Impact of large-scale photovoltaic system on short and long term voltage stability in sub-transmission network

Integration of solar energy based large scale Photovoltaic (PV) generation can offer significant benefits to the power system. Since PV units can be installed close to load centers, improvement in reliability of the network can occur together with a decrease in greenhouse gas emissions. Despite these general benefits, the dynamic voltage characteristics of sub-transmission networks under the influence of large scale PV installations need to be carefully analyzed and existing standards revisited for potential upgrade. This research paper offers analyses of the impact of large scale PV on dynamic voltage stability in sub-transmission network while considering the presence of a number of power system devices typically found in this kind of network. From preliminary results, obtained using the IEEE 14 bus test network, it can be concluded that the integration of large scale PV with proper controller settings can positively influence the dynamic voltage stability with respect to short and long term state variables. It can be also concluded that static voltage stability analysis alone does not adequately capture the implication of large-scale PV on sub-transmission system.