Working principle of three-phase current transformer

A three-phase current transformer is a device used to measure three-phase current. Its working principle is based on electromagnetic induction.
Three-phase current transformers usually consist of an iron core and coils wound around the iron core. This coil is called the secondary coil and the current through the transformer is called the primary current.
When a primary current passes through the primary coil of a transformer, it generates a magnetic field in the core. This magnetic field is transferred through the core to the secondary coil. According to Faraday's law of electromagnetic induction, changes in the magnetic field will generate an induced electromotive force in the secondary coil.
The size of the induced electromotive force is proportional to the size of the primary current. Therefore, by measuring the induced electromotive force in the secondary coil, we can determine the magnitude of the primary current.
In order to accurately measure three-phase current, a three-phase current transformer usually has three secondary coils, which are respectively connected to the three-phase current conducting wires. By measuring the induced electromotive force in three secondary coils simultaneously, we can get the current value of each phase.
Three-phase current transformers are widely used in power systems to monitor and protect electrical equipment to ensure the safe operation of the system.