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International audience; In order to apply advantageously the symmetrical components theory to SLG fault transients in distribution systems we take profit of similitude of transient components in faulty phase current and in zero sequence current on faulty feeder. Then we are able to take into account the load current contribution within voltage drop account of zero sequence equivalent circuit. The result is an Extended Zero Sequence circuit, of better accuracy comparing to Traditional Zero Sequence circuit or Full Sequence 0-p-n circuit. It presents accurately enough a MV system response to an SLG fault occurrence, whereas traditional equivalent circuits assume only one frequency analysis. Consequently, the new zero sequence circuit is more adapted for evaluation of amplitudes of actual transients or for fault location tasks.

International audience; An SLG fault detection task can be out of reach of steady state methods, based on detection of active component in faulty currents. Efficiency of these methods may not be assured when strong capacitive currents on faulty feeder squeeze the phase shift between the faulty and the sound zero sequence currents below actual acquisition limits. Then the way to assure the directional decision is to exploit data recorded in transient regime, where an apparent phase difference is more important than actual phase difference in steady state. This is a consequence of the way the transient regime develops, beginning just after the fault inception with phase opposition between the faulty and the sound current residuals and finishing in steady state with a slight phase advance of the faulty residual over all the sound ones.

International audience; In radial distribution network with no discontinuities in feeders' impedances the shape of traveling wave induced by an SLG fault inception will be modeled by multiple refractions and reflections from busbar, fault and loads. The initial propagation zone presents a rigorous polarity disposition of residual currents, with sound residuals having the same polarity. We can determine the minimal sampling frequency necessary to get in that zone the current data indicating faulty feeder. The initial polarity length does not depend on the fault position, its resistance value or on the soil resistivity, and if scrutinized on all feeders it can point out from busbar to fault in systems with laterals. The propagating waves can thus be involved in directional procedures in lines or in cables. Under certain conditions the directional function can be assumed also in mixed networks, with feeders partly in cables and partly in lines.

International audience; The PWM-supplied permanent magnet synchronous machines are exposed to magnets' heating due to harmonic fields which rotate in relation to rotor. The corresponding losses can be calculated by FE simulation for each frequency, with superposition of all components of the losses. In certain conditions three dimensional modelling is required to get enough precision. However, time-stepping 3D finite element methods coupled with motion equations can lead to excessive computational time. Then a locked rotor approach with current sheet rotating may be interesting. In this case however, the superposition doesn't really work unless special procedure is applied. Magnetic loss dissipation cannot be correctly calculated with simple superposition of individual fields, e.g. the 5th and 7th harmonic rotating in opposite direction. This is because the resulting field has an alternative component with dissipative effects depending on its position. They will be more important if the component oscillates in the middle of magnets and less important in the middle of gap between them.