What is the function of a circuit breaker in a substation?

The function of a circuit breaker in a substation is to protect electrical circuits from overload and fault conditions. When abnormal conditions occur, such as short circuits or excessive current flow, the circuit breaker automatically interrupts the circuit, preventing damage to equipment and ensuring safety. This protective mechanism is essential for maintaining operational reliability within the substation and for safeguarding connected systems from potential hazards caused by electrical faults.

In a substation, the circuit breaker plays a crucial role in the overall protective scheme, helping to isolate faults and prevent cascading failures that could impact larger portions of the electrical grid. By immediately disconnecting the affected section, the circuit breaker helps maintain stability and integrity in electrical distribution.

The other answer choices involve functions that are not primary to a circuit breaker's role. For instance, regulating voltage levels and increasing power supply are typically managed by other devices like transformers and regulators, while backup power sources usually refer to generators or battery systems designed for supporting power during outages, rather than the normal operational tasks of a circuit breaker.