Centralised management of the power supply of a plurality of local power grids

The system has a power supply station (SUB) for supplying power to a local power grid (DEN1) through a switching device (COM1) that is connected to the grid. A power storage unit e.g. motor vehicle's electric battery, is connected to the grid through the switching device. The station receives power from a power supplier operator (PSO). The station determines and assigns a drain mode in which the storage unit supplies power to the grid, and a charge mode in which the station simultaneously supplies power to the grid and the storage unit, to the switching device. An independent claim is also included for a method for managing power supply of local power grids.