Where is the breaker in a substation installed?

A breaker in a substation plays a crucial role in controlling and protecting electrical systems. The correct positioning of the breaker is significant for ensuring the safe operation of the electrical network.

The correct choice indicates that the breaker is located between the low voltage bus and the distribution feeder circuit. This placement is essential because it allows for the isolation of the distribution feeder from the bus, enabling maintenance or emergency operations without disrupting the entire system. Furthermore, by placing the breaker in this location, the system can efficiently manage fault conditions and overloads, protecting the downstream components and ensuring a reliable power supply to end users.

In contrast, the other options refer to locations that do not typically house breakers in standard substation configurations. For instance, positioning a breaker between the primary transformer and the power grid would not effectively isolate sections of the distribution network. Similarly, placing a breaker between the incoming supply and the generator or at the end of the transmission line does not reflect standard practices for protecting and controlling power distribution within substations. These placements would also lead to complications in fault detection and isolation processes, making them less suitable than the chosen option.