The design and use of Rogowski coils

Rogowski coils are difficult to make correctly because of the emphasis that has to be placed on the precision of manufacture and restrictions on the materials that can be used. They are for relatively low frequency ((1MHz) applications and care must be taken with screening any electronic processing. Without an iron core they will not saturate and will thus not suffer from the amplitude limitations of a CT. However their differential performance means they respond well to transients so one ideal application is for protection on power systems. Their response at high frequency means that for measurement on test rigs, where space is a premium, very small cross section Rogowskis can be inserted without the need for arranging loops to fit a more traditional device, so adding inductance. Their weak coupling also benefits this.<>