The simultaneous mitigation of slow and fast voltage fluctuations caused by rooftop solar PV by controlling the charging/discharging of an integrated battery energy storage system

Both slow and fast voltage fluctuations in the connected low voltage (LV) distribution feeder are caused by intermittent variations in solar PV power output, in addition to the variations in load demand where rooftop solar photo-voltaic (PV) unit penetration is higher. A single energy storage system integrated with the solar PV unit can mitigate these fluctuations in voltage profile. A novel analytical approach to mitigate both slow and fast voltage fluctuations simultaneously in the connected LV distribution feeder is proposed, which has not explicitly been addressed in the literature. Integrated battery energy storage systems will be dynamically charged during mid-day to alleviate the voltage rise and discharged during the evening peak hours to alleviate the voltage drop, while simultaneously controlling the fast fluctuations of the PV inverter output to a specified value. The proposed control strategy has been validated using a hypothetical distribution feeder system and results have demonstrated that both the slow and the fast voltage fluctuations in the voltage profile can effectively be alleviated, if the proposed strategy is implemented.