Impact of distributed reactive power control of renewable energy sources in smart grids on voltage stability of the power system

The changes in the German power system to a renewable electricity generation leads to a higher system stress and higher demand of reactive power. As a result, voltage stability tends to become a binding technical criterion. In particular, reactive power demand of Smart Grids is changing with growing installation of renewable energy sources. This effect is considered with an explicit network model. With this model, it is possible to evaluate different strategies of reactive power control of renewable energy sources and quantify their effect on the whole power system. Assessment of voltage stability is done in a two-step approach to minimize computing times. A multidimensional parameter variation is used to quantify voltage stability limits. Results show that different control strategies of renewable energy sources have a significant influence on voltage stability of the power system.