Analysis and Coordinated Provision of Voltage Regulation and Power Smoothing Services in MV-LV Distribution Grids

This paper presents a comparative analysis of data-driven control strategies for voltage regulation (VR) and power smoothing (PS) in distribution grids with distributed renewable energy sources and battery energy storage systems (DBESSs). The main scope of this analysis is to assess the concurrent operation of VR and PS techniques in terms of voltage violation mitigation, DBESS utilization, smoothing capability, etc. The examined control schemes are applied to distribution networks consisting of sub-grids with different voltage levels, i.e., medium-voltage (MV) and low-voltage (LV), to investigate potential interactions focusing on the VR performance. The VR issues are addressed by introducing a new hierarchical coordination framework that actively controls the active and reactive power flows between MV and LV sub-grids. Quasi-static simulations are performed on a MV-LV distribution network consisting of the 33-bus MV benchmark network and the IEEE European LV test feeder, revealing a strong VR interaction between LV and MV sub-grids. In addition, the proposed hierarchical control scheme effectively mitigates the VR issues caused by the uncoordinated operation of the LV and MV sub-grids. Finally, the concurrent operation of VR and PS techniques improves the VR efficacy by means of reducing the required reactive power at the expense of DBESS utilization.