Voltage Harmonic Mitigation by Distributed Renewable Energy Sources in Low-Voltage Distribution Networks: Sensitivity Analysis

The ever-growing penetration of converter-interfaced distributed renewable energy sources (CI-DRES) combined with the presence of non-linear loads (NLLs) might generate serious power quality issues in distribution networks (DNs). Currently, numerous approaches have been proposed for CI-DRES voltage source converters (VSCs) to operate as active harmonic filters; however, most of them mitigate the problem locally without investigating which CI-DRES in the DN would be most appropriate to perform such service. In this paper, a sensitivity analysis is conducted, and a mathematical framework is formulated to assess and quantify the contribution of each CI-DRES to the decentralized harmonic filtering process in a low-voltage (LV) DN with the presence of NLLs based on the location and available capacity of each CI-DRES. The latter is a crucial element since, in the future, the CI-DRES may offer various services simultaneously, e.g., reactive power or virtual inertia. The proposed framework and analysis are verified via simulations in the time domain and via decoupled harmonic power flows considering the benchmark CIGRE LV DN and the IEEE European LV Test feeder under various mixtures of CI-DRES/NLLs. The conclusions will pave the way so that active filtering is treated as a new ancillary service that CI-DRES can offer and it can be introduced in relevant markets.