Accuracy assessment of frequency-domain models for harmonic analysis of residential type photovoltaic-distributed generation units

Abstract

Since Photovoltaic-Based Distributed Generation Units (PV-DGUs) have power electronic interfaces for their grid integration, they can cause harmonic pollution in the system. Thus, the harmonic analysis is required to determine the system's harmonic constrained PV-DGU hosting capacity and proper planning of the harmonic mitigation devices and PV-DGUs. The accuracy of the harmonic analysis highly depends on the validity of the system equipment models. Accessible literature shows that there is not a report on accuracy assessment of the PV-DGU frequency-domain harmonic models. In this paper, firstly, for numerous distorted grid voltage condi-tions, the current harmonic distortion nature of the single-phase transformerless two-level H-bridge residential type on-grid PV inverter is examined in an experimental test system. Secondly, for current harmonic analysis of the examined PV inverter, the accuracy of the widely known frequency-domain models is statistically analyzed under numerous distorted grid voltages. For the accuracy assessment of the models, the measurements obtained from an experimental test system are considered as reference values. Finally, to investigate the effect of the models on the voltage harmonic distortion results of the harmonic analysis, the harmonic penetration analysis algorithm is integrated with the models, and it is simulated for IEEE 33 bus test system.