The impact of dynamic behaviors of distributed grid-connected photovoltaic system on distribution network transient voltage stability

Due to the increasing capacity of grid-connected photovoltaic systems in distribution networks, its impact on the voltage security can´t be ignored. In this paper, based on the voltage stability criterion of maximum transmission power, and considering induction motor voltage response characteristic, the impact of dynamic behaviors of grid-connected photovoltaic systems on transient voltage stability is investigated. Three scenarios have been analyzed, respectively corresponding to three kinds of photovoltaic system´s dynamic behaviors: stopping operation after voltage sags, low-voltage ride-through capability and dynamic voltage support. In addition, P-V curve is applied to do theoretical interpretation for the simulation results in the revised IEEE 33-bus distribution network, and it is testified that grid-connected photovoltaic systems equipped with low-voltage ride-through capability can remarkably improve distribution network transient voltage stability, and the effectiveness would be more prominent with the dynamic voltage support of photovoltaic systems.