Mitigation of rapid voltage variations caused by passing clouds in distribution networks with solar PV using energy storage

Passing clouds can create unacceptable rapid voltage variations in weak distribution networks with a significant solar PV penetration. This paper investigates the benefit of a PV inverter ramp-rate control strategy using battery energy storage for the mitigation of rapid voltage variations. By controlling the discharging/charging operation of the energy storage appropriately, not only the inverter ramp-rate can be maintained at a desired level, but also the voltage variations can be controlled within acceptable limits. Results, from simulation using a real Australian distribution feeder with real load demand and PV output profile, show that with a high penetration of PV, the voltage variations can increase beyond the allowable limit stipulated by the IEC 61000-2-2 standards. However, with the proposed ramp-rate control, the variation can be maintained well below the limits.