Classification of current transformers01-05, 2024

1. Classified by purpose
1) Current transformer (or measuring winding of current transformer): provides grid current information to measuring and metering devices within the normal voltage range.
2) Protective current transformer (or protective winding of current transformer): In the event of a power grid fault, it provides power grid fault current information to relay protection and other devices.
2.Divided by insulation medium
1) Dry type current transformer: It is insulated by ordinary insulation materials that have been impregnated with paint.
2) Cast insulated current transformer: a current transformer formed by casting a mixture of epoxy resin or other resin materials
3) Oil immersed current transformer: It is insulated with insulating paper and oil, and is generally of outdoor type. Currently, it is commonly used in various voltage levels in China.
4) Gas insulated current transformer: The main insulation is composed of SF6 gas.
3.According to the principle of current transformation
1) Electromagnetic current transformer: a current transformer that converts current based on the principle of electromagnetic induction.
2) Optoelectronic current transformer: a current transformer that achieves current conversion through the principle of photoelectric conversion.
4. Classified by installation method
1) Through type current transformer: a current transformer used to pass through a screen or wall.
2) Pillar type current transformer: a current transformer installed on a plane or pillar and used as a primary circuit conductor pillar;
3) Bushing current transformer: A type of current transformer that is directly mounted on an insulated bushing without a primary conductor and insulation.
4) Busbar type current transformer: A current transformer that does not have a primary conductor but has a primary insulation and is directly mounted on the busbar for use.
5.Divided by the number of turns of the primary winding
1) Single turn current transformer: Single turn current transformers are commonly used for high current transformers.
2) Multi turn current transformer: Multi turn is commonly used for medium and small current transformers.
6.Divided by the position of the secondary winding1) Vertical: The secondary winding is located at the bottom of the product and is a commonly used structural form in China.
2) Inverted: The secondary winding is located at the head of the product and is a relatively new structural form in recent years.
7.Divided by current ratio
1) Single current ratio current transformer: refers to a transformer with a fixed number of turns in the primary and secondary windings, which cannot change the current ratio and can only achieve one type of current ratio transformation.
2) Multi current ratio current transformer: that is, the number of turns in the primary or secondary winding can be changed, and the current ratio can be changed to achieve different current ratio transformations;
3) Multiple iron core current transformers: This type of transformer has multiple secondary windings with iron cores to meet the needs of different precision measurements and various relay protection devices. In order to meet the requirements of certain devices, some secondary windings have multiple taps.
8.Classified by the technical performance of protective current transformers
1) Steady state characteristic type: Ensure the error of current in steady state, such as P, PR, PX levels
2) Transient characteristic type: Ensure the error of current during transient, such as TPX TPY TPZ TPS level, etc.
9.Divided by usage conditions
1) Indoor current transformer: generally used for voltage levels of 35KV and below.
2) Outdoor current transformer: generally used for voltage levels of 35KV and above.