Experimental analysis and evaluation of power quality in grid-connected photovoltaic systems

In this thesis, in order to analyze the most common problems of power quality, harmonics and interharmonics, measurements are made in two different photovoltaic (PV) systems installed in two different countries. Using the measured results, it is investigated whether harmonics and interharmonics are harmful or not and whether they meet The International Electrotechnical Commission (IEC-61000) and The Institute of Electrical and Electronics Engineers (IEEE-519) standards. These measurement results are used to evaluate the harmonics distortion values according to the mentioned standards. Also, a detailed analysis of inverters as a harmonic generating component in PV systems is performed. A model is premised as a harmonic source to signify of the power circuit of the Photovoltaic inverters and then this model is verified by simulation and experiments performed in the laboratory environment. Lastly, experimental studies have been carried out in order to investigate how the harmonics from the grid will interact with the PV systems. It has been determined that the inverters are a harmonic source but, it is has been concluded that harmonics and interharmonics distortions injected into the distribution network do not create a major concern.