Advertisements
Advertisements
प्रश्न
Give the advantage of AC in long distance power transmission with an illustration.
Advertisements
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%
APPEARS IN
संबंधित प्रश्न
Draw a labeled diagram of a step-down transformer.
Find the ratio of primary and secondary currents in terms of turn ratio in an ideal transformer.
Name two factors on which the magnitude of an induced e.m.f. in the secondary coil depends.
Describe, with the help of a suitable diagram, the working principle of a step-up transformer. Obtain the relation between input and output voltages in terms of the number of turns of primary and secondary windings and the currents in the input and output circuits.
Describe briefly and two energy losses, giving the reasons for their occurrence in actual transformers ?
A transformer lowers e.m.f. 220 V to 12 volts. If the number of turns in primary are 8800, how many turns are in secondary coil?
In a series resonant RLC circuit, the voltage across 100 Ω resistor is 40 V. The resonant frequency ω is 250 rad/s. If the value of C is 4 µF, then the voltage across L is
A transformer operating at primary voltage 8 kV and secondary voltage 160 V serves a load of 80 kW. Assuming the transformer to be ideal with purely resistive load and working on unity power factor, the loads in the primary and secondary circuit would be:
A transformer consisting of 300 turns in the primary and 150 turns in the secondary gives output power of 2.2 kW. If the current in the secondary coil is 10 A, then the input voltage and current in the primary coil are ______.
The primary coil of a transformer has 60 turns whereas its secondary coil has 3000 turns.
If a current of 5A flows in the primary coil, how much current will flow in a load in the secondary coil? State the assumption you have made regarding the transformer, in this calculation.
