ABSTRACT
This chapter deals with the philosophy of security assessment based on frequency domain models and equal area criterion concepts. It discusses the conventional approach to stability assessment applicable to a single machine against an infinite bus. The chapter concentrates on the simplified network consisting of a series reactance connecting the machine and the infinite bus. It defines the conventional ingredients for power system stability including applications of the swing equation and its alternate forms. In the power systems engineer's terminology, the dynamic equation relating the inertial torque to the net accelerating torque of the synchronous machine rotor is called the swing equation. Frequency domain models of synchronous machines introduced the idea of subtransient, transient, and steady state reactances. Models for a salient pole and round wound synchronous machines were discussed. The chapter concludes with the treatment of transient stability for the general network case, including a flowchart of a transient stability assessment program.
