Answer :
When a transmission line is energized, the wave that propagates on it is current wave and voltage wave.
asked
Mar 20, 2018
by
anonymous
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
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
asked
Jun 18, 2018
by
anonymous
Description : lf a travelling-wave travelling along a loss-less overhead line does not result in any reflection after it has reached the far end, then the far end of the line is
Answer :
lf a travelling-wave travelling along a loss-less overhead line does not result in any reflection after it has reached the far end, then the far end of the line is terminated into a resistance equal to surge impedance of the line
asked
Apr 26, 2018
by
anonymous
Description : Obtain the relationship between the reflection and the transmission coefficients in terms of the intrinsic impedance of the respective mediums when a plane wave propagating normal to the reflection surface between medium 1 and medium 2 reflects on the inter surface
asked
Aug 24, 2019
by
anonymous
Answer :
Reactance relay is preferred for phase fault on short transmission line.
asked
Mar 20, 2018
by
anonymous
Description : 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
Answer :
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 0.02 P.U
asked
May 3, 2018
by
anonymous
Description : Transmission efficiency of a transmission line increases with the
Answer :
Transmission efficiency of a transmission line increases with the increase in power factor and voltage
asked
Apr 26, 2018
by
anonymous
Answer :
The interaction between a transmission line and communication line is minimized by transposing transmission as well as communication lines, increasing the height of the transmission line tower, increasing the distance between the two lines.
asked
Mar 20, 2018
by
anonymous
Answer :
A transmission line is protected by distance protection, time graded and current graded overcurrent protection.
asked
Mar 19, 2018
by
anonymous
Description : For a short transmission line with r/x ratio of is 1.0, the regulation will be zero when the load power factor is
Answer :
For a short transmission line with r/x ratio of is 1.0, the regulation will be zero when the load power factor is 0.707 lead
asked
Apr 30, 2018
by
anonymous
Description : State the impact of inductance and resistance on transmission line performance
Answer :
Impact of inductance on transmission line: 1) It causes IXL drop in transmission line which affects regulation. 2) It is the only parameter which decides power transmission capacity of line i. ... is very small, it causes losses, temperature rise& poor voltage regulation so it cannot be neglected
asked
May 6, 2020
by
anonymous
Description : effect of inductance and capacitance on performance of transmission line.
Answer :
Following are the effect on performance of transmission line: 1. Due to inductance (L) voltage drop in transmission line produces. 2. Capacitor (C) draws charging current ... , transmission line efficiency, voltage regulation & also power factor of transmission line gets affected.
asked
Aug 25, 2019
by
anonymous
Description : effect of line parameter on performance of transmission line.
Answer :
Following are the effect of line parameter on performance of transmission line: 1. Due to resistance (R), voltage drop in transmission line & copper losses in transmission line ... transmission line efficiency, voltage regulation & also power factor of transmission line gets affected.
asked
Aug 25, 2019
by
anonymous
Description : Stability of a transmission line can be increased by
Answer :
Stability of a transmission line can be increased by Shunt capacitor, Series capacitor
asked
May 8, 2018
by
anonymous
Description : The sag of a transmission line is least affected by (A) Self weight of the conductor. (B) Temperature of the surrounding air. (C) Current through the conductor. (D) Ice deposited on the conductor.
Answer :
The sag of a transmission line is least affected by Current through the conductor.
asked
May 8, 2018
by
anonymous
Description : 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
Answer :
In a transmission line if booster transformers are to be used, preferred location will be At the intermediate point
asked
May 8, 2018
by
anonymous
Description : A transmission line of 200 km has a certain A, B, C and D parameters. If the length is reduced to 60 km
Answer :
A transmission line of 200 km has a certain A, B, C and D parameters. If the length is reduced to 60 km A increases, B decreases
asked
Apr 29, 2018
by
anonymous
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
Answer :
Vscos¢s-Vrcos¢r=IR
asked
Apr 28, 2018
by
anonymous
Description : What are the losses in a transmission line?
asked
Mar 10, 2018
by
anonymous
Description : State the limitations of EHVAC transmission line.
