    Question

# Do the same exercise as above with the replacement of the earlier transformer by a 40,000-220 V step-down transformer (Neglect, as before, leakage losses though this may not be a good assumption any longer because of the very high voltage transmission involved).Hence, explain why high voltage transmission is preferred?Exercise:[A small town with a demand of 800 kW of electric power at 220 V is situated 15 km away from an electric plant generating power at 440 V.The resistance of the two wire line carrying power is 0.5 Ωper km.The town gets power from the line through a 4000-220 V step-down transformer at a sub-station in the town.]

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Solution

## Current is 800×10040000=20A(a) line power loss = 202×15=6kW(b) Power supply by the plant =800+6=806 kW(c) Voltage drop on the line is 20×15=300VIt is clear that th epercentage power loss is greatly reduced by high voltage transmission. The power loss is (6×806)×100=0.74%.  Suggest Corrections  1      Related Videos   PHYSICS
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