A distance relaying system utilizing a CT with a turns ratio of 500:5 and a PT with a turns ratio of 20KV:69.3V. The lines AB and BC shown in Fig. has an impedance of (0.03+j0.4)2/Km, the lengths of lines AB and BC are100)Km and 80 Km. a) Find each zone settings of both relays Rab and Rbc then find the response times of main and backup protection for a symmetrical short circuit at 90% of line BC. b) What difference will happen in the tripping time of both relays if the fault occurred through an impedance of (1.2+j20)2 (A4) (10 Marks) B 801e m Rab 100 km Rbc Fig.1