Reactive Electric Spring Application for a Domestic User with Small Photovoltaic Plant

Nowadays, Renewable Energy Sources (RESs) deliver a significant amount of power into the grid. Because of their intermittent nature, the grid power is prone to fluctuate, causing a variation of the supply voltage of the loads. To stabilize the voltage across the critical loads of a user in a simple way, the Electric Spring (ES) concept has been recently proposed. This paper is concerned with an ES that executes the stabilization under the peculiar circumstances of i) a user connected to a prevalently resistive line such as the low-voltage distribution lines in many countries, and ii) an ES exchanging only reactive power. In the paper, the voltage drop induced by a RES power variation is first analyzed to assess the impact of the RES on the supply voltage of the user loads. Afterwards, the reactive ES operation are investigated, setting its working boundaries and presenting its control scheme. The results of Matlab/Simulink simulations verify the effectiveness of the ES action against the RES variability. The work intends to show the potential of reactive ES in a real application where a user equipped with RES is fed by a weak distribution grid.