The quality problems in low irradiance at grid connected photovoltaic  systems

Abstract

Solar Photovoltaic (PV) energy is one of the main topics that have attracted the attention of researchers in recent years. The use of solar energy is increasing rapidly in the world. Although PV energy has many advantages, it has some disadvantages. Among these disadvantages, power factor (PF) and Total Harmonic Distortion (THD) issues are discussed in this article. PF and THD are dependent on the radiation values. The solar inverter output voltage and current waveform should be in sinusoidal waveform. However, the sinusoidal waveform of current and voltage lose their sinusoidal characteristics due to non-linear loads on grid-connected solar system. Harmonic components often occur in grid-connected solar PV systems. In addition, at low irradiance the amplitude of harmonic components increases, whereas the power factor of the PV system decreases. Low power factor and high amplitude of harmonics cause the efficiency of the solar system to decrease. PF and THD values were measured in a particular cloudy day for analysis. The grid-connected PV system was modeled by using Matlab /simulation program and carried out the analysis of the solar PV system. Thus, the analytical expression of the PF and THDI dependent on irradiation were found with a new method by using statistical package for the social sciences (SPSS) program and curve fitting method.