Vertical provision of reactive power for voltage stability

The integration of renewable energy sources is a challenge for networks of all voltage levels. The feed-in of renewable energy sources has an impact on asset loadings and reactive power management to keep the nodal voltages within in the allowed voltage interval. Usually, the overlayed network provides the required reactive power. However, the local provision by the installed renewable energy sources is possible, too. Additionally, their contribution of reactive power to the overlayed network is also conceivable. This paper analyses the theoretical potential of distribution networks to provide reactive power to the superior network with reactive power injection of wind and photovoltaic power plants. Technical restrictions like voltage band violations and asset loadings are considered. The analysis is based on representative network data of the three usual voltage levels of German distribution networks.