(b)
Figure 1 shows a one-line diagram of a synchronous generator supplying an infinite
bus. A three-phase fault occurs at point P. If the generator is delivering 1.0 p.u power
at the instant preceding the fault, use power angle curves and equal area criterion to
determine the critical clearing angle for clearing the fault with simultaneous opening of
the circuit breakers 1 and 2.
(14 marks)
E-1.2 pu
j0.5
800
10001
1000
j0.25
j0.05
j0.5
Fig. 1
Infinite bus
V=120°
