Low-voltage chamber for ring main unit

Abstract

The invention discloses a low-voltage chamber for a ring main unit, and the low-voltage chamber comprises an internal low-voltage compartment which is used for accommodating low-voltage electrical apparatus elements; the outer waterproof compartment is used for wrapping the inner low-voltage compartment; the aviation plug compartment is positioned at the front lower part of the internal low-voltage chamber and is used for accommodating an aviation plug and wiring thereof, and a wiring end of the aviation plug is sealed by adopting a welding combined glue pouring process; wherein the internal low-voltage compartment is isolated from the external waterproof compartment through a rubber sealing ring, and the aviation plug compartment is isolated from other compartments in the ring main unit through sealing rubber strips; and an anti-corrosion coating is formed on the surface of the external waterproof compartment through an integral electrostatic spraying process. Through systematic innovation of the structure, the material and the process, the waterproof performance and the comprehensive reliability of the low-voltage chamber of the ring main unit are remarkably improved.

Description

Technical Field

[0001] The invention relates to the technical field of power distribution equipment, and in particular to a low-voltage chamber for a ring network cabinet. Background Art

[0002] As the global climate becomes more extreme, flooding accidents in distribution rooms caused by heavy rainfall occur frequently, posing a severe challenge to the safe operation of power equipment. As the core equipment in the distribution room, the low-voltage room inside the ring main unit bears the key functions of low-voltage power distribution, control and protection. Its waterproof performance directly determines the overall operating stability of the ring main unit. When the low-voltage room encounters flooding, it is easy to cause equipment corrosion and short-circuit failures, which not only leads to power outages and threatens the safety of production and life, but also significantly increases the cost of power grid operation and maintenance. Therefore, improving the waterproof performance of the low-voltage room has become a technical problem that needs to be solved urgently.

[0003] In the prior art, the waterproof design of the low-voltage room of the ring main unit has the following systematic defects:

[0004] (I) Failure of waterproof isolation of cabinet structure

[0005] Traditional low-voltage room cabinets do not have an effective protection system for water accumulation and humid environments, and lack a multi-layer waterproof barrier. Typical problems include: weak links such as the interface between the bottom of the cabinet and the ground and the joints of the side panels have not been strengthened and sealed. When flooded, water can easily penetrate into the interior through the gaps and directly corrode the electrical components installed in the cabinet. For example, in a power distribution room with low terrain or poor drainage, accumulated water can quickly invade the cabinet, causing insulation failure of components, electrochemical corrosion of metal parts, short circuits and equipment damage.

[0006] (2) The cabinet material has insufficient corrosion resistance

[0007] Existing cabinets are mostly made of ordinary carbon steel or composite materials with low protection levels. When they are in a humid environment for a long time or immersed in water for a short time, the surface protective layer is easily damaged and rusted. Rust not only weakens the structural strength of the cabinet, but also forms pores on the surface of the plate, further reducing the sealing performance; at the same time, the rust particles may fall off and contaminate the internal components, resulting in poor contact or heat dissipation, increasing the risk of equipment failure.

[0008] (III) Waterproof design defects of wiring system

[0009] There is a technical bottleneck in the waterproof treatment of the connection between the mechanism room and the low-voltage room and the cabinet: the traditional threading hole seals and cable joints only meet the conventional moisture-proof requirements and cannot resist the pressure penetration during water immersion. Moisture can form "capillary penetration" along the gap between the cable and the seal and the micropores at the terminal connection, causing the line insulation layer to become damp and the conductor to short-circuit, which in turn causes a chain of failures, seriously affecting the safety and reliability of the low-voltage power distribution system.

[0010] In summary, there are waterproof short - comings in the structural design, material selection, connection protection, etc. of the existing low - voltage compartment of the ring - main unit. It is urgent to construct an integrated waterproof solution through innovative design to cope with the water - immersion threat under extreme weather and ensure the stable operation of the power distribution system. Summary of the Invention

[0011] The technical problem to be solved by the present invention is to provide a low - voltage compartment for a ring - main unit to prevent the corrosion problem after the cabinet body is immersed in water, improve the waterproof effect of wiring, and ensure the stable operation of electrical equipment.

