A bus bar is a copper metal strip, conductor, or group of conductors used to distribute electrical power as a connection or node. A bus is defined as a conductor or group of conductors used to collect electricity from incoming feeders and distribute it to outgoing feeders.
Busbars make power distribution much easier, less expensive, and more flexible than some other more permanent forms of installation and distribution. Bus Bar manufactured is often metallic strips of copper, brass, or aluminum that conduct electricity.
Therefore uninsulated and rigid enough to be supported in the air by insulated supports. These features provide sufficient cooling of the conductors and connect at various points without creating a new joint.
They are also used to connect high voltage equipment in power distribution stations and low voltage equipment in batteries. It is used in houses in switchgear, switchboards, and busbar fences for local high current.
High voltage busbars are used in the substation, generation, and feeder separation. In-home wiring, tires are used in junction boxes, panels.
Types of Bus Bars
1. Single bus bar arrangement
2. Single bus bar arrangement with sectionalization
3. Double bus Double Breaker arrangement
4. Main and transfer bus arrangement
5. Sectionalization Double bus arrangement
6. Ring the main arrangement
7. One and a half Breaker arrangement
8. Mesh arrangement
1. Single Bus bar Arrangement
A single bus arrangement consists of a single busbar to which all incoming and outgoing lines are connected. And this is the simplest design. This arrangement is not used for overvoltage of 33 kV. 11 kV substations often use single busbar systems in substations.
This type of arrangement’s advantages is the low initial cost, lower maintenance costs, and ease of use. A single busbar system’s disadvantage is that if the bus needs to be repaired or if it fails, the power will be completely disconnected. This is not a design for a large power system.
2. Single bus bar Arrangement with Sectionalization
In a single busbar arrangement with sectionalisation, a single busbar is divided into two sections, and the load is equally distributed across all sections. Bus sectioning is used in large substations where large units are installed.
In this arrangement, there are 2 or 3 bus bars numbers. This busbar arrangement uses circuit breakers and disconnectors so that one part’s failure does not cause a complete shutdown.
The main advantage of this arrangement, if a fault occurs in any section of the bus, that section can be isolated without affecting the power from other sections. One section can be totally shut down for maintenance and repair without affecting the supply of other sections.
3. Double Bus Double Breaker Arrangement
A Double bus and Double breaker arrangement have two identical buses that are used so that any incoming or outgoing feeder can be diverted from any bus, similar to a dual bus system. It does not require additional hardware such as bus couplers and switches.
A bus connector is not necessary as switches and not isolators do the work. For a switching operation, it is first necessary to close the isolators and then switch to the bus to which the feeder is to be transferred. He or she then opens the switch and then the isolators associated with the bus from which the feeder is to be transferred.
This type of arrangement provides maximum reliability and supply flexibility. Because failure and maintenance would not interfere with their continuity, the circuit breaker can be disconnected for repairs and routine checks, and the load can be easily transferred to another circuit breaker. But due to the higher cost, such a scheme is rarely used in substations.
4. Main and Transfer Bus Arrangement
In the Main and Transfer bus arrangements such as a device, two buses are used, namely the main bus and the auxiliary bus. The busbar uses a busbar connector that connects the isolating switches and the circuit breaker to the busbar. It is an alternative to the dual bus system. The bus coupler is also used to transfer the load from one bus to another in an overload.
The basic concept of the main and transfer bus arrangement s that each feeder line is directly connected via an isolator to a second bus called a transmission bus. Using isolating switches, it is connected to an intermediate bus, called bypass isolators, and by means of circuit breakers and disconnectors, it is connected to the main bus.
There is one busbar connector compartment in which the changeover busbar and the main busbar are connected through the circuit breaker and the corresponding insulators on both sides of the breaker. If necessary, the transfer bus can be powered from the main bus by shorting the transfer bus connector insulators and then the switch.
The transmission bus power can then be directly fed into the feeder line by closing the bypass isolator. If the main circuit breaker associated with the feeder is turned off or isolated from the system, the feeder can still receive power in this way by passing it on to the transmission bus.
Тhэ Advantages of the main and transfer bus arrangement No interruption of the power supply, as in the event of a fault the load can be switched to the transfer bus. And the disadvantages of the main and transfer bus arrangement. Two tires are used, which increases the cost.
5. Sectionalization Double Bus Arrangement
Sectionalization Double bus arrangement, In this redundant arrangement, busbars are used with the main busbar in sections connected through a busbar connector. The sectional main busbar is used in conjunction with the auxiliary busbar. Each section can be synchronized with any other via the auxiliary bus.
With this arrangement, any section of the bus can be isolated for service. Any section of the bus is removed from the circuit for maintenance and connects to any of the auxiliary buses. But this arrangement increases the cost of the system. Partitioning the auxiliary bus is not required as this will increase the cost of the system.
6. Ring the Main Arrangement
Ring the Main arrangement provides dual power feeds to each feeder loop. Tripping one breaker during service or otherwise does not affect the power to any feeder. This arrangement provides great flexibility since each feeder is powered in two paths so that a section failure does not interrupt the feed. The effect of a malfunction in one section is localized only in this section.
But this system has some disadvantages. First, since it is a closed system, it is almost impossible to expand in the future and therefore not suitable for system development. And Second, for maintenance or any other reason, if any of the circuit breakers in the ring loop are tripped.
The reliability of the system becomes very poor as the closed-loop is opened. Because at this point, any breaker opening in an open-loop will cause an interruption in all feeders between the tripped breaker and the open end of the loop.
7. One and a Half Breaker Arrangement
One and a Half Breaker arrangement has three circuit breakers required for two circuits. Each bus circuit uses a one and a half circuit breaker. This type of arrangement is preferred in large stations where the power transmitted to the circuit is high. This arrangement is an improvement on the previous one to reduce the number of circuit breakers.
This arrangement provides high protection against power loss since a fault in the bus or switch does not interrupt power. It protects the device from power loss. The bus potential is used to drive the relay. With this arrangement, additional circuits are easily added to the system.
8. Mesh Arrangement
In Mesh arrangement, the circuit breakers are installed in the mesh formed by the busbars. Its circuit is tapped from the node point of the mesh. Four circuit breakers control this bus arrangement. The circuit breakers are installed in a mesh formed by busbars. It is used in substations with a large number of circuits.
When a fault occurs in any section, the two circuit breakers must trip or open, resulting in the mesh’s opening. It protects bus bars and faults but has no switchover capability. Therefore, It is Preferred for those substations with a large number of circuits.