Abstract: A metering device includes a standard AC energy meter, and a conversion circuit. The conversion circuit measures the voltages and currents of an installation incompatible with the functional characteristics of the meter. The conversion circuit supplies the meter with AC voltages and currents of values in compliance with the specifications of the meter. The total power supplied to the meter is proportional, except for a known scale factor, to the total power measured on the power system. This device is applied to measuring electrical energy on DC power systems and on AC power systems of a frequency or form incompatible with standard electrical energy meters.

Abstract: The system comprises a central module supplying a distribution network, for example formed by a bus, with permanent DC power. Terminal modules, located near the loads, convert the DC power distributed by the distribution network into DC or AC electrical power adapted to the requirements of each load. A communication bus enables data communication between the various modules.

Abstract: A device connects an external electrical power supply source to an aircraft on the ground to temporarily replace its auxiliary power units. During the overlap period of the two switches used in the aircraft to achieve this transfer, an impedance, preferably a resistance much greater than the internal impedance of the external source is connected in series on the external line. As soon as switching to the external source has been completed, measurement of a sudden drop in the external voltage brings about closing of a static switch which short-circuits the resistance.