Enclosed Insulated Rectangular Busbar with Common Enclosure

1. The GFT(L)M series of enclosed, insulated rectangular busbars—also known as common-box enclosed insulated rectangular busbars (3-35 kV / 250 A - 5000 A)—are developed and manufactured by our company in response to market demands and are designated as nationally promoted standardized products. These products are widely used in high-voltage switchgear substations between switchgear units, between the low-voltage side of transformers and switchgear cabinets, and in transmission and distribution lines for generators. The product’s key features and structural performance are as follows:

Category:

Closed Insulated Bus

Product Description

　　1. Common Enclosed Insulated Rectangular Busbar

　　The GFT(L)M series enclosed, insulated rectangular busbar (3–35 kV / 250 A–5000 A) is a standardized product promoted by the state, developed and manufactured by our company in response to market demands. This product is widely used in high-voltage switchgear between substations, between the low-voltage side of transformers and switchgear, and in transmission and distribution lines for generators. The product’s main features and structural performance are as follows:

　　1) The enclosure is fabricated from high-quality, non-magnetic aluminum alloy sheets and features a fully enclosed structure with excellent corrosion resistance and outstanding heat dissipation performance. The non-magnetic enclosure significantly reduces eddy-current heating caused by high-voltage currents, thereby lowering the temperature of the enclosed busbar enclosure, minimizing electrical energy losses, and increasing current-carrying capacity.

　　2) The conductors shall use rectangular busbars made of high-quality copper and aluminum materials.

　　3) The special flange design allows larger busbar enclosure units to be flexibly assembled, simplifying, standardizing, and systematizing the design and installation of busbar systems.

　　4) Each busbar section shall be equipped with inspection openings reasonably positioned at the upper part (or optionally on the side or at the bottom, depending on site requirements). This allows maintenance personnel to access any location inside the busbar. The inspection openings are fabricated using a bending and flanging process and are fully welded with high-quality flange connections, ensuring that the busbar system’s enclosure achieves an IP54 protection rating.

　　5) For high-current indoor enclosed busbars, ventilation louvers are provided on both sides and at the bottom of the enclosure to enhance heat dissipation and reduce temperature rise.

　　6) The exquisite manufacturing process and rational structural design ensure that, after busbar fabrication, the surface is smooth and flat, meeting the requirement of no water accumulation on the outdoor enclosure. A water drainage device is installed at the bottom of the enclosure, which not only prevents internal water accumulation but also effectively blocks the intrusion of dust and foreign objects.

　　7) The rationalized internal support structure design ensures a safe electrical clearance between each phase busbar, fully meeting the customer’s operational requirements. The grounding terminals designed at the flange openings at the ends of each busbar section enable the busbar system to have a seamless, integrated grounding system once installation is complete. With double insulation and multi-point grounding connections on the enclosure, maintenance work is significantly reduced, and safety performance is markedly enhanced.

　　8) Both the inner and outer surfaces of the enclosed busbar enclosure are coated with a matte paint, and the color can be selected according to customer requirements.

　　9) Common technical parameters

　　2. Enclosed Insulated Tubular Busbar with Common Enclosure

　　As substation capacities increase, the rated currents of the 10kV and 35kV busbars for main transformers are steadily rising (exceeding 3,000 A). Conventional rectangular busbars suffer from drawbacks such as uneven current distribution, a high skin-effect coefficient, increased heat losses, and difficulty in meeting short-circuit current requirements in terms of dynamic stability. The GFGM series of enclosed, insulated tubular busbars (3–35 kV / 1,600–800 A) represent a new type of enclosed, insulated tubular busbar developed by our company in response to market demands. This product represents an upgrade over traditional enclosed, insulated rectangular busbars in all performance aspects and has already been successfully applied in practical engineering projects. Our company provides comprehensive follow-up services throughout the entire process—from design and manufacturing to testing and installation guidance.

　　In addition to possessing the same structural features and performance as enclosed insulated rectangular busbars, this product also offers the following advantages:

　　1) It has a large current-carrying capacity, low skin-effect loss, and low power loss—only one-fourth that of copper-aluminum rectangular busbars with the same cross-sectional area.

　　2) High allowable stress, large short-circuit current, and high mechanical strength.

　　3) The busbar boasts high safety performance and is equipped with an enclosure protection that conventional tubular busbars lack, effectively preventing human contact with live busbars as well as the entry of small animals and metallic objects that could cause busbar losses and phase-to-phase short circuits.

　　4) Common technical parameters

　　3. Technical Performance Requirements for Enclosed Insulated Busbar Systems with Common Enclosure

　　1. Implement technical standards

　　2. Technical Performance Requirements

　　The busbar conductor uses air as the insulating medium, and the appropriate insulation clearance is selected based on different voltage levels.

　　The conductor insulation support is a post insulator, which can be selected based on the voltage level, busbar specifications, and the customer’s requirements for the mechanical load of the post insulator.

　　1) Insulation resistance: The insulation resistance value of each enclosed busbar unit shall be greater than or equal to 100 MΩ (using a 2500V megohmmeter).

　　2) Dielectric Strength: Each section of enclosed busbar undergoes a 1-minute power-frequency withstand voltage test before leaving the factory. The power-frequency withstand voltage and lightning impulse withstand voltage values comply with national standards.

　　3) Earthing system: Complies with the requirements for earthing systems specified in IEC 364-5-54.

　　4) Protection rating: Indoor type: IP40; Outdoor type: IP43, IP54.

　　5) Load performance: Under rated current, the temperature rise of the enclosure complies with the requirements of GB763-90 “Heat Generation during Long-Term Operation of AC Voltage Apparatus.”

　　3. Special Notice

　　1) The enclosed busbar shall be supplied as a complete set by the manufacturer, and the relevant technical requirements for the product must be clearly specified prior to delivery.

　　2) Enclosed busbars require additional heating and dehumidification systems, and temperature and humidity monitoring must be specifically requested; this component is not typically included in the standard busbar package.

　　3) The detailed dimensions of the enclosed busbar shall be determined through on-site surveys and precise measurements conducted by the manufacturer. Based on the actual site conditions and in conjunction with the blueprint design and construction drawings, the dimensions shall be submitted to the design department or the owner for approval.

　　4) The color of the enclosed busbar shall match that of the on-site switchgear or related connected equipment.

　　5) During on-site installation and commissioning of the product, the manufacturer is responsible for providing installation guidance.

Enclosed insulated tubular busbar with common enclosure

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Hubei Bailian New Energy Technology Co., Ltd. Enterprise Code

Hubei Lianhua Power Busbar Manufacturing Co., Ltd. Enterprise Code