CT-type Current Transformer

A CT current transformer commonly referred to as a current transformer (CT), is an indispensable component in power systems. It is a specialized transformer whose primary function is to proportionally convert a large primary-side current into a smaller secondary-side current that can be safely measured and monitored, thereby enabling measurement, metering, and protection of the power system. Commonly used core materials include amorphous alloys, nanocrystalline materials, ferrite, and silicon steel laminations.

The working principle of a CT current transformer is based on Faraday's law of electromagnetic induction. The primary winding typically consists of only one turn. When an alternating current flows through the primary winding, it generates an alternating magnetic field in the core. This magnetic field induces a proportionally reduced secondary current in the secondary winding, which has a larger number of turns. As a result, the secondary current accurately reflects the magnitude and phase variation of the primary current.