What are the types and wiring methods of current transformers (CT)?

1. Classification by purpose

Measurement current transformer (or measurement winding of current transformer. Provides current information of the power grid to measurement and metering devices within the normal working current range.

Protection current transformer (or protection winding of current transformer. Provides power grid fault current information to relay protection and other devices under power grid fault conditions.

2. Classification by insulation medium

Dry-type current transformer: Insulation is made of ordinary insulating materials treated with varnish.

Cast current transformer: Current transformer cast with epoxy resin or other resin mixed materials.

Oil-immersed current transformer: Insulation is made of insulating paper and insulating oil. Insulation, generally outdoor type. At present, it is commonly used in various voltage levels in my country.

Gas insulated current transformer: the main insulation is composed of gas.

3. According to the principle of current conversion

Electromagnetic current transformer: a current transformer that realizes current conversion based on the principle of electromagnetic induction.

Photoelectric current transformer: a current transformer that realizes current conversion through the principle of photoelectric conversion, which is still under development.

4. According to the installation method

Through-type current transformer: a current transformer used to pass through a screen or wall.

Pillar current transformer: a current transformer installed on a plane or pillar, and also used as a conductor pillar for a primary circuit.