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?

1 Answer

Answer :

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.

Related questions

Description : The time taken for a surge to travel a 600 km long overhead transmission line is?

Last Answer : The time taken for a surge to travel a 600 km long overhead transmission line is 0.002s.

Description : 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.

Last Answer : An overhead transmission line has a span of 240m between level supports. 1.52 m 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.

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

Last Answer : A transmission line is terminated at its characteristic impedance. The reflection coefficient is  0

Description : A loss less line terminated with its surge impedance has

Last Answer : A loss less line terminated with its surge impedance has flat voltage profile.

Description : 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

Last Answer : 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 2000 MW .

Description : 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- ... solid conductor is 40 mm, then the radius of each of the bundle conductors would be?

Last Answer : 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- ... conductor is 40 mm, then the radius of each of the bundle conductors would be 30 mm.

Description : 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?

Last Answer : 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 0.05 + 0.2 ln (6010.5).

Description : 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

Last Answer : A loss less line of characteristic impedance Z0 is terminated in pure reactance of –jZ0 value. VSWR is Infinity.

Description : Which of the following characterizes a properly terminated transmission line? A. The line loss is minimum. B. The standing wave ratio is minimum. C. The input impedance is twice the load impedance. D. The standing wave ratio is one.

Last Answer : D. The standing wave ratio is one.

Description : A transmission line of unknown impedance is terminated with two different resistances, and an SWR is measured each time. With a 75 Ω termination, the SWR measures 1.5. With a 300 Ω termination, it measures 2.67. What is the impedance of the line? A. 100 Ω B. 212 Ω C. 300 Ω D. 112 Ω

Last Answer : D. 112 Ω

Description : 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 

Last Answer : 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 

Description : 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 ... (C) partial reflection of reversal of voltage only (D) reflection of reversal of both current and voltage

Last Answer : A travelling wave of surge resistance, Ro on a transmission line is terminated by a load resistance, RL. If RL > Ro then there is partial reflection of reversal of current only

Description : 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

Last Answer : 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 d = 1.5 cm

Description : 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?

Last Answer : P = I^2  *  R 5*10^6  = [(150*10^6) / (110*10^3)  *  R R = 2.7 ohm/phase

Description : A waveguide may also be terminated in a resistive load that is matched to the characteristic impedance of the waveguide. The resistive load is most often called a _____

Last Answer : Dummy resistor

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

Last Answer : Creates  overvoltage.

Description : 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 

Last Answer : D

Description : 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 

Last Answer : Maximum sag = (l^2)/8c So c = T/W c = 1550/0.68 c= 2279.4 Now Maximum sag = (260^2)/8(2279.4) = 3.7 (d)

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

Last Answer : Earth wire on EHV overhead transmission line is provided to protect the line against: lightening surge

Description : 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

Last Answer : Surge impedance of overhead transmission line is normally in the order of 300 - 500 ohms

Description : 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?

Last Answer : 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 an equilateral triangle of sides equal to 'd' then average capacitance and inductance will increase.

Description : 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 fault is  (A) 513.8 V (B) 889.9 V (C) 1112.0 V (D) 642.2 V

Last Answer : 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, ... line. The voltage of the alternator neutral with respect to ground during the fault is 642.2 V

Description : Choose two appropriate auxiliary components of a HVDC transmission system from the following P. D.C line inductor Q. A.C line inductor R. Reactive power sources S. Distance relays on D.C line T. Series capacitance on A.C. line  (A) P and Q (B) P and R (C) Q and S (D) S and T

Last Answer : Choose two appropriate auxiliary components of a HVDC transmission system from the following P. D.C line inductor Q. A.C line inductor R. Reactive power sources S. Distance relays on D.C line T. Series capacitance on A.C. line  (A) P and Q (B) P and R (C) Q and S (D) S and T

Description : 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

Last Answer : 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 2085 MW

Description : The transmission line distance protection relay having the property of being inherently directional is (A) impedance relay (B) MHO relay (C) OHM relay (D) reactance relay

Last Answer : The transmission line distance protection relay having the property of being inherently directional is MHO relay

Description : 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

Last Answer : 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 P / 4

Description : A generator is connected through a 20 MVA, 13.8/138 kV step down transformer, to a transmission line. At the receiving end of the line a load is supplied through a step down transformer of 10 MVA, 138/69 kV rating. A 0.72 ... load (in per unit) in generator will be (A) 36 (B) 1.44 (C) 0.72 (D) 0.18

Last Answer : A generator is connected through a 20 MVA, 13.8/138 kV step down transformer, to a transmission line. At the receiving end of the line a load is supplied through a step down transformer of 10 MVA, 138/ ... MVA and 69 kV in load circuit, the value of the load (in per unit) in generator will be 36 

Description : An HVDC link consist of rectifier, inverter transmission line and other equipments. Which one of the following is true for this link ?  (A) The transmission line produces/ supplies ... ) Both the converters (rectifier and inverter) consume reactive power from the respective connected AC systems

