Effect of Synchronous Generator-Based Distributed Generation Resources on Power System Transient Stability Considering Critical Clearing Time Index

Due to the increase in demand and expansion of power grid, the role of distributed generations (DGs) is of interest in recent studies. Less environmental issues, less harmful emission, the high cost of centralized generation, and improving power quality indices are some of the lucrative points of DGs which makes them attractive. microgrids and active distribution networks are important topics regarding DGs in distribution networks. Although microgrids and active distribution networks have numerous advantages, they have some shortcomings. The presence of inertia-less or low inertia sources in these networks endangers the stability of the upstream network. The aim of this study is investigating the transient stability of the upstream power network by considering the critical clearing time (CCT) in the presence of synchronous generator-based DGs with different penetration levels. The overall behavior of the network in relation to the three-phase faults at different locations of the upstream network will be studied to examine the transient stability. In order to investigate the results, simulations will be carried out on IEEE 9-bus transmission system as the upstream network and the IEEE 33-bus distribution system as an active distribution network connected to it.