of the testing box 1 may not completely cover the upper surface of the testing box 1. Therefore, when the temperature sensor 9 detects that the temperature outside the testing box 1 is too high, the controller can control the electric heating plate 11 to start. The power management module in the inner groove 13 supplies power to the electric heating plate 11. The electric heating plate 11 can fully heat and melt all the flame-retardant and heat-insulating particles 8, so that the formed protective film can completely cover the upper surface of the testing box 1 to protect the testing box 1.

[0047] Meanwhile, when there is a leakage at the wiring position or other locations above the detection box 1, the leakage sensor 10 can detect the leakage and then control the electric heating plate 11 to start through the controller. The electric heating plate 11 heats the flame-retardant and heat-insulating particles 8 to form a fluid that flows on the upper surface of the detection box 1. When the fluid solidifies, it forms a protective layer. This protective layer is not only insulating but also has a flame-retardant protection effect, so that the leakage can be resolved in a timely manner.

[0048] Furthermore, after the flame-retardant and heat-insulating particles 8 form a fluid, they can easily flow into the gaps in the structure, especially at the electrical connection points, forming an encapsulation structure. This not only serves to encapsulate and prevent leakage, but also the flame-retardant and heat-insulating particles have a flame-retardant effect, which can comprehensively protect electrical components from being burned by open flames.

[0049] It is worth mentioning that when the flame-retardant and heat-insulating particles 8 form a protective layer and solidify, when the protective layer is manually peeled off after the fire is extinguished, not only can the protective layer attached to the upper surface of the detection box 1 be peeled off, but the encapsulation structure solidified under the protective layer can also be peeled off. Peeling off the encapsulation structure can also clean the gaps in the structure or the electrical connection points, especially removing the dust from the gaps in the structure or the electrical connection points. During use, this can significantly reduce the operating temperature of the device and help extend the service life of the device.

[0050] Example 2: refer to Figure 8 As shown, the grounding fault detection device for power distribution network also includes a spray hole 16 disposed on the flame-retardant buffer plate 6. In embodiment 2, the leakage hole 12 on the flame-retardant buffer plate 6 is replaced with a spray hole 16. There may be two or more spray holes 16. An elastic diaphragm 17 is fixedly connected in the spray hole 16. The elastic diaphragm 17 can be elastically deformed and can be broken under a certain pressure.

[0051] In Example 2, the flame-retardant and heat-insulating particles 8 in the inner cavity 3 of the box cover are replaced with fire extinguishing dry powder and inert gas, such as carbon dioxide, nitrogen, argon, helium, etc.

[0052] When using fire extinguishing dry powder and carbon dioxide, if a fire occurs outside the detection box 1, the carbon dioxide expands due to the heat inside the box cover cavity 3, causing the elastic diaphragm 17 to bulge. When the pressure increases to a certain level, the elastic diaphragm 17 ruptures, and the carbon dioxide inside the box cover cavity 3 is discharged at high speed to the upper surface of the detection box 1. When the carbon dioxide is discharged, it can carry the fire extinguishing dry powder out and adhere it to the surface of the detection box 1, which serves the purpose of insulation and flame retardancy, preventing the open flame from burning the box cover 2 and then continuing to burn the electrical components inside the detection box 1.

[0053] At the same time, the temperature sensor 9 can also actively monitor the temperature outside the box cover 2. When the temperature rises to a certain threshold, the detection box 1 and the box cover 2 are prone to fire. At this time, the electric heating plate 11 can be actively turned on to heat the inner cavity 3 of the box cover, so that the elastic diaphragm 17 will break in advance and the fire extinguishing dry powder can be attached to the surface of the detection box 1.

[0054] If there is a leakage at the electrical connection point on the upper surface of the detection box 1, the leakage can be detected by the leakage sensor 10. At this time, the electric heating plate 11 can be turned on to heat the inner cavity 3 of the box cover, so that the elastic diaphragm 17 will break in advance. After the fire extinguishing dry powder is attached to the surface of the detection box 1, it will play an insulating role and reduce the leakage.

[0055] Furthermore, the combination of fire extinguishing dry powder and carbon dioxide acts on the surface of the detection box 1, providing excellent flame retardancy and insulation, and is non-toxic and harmless.

