Current transformer or CT is a type of instrumentation transformer which is used to step down higher amps to lower amps.
Electrical power system uses very high values of currents. It is impossible for the relays and instruments to directly monitor such higher values of currents.
A current transformer is an instrumentation transformer which steps down the higher current values to lower safe values so that relays and instruments could easily read it.
A current transformer always connects in series with the circuit. In this white paper, you’ll learn the working and physical construction of current transformer.