Impact of grid connected distributed generation on voltage sag

Distributed Generation (DG) has impacts on the performance when connected to distribution system. The term "distribution generation (DG)" refers to small-scale generation located near the source of the load it serves. Distributed Generation from renewable sources is more and more widely used due to the growing concern on environmental protection. DG can also provide power supply to customers in the event of an outage or during scheduled interruption. DG had impacts on the performance of connected distributed network. Application of distributed generation in distribution system is expected to increase in near future due to its positive impacts such as voltage support, improved reliability, small size and loss reduction. However, DGs may have negative impacts on power quality such as voltage regulation, harmonic distortion, voltage sag, islanding and confliction with relaying and reclosing. A comparative analysis is done on the impact of different types of DGs on voltage profile and voltage sag in distribution system. The analysis shows that voltage profile is improved with DG, with highest voltage for synchronous generator with power factor controller. Synchronous generators with excitation control have less impact on voltage sag compared to other types of generators. Simulation results also shows that volt age sag magnitude is highest for induction generator followed by synchronous generator with power factor control.