A long overhead transmission line is terminated by its characteristic...

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A long overhead transmission line is terminated by its characteristic impedance. Under this operating condition, the ratio of the voltage to the current at different points along the line will?

A long overhead transmission line is terminated by its characteristic impedance. Under this operating condition, the ratio of the voltage to the current at different points along the line will progressively increase from the receiving end to the sending end.

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A transmission line is terminated at its characteristic impedance. The reflection coefficient is  (a) 1 (b) –1 (c) 0 (d) ∞

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A travelling wave of surge resistance, Ro on a transmission line is terminated by a load resistance, RL. If RL > Ro then there is (A) no reflected wave (B) partial reflection of reversal of current only (C) partial reflection of reversal of voltage only (D) reflection of reversal of both current and voltage

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A voltage of 1000 kV is applied to an overhead line with its receiving end open. If the surge impedance of the line is 500 ohm, then the total surge power in the line ill

A 100 km long transmission line is loaded at 110 kV.if the loss of line is 5 MW and the load is 150 MVA, the resistance of the line is?

An overhead transmission line has a span of 240m between level supports. What is the maximum sag if the conductor weight 727 kg/km and has a breaking strength of 6880 kg? Allow the factor of safety of 2. Neglecting wind and ice loading.

A loss less line of characteristic impedance Z0 is terminated in pure reactance of –jZ0 value. VSWR is  (1) 10 (2) 2 (3) 1 (4) Infinity

When a dominant mode wave guide not terminated in its characteristic impedance is excited with a 10 GHZ signal then if d is the distance between two successive minima of the standing wave in the guide then   (A) d = 1.5 cm (B) d is less then 1.5 cm (C) d is greater then 1.5 cm (D) d = 3 cm

For a long uncompensated line the limit to the line loading ill governed by?

what is mean by long transmission line ?

A 10 km long line has a characteristic impedance of 400 ohms. If line length is 100 km, the characteristic impedance is: (1) 4000 Ω (2) 400 Ω (3) 40 Ω (4) 4 Ω

A 50Ω transmission line is terminated in an impedance of 20-j50. What will be the reflection coefficient? A) 0.69 B) 1.69 C) 6.9 D) 16.9

A three phase overhead transmission line has its conductors horizontally spaced with spacing between adjacent conductors equal to 'd'. if now the conductors of the line are rearranged to form and the equilateral triangle of sides equal to 'd' then?

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

A 220 kV, 3 phase transmission line is 60 km long. The resistance is 0.15 ohm / km and the inductance is 1.4 mH / km. Use the short line model to find the power at the sending end when the line is supplying a three phase load of 300 MVA at 0.8 pf lagging at 220 kV.  (A) 5.58MW (B) 80MW (C) 85.58MW (D) 74.42 MW

A three phase 50 Hz, 400 kV transmission line is 300 km long. The line inductance is 0.97 mH/km per phase and capacitance is 0.0115 mF/km per phase. Assume a loss less line. Determine the line wavelength (a line phase constant).  (A) 1250 km (B) 6578 km (C) 4990 km (D) 2445 km

For a single phase overhead line having solid copper conductors of diameter 1 cm, spaced 60 cm between centers, the inductance in mH/km is?

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

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

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

Surge impedance of overhead transmission line is normally in the order of (a) 1- 5 ohms (c) 300 - 500 ohms (b) 20 - 30 ohms (d) 300000 - 500000 ohms

In terms of cost, overhead transmission line is better than underground transmission line in the field of   (a) Insulation (b) Right of way (c) Visibility (d) None of these

For a 500 Hz frequency excitation, a 50 km long power line will be modeled as

The conductor of a 10 km long, single phase, two wire line are separated by a distance of 1.5 m. The diameter of each conductor is 1 cm, If the conductors are of copper, the inductance of the circuit is

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

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 concept of an electrically short, medium and long line is primarily based on the  A) Nominal voltage of the line B) Physical length of the line C) Wave length of the line D) Power transmitted over the 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

A synchronous condenser is used at the receiving end of a transmission line for (A) supplying lagging kVA (B) voltage control (C) frequency control (D) maintaining a higher voltage than at the sending end

A 20-MVA, 6.6-kV, 3-phase alternator is connected to a 3-phase transmission line. The per unit positive-sequence, negative-sequence and zero-sequence impedances of the alternator are j0.1, j0.1 and j0.04 respectively. The neutral of the alternator is connected to ground through an inductive reactor of j0.05 p.u. The per unit positive-, ... The voltage of the alternator neutral with respect to ground during the fault is  (A) 513.8 V (B) 889.9 V (C) 1112.0 V (D) 642.2 V

A 800 kV transmission line is having per phase line inductance of 1.1 mH/km and per phase line capacitance of 11.68 nF/km. Ignoring the length of the line, its ideal power transfer capability in MW is (A) 1204 MW (B) 1504 MW (C) 2085 MW (D) 2606 MW

An 800 kV transmission line has a maximum power transfer capacity of P. If it is operated at 400 kV with the series reactance unchanged, the new maximum power transfer capacity is approximately (A) P (B) 2P (C) P / 2 (D) P / 4

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A loss less transmission line having Surge Impedance Loading (SIL) of 2280 MW is provided with a uniformly distributed series capacitive compensation of 30%. Then, SIL of the compensated transmission line will be (A) 1835 MW (B) 2280 MW (C) 2725 MW (D) 3257 MW

A transmission line conductor at a river crossing is supported from two towers at height. of 30 m and 90m, above water level. The horizontal distance between the towers is 270m, if the tension in the conductor is 1800 kg and the conductor weight 1 kg/m. What is the clearance between the conductor and the water at a point midway between the towers?

A 100 km transmission line is designed for a nominal voltage of 132 kV and consists of one conductor per phase. The line reactance is 0.726 ohm/km. The static transmission capacity of the line, in MW, would be   (a) 240 (b) 132 (c) 416 (d) 720

To increase the visual critical voltage of cporona for an overhead line, one solid phase-conductor is replaced by a "bundle" of four smaller conductors per phase, having an aggregate cross-sectional area equal to that of the solid conductor. If the radius of the solid conductor is 40 mm, then the radius of each of the bundle conductors would be?

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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

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