Current transformers are used to safely measure and monitor electric current flowing in high-voltage power lines. They work by converting high-voltage currents to lower, safer levels that instruments can handle accurately. Common types include wound, toroidal, and bar current transformers. Current transformers perform the important role of allowing current readings to be taken without exposing users to high voltages, by stepping voltages down to standard levels below 5 amps. They enable various metering and protection devices to operate safely.

1. Why testing of Current Transformer is Necessary!
The usage of eleĐtriĐal appliaŶĐes has ďeĐoŵe a ĐoŵŵoŶ pheŶoŵeŶoŶ iŶ eǀerLJoŶe’s life ďut
determining its safety is very necessary aspect in order to ensure a good life. Experts say using the direct
power carrying conductors are not a safer thing to use rather one should use something like voltage
stabilizer which stabilizes the volts and let the required level flow to the electrical devices/ instruments/
appliaŶĐes. TheLJ aĐtuallLJ proǀide ǀoltage aŶd ĐurreŶts to the ŵaŶageaďle leǀels. Let’s edžplore todaLJ
about different aspects of current transformer.
Current transformer!
Invented towards the end of 19th century, transformer has become an integral part of power system
without which the proper functioning and distribution of power would never be possible. It means
stable power supply is the result of transformer. Earlier, DC systems were used for the supply of
electricity but with the installation of current transformer, power distribution becomes flexible as well
as efficient.
This raises a question what is transformer. A transformer is an electrical device which is basically used to
convert the voltage of one magnitude to another without bringing any changes to the frequency. It also
brings changes to voltage without bringing any change to the frequency. It reduces high voltage currents
to lower value and provides convenient electrical current flow with the help of standard ammeter.
Current transformer consists of either one or few primary winding turns due to which it has also been
called as series transformer. One can find variety of current transformers which is an instrument used
for measuring and protecting devices. Here is highlighted few important types of current transformer.
Types of Current Transformer!
Wound current transformer- In this kind of transformer, the primary winding is physically connected in
series with the conductor that carries the measured current flowing in the circuit. However, the
magnitude of the secondary current has been determined by the turns of the current transformer.
Toroidal current transformer- Instead of containing primary winding, the toroidal current transformer
carries the flowing current. Few have split core which permits it to get opened, installed and closed. All
these actions have been performed without disconnecting from the circuit.
Bar type current transformer – The cable or bus bar of main circuit has been used in bar type current
transformer as the primary winding. It is high operating voltage which has been bolted to current
carrying device.
Roles to Perform!
The main role of current transformer for which it is highly known is providing the current adjusted
according to the required level. It helps in reducing the level of current from thousands of amperes to
the standard or required level or as low as 5 amps or even 1 amp. For this purpose, accurate

2. instruments are connected with current transformers which keeps it insulated away from high voltage
power lines. For knowing the current flowing through it, a number of metering applications can be
fouŶd ǁhiĐh iŶĐludes ǁattŵeter’s, poǁer faĐtor ŵeters, ǁatt hour ŵeters, proteĐtiǀe relaLJs, MCB,
magnetic circuit breakers and such more. It ensures the right flow of current.