Power System Model

The conventional quasi‐steady‐state model for transient stability (TS) analysis of power systems assumes that the frequency is constant and equal to the nominal one for the definition of network parameters such as series reactances and shunt susceptances. This chapter presents a frequency dependent (FD) model for TS analysis based on the frequency divider formula (FDF). The FDF indicates that the value of the frequency varies as a continuum along the branches of the grid the boundary conditions are constituted by synchronous machine rotor speeds and measurements at the interconnection buses. Hence, during a transient, the frequency not only varies from bus to bus, but also along the length of series reactances of transmission lines and transformers. The chapter compares the dynamic behavior of the FD model of power system with the conventional TS model as well as of a dynamic phasor model through the 1,479‐bus dynamic model of the AIITS.