Influence of Rogowski coil shielding to measurement results

Rogowski coils (RCs) are usually used for high current measurements from low frequency up to high frequency of a current waveform. These precise and sensitive measurements are very susceptible to interference. A metallic shielding was often used as one of possible solutions. Influences and efficiency of RC shielding to measurement are investigated in the paper. Measurements were carried out for two construction types of RCs. Firstly, usual construction of a RC with uniform winding at non-ferromagnetic toroidal rectangular core. The second RC was constructed with the same core shape, but with an atypical cross wounded winding. Both these constructions are described. These RCs were compared by measurements with and without the shielding. Mathematical model of a RC was built to simulate frequency dependence of the RC constant. Mathematical simulations were validated by measurements of frequency characteristics.