check this site:

en.wikipedia.org/wiki/current_transformer

Hi Guest ,

Sorry what is the relation between CT and your e mail solution. I think you landed at a wrong place .

CT is current transformer. CTs are used in measuring of current flowing in the circuit. Curent transformers(CTs) and Potential transformers(PTs) are classified as instrument transformers. Please refer any Text book on Electrical measurements course offered for B.E course. CTs are also used for sensing elements in Power system protection relays.

Cts used in transmission lines are different from normal CTs used in circuits (LT Side). CTs used in Transmission lines are Vertical post type( with ceramic enclosure). These can be seen in any switching stations( 400KV, 220KV,132KV, 66KV). Contact any CT&PT vendors. They will give you detailed catalogue of Cts used in transmission lines

Main use of Current transformer :

1 - Metering: To measure energy for revenue collection or indication. current transformer is a part of panel indicating meters & kWh meters.

2 - Protection: To protect power system as a part of switch gear.current transformers are used in connection with protection relays.

In low voltage E class insulation will be sufficient while in medium or high voltage oil filled or Epoxy resin insulation is required.

A current transformer on transmission lines reduces the amperage to a ratio that the small metering system can use. Similar to a transformer, it steps down the amperage to a safer level for a display panel.

James