Switchgear System

In commonly, 150 kV use scheme protection is called single bus bar but in 500kV used to double busbar. The different between single bus bar and double busbar are using of many circuit breaker and reability of system.

You can look at this picture on the left, single line of double busbar with one half breaker.

Advantage from one and half CB (breaker) configuration :

1. If busbar A has fault

With open all circuit breaker A and disconnecting switch (DS) A, the power can be supply fully.

2. If busbar B has fault

With open all circuit breaker B and disconnecting switch (DS) B, the power still can be supply fully.

3. If busbar A and B have fault

With open all circuit breaker and siconnecting switch A and B, the power can be supplied although less than normal (not flexibility and unreliable).