Protection Interface Concept for LV Grids with an Efficient Dynamic Voltage Restorer

Power quality (PQ) issues are often the reason for malfunctions and interruptions in the low-voltage (LV) utility grid. Protection from voltage sags and swells can be achieved using dynamic voltage restorer (DVR) circuits. The diffusion of grid scale energy storage has renewed interest for battery-fed DVR converters for voltage support, where sensitive loads are connected to the grid. At the same time, the next generation smart grid calls for the design of efficient and compact power converters with minimum impact on the grid. In this paper, a concept design for a battery-fed DVR is proposed with particular focus on energy efficiency and power density. The layout, operation and control strategy of the converter are presented and supported by simulation results. The study lays the basis for the implementation of a 30-kVA prototype.