(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°
