Analysis of Inherent Steady State Stability of Synchronous Machines by the Eigen Values Method （Part 1） -Damper-less Salient-pole-type Synchronous Machines-

This paper presents an analysis of the inherent steady state stability of damper-less salient-pole-type synchronous machines. Although some methods have been used for this problem, this paper uses eigen values method because it gives the most exact solutions for the problem and both step-out and hunting instabilities can be evaluated by using the method. The effects of various parameters on the steady state stable region of synchronous mrchines are discussed in this paper. At first, the characteristics of the eigen values of synchronous machines are considered after deriving the linearized version of basic differential equations, and it is shown that the steady state stability of synchronous machines is generally determined by the three dominant eigen values. Next, calculations of the steady state stable regions for the various circuit conditions of a syn-cronous generator system are carried out, and the effects of circuit parameters on the stable region, especially on the hunting region, are discussed