Impact of internal impedances of distributed synchronous generators on voltage stability analysis

As more distributed generation (DG) sources have been installed at the locations closer to customers, generator internal impedances (GIIs) can cause more significant impacts on voltage stability analysis. This paper is aimed to investigate the relationship of generator locations and GII influences on voltage stability analysis. For this purpose, generators are first modeled as voltage phasors behind transient equivalent impedances. Then, the extended L-index is used to include GIIs into voltage stability analysis. The index values with and without considering the GIIs on system voltage stability are compared for two test systems. Simulation results show that neglecting GIIs may lead to inaccurate or even incorrect judgment, particularly when the generators are close to load centers.