Calculating Method of Dynamic Stability in a Multi-machine System allowing for Margin

Abstract

First, the equivalent circuit of a power system transformed into the form of Lagrangian tree is applied to obtain the basic equations required for criterion of system stability. On the next step, the characteristic equation can be obtained by transformation of the matrices which consist of the coefficients of basic equations. Furthermore, a new concept about the margin of system stability is proposed, and the assessment of system stability is carried out by obtainning the root-loci of a characteristic equation.