Rogowski Coils

Here at AGW we have experienced an increase in interest and demand for flexible Rogowski coils, used in applications such as sensors in electrical protection systems and monitoring current in electricity sub-stations. Our winding technique used in manufacture means we have developed a successful technique to feed the finished end of the winding back through the centre of the flexible tube to meet the start of the winding.

What makes a Flexible Rogowski coil different to a Current Transformer?

Standard Current Transformers require a closed loop core to carry the winding. This core must fit around the primary conductor, which is being measured, which can be very difficult to achieve when the primary conductor is physically large or is difficult to access.

A flexible Rogowski coil does not require a closed loop core like a Current Transformer. The two connections of the secondary winding are brought out at the same position and the finish of the winding is brought back to the position of the start. This leaves a free end that can be wrapped around the conductor which is being measured. Obviously, the coil needs to be flexible, in order to be wrapped.

An integrator circuit, which is attached to the Rogowski coil, then provides the information about the current ratio.