Modeling arrays of rectilinear solenoids for current sensing

Rogowski Coils (RCs) are traditional current sensors; they have been very well known in the laboratories for decades, especially for the measurement of high frequency current pulses. The output voltage at the open terminals of the RC is proportional to the time derivative of the current passing through it. The closed loop geometry of the RC makes it possible to realize the Ampere's circulation so that the accuracy of the current transducer is not affected by external currents. In many industrial applications (e.g. current measurement in circuit breakers) RCs of small dimensions are needed for mass production. Since the realization of a rectilinear solenoid is much easier and less expensive than a toroidal one (as the traditional RC), it is of interest to investigate the performances of what can be defined as a “discrete” RC. The electromagnetic and geometrical properties of this kind of discrete RCs are numerically analyzed with the help of a magnetic vector potential formulation. In particular, the capability of different configurations to reject external magnetic fields is analyzed.