Double Bus Double Breaker Scheme. Substations with the double bus double breaker arrangement require twice the equipment as the single bus scheme but are highly reliable. One bus serves as main bus whereas other bus serves as main as well as transfer bus.
Load balancing between buses can be achieved by shifting circuits from one bus to the other. Although such a scheme is very costly yet it affords the best maintenance facilities for the circuit breakers thus when one of the circuit breakers is being opened for repairs and usual checks the load can be shifted on the other circuit breaker easily. A double bus double breaker scheme is a high cost arrangement since each line has two breakers and requires a larger area for the substation to accommodate the additional equipment.
Double breaker double bus configuration.
Substations with the double bus double breaker arrangement require twice the equipment as the single bus scheme but are highly reliable. In this configuration each circuit has two dedicated circuit breakers. The only difference is that here every feeder is connected to both of the buses in parallel through individual breaker instead only isolator as shown in the figure. This is especially true in a low pro file configuration.