[0012] To solve the above - mentioned technical problem, the present invention provides a low - voltage compartment for a ring - main unit, including:

[0013] An internal low - voltage compartment for accommodating low - voltage electrical components;

[0014] An external waterproof compartment for wrapping the internal low - voltage compartment;

[0015] An aviation - plug compartment located at the front lower part of the internal low - voltage compartment for accommodating aviation plugs and their wiring, and the wiring ends of the aviation plugs are sealed by a welding combined with potting process;

[0016] Among them, the internal low - voltage compartment and the external waterproof compartment are isolated by a rubber sealing ring, and the aviation - plug compartment and other compartments in the ring - main unit are isolated by a sealing strip; the surface of the external waterproof compartment is formed with an anti - corrosion coating through an overall electrostatic spraying process.

[0017] Preferably, the external waterproof compartment includes a front panel that matches the shape of the internal low - voltage compartment. The front panel is integrally welded by argon arc welding using a 304 stainless - steel plate, and the weld seam is pickled and passivated after welding.

[0018] Preferably, the overall electrostatic spraying process includes the following steps:

[0019] Pickle with an alkaline degreaser or nitric acid solution to form a rough surface, and then spray a passivation solution to form a passivation film;

[0020] Spray an anti - rust epoxy primer;

[0021] Spray a waterproof epoxy polyester powder coating topcoat;

[0022] Two curing processes.

[0023] Preferably, the film thickness of the electrostatically sprayed anti - rust epoxy primer is 15 - 30μm; the film thickness of the topcoat is 40 - 90μm, and the film thickness in the weld seam area is thickened to ≥25μm.

[0024] Preferably, in the two-curing process, the primary curing temperature is 160-210°C and the time is 15-20 minutes to make the powder coating level, and the secondary curing temperature is 190-210°C and the time is 10-20 minutes to ensure that the coating is completely cross-linked, and the temperature fluctuation of the curing furnace is ≤5°C.

[0025] Preferably, the front panel of the external waterproof compartment is fastened and sealed by evenly distributed bolts and silicone sealing strips.

[0026] Preferably, an observation window is embedded in the front panel and fixed by a sheet metal pressing frame combined with a sealing strip. During installation, sealant is applied around the observation window, and a waterproof sealing interface is formed after crimping.

[0027] Preferably, the interior of the aviation plug includes a copper alloy shell, a copper alloy gold-plated contact and a sealing ring, and is fixed by opening a mounting hole at a corresponding position of the aviation plug compartment.

[0028] Preferably, the connection terminal of the aviation plug adopts a double sealing process of argon arc welding and waterproof sealant injection, the welding parameters are adjusted according to the material and wire diameter of the wire, and after injection, the sealant completely covers the connection and solidifies to form a sealing layer.

[0029] Preferably, a support frame is provided outside the internal low-pressure compartment, and the front panel of the external waterproof compartment is welded to the support frame, and together with the support frame, a closed space enclosing the internal low-pressure compartment is formed.

[0030] The implementation of the present invention has the following beneficial effects: the present invention significantly improves the waterproof performance and comprehensive reliability of the low-voltage chamber of the ring main unit through systematic innovation of structure, material and process:

[0031] The multi-layer physical isolation structure constructs a three-level waterproof barrier: the external waterproof compartment is welded by 304 stainless steel argon arc welding, and combined with silicone sealing strips and electrostatic spray coatings to form a high-strength shell, which can effectively block the intrusion of external liquid water such as rain and immersion; the aviation plug compartment uses an IP68-level waterproof aviation plug and a "welding + glue filling" process to cut off the path for moisture to be introduced into the wiring; the internal low-voltage compartment is completely isolated from the outside through a sealed design to ensure that core components such as circuit breakers are protected from water vapor erosion.

[0032] The materials and surface treatment process greatly enhance the corrosion resistance: after welding, the front panel is pickled and passivated to eliminate the oxide layer, and a dense coating is formed by combining degreasing, pickling, passivation pre-treatment and double-layer electrostatic spraying, which significantly extends the service life of the cabinet in harsh environments such as humidity and salt spray, and reduces maintenance costs.