Answer :
Following are the Limitations of EHVAC Transmission: 1. Insulation cost increases as voltage increases 2. Skin effect is more 3. Proximity effect is more. 4. Corona loss increases. 5. Radio ... 18. EHVAC is economical only for bulk amount of power is to be transmitted over long distance.
asked
May 22, 2020
by
anonymous
Description : State line parameters of transmission line.
Answer :
Following are the of Line parameters of transmission line: 1. Resistance 2. Inductance 3. Capacitance
asked
May 22, 2020
by
anonymous
Description : While calculating performance of medium transmission line, what assumptions are made in case of (i) Nominal 'T' Method (ii) Nominal 'TT' Method.
Answer :
(i) Assumptions are made in case of Nominal 'T' Method: a. It is assume that line capacitance is connected at center of transmission line. b. It is assume that half ... assumed that transmission line resistance & reactance per phase is connected in between two half transmission line capacitance
asked
Aug 25, 2019
by
anonymous
Description : HVDC transmission line in India:
Answer :
HVDC transmission line in India: S.N . From To Voltage 1 Rihand (U.P) (from 1990) Dadri +- 500 KV (bipolar) 2 Talcher- is the biggest ... (Chandrapur) Western Region 140KV 8 Connecting Southern region(Vizag- Gajuwaka) Eastern Region 140KV
asked
Aug 25, 2019
by
anonymous
Description : Why is transmission line 11kV, 33kV 66kV Not Is 10kV, 20kV, 30kV ?
Answer :
10kv plus to compensate losses in olden days 1kv were added and transmitted. Since all equipment used for transmission have a multiple of 11 from olden days, still that is being followed even though the losses are ... voltages, multiples of 11 is eazy for winding ratios.. i.e. 11kv to 33kv is 1:3.
asked
Aug 18, 2019
by
anonymous
Description : Series capacitive compensation in EHV transmission line is used to
Answer :
To maintain voltage stability
asked
Apr 29, 2018
by
anonymous
Description : what is mean by medium transmission line ?
Answer :
The transmission line which have length between 80 km to 250 km is known as medium transmission line.
Description : what is mean by short transmission line ?
Answer :
The transmission lines which have length less than 80 km is known as short transmission lines.
Description : what is mean by long transmission line ?
Answer :
The transmission line which have length more than 250 km are known as long transmission lines.
Description : The coefficient of reflection for current wave is
Answer :
The coefficient of reflection for current wave is 1 or -1
asked
May 3, 2018
by
anonymous
Description : If it takes a transmitted signal 1m sec to go up to the target and come back after reflection, how far is the transmitter from the target? A) 150 Km B) 150 m C) 15 Km D) 1500 m
Answer :
If it takes a transmitted signal 1m sec to go up to the target and come back after reflection, how far is the transmitter from the target? A) 150 Km B) 150 m C) 15 Km D) 1500 m
asked
Jun 18, 2018
by
anonymous
Description : i) State the significance of modulation index in AM transmission. ii) Explain the effect of modulation index on AM wave with waveforms.
Answer :
Significance of modulation index in AM transmission It is used to determine the strength and quality of transmitted signal. If the modulation index is small, then the amount of variation in ... amplitude part of its information is lost in the process of modulation which is undesirable.
asked
Aug 4, 2019
by
anonymous
Description : The reactive power transfer over a line mainly depends on
Answer :
The reactive power transfer over a line mainly depends on lVsl- lVRl
asked
Apr 27, 2018
by
anonymous
Answer :
Impedance relays are used for phase faults on long line.
asked
Mar 20, 2018
by
anonymous
Answer :
Series capacitors on transmission lines are of little use when the load VAR requirement is small.
