Impact of a Weak Grid-network on a Grid-tied Solar Photovoltaic System Supplying a Non-linear Load

Solar photovoltaic (PV) technology is gaining more attention due to its low maintenance and operation costs. However, a grid-tied solar PV system as well as non-linear loads feed harmonic currents into the grid network, severely affecting the power quality. Recently, studies on power quality issues in grid-tied solar PV systems have been conducted without considering the impact of a grid network quality. A grid network can either be strong or weak, depending on the geographical area. In this study, the impact of a weak grid network on the output performance of a grid-tied solar PV system supplying a non-linear load is investigated. The Fast Fourier Transform (FFT) has been used to evaluate the percentage of the total harmonic distortion (THD). The study found that integrating a weak grid network into a solar PV system while supplying a non-linear load, can negatively impact both the current and voltage THD percentages. Hence, it is of great significance to analyze the quality of a grid network before designing a filter to be used to mitigate the harmonics injected by a distributed generation system. As a future study, a filter that can effectively handles a wide range of grid impedance variations needs to be designed.