Computer aided techniques for estimation and reduction of electromagnetic measurement devices uncertainties

At non-linear electromagnetic measurement systems, the finite element method is the most convenient tool for the system analysis and measurement uncertainties budget estimation. Two non-linear devices will be analyzed by finite element method: electrical steel sheet testing device-Epstein frame and combined current-voltage instrument transformer. The Epstein frame must comply with the standard IEC 60404-2:1996+A1:2008, and the combined instrument transformer with the IEC 60044-3: 2002. The Epstein frame forms an unloaded transformer and the analytical transformer theory introduces some approximations. The main approximation is introduced by the standard IEC 60404-2 (through the presumption of constant, invariant to the specimen grade effective magnetic path length). The finite element method results will enable an Epstein frame and combined current-voltage instrument transformer prototype design (by using a computer program based on genetic algorithm with minimal uncertainty budget as goal function) with reduced measurement uncertainty, which will be experimentally verified in the Metrological Laboratory for Electromagnetic Quantities at the Faculty of Electrical Engineering and Information Technologies-Skopje