Voltage control in smart distribution grids — Overview and practical experience of available solutions

Ensuring voltage stability according to EN50160 has become a major challenge in today´s distribution grids due to the increasing number of fluctuating distributed energy resources (DER) connected on the medium and low voltage level. On the 2012 CIRED workshop EnBW Regional AG presented the regulated distribution transformer (RDT) as a powerful tool to achieve voltage control at the MV/LV-substation. Line voltage controllers complement this solution and are especially useful to avoid voltage problems when large loads or generation units are connected at the end of a long feeder line. This paper discusses different technological approaches to voltage control and provides use cases for the application of substation-based solutions as well as voltage regulators for single feeders. Moreover, a hands-on example from the grid of EnBW Regional AG is discussed. This includes actual on-site measurement data and a simulation on the expected operation of the first line voltage controller which was only recently put into operation.