Current transformers are classified by principle

1. Electromagnetic current transformer: a current transformer that realizes current transformation according to the principle of electromagnetic induction.

2. Electronic current transformer:

For example:

(1) Optical current transformer refers to the use of optical devices as the current sensor to be measured, and the optical devices are composed of optical glass, all-fiber, etc.

(2) Air core coil current transformer. Also known as Rogowski coil current transformer. Air-core coils are often made of enameled wires evenly wound on an annular skeleton. The skeleton is made of non-ferromagnetic materials such as plastics and ceramics. Its relative permeability is the same as that of air. This is the difference between air-core coils and iron-core coils A distinctive feature of current transformers.

(3) Iron core coil type low power current transformer (LPCT). It is a development of the traditional electromagnetic current transformer. It is designed according to high-impedance resistance, under very high primary current, the saturation characteristic is improved, the measurement range is expanded, the power consumption is reduced, and the overcurrent and full offset short-circuit current up to short-circuit current can be measured with high accuracy without saturation. , measurement and protection can share a low-power current transformer with iron core coil, and its output is a voltage signal.