Current Transformer AKA

Type AKA current transformers are usually used in encased ducts, so-called isolated phase bus ducts (IBPs). The CT’s transform high currents up to 50,000 A into standardised, equivalent values for meters, measuring equipment and protection devices.

Power stations use IPB ducts between the generator on the one side and the generator transformer and its station-service feeders on the other. AKA current transformers are designed to be installed in these systems. The current transformer is fixed in place inside the casing. The distance between the transformer's internal diameter and the duct's primary conductor is determined by the system voltage, with the insulation being implemented with a sufficient distance between the primary conductor and the transformer's internal diameter.

The transformer's active parts are cast in an epoxy resin specifically designed to withstand high temperatures. Depending on the requirements, up to five mutually galvanically isolated current transformer cores can be fitted and used to provide protection or for measurement tasks. As all the active parts are dimensioned and made to order, they can be manufactured in accordance with all international, national and customer-specific standards. Protection classes for transient transmission behaviour (TPY, TPZ) are also possible. A wide variety of casting moulds enables current transformers to be produced for virtually any kind of duct with an internal diameter of up to 1,200 mm, meaning that various voltages, conductor diameters, transmissions and class requirements can be handled with ease. The secondary terminals are designed as cast bushes, positioned on the transformer housing and connected via a special flanged opening in the duct casing. Its special design allows the transformer to be used in Zone 2 areas at risk of explosion in accordance with its official type test certificate. Type AKA current transformers can also be used in open systems if the distance between their internal diameters and the primary conductors is large enough.