How are current transformers classified?

News | company news | May 17,2024

How are current transformers classified?

According to use

Current transformer for measurement (or measurement winding of a current transformer. Within the normal operating current range, it provides current information of the power grid to measurement, metering and other devices;

Protection current transformer (or protection winding of current transformer. In the power grid fault state, it provides grid fault current information to relay protection and other devices.

According to insulation medium

Dry-type current transformer: made of ordinary insulating materials dipped in paint as insulation;

Casting current transformer: a current transformer cast with epoxy resin or other resin mixed materials;

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

Gas insulated current transformer: The main insulation consists of gas.

According to the principle of current transformation

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

Furthermore, the photoelectric current transformer, which achieves current conversion through the principle of photoelectric conversion, is still under development.

According to installation method:

Penetration current transformer: This type of current transformer is use to pass through a screen or wall.

Pillar-type current transformer: Positioned on a plane or pillar, this current transformer also serves as a primary circuit conductor pillar.

Bushing type current transformer: Install without a primary conductor and primary insulation, this current transformer is directly mount on an insulated bushing.

The characteristic of an active electronic current transformer is that the primary sensor is an air-core coil, and the high-voltage side electronic components need to be power by a power supply to work.

In contrast, the passive magneto-optical glass electronic current transformer relies on magneto-optical glass as the primary sensor and does not require a power supply.