[0033] Refined sealing design ensures waterproof performance in all scenarios: The high temperature resistance and anti-aging properties of the silicone sealing strip ensure the sealing stability under long-term use; The observation window adopts a double-sealing structure of sheet metal pressing frame + sealing strip, eliminating the hidden danger of water seepage while realizing visual operation; The aviation plug has stable electrical performance, effectively avoiding faults such as short circuit and poor contact caused by water ingress into the circuit.

[0034] Systematic design improves engineering applicability: The functional partitions of each compartment are clearly defined. The external waterproof compartment and the internal low-voltage compartment are welded and fixed through the support frame, with a compact and stable structure; The layout of the aviation plug compartment is reasonable, facilitating the connection and docking between cabinets. The overall solution combines waterproof reliability and installation convenience, and is applicable to power distribution scenarios with rainy weather, high humidity, and easy water immersion (such as outdoor ring main units, underground distribution rooms, etc.), providing long-term protection for the safe operation of power equipment. Brief Description of the Drawings

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0036] Figure 1 It is a schematic side view structure diagram of a low-voltage compartment for a ring main unit in an embodiment of the present invention.

[0037] Figure 2 It is a schematic three-dimensional structure diagram of a low-voltage compartment for a ring main unit in an embodiment of the present invention.

[0038] Figure 3 It is an assembly schematic diagram of the front panel of the external waterproof compartment in an embodiment of the present invention. Detailed Embodiments

[0039] The following descriptions of the embodiments refer to the drawings to illustrate specific embodiments in which the present invention can be implemented. In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "longitudinal", "length", "circumferential", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation of the present invention.

[0040] Please refer to Figure 1 and Figure 2 as shown, an embodiment of the present invention provides a low-voltage compartment for a ring main unit, including:

[0041] The internal low-voltage compartment 1 is used to accommodate low-voltage electrical components;

[0042] The external waterproof compartment 2 is used to wrap the internal low-voltage compartment 1;

[0043] The aviation plug compartment 3 is located at the front lower part of the internal low-voltage compartment and is used to accommodate the aviation plug 4 and its wiring. The wiring terminal of the aviation plug 4 is sealed by a welding combined with potting process;

[0044] Among them, the internal low-voltage compartment 1 and the external waterproof compartment 2 are isolated by a rubber sealing ring, and the aviation plug compartment 3 and other compartments in the ring main unit are isolated by a sealing strip; The surface of the external waterproof compartment 2 is formed with an anti-corrosion coating through an overall electrostatic spraying process.

[0045] Specifically, the low-voltage compartment of the ring main unit in the embodiment of the present invention improves the waterproof performance systematically through structural optimization, material and process innovation, and sealing design improvement. The following is a specific description.

[0046] In the embodiment of the present invention, the low-voltage compartment adopts a three-layer physical isolation structure, including an internal low-voltage compartment 1, an external waterproof compartment 2, and an aviation plug compartment 3. The functions and connection methods of each compartment are as follows:

[0047] The internal low-voltage compartment 1 is located in the core area of the low-voltage compartment and is used to accommodate standard electrical components such as low-voltage circuit breakers and protection devices. The internal low-voltage compartment 1 adopts an openable instrument door design. There is a support frame 5 with a certain height outside the internal low-voltage compartment 1.

[0048] The external waterproof compartment 2 includes a front panel 20, whose contour matches the shape of the internal low-voltage compartment 1 to form a wrapped protection. During assembly, the front panel 20 is welded to the support frame 5, so as to jointly form a space that completely wraps the internal low-voltage compartment 1 with the support frame 5, becoming the external waterproof compartment 2.

[0049] Specifically, the front panel 20 is integrally welded and formed by 304 stainless steel plate through argon arc welding. The welding process parameters are as follows:

[0050] The welding current for thin plates (1 - 3 mm) is 25 - 100 A, and the welding temperature is 150°C - 350°C;

[0051] The welding current for medium-thick plates (4 - 6 mm) is 100 - 150 A, and the welding temperature is 250°C - 450°C;

[0052] After welding, pickling and passivation treatment is carried out on the weld: Apply pickling and passivation paste for 30 minutes, and clean it with a stainless steel brush until it is silver-white to eliminate the welding oxide layer.

