Load effects on voltage stability in distribution network with considering of distributed generation

The improvement of voltage stability is considered as one of the key issues in the design and assessment of power systems. Also, the location and size of distributed generation units (DG) in distribution networks (DN) play a significant role on improve of voltage stability and reduce losses in the network. This paper show the load characteristic effect on P-V curves operation, where it push the system to near or far from the saddle nose bifurcation (SNB). We proposed a modified voltage stability (MVS) index with considering of DG units as well as a ZIP load model, in order to analysis of voltage stability in standard IEEE-34 buses unbalance DS.