A comprehensive analysis of voltage stability indices in the presence of distributed generation

The penetration level of conventional and renewable distributed generation (DG) has increased recently. Voltage stability is a key factor in determining optimal location and size of DGs in electric grid. DGs connected to distribution networks are potential to improve the system voltage stability. Placing DG units at weakest load buses (candidate buses) is a widely used technique which requires utilizing an effective voltage stability index. This paper evaluates the effectiveness of various voltage stability indices on utilizing DGs units optimally within certain limits and constraints. Important recommendations are concluded. The proposed study is demonstrated through power flow studies in IEEE 5-bus test system, using several scenarios of active and reactive load increase.