[0053] For the outer layer of the panel 20 of the external waterproof compartment 2, an integral electrostatic spraying process is also required. This design can effectively prevent the problem of rusting after the cabinet is immersed in water, thereby preventing the impact on the waterproof performance of the equipment after water immersion and extending the waterproof life of the equipment. Specifically, the integral electrostatic spraying process is as described below:

[0054] (1) Pretreatment

[0055] Degreasing: Use an alkaline degreaser with a pH of 9 - 11 (such as NaOH solution), at a temperature of 50 - 60°C, soak for 20 minutes to remove surface grease.

[0056] Pickling: Use a 15% - 20% nitric acid solution, soak at room temperature for 10 minutes to form a dull white rough surface (surface roughness Ra 1.5 - 3.0μm).

[0057] Passivation: Spray a passivation solution containing chromate (pH 4.5 - 5.5) to form a passivation film with a thickness of 0.5 - 1.0μm to enhance the adhesion of the coating.

[0058] Optionally, sandblasting can also be carried out: Use quartz sand or steel shot to increase the surface roughness (the Ra value is controlled at 1.5 - 3.0μm).

[0059] (2) Electrostatic spraying:

[0060] Select an anti-rust epoxy primer for the primer, with a film thickness of 15 - 30μm, a spraying voltage of 60 - 80kV, and an atomizing air pressure of 0.4 - 0.6MPa.

[0061] Select a waterproof powder coating (such as an epoxy polyester system) for the topcoat, with a film thickness of 40 - 90μm, and thicken the local key areas (such as welds) to ≥25μm.

[0062] (3) Curing process:

[0063] Primary curing: Temperature 160 - 210°C, time 15 - 20 minutes, to level the powder coating;

[0064] Secondary curing: Temperature 190 - 210°C, time 10 - 20 minutes, to ensure complete cross-linking of the coating. The curing furnace needs to heat evenly, with a temperature fluctuation ≤5°C.

[0065] Verified by experiments, after being treated with the above integral electrostatic spraying process, in the salt spray test (5% NaCl solution, 35°C, continuous spraying for 72 hours), there is no obvious rust or red rust on the surface of the front panel 20, showing good anti-rust performance.

[0066] The front panel 20 of the external waterproof compartment 2 is uniformly fastened to the support frame 5 by bolts. The distribution positions of the bolts are designed according to the size and stress conditions of the front panel to ensure effective fastening in each area. A silicone rubber sealing strip is embedded at the edge of the front panel 20, and its performance parameters are: density 1.3 - 1.35 g / cm 3 ³, tensile strength 6 - 8 MPa (ordinary type), elongation at break 300% - 400%, hardness 60 - 65 Shore A, tear strength ≥ 6 MPa, temperature resistance range - 60 °C to 250 °C (long - term use temperature), can withstand 260 °C in the short term, has good resistance to organic solvents, ozone, and ultraviolet aging, and a low permanent deformation rate (such as deformation ≤ 50% at 200 °C for 48 hours). These properties endow it with excellent waterproof performance.

[0067] Furthermore, please refer to Figure 3 As shown, there are also several observation windows 21 on the front panel 20. The observation windows 21 are fixed by the installation method of sheet metal pressing frame plus sealing strip pressing. During installation, sealant is first applied around the observation window 21, then it is placed into the sheet metal pressing frame, and then tightly pressed onto the front panel 20 through the sealing strip 22 to ensure the sealing effect between the observation window 21 and the front panel 20, realizing visual operation while ensuring waterproofing.

