The effect of size of DG on voltage flicker and voltage sag in closed-loop distribution system

Application of distributed generation (DG) in distribution system is expected to increase in the near future due to its positive impacts such as voltage support, improved reliability, small size and losses reduction. However DGs may have negative impacts on power quality, such as voltage regulation, harmonic distortion, islanding and confliction with relaying and reclosing. This paper investigates the effect of the Distributed Generation (DG) and its size on voltage flicker and voltage sag which is considered recently as an urgent power quality problem that can affect motor starting, temperature rise, overloading of generators, motors and may cause health risk problems due to the annoying light flicker which is consequence of voltage fluctuation. The effect of different sizes of DG on the voltage flicker and voltage sag in different buses of IEEE 34 buses meshed distribution system has been investigated. To support this argument, simulations are achieved on MATLAB/SIMULINK, where the results reveal the amount of effect of DG on voltage flicker and voltage sag for different types of buses of meshed distribution system.