A bus duct, also known as a busway, is a type of electrical distribution system that is used to transfer power from a source to multiple loads. It consists of a metal enclosure containing one or more conductors, which are typically made of copper or aluminum. Bus ducts are commonly used in industrial and commercial buildings, as well as in power generation and substation applications.
The main advantage of using a bus duct system is that it allows for a more efficient and reliable method of power distribution. It eliminates the need for individual conductor runs and reduces the potential for loose connections or other types of electrical faults. Additionally, bus ducts are relatively easy to install, maintain and upgrade, which makes them a cost-effective solution for many applications.
Bus duct may also be used to pass medium voltage wires over buildings , water towers and other structures, (mainly to give easy access for maintenance).
Type of Bus Ducts
Rigid bus duct: This type of bus duct is made of metal and has a rigid structure. It is commonly used in industrial and commercial buildings and is known for its durability and longevity.
Flexible bus duct: This type of bus duct is made of a flexible material and can be bent or shaped to fit into tight spaces. It is commonly used in situations where the bus duct needs to be routed around obstacles or through tight spaces.
Plug-in bus duct: This type of bus duct is designed to allow for easy maintenance and upgrades. It features removable sections that can be easily replaced or added to as needed.
Segregated phase bus duct: This type of bus duct is used to transfer power between different phases, it's also known as multi-phase bus duct.
Insulated bus duct: This type of bus duct is used to transfer power in an electrical substation or other high-voltage application, where the insulation is needed to prevent electrical arcing or failure.
Non-Segregated phase bus duct: This type of bus duct is used to transfer power between same phases, it's also known as single-phase bus duct.
The type of bus duct that is used will depend on the specific application, environmental conditions, and the level of power that needs to be distributed.
Technical Explanation of Bus Duct
In the above picture, a segregated phase bus system is displayed. This type of bus duct separates each phase of the electrical power distribution into its own metallic enclosure with a barrier between them.
This barrier provides a magnetic shield and isolates each phase from each other, similar to an isolated phase bus system (IPB). The metallic barriers also act as Faraday cages to balance the fields produced by the conductors inside the enclosure. This type of bus duct is designed to prevent short-circuits and reduce the effect of one phase on the other by arresting the magnetic field.
It operates like an enclosure with an interleaving arrangement, which balances the fields to a great extent and allows only a moderate field in the space. The enclosure can be made of MS or aluminum and the barriers are also made of the same metal. This type of bus duct is typically used in high voltage systems 3.3-11 kV and current ratings above 3000 A and up to 6000 A. Only aluminum enclosures should be preferred to minimize losses and enclosure heating.
Where is Bus Duct used?
Industrial and commercial buildings: Bus ducts are commonly used in industrial and commercial buildings to distribute power to multiple loads. They are particularly useful in large buildings where a high level of power is required, such as factories, warehouses, and shopping centers.
Power generation and substations: Bus ducts are also used in power generation and substation applications to transfer power from the source to the loads. They are commonly used in power plants, wind farms, and hydroelectric plants..
Data centers: Bus ducts are used to distribute power to servers and other equipment in data centers, providing a reliable and efficient method of power distribution..
Transportation: Bus ducts are used to power buses, trams, and trains, providing a safe and reliable method of power distribution for these vehicles..
High-rise buildings: Bus ducts are used in high-rise buildings to distribute power to multiple floors, they are also used to transfer power between different levels of the building..
Hospitals and other critical facilities: Bus ducts are used in hospitals and other critical facilities to ensure that power is always available for essential equipment and systems..
Airports and other transportation hubs: Bus ducts are used in airports and other transportation hubs to distribute power to multiple loads, including lighting, security systems, and other essential equipment..
Overall, bus ducts provide a flexible and efficient method of power distribution in a wide range of applications, ensuring that power is always available where and when it is needed.
Why use bus duct instead of cable?
There are several reasons why bus ducts may be preferred over cables for power distribution:
Efficiency: Bus ducts provide a more efficient method of power distribution than cables. Because bus ducts are designed to transfer power to multiple loads at once, they eliminate the need for individual conductor runs and reduce the potential for loose connections or other types of electrical faults.
Flexibility: Bus ducts are more flexible than cables, allowing them to be routed around obstacles or through tight spaces. This is particularly useful in situations where the power distribution system needs to be expanded or modified.
Durability: Bus ducts are typically constructed from heavy-duty materials such as aluminum or copper, making them more durable and resistant to environmental hazards such as corrosion. This is particularly important in harsh industrial environments.
Maintenance: Bus ducts are relatively easy to install, maintain and upgrade, which makes them a cost-effective solution for many applications.
Safety: Bus ducts have a high level of insulation to protect against electrical arcing and failure, this feature is important in high voltage application. Additionally, they may have built-in monitoring and diagnostic systems to help identify and troubleshoot any issues that may arise, this feature increases the safety of the system.
Space: Bus ducts take up less space than a bundle of individual cables and are typically more compact. This can be beneficial in situations where space is limited.
Cost: Bus duct systems can be more expensive than cables initially, but over the long run, they are more cost-effective due to their efficiency, durability and easy maintenance.
While cables may be suitable for certain applications, bus ducts provide a more efficient, flexible, and durable method of power distribution in many industrial and commercial settings.
What is the difference between busbar and bus duct?
A busbar and a bus duct are both used for the distribution of electrical power, but they have some key differences in their design, installation, safety, flexibility, maintenance and space.
A busbar is a long, flat piece of conductive material, typically made of copper or aluminum, that is used to transfer power from a source to multiple loads. Busbars are typically installed by running them through walls, ceilings or floors, and then connecting them to the power source and the loads. While busbars are simple and easy to install, they can be dangerous to work with since they are typically exposed and can be touched. Additionally, they are less flexible and can be difficult to maintain and repair.
On the other hand, a bus duct is a metal enclosure that contains one or more busbars and is used to transfer power in the same way. Bus ducts are usually installed above or below ground level, and are connected to the power source and loads through openings in the enclosure. Bus ducts are enclosed, which provides a safer method of power distribution, and they also have a high level of insulation to protect against electrical arcing and failure. Additionally, they are more flexible and can be bent or shaped to fit into tight spaces, which makes them more versatile for power distribution. They are also relatively easy to install, maintain and upgrade, which makes them a cost-effective solution for many applications. However, bus ducts can be more expensive and take up more space.