[0056] In practical use, flame-retardant silicone composite particles can be added to the fire extinguishing dry powder. When the fire extinguishing dry powder is heated, the flame-retardant silicone composite particles are heated and enter the surface of the test chamber 1 along with the fire extinguishing dry powder. This allows the fire extinguishing dry powder to adhere to the surface of the test chamber 1, avoiding the phenomenon of uneven distribution of the fire extinguishing dry powder leading to a reduction in fire extinguishing effect. Furthermore, based on the fire extinguishing dry powder being adhered to the surface of the test chamber 1 by the flame-retardant silicone composite particles, even if the cover 2 is damaged, it can still protect the electrical components inside the test chamber 1, providing strong protection.

[0057] It should be noted that the particle size of flame-retardant silicone composite particles should be controlled between 50 micrometers and 500 micrometers. This particle size range can ensure the uniform distribution of particles in the fire extinguishing dry powder without negatively affecting the flowability of the fire extinguishing dry powder. If the particles are too large, it may cause uneven spraying of the fire extinguishing dry powder and affect the fire extinguishing effect.

[0058] In its unheated state, the flame-retardant silicone composite granules will not adhere to the fire extinguishing dry powder. This characteristic ensures that the fire extinguishing dry powder and the flame-retardant silicone composite granules remain separated during storage and transportation, avoiding problems such as clumping or blockage of the fire extinguishing dry powder caused by premature adhesion. The adhesive properties are only triggered when the flame-retardant silicone composite granules are heated to a certain degree.

[0059] When flame-retardant silicone composite particles are sprayed along with fire extinguishing dry powder and impact the target surface, the smooth film layer on the outer surface of the particles is damaged. This impact force causes the particles to deform, and the surface structure becomes protruding or concave, thereby destroying the smooth film layer. At this time, the adhesive properties of the particles are activated, and they can firmly adhere to the target surface.

[0060] During the fire extinguishing process, the fire extinguishing dry powder and flame-retardant silicone composite particles are sprayed together onto the target surface. Due to the particle size and characteristics of the flame-retardant silicone composite particles, they can be evenly distributed in the fire extinguishing dry powder, ensuring that the fire extinguishing dry powder can evenly cover the surface of the test box 1. This uniform distribution helps to improve the fire extinguishing effect and avoid fire extinguishing failure caused by uneven distribution of the fire extinguishing dry powder.

[0061] When the fire extinguishing dry powder and flame-retardant silicone composite particles adhere to the target surface, even if the lid 2 is damaged, the flame-retardant silicone composite particles can still protect the electrical components inside the test box 1. Furthermore, after being heated, the flame-retardant silicone composite particles can adhere to the surface of the test box 1, forming a protective film to prevent the fire extinguishing dry powder from directly contacting the electrical components, thereby avoiding potential damage to the electrical components caused by the fire extinguishing dry powder.

[0062] It should also be noted that the surface of flame-retardant silicone composite particles usually contains a variety of chemical bonds, such as silicon-oxygen bonds (Si-O-Si) and metal-oxygen bonds (such as Mg-O-Si, Al-O-Si). These chemical bonds will react with external substances under specific conditions (such as heating or chemical treatment) to form a dense oxide film (smooth film layer).

[0063] For example, when silicate ions (Si(OH)4) are hydrolyzed, they are rapidly adsorbed onto the surface of nanoparticles and form Mg-O-Si and Al-O-Si bonds with them, forming a continuous silicon film.

[0064] During heating, silicone rubber molecules undergo thermal degradation, generating silica (SiO2) particles. These particles deposit on the surface of the expanded microspheres, making the expanded barrier layer more dense and stable. For example, below 300°C, the surface expander of the intumescent flame-retardant silicone rubber dehydrates and expands, forming a stacked structure of thin-walled hollow microspheres. At the same time, the SiO2 particles generated by the thermal degradation of silicone rubber molecules are deposited on the surface of the expanded microspheres, forming a robust expanded barrier layer. When the flame-retardant silicone composite particles are sprayed out with the fire extinguishing dry powder and impact the target surface, the smooth film layer on the outer surface of the particles will be destroyed. This impact force causes particle deformation, resulting in protruding or concave surface structures. Experiments have shown that under flame conditions, the char layer structure of intumescent flame-retardant silicone rubber remains highly stable and intact even under the action of a high-intensity spray gun flame. However, as the impact force increases, the char layer is damaged, exposing the internal sticky material. After the smooth film on the surface is damaged, the chemical bonds (such as silicon-oxygen bonds and metal-oxygen bonds) that were originally protected by the film are exposed. These chemical bonds have high reactivity and can react chemically with the substances on the target surface to form new chemical bonds, thereby achieving adhesion.

