Harmonic spectrum estimation and analysis of the voltage at the PCC of the distribution network connected to solar plant based on parametric algorithm (Music)

In recent years, distribution network-connected single-phase and three-phase solar power plants have been growingly used in order to increase network sustainability, reduce loss, and improve voltage profile. Merging renewable distributed generation sources (DG) in distribution networks has caused some problems in measurement of power quality parameters. The use of electronic power devices in photovoltaic systems leads to injection of harmonic and inter-harmonic components into the distribution networks and, consequently, deviation of the network frequency around the main frequency; furthermore, the switching frequency of static inverters used in DG sources causes an increase in emission of supra-harmonics. Type and structure of devices used in static inverters of photovoltaic systems play fundamental role in generation and injection of harmonics, inter-harmonics, and supra-harmonics. The present paper is aimed to analyze the harmonic spectrum analysis in range of 0-2KHz caused by 2&3-level inverters used in a photovoltaic system using MUSIC parametric algorithm. The spectrum analysis results obtained from the above-mentioned simulation would be compared with other methods such as FFT (Fast Fourier Transform) algorithm and Welch's algorithm. Then the photovoltaic system's harmonic emission rate in frequency range of 2-150 KHz caused by 2&3-level inverter would be evaluated. Simulation has been performed as Real-time in Matlab/Smiulink Software environment. Results indicated that the harmonic spectrum analysis in presence of DG sources using MUSIC algorithm had high resolution and low error percentage; furthermore, the emission rate of supra-harmonics (2-150 KHz) using NPC 3-level inverter has been reduced by 50%.