Mutual inductances comparison in Rogowski coil with circular and rectangular cross-sections and its improvement

Rogowski coils are increasingly used to measure AC, high amplitude and transient currents in power industry. One of the most important applications of them is current measurement of industrial electronic devices. Since they have no iron core, they are not saturable. However, due to this phenomenon, their mutual inductance varies by changing their structures. In this paper, the effects of two kinds of cross-sections in Rogowski coils, named Circular and Rectangular, on mutual inductance of coils are compared and their mutual inductance variations are investigated. Also, the methods for increasing mutual inductance are presented. Finally, the method to obtain an optimum mutual inductance in Rogowski coil is suggested. Simulation results are also presented.