Technical comparison of measures for voltage regulation in low-voltage grids

Abstract

As photovoltaics (PV) is mainly connected (∼70% of the power) to the low-voltage (LV) grid, the distribution system operators face new challenges to provide the required voltage quality. Mainly, voltage rise caused by the generation of PV leads to grid extension measures. In this study, the effects of a high PV generation on the grid in Epplas will be evaluated along with the detailed simulation of the different measures for voltage maintenance in LV grids. As a result, the curtailment of the generation power by generation management or storages or the proportionate installation of PV can be seen as measures with the highest potential to reduce the voltage rise. Solutions such as the regulated distribution transformer or string voltage regulators decouple the LV grid from the local medium-voltage grid and can be considered useful for the integration of additional PV plants and the operation of the LV grid. Reactive power control can lower the voltage effectively and is already provided by the inverters of the PV but comes with an increased loading of the lines.