In this paper, the magnetic losses of a supply current sensor dedicated to circuit breakers are investigated. Measurements were performed using an accurate calorimeter covering a measurement range of [1 mW; 10 W]. Several frequencies and voltages were tested. A model of the sensor's core material (NO SiFe sheet M250-50A) was built with the Loss Surface (LS) dynamic hysteresis model and implemented in a 3D FEM computation tool. The sensor was simulated and iron losses were computed. Comparison between experiments and simulation shows a high concordance that leads to conclude about the reliability of the LS model.

A wide range of current-sensing techniques has been developed to satisfy various electrical and electronics applications requirements. In high-voltage applications, the main issue is the electrical isolation with accurate measurement at low signal levels. Isolated shunt technology is an attractive and versatile solution for current sensing. Electrical isolated products usually need a power supply at both low and high voltage sides. An original topology that needs only one power supply at the secondary (low voltage) side is reported. In this paper, we introduce an implementation of an integrated shunt current-measurement microsystem based on a 6 kV isolated micro-transformer. This work finds its applications in many domains such as hybrid or electric vehicle battery monitoring or motor control, system building automation or smart grids, where small size and low cost are required.

Under high-supply current, residual circuit breakers are subject to abnormal tripping, caused by false residual currents. Geometric or magnetic anomalies in the circuit breaker ring core seem to be responsible for these abnormal currents. This paper studies a few anomalies (spiral shape effect, conductor eccentricity, lamination effect) and calculates different contributions using the finite element simulations. The results show that the ring core, made of thin wound magnetic tape, is particularly sensitive to primary conductor eccentricity.

Afin d'ameliorer la fiabilite dans la protection differentielle et diminuer les declenchements intempestifs, le tore de detection a ete modifie.Selon l'invention, differentes solutions sont apportees pour homogeneiser le flux magnetique au sein du tore (2) au niveau de l'extremite (8) du ruban (4) en materiau magnetique, en particulier par la presence d'une cale ou d'une decoupe de la partie d'extremite (18) du ruban, par exemple sur une spire complete.