Experience with using Rogowski coils for transient measurements

Rogowski coils have been used for detection and low-accuracy measurement of electric currents for decades. They are now the preferred method of current measurement for a whole range of measurements and investigations because they have more suitable features than current transformers and other iron-cored devices. A Rogowski coil is basically a toroidal winding placed round the conductor to be measured. The output from the winding is an EMF proportional to the rate of change of current. The coils are designed to give a high degree of rejection to external magnetic fields