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A transmission line is protected by distance protection, time graded and current graded overcurrent protection.

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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.

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

Answer : Reactance relay is preferred for phase fault on short transmission line.

Answer : When a wave propagates on a transmission line, it suffers reflection several times at sending and other end.

Answer : When a transmission line is energized, the wave that propagates on it is current wave and voltage wave.

Description : Stability of a transmission line can be increased by

Answer : Stability of a transmission line can be increased by Shunt capacitor, Series capacitor

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.

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.

Answer : Large internal faults are protected by merz price percentage differential protection.

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. 

Description : State line parameters of transmission line. 

Answer : Following are the of Line parameters of transmission line:  1. Resistance  2. Inductance  3. Capacitance

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

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. 

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 

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 

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. 

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.

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 

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

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

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

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

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

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

Answer : Vscos¢s-Vrcos¢r=IR

Description : What are the losses in a transmission line?

Description : Thyristor can be protected from over voltages by using

Answer : Thyristor can be protected from over voltages by using Voltage clamping device

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 : The inductive interference between power and communication line can be minimized by transposition of the power line, transposition of the communication line.

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.

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

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 ... 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

Description : The reactive power transfer over a line mainly depends on

Answer : The reactive power transfer over a line mainly depends on lVsl- lVRl

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

Answer : Impedance relays are used for phase faults on long line.

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

Description : How many insulator disc used for 33 kV transmission voltage line?

Answer : 5,As 33kv is Vrms

Description : Explain following techniques related to energy conservation in transmission and distribution system. (i) By balancing phase currents (ii) Variable technical losses (I2R losses).

Answer : (i) Balancing Phase currents: Proper (healthy balanced) three phase loads always draw equal currents in all lines but single phase loads in the 3 phase 4 wire system or loads connected between two ... . 11) Minimize I2R losses. 12) Balance the load currents. 13) Regulate the system voltages.

Description : 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

Answer : In voltage source converter based HVDC transmission system the active power is controlled by changing phase angle of the converter ac input voltage

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

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

Description : What is meant by extra high voltage transmission?

Answer : HT & LT  two types transmission in industrial line 

Answer : Annual depreciation as per straight line method, is calculated by the capital cost minus the salvage value, is divided by the number of years of life.

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) 

Description : State the advantages of use of high voltage in transmission of Electric power. 

Answer : Advantages: 1. As Transmission voltage increases, current decreases. 2. As current decreases, cross section of conductor decreases. 3. As cross section of conductor decreases, its ... high voltage transmission line, successful interconnection of transmission line is possible than low voltage. 

Description : Differentiate between overhead transmission and underground transmission.

Answer : Points Overhead line  Underground cable Capital cost  Less More Erecting cost  Less More Time require for completion of work Less More Flexibility More ... Space consumed Space consumed  No space consumed Appearance Not good  Very good 

Description : State features of wireless power transmission. 

Answer : Features of wireless power transmission:  1. Energy delivered anywhere in the world 2. Zero fuel cost 3. Less losses 4. Less use of copper wires 5. More efficiency 6. Minimum long- ... on cables would never exist in the transmission.  7. Power theft would be not possible at all. 

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

Description : What is the advantage of AC over DC electrical transmission?

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