Characteristics of disturbance in frequency 9-150 kHz and harmonic distortion of the on-grid rooftop photovoltaic system for resistive and inductive load

Abstract

Direct current (DC) electricity generated from photovoltaic (PV) needs to be converted into alternating current (AC) using an inverter so that it could be combined with electricity from the grid. However, the inverter could distort the AC waveform in the form of harmonics and disturbance in the frequency range of 9-150 kHz caused by its switching characteristics which could reduce power quality, disrupt the power line communication (PLC) system, or other electronic equipment connected in the same network. This study investigated the characteristics of the disturbances in the frequency range of 9-150 kHz generated by the on-grid rooftop PV system and observed the correlation with harmonic distortion. There were three types of load used in this study, i.e. pure resistive loads, pure inductive loads, and combination of resistive-inductive loads. The measurements were carried out using an oscilloscope to obtain a time-domain signal, which later processed by Matlab using FFT to see its frequency response, and power quality analyzer to see its harmonic distortion. The results show that each type of load has different relationship characteristics between disturbance and harmonic distortion.