Impact of the Measurement Time Resolution on Energy Key Performance Indicators for Distributed Energy Resources: An Experimental Analysis

The growing presence of Renewable Energy Sources (RESs) is heavily affecting the control and management of distribution grids. Battery Energy Storage Systems (BESSs) are increasingly adopted to mitigate the adverse impacts caused by the uncertainty of RES generators. Most of the existing works in the literature aims at using BESSs to maximize the self-consumption of energy provided by RES generators or focuses on the mitigation of voltage and/or frequency drift effects. More recently, some research works also studied the effects that BESSs have on the active power flows at the Point of Common Coupling (PCC) of prosumers. All these studies are based on the definition of proper energy Key Performance Indicators (KPIs) based on heterogeneous information collected from several measurement devices deployed in the field. This also means that the results of such studies could be significantly affected by the quality of data, particularly concerning the time resolution of the measurements. To better highlight this concern, this paper proposes an analysis of the impact of the time resolution of measurements on the evaluation of the absolute power ramp reduction at the PCC of prosumers in presence of BESS installations. The analysis was performed on real data collected from the eLUX lab of the University of Brescia, Italy, by varying the time resolution from 5 s to 15 min. The results of the analysis demonstrated that the time resolution has a great impact on the evaluation of the considered KPI, by leading to completely different performance assessments.