Simulation Model for a Rogowski Cord Measurement System

Rogowski coil measuring systems are linear systems due to the absence of magnetic cores. They work on the principle of electromagnetic induction. These systems generally include two galvanically separated circuits: a primary circuit, for which it is desired to determine some quantities (e.g. conduction currents) or parameters, and a secondary circuit, supplied through the magnetic field, where the Rogowski coil is a part. In this paper the secondary circuit is closed through the internal resistance of a ballistic galvanometer. We started from a real system, for which some of the parameters are known, and the aim was to create and validate an equivalent electrical scheme of the entire system. Firstly, the self and mutual (unknown) inductances were determined by numerical modeling. Then the electrical diagram of the system was realized; the input quantity was the current through the primary circuit (having a step variation), and the output quantity was the maximum indication (deviation) of the galvanometer. The results of the simulations were compared with the experimental results, obtaining a very good correspondence of them.