Dynamic Analysis of Voltage Control Strategies by Decentralized Energy Resources

Modern power systems frequently operate near to critical operating limits due to the shut-off of many conventional power plants caused by the integration of renewable energy resources in the grid. In the past, voltage control was mainly provided by conventional power plants not only after failures in the grid, but also in case of sudden changes in the reactive power demand. Regarding the shut-off of these generating units, Distributed Energy Resources (DERs) must provide ancillary services such as voltage control, to guarantee a stable and reliable grid operation in future scenarios. Since most DER are connected to the distribution grid level, they are capable to provide reactive power where it is most needed while also aiding the transmission system. However, different strategies such as constant power factors cosφ can lead to overvoltages in low load hours. Hence, new voltage control strategies are already introduced and analysed by several studies using static investigations. This paper will analyse three different voltage control strategies in dynamic simulations in distribution grids under the consideration of load tap changer. Moreover, innovative voltage control schemes are implemented in dynamic models for Battery Energy Storage Systems (BESS), Photovoltaic (PV) and Combined Heat and Power (CHP) plants.