Q3. Q4. Q5. Q6. Q7. Consider the faults on line-1. For which fault location (or locations) the critical clearing time

is the smallest? Write down the reason brieﬂy (do NOT use the equation of critical clearing angle and/or time in your explanation). (10 marks) Does any fault on Line-2 result into a smaller critical clearing time compared to the Line-l

fault scenario (or scenarios) identiﬁed in Q3? For either answer (yes or no), write down the

reason brieﬂy (do NOT use the equation of critical clearing angle and/or time in your

explanation). (10 marks) Consider the fault scenario identiﬁed in Q3 (or Q4), i.e. the fault scenario results into the

smallest critical clearing time. a. Calculate the maximum power outputs of the generator before, during and after fault

Pmax, Pmaxl and me2, respectively. (5 marks) b. Plot approximately the power-angle curves of the generator before, during and after the

fault. Indicate the pre-fault, critical clearing and maximum angles, and the acceleration

and deceleration areas, (15 marks) c. Calculate the critical clearing angle and critical clearing time. (5 marks) Suppose that clearing time of the line breakers are 100ms. Write a Matlab Script that

computes the swing curve using step-by-step method. Use 10 ms time step and plot the power

swing curve for 2 s period. Is the system stable? (30 marks) If the system is stable in Q6, repeat the simulations by increasing the clearing time with 5

ms until unstable scenario is obtained. Plot the swing curves for all simulations. Is the critical

clearing time obtained in Q5.c consistent with the simulations? (10 marks)