An Experimental Analysis of the Impact of a Grid-Tied Photovoltaic System on Harmonic Distortion

Abstract

This study presents analyses of the results of selected experimental power quality (PQ) data obtained on a grid-tied photovoltaic (PV) system composed of different PV modules technologies and four PV inverters integrating the grid at the point of common coupling. A PQ analyzer is utilized to collect the data from the 110 kW PV system for two weeks. The measured PQ data was obtained by following South Africa and international power quality measurement standards. The data measured were RMS voltage, RMS current, voltage unbalance, frequency, voltage total harmonic distortion (THDV), current total harmonic distortion (THDI), active and reactive power. Voltage unbalance, frequency, voltage total harmonic distortion (THDV), current total harmonic distortion (THDI) have been appraised and juxtaposed with the requirements of the South Africa Renewable Energy Grid Code. These parameters were all found within the regulated limits, except for the current total harmonic distortion (THDI) that exceeded the grid code limit due to sudden voltage variations. This occurrence is observed primarily at dawn and dusk when the PV inverter output active power is at the lowest level. This study's performance analysis contributes to evaluating large-scale PV systems inverters’ behaviour and their impact on the distribution grid power quality at different power generation levels.