In a substation the following equipment is not installed

Answer: Option A

Definition: A substation is a part of the power system used to transform voltage levels, control power flow, and provide protection and switching operations.

Equipment in substations: Common equipment includes series capacitors for voltage support, shunt reactors for reactive power control, and voltage transformers for measurement and protection purposes.

About exciters: Exciters are devices used to supply DC field current to the rotor winding of synchronous machines such as generators or motors. They are installed in power plants or generator systems, not in substations.

Reason: Since substations do not contain generating units, there is no need for exciters, making them absent from substation installations.

Conclusion: Among the given options, exciters are not installed in substations.