Regulation strategies for mitigating voltage fluctuations induced by photovoltaic solar systems in an urban low voltage grid

Transient clouds cause rapid changes in the power output of Photovoltaic (PV) solar systems. These ramp rates may lead to power quality problems, such as voltage fluctuations, in the low-voltage (LV) electricity grid. This paper firstly assesses the impact of a growing number of distributed PV systems on the voltage profile in a LV grid by considering PV penetration rates of 40%, 70% and 100% of the local rooftop capacity. Next, the potential of active power curtailment, grid reinforcement and supercapacitors to prevent or mitigate these voltage fluctuations are examined. The experiments in this study are based on simulations run with a two-second time resolution for an urban LV grid located in Utrecht, the Netherlands. This study identifies that problematic fluctuations occur already at a 40% PV penetration rate and are expected up to 7.4% of time for a 100% PV penetration scenario. Additionally, the local deployment of either active power curtailment or supercapacitors are identified as adequate strategies to regulate the occurring voltage fluctuations. Finally, the most stable voltage profile and the lowest number of problematic voltage fluctuations are found in case of adopting supercapacitors as part of the PV system.