Anti-electromagnetic interference low-voltage cabinet

Abstract

The utility model discloses an anti-electromagnetic interference low-voltage cabinet, which comprises a cabinet body and a cabinet door which are hinged with each other, electrical elements are arranged in the cabinet body, ventilation holes are correspondingly arranged on the cabinet body and the cabinet door, and metal filter screens for dust prevention and electromagnetic shielding are arranged in the ventilation holes. According to the utility model, the anti-electromagnetic interference effect of the low-voltage cabinet can be effectively improved.

Description

Technical Field

[0001] The utility model relates to the technical field of electrical equipment, in particular to a low-voltage cabinet capable of resisting electromagnetic interference. Background Art

[0002] The new development context has placed higher demands on the quality of various types of instrumentation and control equipment. Especially with the continued advancement of localization, electromagnetic compatibility (EMC) is a crucial metric in evaluating I&C equipment. Currently, various electronic devices face varying electromagnetic environments during their use. Only by paying close attention to EMC can we ensure the safe and stable operation of the system.

[0003] A low-voltage cabinet is a device used in power distribution systems, primarily for distributing, controlling, protecting, and monitoring electrical energy. It transforms and distributes input electrical energy, safely and stably supplying it to various electrical devices, ensuring the normal operation of the power system. Traditional low-voltage cabinets have few targeted measures to combat the effects of electromagnetic interference. Conventional cabinets and electrical design layouts fail electromagnetic compatibility tests and are prone to performance degradation or even failure in electromagnetic interference environments, impacting the stable operation of the power system. Therefore, developing a low-voltage cabinet with efficient electromagnetic interference resistance is particularly important.

[0004] In response to the above problems, the utility model patent document with application number CN202221476999.3 discloses a low-voltage distribution cabinet with anti-electromagnetic interference function, including a cabinet body, a plurality of equally spaced mounting seats fixedly installed on the top of the cabinet body, a slot provided on the lower surface of the mounting seat, a card slot provided on the mounting seat at the slot, a plug rod sleeved on the bottom of the mounting seat, and a filter fixedly connected to the bottom of the plug rod. The application achieves the anti-electromagnetic interference function by adjusting the distance between the control elements of each electrical equipment to avoid mutual interference between electrical equipment.

[0005] The above technical solution can adjust this feature by utilizing the position of the mounting plate, thereby increasing the distance between each electrical device during installation and avoiding mutual interference between the electrical devices. However, it still has certain shortcomings when used: the anti-interference ability is limited by only adjusting the distance between each electrical device, and while ensuring good anti-electromagnetic interference, the volume of the low-voltage distribution cabinet will be increased, thereby increasing the manufacturing cost. At the same time, during the use of the low-voltage distribution cabinet, it will not only be affected by electromagnetic interference from internal components, but also by electromagnetic interference from the external environment. The application does not take protective measures against external interference.

[0006] The invention patent document with application number CN202310713556.4 discloses a low-voltage cabinet with anti-interference function, including a cabinet body, the surface of the cabinet body is rotatably connected to a cabinet door, support frames are fixed at the corner positions inside the cabinet body, and placement mesh plates are arranged between the support frames. The surface of the cabinet body is provided with a high-efficiency heat dissipation mechanism, and the interior of the high-efficiency heat dissipation mechanism includes a heat dissipation component, an air duct and a blower. The inner wall of the cabinet body is provided with an anti-interference mechanism, and the interior of the anti-interference mechanism includes an anti-interference component, a connecting plate and a fastening bolt. The placement mesh plate is slidably connected to the support frame through an inspection mechanism, and the inspection mechanism consists of a limiting component, a tripod and a slide groove.

