# Transmission of power by a.c. cables is impossible beyond

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Transmission of power by a.c. cables is impossible beyond

(a) 500 km (b) 300 km (c) 250 km (d) 45 km

Transmission of power by a.c. cables is impossible beyond 45 km

## Related questions

The main limitation for power handling capability of short length transmission lines and cables is (A) power factor (B) stability (C) thermal effect limit (D) conductor size

If 3000 kW power is to be transmitted over a distance of 30 km, the desirable transmission voltage will be.  (A) 11 kV (B) 33 kV (C) 66 kV (D) 132 kV

Stability of a transmission line can be increased by

To increase power transfer capability of a long transmission line, we should:  (1) Increase line resistance (2) Increase transmission voltage (3) Decrease line reactance (4) Both (2) & (3)

The inductance of a power transmission line increases with (A) decrease in line length. (B) increase in conductor diameter. (C) increase in spacing between phase conductors. (D) increase in load current carried by conductors.

Which of the following is used for power factor improvement in transmission line ? (a) Three phase induction (b) An overexcited three phase synchronous motor running on no load (c) Three phase AC series motor (d) Choke

Fuse wire protection system is usually not used beyond: a. 10A b. 25A c. 50A d. 100A

The power loss in a transmission line depends on (a) current in the line. (b) resistance of the line. (c) length of the line. (d) All of the above

The inductance of single phase two wire power transmission line per km gets doubled when the  (a) Distance between wires is doubled  (b) Distance between the wires is increased four fold  (c) Distance between the wires is increased as square of the original distance  (d) Radius of the wire is doubled

The economic size of a conductor in transmission and distribution lines of electric power is decided by (a) Ohm’s law (b) Kelvin’s law (c) Kirchhoff’s law(d) Faraday’s law

If diameter of each conductor of a transmission line is ‘d’, then the diameter of n-layer stranded conductor will be (a) (2n – 1) d (b) (2n + 1) d (c) (3n – 1) d (d) (3n + 1) d

An overhead transmission line has a span of 260 m. The weight of the conductor is 0.68 kg/m. The maximum allowable tension in the line is 1550 kg. Maximum sag of the line should be (a) 5.8 m (b) 4.6 m (c) 2.7 m (d) 3.7 m

The input impedance of a short circuited loss less transmission line of characteristic impedance 50 Ohm is

The mechanical power developed by the armature of a d.c. motor is equal to?

The input of an A.C. circuit having power factor of 0.8 lagging is 40 kVA The power drawn by the circuit is?

The maximum transmission power efficiency of DSB-C Amplitude modulation is : a. 25% b. 33.33% c. 50% d. 100%

The size of a conductor used in power cables depends on the:  (A) operating voltage  (C) current to be carried (B) power factor (D) type of insulation used

In case of a ‘High Voltage DC’ transmission, how many minimum conductors are required?

A transmission line has 1 P.0 impedance on a base of 11 KV, 100 MVA. On a base of 55 KV. it will have a P.0 impedance of

A transmission line to be reciprocal, the condition is (a) A = D (b) AC – BD = 1 (c) AD – BC = 1 (d) AB – CD = 1

The degree of protection by ground wire depends upon the a. Arcing angle b. Shielding angle c. Power factor d. All of above

The apparent power drawn by an A.C. circuit is 10 kVA and active power is 8 kW. The reactive power in the circuit is?

When measuring insulation resistance of cables using d.c. source, the galvanometer used should be initially short circuited because  (A) Cables have a low value of capacitance which draws a high value of charging current (B) Cables have a low value of initial resistance (C) Cables have a high value of capacitance which draws a high value of charging current (D) Cables have a low value of capacitance and initial resistance

In an AC transmission line difference in phase of voltage at two ends of the line is due to (a) System voltage (b) Insulators (c) Resistance of line (d) Reactance of line

Which of the following relations is true for long transmission line ? (a) VS = AVR – BIR (b) VS = BVR + AIR (c) VS = AVR + BIR (d) VS = BVR – AIR

Effect of increase in temperature in an overhead transmission line is (a) to increase stress and length both (b) to decrease stress and length both (c) to decrease stress and increase length (d) None of the above

What type of insulator will be used if the direction of the transmission line is to be changed?

In case the height of transmission tower is increased, which of the following parameter is likely to change?  (A) Resistance (B) Inductance (C) Capacitance (D) None of the above

The purpose of guard ring in transmission lines is to  (1) reduce the earth capacitance of the lowest unit. (2) increase the earth capacitance of the lowest unit. (3) reduce the transmission lines losses. (4) reduce the reactance of the line

Real power flow in transmission lines is controlled by (A) tap changing transformer (B) voltage regulating transformer (C) phase-angle regulating transformer (D) booster transformer

In voltage source converter based HVDC transmission system the active power is controlled by changing (A) phase angle of the converter ac input voltage (B) supply frequency of the converter ac input voltage (C) magnitude of the converter ac input voltage (D) DC voltage at the inverter terminals

The diameter of conductor used in LT 660 V grade power cables depends on

A transmission line of 200 km has a certain A, B, C and D parameters. If the length is reduced to 60 km

The effect of corona in high voltage a.c. transmission line is  A) Increased energy loss in the transmission line B) Increased line reactance C) Increased line to line capacitance D) All of the above

A long transmission line has considerable ……………….. effect. A) series capacitance B) shunt capacitance C) series inductance D) shunt inductance

A single-line-to-ground fault on a overhead transmission line creates (A) voltage sag (B) voltage swell (C) over voltage (D) voltage flicker

For a transmission line open circuit and short circuit impedances are 20 Ω and 5 Ω. Then characteristic impedance is: (1) 100 Ω (2) 50 Ω (3) 25 Ω (4) 10 Ω

In a transmission line if booster transformers are to be used, preferred location will be  (A) At the receiving end (B) At the sending end (C) At the intermediate point (D) Anywhere in the line

The presence of earth in case of overhead transmission line (a) increases capacitance (b) increases inductance (c) decreases capacitance (d) decreases inductance

Why are shunt reactors connected at the receiving end of long transmission line system: (1) To increase the terminal voltage (2) To compensate voltage rise caused by capacitive charging at light load (3) To improve power factor (4) None of these

In which of the following transmission lines, the value of the Shunt admittance should be approximated to zero ? (A) A 66 kV 35 km long line (B) A 132 kV 200 km long line (C) A 220 kV 300 km long line (D) A 400 kV 500 km long line

The main consideration for operating transmission line at high voltage is (a) to increase efficiency only. (b) to reduce power loss only. (c) to increase power transmission capability only. (d) All of the above

Earth wire on EHV overhead transmission line is provided to protect the line against:

how the booster is connected in transmission line ?