Smart storage for active distribution networks estimation and measurement solutions

Active distribution networks emerged when power generation units have been connected into LV or MV grids. Most of these generators are based on renewables (PV, wind) which have an intermittent character and are dispersed over a large area. In order to cope with the unpredictability of the generation, the best solution is, despite its high cost, to deploy electrical energy storage units. Further intelligent control of the distribution network is using the storage not only for energy leverage (minutes-term balance of generation and consume) but also for system services, as during perturbations following faults in the network. This paper presents such an application - intended to cope with the lower level of inertia in the active distribution networks, due to intensive use of static converters for power transfer. The resulting virtual synchronous generator (VSG) is developed around electrical storages, selected as a function of the application case and desired nominal power of the VSG. All algorithms rely on the State of Charge (SOC) signal describing the storage status. An automated system dedicated to continuous estimation of the SoC is presented, as to be integrated into a more complex on-line VSG application.