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प्रश्न
Give the advantage of AC in long distance power transmission with an illustration.
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उत्तर
- When power is transmitting for long-distance a fraction of power is lost due to joule heating (I2R).
- This power loss can be tackled either by reducing current i or by reducing resistance R of a transmission line.
- At the transmitting point, voltage is increased and the current is decreased by a step-up transformer.
- This reduced current at high voltage reaches the destination without applicable loss.
- At the receiving point, voltage is decreased and current is increased by step down transformer.
- Example 1:
2MW power is transmitted at 40Ω with 10 kV voltage
I = `"P"/"V" = (2 xx 10^6)/(10 xx 10^3)` = 200 A
Power loss = I2 R = (200)2 × 40 = 1.6 × 106 W
% of Power loss = `(1.6 xx 10^6)/(2 xx 10^6) xx 100 % = 80%` - Example 2:
When 2MW power at 40 Q is transmitted with 100 kV voltage.
I = `"P"/"V" = (2 xx 10^3)/(100 xx 10^3)` = 20 A
Power loss = I2 R = (200)2 × 40 = 0.016 × 106 W
% of power loss = `(0.016 xx 10^6)/(2 xx 10^6) xx 100%`
= 0.8 × 100% = 80%
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संबंधित प्रश्न
Draw a labeled diagram of a step-down transformer.
Express the turn ratio in terms of voltages.
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State the underlying principle of a transformer. How is the large scale transmission of electric energy over long distances done with the use of transformers?
The 300 turn primary of a transformer has resistance 0.82 Ω and the resistance of its secondary of 1200 turns is 6.2 Ω. Find the voltage across the primary if the power output from the secondary at 1600V is 32 kW. Calculate the power losses in both coils when the transformer efficiency is 80%
Read the following paragraph and answer the question:
Long distance power transmissions
The large-scale transmission and distribution of electrical energy over long distances is done with the use of transformers. The voltage output of the generator is stepped up. It is then transmitted over long distances to an area sub-station near the consumers. There the voltage is stepped down. It is further stepped down at distributing sub-stations and utility poles before a power supply of 240 V reaches our homes.
A power transmission line feeds input power at 2300 V to a step down transformer with its primary windings having 4000 turns. The number of turns in the secondary in order to get output power at 230 V are ______.
The primary coil of a transformer has 800 turns and the secondary coil has 8 turns. It is connected to a 220 V ac supply. What will be the output voltage?
