Question

a) A hydro-electric power station has a reservoir of area 2.4 square kilometre and capacity 5milliom cubic metres. the effective haed of water is 100m, the penstock, turbine and generator efficiencies are 955,90% and 85% respectively.

i) Calculate the total electrical energy that can be generated from the power station

ii) if the load of 15MW has been supplied for 3 hours, find the fall in reservoir level

b) Determine the most economical conductor cross section area to transmit a 3 phase balanced load which varies through the year as follows, 1800kVA for 1500hrs, 800kVA for 1600hrs and no load for 5660hrs, the transmission voltage is 33kV. The annual interest and depreciation charges total 10%, Energy cost $0.417 per/kWh. The conductors to be used are of copper costing $34.5/kg and having a density of 8860kg/m3. the resistance of single conductors of c.s.a km2is 0.177Ω. Also calculate the conductor diameter, the maximum current density.

Answer 1