Voltage Stability Assessment for a Realistic Power System: the Italian Case

This paper describes the fundamentals of the Voltage Stability Assessment (VSA) approach adopted in OMASES, an integrated platform for Dynamic Security Assessment, and its application to a realistic grid model, namely the Italian national grid. In the first part the authors illustrate the Quasi Steady State (QSS) method and the calculation of the Secure Operation Limits (SOLs) by means of the OMASES module VSAP. In the second part the grid under test is examined and the VSA process is described: several contingency scenarios are built, considering n-1 and n-2 contingencies related to the loss of lines and generators and applying two different stress directions. Finally, results of the analysis are shown and commented. In case of low security margins also the necessary load shedding actions are calculated and illustrated.