LV Grid Voltage Control with Battery Energy Storage Systems

The increasing amount of photovoltaic systems connected to the LV grid causes many problems to the distribution system operators. The main concerns are the high harmonic output, reverse power flow, local voltage rise, sensitivity to frequency changes (which is the impact of decreasing system inertia) and inaccurate scheduling. To enable further PV capacity to be built in to LV grids, while meeting the power quality requirements, new ways of grid development should be implemented. The rapid cost reduction of energy storage technologies allows for the deployment of battery energy storage systems for voltage control. During peak PV generation voltage rise can be dealt with by charging the batteries, while discharging during peak hours could solve the problems caused by voltage drops. The purpose of this study is to describe the principle of operation of these systems and to demonstrate one of the first such Hungarian BESS projects in detail. Commonly used voltage control methods are described briefly, then DIgSILENT Power Factory is used to model the operation of the examined battery energy storage system. Simulation results are validated with real voltage measurements of the project.