Critical parameters for mutual inductance between Rogowski coil and primary conductor

We present the results of an analytical study aimed at characterizing the mutual inductance M of Rogowski coils for generic paths of the primary wire and for nonuniform windings. In order to obtain such data, we performed a series of calculations based on the method of the mutual partial inductances and on the application of the Biot-Savart-Laplace law. Finally, we discuss the role of some critical parameters affecting M.