[0007] The above technical solution fixes the anti-interference component by providing an anti-interference mechanism and using fastening bolts to fix the connecting plate to the inner wall of the cabinet. Under the action of the gold wire woven mesh layer and the shielding mesh layer, it can effectively shield external signal interference. At the same time, since the electrical equipment inside the cabinet is not easily susceptible to electromagnetic interference, the anti-interference function of the low-voltage distribution cabinet is achieved, thereby improving the use effect of the low-voltage distribution cabinet. Although the above technical solution uses a gold wire woven mesh layer and a shielding mesh layer, the anti-interference effect needs to be further improved because there are no targeted shielding measures designed for the various holes in the cabinet and the gaps between the door panel and the cabinet. Utility Model Content

[0008] The purpose of the utility model is to provide a low-voltage cabinet with electromagnetic interference resistance, which can effectively improve the electromagnetic interference resistance of the low-voltage cabinet.

[0009] The utility model adopts the following technical solutions:

[0010] A low-voltage cabinet resistant to electromagnetic interference comprises a hinged cabinet body and a cabinet door. Electrical components are arranged in the cabinet body. Ventilation holes are correspondingly arranged on the cabinet body and the cabinet door. Metal filters for dust prevention and electromagnetic shielding are arranged in the ventilation holes.

[0011] Preferably, corresponding contact portions between the cabinet body and the cabinet door are provided with sealing strips for dust prevention and electromagnetic shielding.

[0012] Preferably, the cabinet is arranged on a base, and the cabinet is grounded via the base.

[0013] Preferably, a grounding device is provided on the cabinet body and / or the cabinet door, and the cabinet body and / or the cabinet door are grounded via the grounding device and the base.

[0014] Preferably, a metal cable tray is provided in the cabinet, and the metal cable tray is grounded through the cabinet and the base.

[0015] Preferably, the cabinet includes a cabinet frame and a cabinet panel, and the cabinet frame is grounded via a base.

[0016] Preferably, an AC filter and / or a DC filter is provided in the cabinet, the AC filter and / or the DC filter are electrically connected to the corresponding AC line terminal and / or DC line terminal, and the housing of the AC filter and / or the DC filter is grounded.

[0017] Preferably, the connection cables of the electrical components in the cabinet are classified and placed according to their anti-electromagnetic interference capabilities, and the classified connection cables are arranged at intervals.

[0018] Preferably, the cabinet door is only provided with ventilation holes, and the cabinet body is only provided with ventilation holes and cabinet connecting holes.

[0019] Preferably, a plurality of functional rooms are provided inside the cabinet, and reinforcing ribs are provided between the partitions of each functional room and the cabinet frame.

[0020] The utility model installs a metal filter for dust prevention and electromagnetic shielding inside the ventilation hole, which can not only ensure the effective shielding and grounding of the ventilation hole, but also meet the IP4X protection level requirements, thereby effectively improving the anti-electromagnetic interference effect of the low-voltage cabinet;

[0021] Furthermore, the present invention provides sealing strips for dustproofing and electromagnetic shielding at the corresponding contact parts between the cabinet body and the cabinet door, thereby meeting the IP4X protection level and effectively preventing external electromagnetic interference signals from entering the cabinet body, thereby meeting the electromagnetic interference test.

[0022] Furthermore, the present invention provides a grounding device on the cabinet body and / or the cabinet door, and the cabinet body and / or the cabinet door are grounded via the grounding device and the base, thereby improving the reliability of the cabinet body in preventing electromagnetic interference;

[0023] Furthermore, the utility model also provides a metal cable tray in the cabinet, and the high-voltage cables are arranged in the metal cable tray. The metal cable tray is grounded through the cabinet and the base by connecting wires to eliminate the electromagnetic field effect generated by the high-voltage cables after they are energized as much as possible.

[0024] Furthermore, the present invention also provides an AC filter and / or a DC filter in electrical connection with the corresponding AC line terminals and / or DC line terminals in the cabinet, thereby effectively eliminating harmonics in the voltage and current and reducing electromagnetic interference to the equipment and systems in the cabinet.

[0025] Furthermore, the present invention also takes into account the different anti-electromagnetic interference capabilities of different cables, classifies different cables according to their anti-electromagnetic interference capabilities, and then stores each type of cable in separate compartments, thereby minimizing costs and reducing electromagnetic compatibility risks;

[0026] The utility model effectively improves the anti-electromagnetic interference effect of the low-voltage cabinet by combining multiple anti-electromagnetic interference measures. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural diagram of the utility model;

[0028] Figure 2 This is a schematic diagram of the structure of the cabinet door in the present invention;

[0029] Figure 3 This is a structural diagram of the lower panel of the cabinet frame in the present invention;

[0030] Figure 4 This is a schematic diagram of the layout of the electrical components inside the cabinet of the present invention.