[0065] The formation of a smooth film on the surface of flame-retardant silicone composite particles is mainly achieved through the formation of chemical bonds, the growth of silicon films, and nucleation processes. After this smooth film is broken under heating or impact, the internal chemical bonds and adhesive substances are exposed. Through the breaking and recombination of chemical bonds, physical adsorption and chemical adsorption, as well as the influence of heat treatment, a firm adhesion to the target surface is achieved. This characteristic gives flame-retardant silicone composite particles a significant advantage in the application of fire extinguishing dry powder, which can effectively improve the fire extinguishing effect and protect the electrical components on the target surface.

[0066] Example 3: Reference Appendix Figures 9 to 11 As shown in the figure, an automatic sealing mechanism 18 is provided between the test box 1 and the box cover 2 in this invention. When the test box 1 and the box cover 2 are closed to each other, the automatic sealing mechanism 18 can automatically seal the connection between the test box 1 and the box cover 2, ensuring the waterproof and dustproof performance of the test box 1.

[0067] Further reference Figure 10 As shown, the automatic sealing mechanism 18 includes a first sealing groove 19 and a second sealing groove 20. The first sealing groove 19 is disposed on the bottom surface of the box cover 2, and the second sealing groove 20 is disposed on the upper surface of the detection box 1. A rubber sealing airbag 22 is movably disposed in the first sealing groove 19. The rubber sealing airbag 22 is connected to the upper end of the first sealing groove 19 through an elastic mechanism. A first connecting rod 23 is fixedly disposed at the bottom of the rubber sealing airbag 22. A first magnetic plate 24 is fixedly disposed at the lower end of the first connecting rod 23. A second magnetic plate 25 is fixedly disposed on the lower inner wall of the second sealing groove 20. The first magnetic plate 24 and the second magnetic plate 25 are attracted to each other.

[0068] When the lid 2 is placed on the test box 1, the attraction between the first magnetic plate 24 and the second magnetic plate 25 pulls the lower end of the rubber sealing airbag 22 into the interior of the second sealing groove 20. At this time, the rubber sealing airbag 22 seals the joint between the test box 1 and the lid 2, achieving a better seal.

[0069] The elastic mechanism in this invention includes a spring 30, which is fixedly connected to the upper inner wall of the first sealing groove 19. An upper connecting plate 26 is fixedly provided at the lower end of the first sealing groove 19 and is fixedly connected to the upper surface of the rubber sealing airbag 22. When the box cover 2 is removed from the detection box 1, the spring 30 will pull the rubber sealing airbag 22 back into the first sealing groove 19 because the first magnetic plate 24 and the second magnetic plate 25 are separated. This avoids the problem of the rubber sealing airbag 22 being exposed to the outside and aging severely, and increases the service life of the automatic sealing mechanism 18.

[0070] Furthermore, an air chamber 21 is provided inside the cover 2. The air chamber 21 is located above the first sealing groove 19. A piston plate 28 is slidably arranged in the air chamber 21. A second connecting rod 27 is fixedly arranged at the bottom of the piston plate 28. The second connecting rod 27 extends movably into the interior of the first sealing groove 19, and one end of the second connecting rod 27 that extends movably into the interior of the first sealing groove 19 is fixedly connected to the upper surface of the upper connecting plate 26. The bottom of the air chamber 21 is connected to the interior of the rubber sealing airbag 22 through a hose 29.

[0071] During operation, when the rubber sealing airbag 22 moves to the seam between the test box 1 and the box cover 2, the second connecting rod 27 pulls the piston plate 28 and delivers the air in the air chamber 21 to the rubber sealing airbag 22 through the hose 29, causing the rubber sealing airbag 22 to expand and increase the sealing effect. When the box cover 2 is removed from the test box 1, the piston plate 28 will draw out the air from the rubber sealing airbag 22 during the resetting process, thus reducing the volume of the rubber sealing airbag 22 and making it easier to be put into the first sealing groove 19. Due to the change in volume, the rubber sealing airbag 22 can reduce wear between mechanical structures and ensure good sealing performance during use, which is quite practical.

[0072] It should be noted that the rubber sealing airbag 22 has chamfered corners 31 at its edges, which further reduces the resistance and friction during the movement of the rubber sealing airbag 22.

