3. For the shown 11kV three phase system - Select appropriate current transformers at buses A and B
- Set the downstream relay RBC as main protection for faults at remote end “c” and find its trip times using CO-8 TDOC chart.
- Set the upstream relay RAB as backup protection and find its trip times using CO-8 TDOC chart

An air-conditioning system consists of a heating section and an evaporative cooler. air enters the heating section at 10°c and 70 percent relative humidity at a rate of 30m^3/min, and it leaves the evaporative cooler at 20°c and 60 percent relatively humidity. if the air conditioning system operates at a total pressure of 98 kpa, determine (a) the temperature and relative humidity of the air when it leaves the heating section, (b) the rate of heat transfer in the heating section, and (c) the rate of water added to air in the evaporative cooler