[0031] In the figure, 1. Cabinet door; 2. Cabinet body; 3. Top panel; 4. Side panel; 5. Metal filter; 6. Grounding stud; 7. Metal elastic contact strip; 8. Reinforcement rib; 9. Bottom panel; 10. Cable entry and exit holes; 11. Channel steel; 12. DC power unit; 13. DC filter; 14. Outlet terminal; 15. DC input terminal; 16. AC input terminal; 17. AC filter; 18. AC control circuit; 19. Signal circuit; 20. Mounting hole. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Those skilled in the art should know that the embodiments described below are part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0033] The following describes various non-limiting embodiments of the present invention in detail. The numbers of any elements in the drawings are for illustration only and not for limitation, and any names are for distinction only and do not have any limiting meaning.

[0034] The principle and spirit of the present invention are explained in detail below with reference to several representative embodiments of the present invention.

[0035] like Figures 1 to 4 As shown, the low-voltage cabinet for resisting electromagnetic interference described in the utility model includes a hinged cabinet body 2 and a cabinet door 1, electrical components are arranged in the cabinet body 2, ventilation holes are correspondingly arranged on the cabinet body 2 and the cabinet door 1, and a metal filter 5 for dust prevention and electromagnetic shielding is arranged in the ventilation holes.

[0036] In the prior art, ventilation holes are mostly set on the low-voltage cabinet body 2, but the plastic filter is installed in the ventilation holes, which can easily cause external electromagnetic interference signals to enter the cabinet body 2 through the ventilation holes, causing the electrical components of the low-voltage cabinet to be subject to electromagnetic interference from the external environment. In the present utility model, ventilation holes can be correspondingly set on the top panel 3, the rear panel and the cabinet door 1 of the cabinet body 2, and a metal filter 5 for dust prevention and electromagnetic shielding can be installed inside the ventilation holes. In this embodiment, the metal filter 5 can be made of a copper material with a mesh size of 30 or more, and the filter can be grounded through the cabinet body 2, which can not only ensure effective shielding and grounding at the ventilation holes, but also meet the IP4X protection level requirements, thereby effectively improving the anti-electromagnetic interference effect of the low-voltage cabinet.

[0037] The arrangement of the metal filter 5 is based on the same design concept. In the present invention, a sealing strip for dust prevention and electromagnetic shielding is further arranged at the corresponding contact portion between the cabinet body 2 and the cabinet door 1 . The sealing strip can be grounded through the cabinet body 2 .

[0038] In this embodiment, the sealing strip can be a metal elastic contact strip 7, such as a metal elastic contact strip 7 made of copper. When the cabinet 2 is closed by the cabinet door 1, the metal elastic contact strip 7 seals the cabinet 2 through the gap between the cabinet doors 1 with a certain pressure, which not only meets the IP4X protection level, but also effectively prevents external electromagnetic interference signals from entering the cabinet 2, thereby meeting the electromagnetic interference test.

[0039] In this utility model, to ensure effective grounding, the cabinet 2 can be mounted on a base, which provides grounding to the cabinet 2. In this embodiment, the base is grounded at its lower end, and a connection portion made of channel steel 11 is provided at its upper portion. The bottom of the cabinet 2 is adapted to the connection shape of the channel steel 11. The bottom of the cabinet 2 is bolted to the base using eight mounting holes 20 provided on the channel steel 11. The bottom of the cabinet 2 is in close contact with the channel steel 11, ensuring effective grounding.

