The grid-connected photovoltaic (PV) power generation system is expected to be more widespread in distribution systems due to increasing fossil-fuel cost. Recent advances in PV technology and great demand has led to cost reductions. This paper presents the effects of PV system installation location on the power quality of the distribution system. A measurement setup is prepared for a PV grid-contected system. The system consists of a PV array and a grid-connected inverter. The measured data are used to investigate the effects of a PV system. A feeder line with PV system is simulated in Matlab. This study focuses on both radial and loop operated distribution system. The distribution system's power quality, in terms of voltage, active power, total losses, and power factor of the network are presented. The simulation results show that implementation of the PV grid-connected system could improve the power quality of a distribution feeder.