[0068] The aviation plug compartment 3 is located in the front - lower area of the internal low - voltage compartment 1. The aviation plug compartment 3 is a non - waterproof compartment. The connections between the mechanism compartment and the low - voltage compartment, and between cabinets are all docked through the IP68 - level waterproof aviation plug 4 in this aviation plug compartment 3. The internal wiring of the aviation plug 4 adopts the process of welding + potting to effectively ensure the waterproof effect. The aviation plug compartment 3 is sealed by a cover plate 30. The cover plate 30 and the front panel 20 of the external waterproof compartment 2 can be integrally welded or fastened by bolts. A sealing rubber strip is used to isolate the aviation plug compartment 3 from other compartments to ensure the isolation effect between the aviation plug compartment 3 and other compartments.

[0069] As an example, the IP68 - level waterproof aviation plugs selected in the embodiments of the present invention are of models YD30 - 10ZJ / TK / B, YDT30 - 6ZJ / TKF / B, and YWT25 - RJ45J2T. Its internal structure includes a copper - alloy housing and copper - alloy gold - plated contact parts, and an internal sealing ring is provided for waterproof sealing. The installation method is to open installation holes at the corresponding positions of the aviation plug compartment 3 and fix the aviation plug 4 in the holes to ensure a stable connection.

[0070] The welding process at the internal wiring of the aviation plug 4 uses argon arc welding, and the specific welding parameters are adjusted according to the wire material and wire diameter to ensure firm welding. The potting process steps are: after welding is completed, clean the internal wiring of the aviation plug 4, and then pour special waterproof sealing glue to evenly cover the wiring, and form a sealing layer after curing to effectively prevent moisture from entering.

[0071] With this wiring connection method, under the dual protection of the waterproof design of the IP68 waterproof aviation plug and the welding + potting process, even in extremely humid environments, the stability of electrical connections can be ensured. In the IP68 waterproof test (water depth of 4 meters, immersion time of 72 hours, normal temperature environment), after the test, the appearance of the aviation plug 4 was inspected and there were no phenomena such as deformation, corrosion, coating peeling, water leakage, etc. The electrical performance test and function test were both normal, effectively reducing the failures caused by water ingress into the circuit.

[0072] As can be seen from the above description, the hierarchical structure of the embodiment of the present invention blocks moisture outside the external waterproof compartment 2 and the aviation plug compartment 3 through physical isolation and sealing design, effectively preventing moisture from penetrating into the internal low-voltage compartment 1 and ensuring the safety of key components. The external waterproof compartment 2 blocks most of the moisture, and the sealing measures in the aviation plug compartment 3 prevent moisture from being introduced by the wiring, creating a safe environment for the internal low-voltage compartment 1.

[0073] Compared with the prior art, the beneficial effects brought by the embodiment of the present invention are that through systematic innovations in structure, materials, and processes, the waterproof performance and comprehensive reliability of the low-voltage compartment of the ring main unit are significantly improved:

[0074] The multi-layer physical isolation structure constructs a three-level waterproof barrier: The external waterproof compartment is formed by argon arc welding of 304 stainless steel, combined with a silicone rubber sealing strip and an electrostatic spraying coating to form a high-strength outer shell, which can effectively block the intrusion of external liquid water such as rainwater and immersion water; the aviation plug compartment cuts off the path of moisture introduced by the wiring through the IP68 waterproof aviation plug and the "welding + potting" process; the internal low-voltage compartment is completely isolated from the outside through a sealing design to ensure that core components such as circuit breakers are not eroded by water vapor.

[0075] The materials and surface treatment processes significantly enhance the corrosion resistance: After the front panel is welded, pickling and passivation are carried out to eliminate the oxide layer, combined with degreasing, pickling, and passivation pretreatment and double-layer electrostatic spraying to form a dense coating, significantly extending the service life of the cabinet in harsh environments such as humidity and salt spray, and reducing the maintenance cost.

[0076] The refined sealing design ensures the waterproof effect in all scenarios: The high temperature resistance and anti-aging performance of the silicone rubber sealing strip ensure the sealing stability under long-term use; the observation window adopts a double-sealing structure of sheet metal pressing frame + sealing rubber strip, eliminating the potential for water seepage while enabling visual operation; the electrical performance of the aviation plug is stable, effectively avoiding faults such as short circuits and poor contact caused by water ingress into the circuit.