[0040] In the present invention, a grounding device is provided on the cabinet body 2 and / or the cabinet door 1, and the cabinet body 2 and / or the cabinet door 1 are grounded via the grounding device and the base. In this embodiment, a grounding device can be provided on the top panel 3, the rear panel and the cabinet door 1 of the cabinet body 2, and the grounding device can adopt a grounding stud 6, which realizes the grounding effect through the cabinet body 2 and the base. When realizing the connection between the grounding stud 6 and the cabinet body 2, a grounding wire provided with a copper nose can be used for connection, and the grounding wire copper nose provided on the grounding stud 6 can be compressed by a toothed washer and a nut to ensure good contact. In particular, the grounding stud 6 welded on the door panel, after the grounding wire copper nose is compressed by a toothed washer and a nut, can effectively prevent the grounding wire from having poor contact with the cabinet door 1 after the cabinet door 1 is sprayed, thereby improving the reliability of the cabinet body 2 in preventing electromagnetic interference.

[0041] Since the high-voltage cables will generate a large electromagnetic field after being energized, in order to prevent the electromagnetic interference caused by this electromagnetic field, in the utility model, a metal cable tray is provided in the cabinet 2, and the high-voltage cables are arranged in the metal cable tray. The metal cable tray is grounded through the cabinet 2 and the base through the connecting wires to minimize the influence of the electromagnetic field generated after the high-voltage cables are energized.

[0042] In the present invention, the cabinet 2 includes a cabinet frame and a cabinet panel. The upper, lower, left, right, and rear sides of the welded cabinet 2 frame are each provided with a corresponding cabinet panel. The front side of the cabinet frame is hinged to the cabinet door 1. The cabinet 2 is grounded via the base. The left, right, and rear sides of the cabinet frame are respectively provided with side panels 4 for sealing. The bottom panel 9 of the cabinet 2 is provided with a cable entry and exit hole 10. The cable entry and exit hole 10 is installed with a rubber gasket. The rubber gasket not only prevents cable wear, but also, to a certain extent, isolates electromagnetic interference from entering the interior of the cabinet 2 through the cable. The metal filter 5 in the ventilation hole, the sealing strip provided at the corresponding contact portion of the cabinet 2 and the cabinet door 1, the grounding stud 6, and the metal cable tray can all be grounded through the cabinet 2 frame and the base.

[0043] In the present invention, several functional rooms for installing different electrical components are provided inside the cabinet 2, such as AC input terminals 16, DC input terminals 15, output terminals 14, AC filters 17, DC filters 13, DC power units 12, AC control circuits 18, signal circuits 19 and other electrical components. The AC and DC circuits, power units and strong and weak currents are installed separately, and reinforcing ribs 8 are provided between the partitions of each functional room and the frame of the cabinet 2 to improve the supporting strength.

[0044] When designing the electrical layout and installation process of the low-voltage cabinet:

[0045] To ensure effective filtering and electromagnetic compatibility (EMC), filtering encompasses all measures to reduce conducted signals. This includes the electrical and mechanical structure of the filter unit, grounding of the filter housing, and resistive loads on the conductors. Furthermore, filtering encompasses cables, particularly power cables, which must meet the conducted emission limits specified in the standard. Furthermore, the filter circuit must ensure that it does not compromise the shielding of the housing, enclosure, or enclosure.

[0046] Therefore, in the present invention, an AC filter 17 and / or a DC filter 13 are installed within the cabinet 2. These filters are electrically connected to the corresponding AC line terminals 16 and / or DC line terminals 15. The housings of the AC filters 17 and / or DC filters 13 are grounded. The AC filters 17 and DC filters 13 effectively eliminate harmonics in the voltage and current, reducing electromagnetic interference (EMI) that may affect the equipment and systems within the cabinet. The connection between the AC filters 17 and DC filters 13 is conventional in the art and will not be further described here.

[0047] Cabling performance considerations require careful consideration. Cables and transmission lines interact with their electromagnetic environment. The energy and signals transmitted through the cable generate electromagnetic fields in and around the cable. Ideally, a perfectly symmetrical coaxial cable with a solid shield would generate zero electromagnetic fields. However, cables can also absorb electromagnetic signals from their surroundings and transmit them to devices. Therefore, coexisting different types of cables creates the risk of coupling.

[0048] In order to solve the above problem, in the present invention, the connection cables of the electrical components in the cabinet 2 are classified and placed according to the anti-electromagnetic interference capability, and the classified connection cables are arranged at intervals.

