Problem 3 (20 Marks) A salient pole synchronous motor is connected to an infinite bus over a short feeder whose impedance is purely reactive. The power-angle curve curve for for transient condition is P'(8') = 1.3 sin '+ 0.2 sin 28' where the amplitudes are in per unit (pu) on the machine rated base values. With the motor operating initially unloaded a shaft load of 0.70 pu is suddenly applied. Note that since this is a salient pole machine 8'max # 180° - 8'ss a) Compute the operating torque angle 8's. (5 Marks) b) Assuming 8'ss = 25° and 8'max = 136.2°, compute areas A1 and A2. Does the salient pole motor remain in synchronism with the infinite bus? Why? (8 Marks) c) Compute maximum torque angle 82 and the corresponding maximum torque P (82) that the motor can operate and remain in synchronism with the infinite bus. (7 Marks)