The breaker-and-a-half configuration consists of tow main buses , each normally energized ,Electrically connected between the buses are three circuit breakers

The breaker-and-a-half configuration provides for circuit breaker maintenance, since any breaker can be removed from service without interrupting any circuits.

Additionally, faults on either of the main buses cause no circuit interruptions. Failure of a circuit breaker results in the loss of two circuits if a common breaker fails and only one circuit if an outside breaker fails

Because of the importance of this type of substations, we have provided you with this course, in which is a detailed explanation of a substation in the Kingdom of Saudi Arabia. We will talk about the most important basics of operation and interlock circuits

We will talk about synchronization circuits and why there is more than one synchronization system in the substations ,

Of course, we will talk in detail about the protection philosophies followed in those substations and how to send trip orders to the remote end substations.

The points we will talk about in the course :-

• CT Methods in Breaker and a Half Substations

• The importance of Double Operation

• The Conditions of closing CB in test and service position (upper - central - lower) CB

• The Interlock of (upper - central - lower) CB

• Spring discharge circuit and how can modified it

• Why is there more than one relay and circuit for synchronization ?

• DS\ES conditions for maintenance position and service position

• Trip philosophy of Tee protection 87TEE

• Philosophy of differential protection with auto transformer

• Philosophy of line differential distance protection

• Send and receive trip from local end to remote end

• Philosophy of BusBar Protection

• Philosophy of circuit breaker failure

• Philosophy of pole discrepancy