3. Main station diagrams used

The most common substations can be characterized by three design principles:

• substations with one circuit breaker per feeder ;

• substations with several circuit breakers per feeder ;

• loop stations.

In addition, the simplest substations can be fitted with shunt circuit breakers or connected as aerials.

The following examples, which can be found on both French and foreign networks, illustrate the characteristics common to each family.