Why reactors are used in substations?

Reactor is nothing but having a wound coil inside it having high impedence. Suppose there is an short circuit in transmission line it limits the short circuit current to safer value which prevents the connected equipment i.e breaker or transformer.

A reactor is a coil which has large number of turns and whose ohmic resistance value is much greater. Reactors are used to limit the short circuit currents which can cause damage to the equipment’s of the power system. The additional reactance added in series with the system for protection, are called reactors.

Reactors are also used to protect the circuit breakers of different ratings.  They are used to limit the short circuit currents according to the capacity of circuit breakers.

In order to limit the short circuit current to that value which circuit breaker can handle reactors are used.They are also used for improve the power factor.