What are the types of tubular bus ducts used in modern power transmission and transformation construction?

1. Divided by insulation method.Tube type busbars are divided into fully insulated and semi insulated types.

Fully insulated tube type busbar: using copper, aluminum, or alloy tubes as conductors, with an external insulation layer, the insulation effect can be achieved solely by the insulation layer. The surface potential is zero, touchable, and suitable for any environment. It operates stably and safely with a high level of protection.

Semi insulated tube type busbar: The same copper tube, aluminum tube or alloy tube is used as the conductor, and the insulation layer is also applied externally, but the insulation layer is relatively thin, mainly relying on insulators for insulation, and has not yet achieved full protection. The operating surface has induced current and is suitable for outdoor overhead incoming lines.

2. ToClassification based on material.The tubular busbar is divided into:Aluminum tube busbar, copper tube busbar, aluminum magnesium silicon alloy tube busbar, square tube busbar.

Aluminum tube busbar: a tube busbar mainly made of aluminum or aluminum alloy as the conductor. The conductivity of aluminum is second only to silver, copper, and gold. Although its conductivity is only 2/3 of copper, its density is only 1/3 of copper. Therefore, in order to achieve the same amount of electricity transmission, aluminum tube busbars often need to be enlarged and thickened. In addition, the oxide film on the surface of aluminum not only has the ability to resist corrosion, but also has a certain degree of insulation. In addition, aluminum tube busbars are inexpensive, making them widely used in power construction projects with cost requirements.

Copper tube busbar: As the name suggests, a copper tube busbar with copper as the conductor has the best conductivity and longest service life. It is widely used in power construction projects that require high current transmission, but its price is relatively high. It can be used in projects with low budget requirements.

Aluminum magnesium silicon alloy tubular busbar: a deformation alloy with aluminum as the base element and magnesium and silicon as the main alloying elements. Has good weldability and corrosion resistance.

Square tube busbar: Due to its square shape, it is also known as square tube busbar. It is made by casting and is also known as cast tube busbar. It has high protection, safety and durability.

In order to address the negative impact of screen movement on the busbar during the operation of transformers, generators, and distribution cabinets, soft connections or copper braided tapes are used outside their connection to the busbar trunking, and rubber pads are added between the external chargers to reduce vibration; For the busbar trunking body, a damper is installed in the system to provide elastic support for the porcelain bottles and conductive bars, effectively avoiding mechanical and ground wave damage to the enclosed busbar caused by the shell.
The heat transfer of the bus duct mainly relies on thermal radiation. In order to make good use of thermal radiation, light gray paint is sprayed on the outer surface of the bus duct to reduce the absorption of visible light. Black paint is sprayed on the inner surface of the bus duct to enhance the radiation of internal heat to the shell and prevent corona.
In order to avoid accidental condensation caused by temperature changes outdoors and indoors in winter, wall sleeves are installed at the penetration points to isolate the outdoor and indoor busbars; When installed vertically Inside the flange When installed horizontally, the flange is on the outside.
In order to improve the allowable operating temperature rise of the busbar mast, prevent electrolytic corrosion of the joints in coastal open air and severe electrochemical corrosion atmosphere, and reduce contact resistance, all joints are treated with silver plating to increase the allowable temperature rise of the joints to 65K, which is much higher than the normal operating temperature rise.
In order to avoid the resonance frequency range of the bus duct (for a single bus, the resonance frequency range is 35-135Hz) and reduce the electric force acting on the bus, the span between insulators should be reasonably determined, and the type, specification, and strength level of insulators should be selected.
In order to monitor the temperature of detachable joints, sealed observation windows are installed at the connection outlets between transformers, generators, distribution cabinets, and bus ducts. Temperature is directly measured through temperature sensors or far-infrared measuring devices to monitor the operation of the bus system.
For the convenience of users, current transformers can be installed at the generator outlet and the primary side of the excitation transformer according to their needs, making it easy for users to detect the current.

When installing metal cable trays vertically or obliquely, measures should be taken to prevent wires or cables from moving in the slots.

2. All phase and neutral wires of the same circuit should be placed in the same metal trunking

3. The trunking of tubular busbars is suitable for indoor drying in normal environments and places that are not easily damaged by machinery, but should not be used in areas where metal trunking is severely corroded.

4. The lines drawn in metal cable trays can be wired, such as metal pipes, hard plastic pipes, semi-rigid plastic pipes, metal hoses, or cables. The lead out part should not damage the busbar or cable

5. The tubular bus duct should be grounded or reliably grounded, but should not be used as a grounding wire for equipment.

6. The lines should be smooth and not deformed, and the inner wall should be smooth and free of burrs.

Installation form: The basic form can be divided into vertical installation and horizontal installation. Horizontal installation can be arranged in multiple layers. It can also be designed according to the on-site situation.

Determination of transmission busbar and installation method: The current carrying capacity of the transmission busbar must meet the total electrical load of all equipment in the work site.

There should be a layout plan for the position and direction of the transmission busbar, and the determination of the support form should be carried out through on-site survey.

The installation diagram shows the basic form, in which the horizontal installation can increase or decrease the number of layers according to the needs of the work site, and the connection between the bracket and the I-beam can be connected at the I-beam reinforcement or the reinforcement plate.

The arrangement of busbars should be in a straight line, and there should be no walls or other objects obstructing the range they pass through, including bends. It is particularly important to note that when connecting two sets of electrical busbars, there should be a height difference and vertical connections should be made. Similar situations should also be noted at the connection points, and appropriate installation space should be provided.