asked
Mar 20, 2018
by
anonymous
Description : The voltage of transmission can be regulated by (A) Use of tap changing transformers (B) Switching in shunt capacitors at the receiving end during heavy loads (C) Use of capacitors to neutralize the effect of series reactance (D) Any of the above methods
Answer :
The voltage of transmission can be regulated by (A) Use of tap changing transformers (B) Switching in shunt capacitors at the receiving end during heavy loads (C) Use of capacitors to neutralize the effect of series reactance (D) Any of the above methods
Answer :
Ungrounded neutral transmission system is not recommended because of system insulation being overstressed due to over voltages, insulation overstress may lead to failure and subsequent phase to phase faults, being inadequately protected against ground fault.
asked
Mar 20, 2018
by
anonymous
Description : A lightening arrester connected between the line and earth in a power system (1) protects the terminal equipment against travelling surges (2) protects the transmission line against direct lightening strokes (3) suppresses high frequency oscillations in the line (4) reflects back the travelling wave approaching it
Answer :
A lightening arrester connected between the line and earth in a power system protects the terminal equipment against travelling surges
asked
Apr 29, 2018
by
anonymous
Description : The surge impedance for over head line is taken as (1) 10-20 ohms (2) 50-60 ohms (3) 100-200 ohms (4) 1000-2000 ohms
Answer :
The surge impedance for over head line is taken as 100-200 ohms
asked
May 1, 2018
by
anonymous
Answer :
The inductive interference between power and communication line can be minimized by transposition of the power line, transposition of the communication line.
asked
Mar 20, 2018
by
anonymous
asked
Jan 21, 2020
by
Shubham
Description : requirements or properties of the line supports used in transmission and distribution.
Answer :
Following are requirements or properties of the line supports used in transmission and distribution. 1. High mechanical strength:- It should have high mechanical strength to withstand against - ... . 8. Appearance: It should have good appearance or They must be of pleasing shape
asked
Aug 25, 2019
by
anonymous
Description : How many insulator disc used for 33 kV transmission voltage line?
Answer :
5,As 33kv is Vrms
asked
Dec 5, 2017
by
anonymous
Description : Pure inductive circuit takes power from the A.C. line when?
Answer :
It takes power when voltage decreases and current increases.
asked
Mar 25, 2018
by
anonymous
Description : For transmission line, the incident voltage Ei = 6V, and Er = 3V. Calculate: (1) Reflection coefficient (2) Standing wave ratio
Answer :
(1)Reflection coefficient (2) Standing wave ratio (1)Reflection coefficient Reflection coefficient R=Er/Ei =3/6 R=0.5 (2) Standing wave ratio SWR=Ei+Er/Ei-Er =6+3/6-3 SWR =3
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) zero sequence currents are absent on both sides of the transformer (C) zero sequence currents are present on the secondary side but not on the primary side (D) zero sequence currents are present on the primary side but not on the secondary side
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
asked
Apr 29, 2018
by
anonymous
Description : State the effects of low power factor on efficiency and voltage regulation of short transmission lines.
Answer :
i) Effect of Low power factor on efficiency:- When power factor of load reduces current drawn by transmission line increases so copper losses in transmission line increases, hence transmission ... increases, so voltage drop in transmission line increases so regulation increases. (Become Poor)
asked
May 22, 2020
by
anonymous
Description : State the classification of transmission lines depending on length of transmission lines.
Answer :
A) According to Voltage level: ( 2 Marks) a) High voltage Transmission Line (HV) up to 33 KV b) Extra High Voltage Transmission Line (EHV) above 33 KV up to 400 KV c) Ultra ... Transmission Line: - The length of Long transmission Line is above 200KM and its line voltage is above 100KV
asked
May 22, 2020
by
anonymous
Description : A light ray travelling from denser to rarer medium at an angle of incidence more than critical angle of concerned media pair suffers. (1) reflection (2) refraction (3) diffraction (4) total internal reflection
Answer :
total internal reflection
Description : A transmission line is terminated at its characteristic impedance. The reflection coefficient is (a) 1 (b) –1 (c) 0 (d) ∞
Answer :
A transmission line is terminated at its characteristic impedance. The reflection coefficient is 0
asked
May 16, 2018
by
anonymous
Description : 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
Answer :
By
asked
May 8, 2018
by
anonymous