01.Single Bubar 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.
Single Bubar configuration & Operation
First, we look at the very simple representation of single busbar configuration.
Line 1 is charged from a remote substation. After closing its circuit breaker, the HV bus gets charged. Line 2 is charged the same way.
Now, the main HV bus is energized by two incoming line feeders. To supply power to the MV outgoing feeder, we need to close the transformer HV breaker. Once closed, the transformer is charged on the HV side. By closing the MV breaker, the MV bus gets charged and supplies power to consumers.
On the right-hand side, transformer 2 is also charged like transformer 1 to avoid overloading.
The complete substation operates ideally without any busbar faults.
Once the fault is cleared, then the same process will be followed to charge the busbar and transformer to feed the power through MV outgoing feeders as shown in first diagram.
Single Bubar configuration- Fault case study
The busbar is protected by a busbar protection relay in case a fault occurs within the bus zone or incoming highlines.
When a busbar fault happens, the relay detects it and immediately sends a trip command to all circuit breakers connected to the HV bus. A trip command is also sent to the remote substation to open the line breaker connected there.
As a result, the total power is interrupted, and the fault is isolated from the entire grid.
Advantages:
Simple operation & Design
Low cost / Space
Compact layout
Easy maintenance
Disadvantages:
Poor reliability,
Limited flexibility,
Longer outage time,
Disruption to protection coordination due to complete station shutdown.