[0049] In the present invention, taking into account the different anti-electromagnetic interference capabilities of different cables, different cables can be divided into three categories according to their anti-electromagnetic interference capabilities, namely sensitive type, unaffected type and self-electromagnetic interference type. Then, each type of cable is classified and stored. When the distance between each type of cable is generally about 0.1 meter, the cost can be minimized and the electromagnetic compatibility risk can be reduced to the greatest extent.

[0050] In this utility model, for overall shielding purposes, only ventilation holes are provided on the cabinet door 1, and only ventilation holes and cabinet-joining holes are provided on the side panels of the cabinet body 2. Metal plugs are temporarily installed in the cabinet-joining holes, which can be removed when the low-voltage cabinets are joined. No unnecessary holes are designed on the exterior of the entire low-voltage cabinet, thereby minimizing the risk of external electromagnetic interference signals entering the interior of the cabinet body 2.

[0051] In summary, the present invention effectively improves the anti-electromagnetic interference effect of the low-voltage cabinet by combining multiple anti-electromagnetic interference measures.

[0052] According to the above description of this specification, those skilled in the art may also understand that the terms used below, such as "up", "down", "front", "back", "left", "right", "inside", "outside" and other terms indicating orientation or positional relationships are based on the orientation or positional relationships shown in the drawings of this specification. They are only for the purpose of facilitating the explanation of the scheme of the utility model and simplifying the description, rather than explicitly or implicitly indicating that the devices or elements involved must have the specific orientation, be constructed and operated in a specific orientation. Therefore, the above-mentioned orientation or positional relationship terms cannot be understood or interpreted as limitations on the scheme of the utility model.

[0053] In addition, in the description of this specification, “a plurality of” means at least two, for example, two, three or more, etc., unless otherwise clearly and specifically defined.

Claims

1. A low-voltage cabinet for resisting electromagnetic interference, comprising a hinged cabinet body and a cabinet door, wherein electrical components are arranged in the cabinet body, characterized in that: The cabinet body and the cabinet door are correspondingly provided with ventilation holes, and metal filters for dust prevention and electromagnetic shielding are provided in the ventilation holes; a metal cable tray is provided in the cabinet body, and the metal cable tray is grounded through the cabinet body and the base.

2. The low-voltage cabinet for resisting electromagnetic interference according to claim 1, characterized in that: The corresponding contact parts of the cabinet body and the cabinet door are provided with sealing strips for dust prevention and electromagnetic shielding.

3. The low-voltage cabinet against electromagnetic interference according to claim 1, characterized in that: The cabinet body is arranged on the base, and the cabinet body is grounded via the base.

4. The low-voltage cabinet for resisting electromagnetic interference according to claim 1, characterized in that: The cabinet body and / or cabinet door are provided with a grounding device, and the cabinet body and / or cabinet door are grounded via the grounding device and the base.

5. The low-voltage cabinet against electromagnetic interference according to claim 3, characterized in that: The cabinet comprises a cabinet frame and a cabinet panel, and the cabinet frame is grounded via a base.

6. The low-voltage cabinet against electromagnetic interference according to claim 1, characterized in that: An AC filter and / or a DC filter is provided in the cabinet, the AC filter and / or the DC filter are electrically connected to the corresponding AC line terminal and / or the DC line terminal, and the housing of the AC filter and / or the DC filter is grounded.

7. The low-voltage cabinet against electromagnetic interference according to claim 1, characterized in that: The connection cables of the electrical components in the cabinet are placed in categories according to their anti-electromagnetic interference capabilities, and the various types of connection cables placed in categories are arranged at intervals.

8. The low-voltage cabinet against electromagnetic interference according to claim 1, characterized in that: The cabinet door is only provided with ventilation holes, and the cabinet body is only provided with ventilation holes and cabinet merging holes.

9. The low-voltage cabinet against electromagnetic interference according to claim 5, characterized in that: A plurality of functional rooms are arranged inside the cabinet body, and reinforcing ribs are arranged between the partitions of each functional room and the cabinet body frame.

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