Increasing demand for voltage control in secondary substations

German grid operators are facing increasing challenges regarding voltage limits in grids with large numbers of installed PV systems. In order to allow for the development of advanced technical solutions to overcome these challenges and therefore to increase the capability to install PV in low voltage distribution grids, a model to assess the voltage level in grids with different levels of PV penetrations has been developed. Results show a strong need for voltage control in secondary substations and derive basic guidelines for application as well as development criteria.