[0073] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A grounding fault detection device for power distribution network, comprising a detection box (1) and a box cover (2), the box cover (2) is openably arranged on the detection box (1), a grounding fault detection mechanism is arranged in the detection box (1), and a panel is packaged on the upper surface of the detection box (1), the panel is provided with an LED display screen (4) and a wiring terminal (5), characterized in that: The box cover (2) has an inner cavity (3) inside, and a flame-retardant buffer plate (6) is installed in the inner cavity (3). The flame-retardant buffer plate (6) is made of flame-retardant buffer material, and the area formed between the flame-retardant buffer plate (6) and the inside of the box cover (2) is filled with flame-retardant medium. ​ Flame retardant media include: the use of flame retardant heat insulation particles (8) or: Use carbon dioxide and dry extinguishing powder; Among them, the flame-retardant heat-insulating particles (8) are particles made from any one of the following: silicone resin encapsulation material, flame-retardant polycarbonate material, and epoxy resin potting mixture. The carbon dioxide and fire extinguishing dry powder also contain flame-retardant silicone composite particles, which have a smooth film layer on their surface.

2. A ground fault detection device for an electrical distribution network according to claim 1, characterized in that: The flame-retardant buffer plate (6) is provided with an inner groove (13) and a groove (7) on its upper and lower surfaces, respectively. The inner groove (13) and the groove (7) are quadrilateral grooves. The flame-retardant buffer plate (6) is provided with several through holes (12).

3. A ground fault detection device for an electrical distribution network according to claim 1, characterized in that: The detection box (1) is provided with a reserved cavity (15), which is used to install a communication module, an alarm module, a power management module and a data storage module.

4. The apparatus for ground fault detection for an electrical distribution network of claim 1, wherein: The flame-retardant buffer plate (6) is provided with a spray hole (16), and an elastic diaphragm (17) is fixedly connected in the spray hole (16).

5. A grounding fault detection system for power distribution networks, characterized in that: The ground fault detection device for power distribution networks according to any one of claims 1-4 further includes: Temperature sensor (9), leakage current sensor (10) and electric heating plate (11) are provided. The electric heating plate (11) is fixedly installed on the inner wall of the box cover (2). The electric heating plate (11) is in contact with the flame-retardant heat-insulating particles (8). The temperature sensor (9) is installed on the outer surface of the box cover (2). The leakage current sensor (10) is installed on the inner surface of the box cover (2) and corresponds to the top of the detection box (1).

6. A ground fault detection system for a power distribution network according to claim 5, characterized in that: Also includes: Communication module, alarm module, power management module, and data storage module; The communication module, alarm module, power management module and data storage module are installed inside the reserved cavity (15) in the detection box (1); The communication module uses a 4G / 5G wireless communication module or an RS485 wired communication module. The data storage module uses a large-capacity memory to store historical detection data and fault records.

7. A ground fault detection system for a power distribution network according to claim 6, characterized in that: The alarm module uses an audible and visual alarm device. The sound and light alarm device is positioned on the bottom surface of the panel, and the panel has a transparent glass plate area and a sound hole. The glass plate area allows light to pass through the sound and light alarm device, and the sound hole allows sound to pass through the sound and light alarm device.

8. A ground fault detection system for a power distribution network according to claim 6, characterized in that: The power management module uses a DC battery and is equipped with a solar charging panel and an external power interface. Among them, the solar charging panel is installed on the upper surface of the box cover (2), the DC battery is installed in the reserved cavity (15), the DC battery and the solar charging panel are connected by wires, the wires are pre-embedded, and the reserved cavity (15) is also equipped with a solar energy conversion device that converts solar energy into electrical energy.

9. A ground fault detection system for a power distribution network according to claim 5, characterized in that: The flame-retardant buffer plate (6) and flame-retardant heat-insulating particles (8) are installed inside the detection box (1) to protect the periphery of the grounding fault detection mechanism.

10. A ground fault detection system for a power distribution network according to claim 5, characterized in that: The temperature sensor (9), leakage current sensor (10), and electric heating plate (11) are connected by a controller; When a fire occurs outside the test box (1), the temperature will rise. When the temperature sensor (9) detects that the temperature outside the test box (1) is too high, the controller controls the electric heating plate (11) to start. The power management module in the inner groove (13) supplies power to the electric heating plate (11). The electric heating plate (11) fully heats and melts all the flame-retardant heat insulation particles (8), so that the protective film formed can completely cover the upper surface of the test box (1) to protect the test box (1). When there is a leakage at the wiring position or other position above the test box (1), the leakage sensor (10) detects the leakage and controls the electric heating plate (11) to start through the controller. The electric heating plate (11) heats the flame-retardant heat insulation particles (8) to form a fluid that flows on the upper surface of the test box (1). When the fluid solidifies, it forms a protective layer.

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