Define the term first saving transient stability for a singl

Define the term \'first saving transient stability\' for a single machine connected to an infinite bus How would the definition change is you had multiple generators and no infinite bus? State all assumption made in the classical analysis of transient stability

Solution

(a) first swing stability :

A power system is said to be first swing stable if the post-halt angle in the centre of interia reference frame, of all seerely distributed machines(SDM) initially incereases until a peak value is reached ,where the angle starts returning to the equilibrum point. existance of peak angle and hence zero speed of all SDM\'s guarantees the first swing stability of the system . the first swing stability will also known as the rotor angle stability .

(c) assumptions made in the classical analysis of transient stability :

(1) the mechanical power input to each synchronous machine is constant

(2) damping or asynchorous power is negligible

(3) the synchorous machine are represeted electrically , by constant voltage behind transient reactance models

(4) the motion of each synchoronous machine rotor is at a fixed angle relatie to the angle of voltage behind the transient reactance

(5) loads are represented by constant impendence

(2)