Study of the impact of the increasing penetration of renewable energy sources on voltage sags in HV networks

The increasing integration of renewable energy sources into power systems is significantly impacting the operation of the latter. Specifically, the replacement of large conventional thermal power plants with wind farms and distributed photovoltaic (PV) systems reduces the overall short-circuit power of the network. Such a shift, where traditional synchronous generators are increasingly displaced by static generation, introduces several challenges, including a reduction in short-circuit capacity. In this context, this paper investigates the impact of the above-mentioned short-circuit power reduction on voltage sags on the high-voltage (HV) power system section, encompassing both transmission and subtransmission networks. The analysis focuses on how the reduction in short-circuit power affects the contours of areas having equal voltage sag magnitude, as well as the vulnerable area of the network surrounding the fault location.