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

Different types of steels contain different elements that alter the characteristics of the steel. for each of the following elements, explain what the element does when alloyed with steel.

Water in a partially filled large tank is to be supplied to the roof top, which is 8 m above the water level in the tank, through a 2.2-cm-internal-diameter pipe by maintaining a constant air pressure of 300 kpa (gage) in the tank. if the head loss in the piping is 2 m of water, determine the discharge rate of the supply of water to the roof top in liters per second.

A3-mm-thick panel of aluminum alloy (k 177 w/m-k, c 875 j/kg-k and ? = 2770 kg/m) is finished on both sides with an epoxy coating that must be cured at or above t,-150°c for at least 5 min. the production line for the curing operation involves two steps: (1) heating in a large oven with air at ts,0-175°c and a convection coefficient of h, 40 w/m2. k, and (2) cooling in a large chamber with air at 25°c and a con- vection coefficient of he 10 w/m2.k. the heating portion of the process is conducted over a time interval te which exceeds the ime required to reach 150°c by 5 min (h = r + 300 s). the coating has an emissivity of ? = 0.8, and the temperatures of the oven and chamber walls are 175 and 25°c, respectively. if the panel is placed in the oven at an initial temperature of 25°c and removed from the chamber at a safe-to-touch tempera ture of 37°c, what is the total elapsed time for the two-step curing operation?