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(a) Draw the diagram of a device which i...

(a) Draw the diagram of a device which is used to decrease high S voltage into a AC voltage and state its working principle. Write four sources of energy loss in this device.
(b) A small town with a demand of 1200 kW of electric power at 220 V is situated 20 Km away from an electric plant generating power at 440V. The resistance of the two wire line carrying power is `0.5 Omega` per km. The town gets the power from the line thruough a 4000-220 V step-down transformer at s sub-station in the twon. Estimate the line power loss in the from of heat.

Text Solution

Verified by Experts

(b) Total resistance of the line = length `xx` resistance per unit length
= 40 km `xx 0.5 = 20 Omega`
Current flowing in the line I = P/V
`1200 xx 10^(3)//4000 = 300 A `
Power loss = `I^(2) R = (300)^(2)xx 20 ` = 1800 kW
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