Introduction to Electrical Power and Power Electronics

76 Introduction to Electrical Power and Power Electronics

will accelerate under the prime mover input power, accelerating to increase the rotor

angle to δ

2

. If the fault is cleared in time and the circuit breaker is closed under the

automatic reclosure scheme (common on most systems), the generator starts deliver-

ing electrical power in excess of the prime mover input and starts decelerating to its

original power angle δ

1

after the inertial overshoot to δ

3

. The transient swing will

be such that the accelerating area A

a

is equal to the decelerating angle A

d

. The maxi-

mum allowable fault clearing time for stability can be determined by applyi