Protection Class CT

Protection current transformers are used to control protective relays that have the role of disconnecting downstream circuits in the event of a current surge. Proportional transmission behaviour of the transformer up to a multiple of the nominal current is required for the reliable function of this relay.
The dimensioning of this transformer design safeguards proportional current transmission up to a multiple of the nominal current.

Protections CTs are designed to be used with protective and trip relays in order to open circuit breakers. These CTs can handle higher currents during fault conditions and this is determined by their class rating. The main types of protection CTs are; PVC tape wound and resin cast.