[0077] Systematic design enhances the engineering applicability: The functional partitions of each compartment are clearly defined. The external waterproof compartment and the internal low-voltage compartment are fixed by welding with a support frame, and the structure is compact and stable. The aviation plug compartment has a reasonable layout, facilitating the connection and docking between cabinets. The overall solution combines waterproof reliability and installation convenience, and is suitable for power distribution scenarios with rainy weather, high humidity, and easy water immersion (such as outdoor ring main units, underground power distribution rooms, etc.), providing long-term protection for the safe operation of power equipment.

[0078] The above-disclosed are only the preferred embodiments of the present invention. Of course, the scope of the rights of the present invention cannot be limited thereby. Therefore, equivalent changes made according to the claims of the present invention still fall within the scope covered by the present invention.

Claims

1. A low-voltage compartment for a ring main unit, characterized in that, include: Internal low-voltage compartment, used to accommodate low-voltage electrical components; an outer waterproof compartment for enclosing the inner low-pressure compartment; The aviation plug compartment is located at the front lower part of the internal low-voltage chamber and is used to accommodate the aviation plug and its wiring. The wiring terminal of the aviation plug is sealed by welding combined with glue filling process; Among them, the internal low-pressure compartment and the external waterproof compartment are isolated by a rubber sealing ring, and the aviation plug compartment and other compartments in the ring network cabinet are isolated by sealing strips; the surface of the external waterproof compartment is formed with an anti-corrosion coating through an overall electrostatic spraying process.

2. The low-voltage compartment for a ring main unit according to claim 1, wherein The external waterproof compartment includes a front panel that matches the shape of the internal low-pressure compartment. The front panel is formed by integrally welding 304 stainless steel plates through argon arc welding, and the weld is pickled and passivated after welding.

3. The low-voltage chamber for the ring main unit according to claim 1, characterized in that, The overall electrostatic spraying process comprises the following steps: Use alkaline degreasing agent or nitric acid solution to pickle to form a rough surface, and then spray passivation liquid to form a passivation film; Spray anti-rust epoxy primer; Spray waterproof epoxy polyester powder coating topcoat; Two-step curing process.

4. The low-voltage chamber for a ring main unit according to claim 3, characterized in that, The film thickness of the electrostatically sprayed anti-rust epoxy primer is 15-30 μm; the film thickness of the topcoat is 40-90 μm, and the weld area is thickened to ≥25 μm.

5. The low-voltage compartment for a ring main unit according to claim 3, characterized in that, In the two-step curing process, the first curing temperature is 160-210°C and the time is 15-20 minutes to make the powder coating level, and the second curing temperature is 190-210°C and the time is 10-20 minutes to ensure that the coating is completely cross-linked. The temperature fluctuation of the curing oven is ≤5°C.

6. The low-voltage compartment for a ring main unit according to claim 1, characterized in that, The front panel of the external waterproof compartment is fastened and sealed by evenly distributed bolts and silicone sealing strips.

7. The low-voltage compartment for a ring main unit according to claim 6, characterized in that, The front panel is embedded with an observation window, which is fixed by a sheet metal pressing frame combined with a sealing strip. During installation, sealant is applied around the observation window, and a waterproof sealing interface is formed after crimping.

8. The low-voltage compartment for a ring main unit according to claim 1, characterized in that, The interior of the aviation plug includes a copper alloy shell, a copper alloy gold-plated contact and a sealing ring, and is fixed by opening a mounting hole at a corresponding position of the aviation plug compartment.

9. The low-voltage compartment for a ring main unit according to claim 8, characterized in that, The connection end of the aviation plug adopts a double sealing process of argon arc welding and waterproof sealant injection. The welding parameters are adjusted according to the material and wire diameter of the wire. After injection, the sealant completely covers the connection and solidifies to form a sealing layer.

10. The low-voltage chamber for a ring main unit according to claim 1, characterized in that, A support frame is provided outside the internal low-pressure compartment, and the front panel of the external waterproof compartment is welded to the support frame, and together with the support frame, a closed space enclosing the internal low-pressure compartment is formed.

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