Design and control of an energy storage system for voltage flicker caused by clouds passing over photovoltaic systems

MSc defense of Lynrick Wix

As more and more solar panels are installed in households, a problem arises due to the power from the solar panels fluctuating throughout the day due to clouds passing over the solar panels. This in turn causes voltage flickers in the household which can be visible/irritable to the human eye and damage appliances in the household. This problem can be solved by making use of an energy storage system (ESS) which delivers active power in order to reduce or avoid the voltage fluctuations above the visible flicker threshold from occurring. In this thesis, a novel control algorithm is designed and implemented in two different ways to control the active power dispatch of tthe ESS with the main goal of avoiding any voltage flickers from occurring. Simulation results using pre-existing PV system data showed that for that the most (if not all) voltage flickers were eradicated using the two control algorithm implementations. Furthermore two different experimental setups were built and/or commissioned to validate the control algorithm functionality, for which the experiment results showed that the DC connected ESS experiment setup operating in power control mode had the best performance in terms of avoiding any visible voltage flickers from occurring. Finally, a conclusion based on the results is given with future work and as well as recommendations for the continuation of this
research.