Page 7 of 7 Problem 7 Consider the circuit shown in Figure (6) Assume that E = 1.25 p.u., and V = 1.00 p.u. The active component of the load on the circuit is 3 p.u., when a three phase short circuit takes place in the middle of transmission line 3. a) It is known that the system will remain stable when this fault is sustained. Determine the maximum angle of oscillations [5 points] b) Assume now that the active component of the load on the circuit is 3.2 p.u., when the fault takes place. Verify that the system will be unstable under sustained fault conditions. [5 points] c) Assume that for the conditions of part (b.) the fault is cleared at 8 = 85° by opening the circuit breakers at both ends of line 3. Carry out the necessary calculations to show that the system will remain stable under these conditions. [5 points] Tax d) Determine the maximum angle of oscillations & under the assumptions of part (c.) [10 points] Line 2 V E Line 1 P O+ j 0.08 Line 3 j0.03 j0.05 j 0.08 16-Elec-B7/May2017 Figure (6) Circuit for Problem (7)