Power Smoothing as a Mitigation Action against Rapid Voltage Changes: A Comparative Study

The proliferation of converter-interfaced renewable energy sources (CIRES) in distribution networks (DNs) has necessitated the revision of metrics and practices employed by DN operators (DNOs) to assess and preserve voltage quality within their grids. In this context, a voltage quality index that remains overlooked is that of rapid voltage changes (RVCs). To this end, this paper investigates the impact of volatile CIRES generation on RVCs. The RVCs are quantified based on the definitions of the IEC 61000-4-30:2015 and IEEE 1547:2018 Standards. Additionally, power smoothing (PS) by CIRES, employing an energy storage system (ESS), is introduced as a promising mitigation action. Specifically, three well-established PS methods are compared in terms of their RVC-suppressing capability and the associated stress of the ESS. Moreover, a sensitivity analysis concerning the location of the PS-performing CIRES is conducted. The investigation is performed by means of simulations on the IEEE European Low Voltage (LV) test feeder. The results reveal that the operation of CIRES under a PS scheme can enhance voltage quality by suppressing RVCs.