Dynamic simulation of voltage collapses

The authors show some examples of dynamic simulations of voltage phenomena using a new general purpose stability program (EUROSTAG) covering in a continuous way the classical fields of transient, mid-term and long-term stability, and also the quasi steady state conditions of a power system. The three examples show the ability of dynamic simulations to study in depth all the phenomena taking part in the voltage collapses. The first example considers the case of an infinite bus feeding a reactive load through a purely reactive line. With this simple example, it is possible to show the basics of voltage instability. The second example illustrates the operation of a system on the lower part of the V, P curve. A two bus system is considered. The third example shows transient phenomena merged with mid-term voltage dynamics