07.Double Busbar with Bus coupler + Transfer Buscoupler configuration
What is busbar?
A busbar is a metallic conductor (usually copper or aluminium) used in substations to collect and distribute electric power. It connects multiple incoming and outgoing transmission lines and equipment like transformers within the substation.
Since the busbar is a critical node in the power system, any fault on it can cause widespread outages. Therefore, fast and reliable protection is essential.
Double Busbar with Bus coupler with Transfer Busbar configuration
This configuration consists of Busbar 1 and Busbar 2 connected by a bus coupler, along with a third transfer busbar that serves the same function as the previously discussed bypass isolator arrangement. This setup offers increased operational flexibility, enables maintenance of breakers or busbars without interrupting supply, and enhances system reliability by allowing seamless load transfer between buses.
Normal Operation
All these operations are carried out just like in a standard double busbar system with a bus coupler. This setup allows different switching options such as connecting all bays to Busbar 1, splitting them between Busbar 1 and Busbar 2, or connecting all bays to Busbar 2. It also allows smooth transfer of load from Busbar 1 to Busbar 2 and vice versa without interrupting the power supply. Lines and transformers can stay energized during these operations, as shown in the Double Busbar with Bus coupler configuration.
Load Transfer Condition with Transfer Bus Coupler during a Breaker Fault
To perform this operation, we need to ensure that all transfer isolators are in the open condition.
First, close the Transfer Isolator of the Transfer Bus Coupler and the Bus Isolator corresponding to the busbar to which the connection is to be made. Then, open the breaker associated with the Line 2 disconnectors.
Next, close the Transfer Isolator of Line 2, followed by closing the Transfer Bus Coupler Circuit Breaker to connect the line to Busbar 1.
You can now observe the power flow through the circuit.
The same method is to be followed if there is a problem with any other bay circuit breaker. However, note that only one bay at a time can be operated in this manner with the given busbar arrangement.
Advantages:
Higher reliable
Higher flexible
Less outage time
Very supportive for Protection coordination
Burden to Buscoupler will be reduced
Dis Advantages:
Very Higher cost
Very Higher space
Higher maintenance
