In a DC transmission line?

1 Answer

Answer :

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

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Last Answer : 100%

Description : High Voltage DC (HVDC) transmission is mainly used for  (A) bulk power transmission over very long distances (C) inter-connecting two systems with same nominal frequency (C) eliminating reactive power requirement in the operation (D) minimizing harmonics at the converter stations

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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

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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

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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

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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

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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 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?

Last 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.

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 : 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?

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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 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 : 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 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?

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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 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 : A DC reactor is connected in series with each pole of a converter station in order to: A) prevent commutation failures in the inverter B) supply reactive power to the converter C) improve system stability D) increase the power transfer capability

Last Answer : A DC reactor is connected in series with each pole of a converter station in order to:  prevent commutation failures in the inverter

Description : A cylinder rotor generator delivers 0.5 pu power in the steady-state to an infinite bus through a transmission line of reactance 0.5 pu. The generator no-load voltage is 1.5 pu and the infinite bus voltage is 1 pu. The ... fault at the generator terminal is  (A) 53.5 (B) 60.2 (C) 70.8 (D) 79.6

Last Answer : A cylinder rotor generator delivers 0.5 pu power in the steady-state to an infinite bus through a transmission line of reactance 0.5 pu. The generator no-load voltage is 1.5 pu and the ... clearing angle, in degrees, for a three-phase dead short circuit fault at the generator terminal is 79.6

Description : The power flow problem mathematical model for a linear transmission network (A) is non-linear (B) is linear (C) considers time variation of generation (D) does not consider tap-changing transformers

Last Answer : The power flow problem mathematical model for a linear transmission network is non-linear

Description : Corona loss in transmission lines can be reduced by (A) using small diameter conductors (B) using bundled conductors (C) using less spacing between conductors (D) increasing the transmission line voltage

Last Answer : Corona loss in transmission lines can be reduced by using bundled conductors

Description : Precise control of reactive current flow entering the transmission and distribution systems can be minimized by using (A) synchronous condenser (B) static VAR capacitor (C) capacitor bank (D) thyristor switched reactor in parallel with capacitor

Last Answer : Precise control of reactive current flow entering the transmission and distribution systems can be minimized by using (A) synchronous condenser (B) static VAR capacitor (C) capacitor bank (D) thyristor switched reactor in parallel with capacitor

Description : If a 5-bus test system contains 6 transmission lines and one transformer, how many non-zero elements are there in the system Y-bus ? (A) 25 (B) 12 (C) 11 (D) 19

Last Answer : If a 5-bus test system contains 6 transmission lines and one transformer, 19 non-zero elements are there in the system Y-bus.

Description : The zero sequence current of a generator for line to ground fault is j 2.4 p.u. The current through the neutral during the fault is (a) j 0.8 p.u (b) j 2.4 p.u. (c) j 0.24 p.u. (d) j 7.2 p.u. 

Last Answer : j7.2

Description : 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

Last Answer : The concept of an electrically short, medium and long line is primarily based on the  Physical length of the line 

Description : Shunt compensation in an EHV line is used to (A) Improve stability. (B) Improve the voltage profile. (C) Reduce the fault level. (D) Substitute for synchronous phase modifier.

Last Answer : Shunt compensation in an EHV line is used to Improve the voltage profile.

Description : If an unsymmetrical line to ground fault occurs at the secondary terminals of a delta/star, ungrounded transformer, then  (A) zero sequence currents are present on both sides of the transformer  (B) ... side  (D) zero sequence currents are present on the primary side but not on the secondary side

Last Answer : If an unsymmetrical line to ground fault occurs at the secondary terminals of a delta/star, ungrounded transformer, then zero sequence currents are absent on both sides of the transformer 

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

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

Description : The function of the earth wire in an extra high voltage line is to?

Last Answer : The function of the earth wire in an extra high voltage line is to provide a shield to the phase conductors from direct lightning stroke.

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

Last Answer : For a long uncompensated line the limit to the line loading ill governed by stability limit.

Description : With 100 % series compensation of line.

Last Answer : the circuit is series resonant at power frequency and high transient current.

Description : A 60 Hz, 320 km lossless line has Bending end voltage 1.0 p.u, The receiving end voltage on no load is?

Last Answer : A 60 Hz, 320 km lossless line has Bending end voltage 1.0 p.u, The receiving end voltage on no load is 1.088 p.u.

Description : If a line is 100 % series compensated it may result into series resonance at power frequency of?

Last Answer : If a line is 100 % series compensated it may result into series resonance at power frequency of 50 Hz.

Description : The X:R ratio of 220 kV line as compared to 400 kV line is?

Last Answer : The X:R ratio of 220 kV line as compared to 400 kV line is smaller.

Description : A two conductor 1 - pi line operates at 50 Hz.The diameter of each conductor is 20 mm and the spacing between the conductors is 3m, The height of conductor above the ground is 6 m. The capacitance of the line to neutral will be?

Last Answer : A two conductor 1 - pi line operates at 50 Hz. The diameter of each conductor is 20 mm and the spacing between the conductors is 3m, The height of conductor above the ground is 6 m. The capacitance of the line to neutral will be 9.7 pF/m.

Description : A three phase 50 Hz line consists of three conductors each of diameter 21 mm, The spacing between the conductors all follows:A - B = 3m, B - C = 5m, C - A = 3.6mIf the line operates at 132 k V, the reactive voltampere generatd by the line per km is?

Last Answer : A three phase 50 Hz line consists of three conductors each of diameter 21 mm, The spacing between the conductors all follows:A - B = 3m, B - C = 5m, C - A = 3.6mIf the line operates at 132 k V, the reactive voltampere generated by the line per km is  51.70 kVAr.

Description : A two conductor 1 - pi line operates at 50 Hz.The diameter of each conductor is 4 cm and are spaced 6 m apart. What is the capacitive susceptance to neutral per km?

Last Answer : A two conductor 1 - pi line operates at 50 Hz. The diameter of each conductor is 4 cm and are spaced 6 m apart. 3.06 x 10-9 s/km is the capacitive susceptance to neutral per km.