Mitigating Overvoltage in Power Grids with Photovoltaic Systems by Energy Storage

The rise of photovoltaic (PV) penetration is contributing to the increasing incidence of overvoltage detection in the electrical grid during times of high-power generation. Overvoltage can cause disturbances or (partial) failures in the electrical supply network, since the components used are designed for a certain voltage band. One option to counteract too high voltage levels and thus ensure power quality, grid stability and resilience is the absorption of active power by means of a battery energy storage system (BESS). In this paper, we first built a suitable simulation setup for a typical European network section, including a large-scale PV system connected to the 10 kV level and a BESS model. A suitable charging and discharging algorithm for the BESS with the aim to realize peak shaving for the grid voltage was developed and implemented. Simulations, performed in MATLAB/Simulink®, show the dependence of the battery capacity and power on the grid-serving effect of BESS. By determining appropriate values for these two factors a significant reduction of the voltage level could be achieved.