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Explain how power can be transmitted efficiently to long distance. |
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Answer» Solution :i. The electric power generated in a power station SITUATED in a remote place is transmitted to different regions for domestic and industrial use. ii. For long distance transmission, power lines are MADE of conducting material like aluminium. There is always some power loss associated with these lines. iii. If I is the current through the wire and R the resistance, a considerable amount of electric power `I^(2)R` is dissipated as heat. Hence, the power at the receiving end will be lesser than the actual power generated. iv. However, by transmitting the electrical energy at a HIGHER voltage, the power loss can ve controlled as is evident from the following two cases.  Case (1) A power of 11,000 W is transmitted at 220 V. Power P = VI `I=(P)/(V)=(11,000)/(220)=50A` If R is the resistance of line wires, Power loss `=I^(2)R=50^(2)R=2500(R)" watts. "` Case (2) 11,000 W power is transmitted at 22,000 V. `I=(P)/(V)=(11,000)/(22,000)=0.5A` Power loss `=I^(2)R=(0.5)^(2)=R=0.25(R)` watts. Hence it is evident that if power is transmitted at a higher voltage the loss of energy in the form of heat can be CONSIDERABLY reduced. |
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