Last Answer : An HVDC link consist of rectifier, inverter transmission line and other equipments. Which one of the following is true for this link ?  (A) The transmission line produces/ supplies ... ) Both the converters (rectifier and inverter) consume reactive power from the respective connected AC systems

Description : 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

Last Answer : 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 2280 MW

Description : For enhancing the power transmission in along EHV transmission line, the most preferred method is to connect a  (A) Series inductive compensator in the line (B) Shunt inductive compensator at the ... (C) Series capacitive compensator in the line (D) Shunt capacitive compensator at the sending end

Last Answer : For enhancing the power transmission in along EHV transmission line, the most preferred method is to connect a Series capacitive compensator in the line

Description : For a fixed value of complex power flow in a transmission line having a sending and voltage V, the real power loss will be proportional to  A) V B) v2 C) 1/V2 D)1/V

Last Answer : For a fixed value of complex power flow in a transmission line having a sending and voltage V, the real power loss will be proportional to 1/V2

Description : Which of the two generalized constants of a transmission line are equal?  (a) B & C (B) A & B (c) A & D (D) B & D

Last Answer : Which of the two generalized constants of a transmission line are equal?  (a) B & C (B) A & B (c) A & D (D) B & D

Description : Series capacitive compensation in EHV transmission line is used to

Last Answer : To maintain voltage stability 

Description : The sending end and receiving end voltages of a three-phase transmission line are 10 kV/ph and 9.5 kV/ph, respectively. If the resistance drop is 150 V/ph and receiving end power factor is 0.8, the sending end power factor is (A) 0.745 lagging (B) 0.775 lagging (C) 0.8 lagging (D) 0.85 lagging

Last Answer : Vscos¢s-Vrcos¢r=IR

Description : The transmission line feeding power on either side of the main transmission line is called?

Last Answer : The transmission line feeding power on either side of the main transmission line is called Secondary transmission.

Description : For a transmission line with negligible losses, the lagging reactive power (VAR) delivered at The receiving end, for a given receiving end voltage, is directly proportional to the?

Last Answer : For a transmission line with negligible losses, the lagging reactive power (VAR) delivered at The receiving end, for a given receiving end voltage, is directly proportional to the line voltage drop.

Description : A lossless radial transmission line with surge impedance loading?

Last Answer : A lossless radial transmission line with surge impedance loading takes negative VAr at sending end and zero VAr at receiving end.

Description : The line conductor of a transmission line has an overall diameter of 19.53 mm, weight 0.844 kg/m and an ultimate breaking strength of 7950 kg. If the factor of safety is to be 2, when conductor ... .5 kg/m. What is the vertical sag, corresponding to this loading for a 300 m span level supports?

Last Answer : The line conductor of a transmission line has an overall diameter of 19.53 mm, weight 0.844 kg/m and an ultimate breaking strength of 7950 kg. If the factor of safety is to be 2, when conductor ... 5 kg/m. 5.22 m is the vertical sag, corresponding to this loading for a 300 m span level supports.

Description : 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 ... . What is the clearance between the conductor and the water at a point midway between the towers?

Last Answer : 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 ...  54.94 m is the clearance between the conductor and the water at a point midway between the towers.

Description : If in a short transmission line, resistance and inductance are found to be equal and regulation appear. to be zero, then the load will?

Last Answer : If in a short transmission line, resistance and inductance are found to be equal and regulation appear. to be zero, then the load will be 0.707 lagging.

Description : For an existing ac transmission line, the string efficiency is 80%, if dc voltage is supplied for the same setup, the string efficiency will be?

Last Answer : 100%

Description :  A single-phase transmission line of impedance j 0.8 ohm supplies a resistive load of 500 A at 300 V. The sending end power factor is?

Last Answer :  A single-phase transmission line of impedance j 0.8 ohm supplies a resistive load of 500 A at 300 V. The sending end power factor is 0.6 lagging.

Description : 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

Last Answer : 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 240 

Description : In a DC transmission line?

Last Answer : In a DC transmission line there are no effects due to inductive and capacitive reactances.

Description : Why Earth Wire is provided in the overhead transmission lines?

Last Answer : Earth wire is provided above the overhead transmission lines for protection against lightning strokes. The ground wire or earth wire protects the phase conductors or line conductors by attracting itself the ... traveling waves set in the lines by acting a short circuit secondary of the line current

Description : Most of the high voltage transmission lines in India are (a) underground (b) overhead (c) either of the above (d) none of the above

Last Answer : (b) overhead

Description : The advantage of cables over overhead transmission lines is (a) easy maintenance (b) low cost (c) can be used in congested areas (d) can be used in high voltage circuits

Last Answer : (c) can be used in congested areas

Description : What is the material used for overhead transmission lines?

Last Answer : Answer: ACSR conductors are employed.

Description : Which of the following materials is used for overhead transmission lines ? (a) Steel cored aluminium (b) Galvanised steel (c) Cadmium copper (d) Any of the above

Last Answer : (d) Any of the above

Description : Most of the high voltage transmission lines in India are (a) underground (b) overhead (c) either of the above (d) none of the above

Last Answer : (b) overhead