Ungrounded neutral transmission system is not recommended because of system?

by

1 Answer

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.

by

Related questions

To protect the power transformer (Y-Y with neutral grounded) against fault, what type of connection do the CTs have ?

Description : To protect the power transformer (Y-Y with neutral grounded) against fault, what type of connection do the CTs have ?

Last Answer : To protect the power transformer (Y-Y with neutral grounded) against fault, what type of connection do the CTs have ? Δ-Δ connection

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

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

Last 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.

The permissible voltage variation in transmission and distribution system is:

Description : The permissible voltage variation in transmission and distribution system is:  (A) ± 0.1% (B) ± 1% (C) ±10% (D) ± 25%

Last Answer : The permissible voltage variation in transmission and distribution system is: ±10%

In voltage source converter based HVDC transmission system the active power is controlled by changing

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

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

If a 5-bus test system contains 6 transmission lines and one transformer, how many non- zero elements are

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.

In a three-phase supply floating neutral is undesirable because it way give rise to?

Description : In a three-phase supply floating neutral is undesirable because it way give rise to?

Last Answer : In a three-phase supply floating neutral is undesirable because it way give rise to unequal line voltages across the load.

What happens when a neutral wire touches a phase wire ?

Description : What happens when a neutral wire touches a phase wire ?

Last Answer : Maximum current flow due to Short circuit, limited value of fuse will burn else apparatus and conductor will be damaged.

Explain the meaning of following terms: i) MCB ii) Socket outlet iii) Neutral iv) Fuse-link

Description : Explain the meaning of following terms: i) MCB ii) Socket outlet iii) Neutral iv) Fuse-link

Last Answer : i) MCB:  Miniature circuit breaker operates automatically at the time of fault or over load. And it is used for the protection of electrical installation. They are available from 0.5 A to 100 Amps. ... melts automatically at the time of fault or over load. Fuse must be replaced after the fault.

The magnetic neutral plane shifts in a dc machine

Description : The magnetic neutral plane shifts in a dc machine (A) in the direction of motion of motor (B) in the direction of motion of generator (C) due to increase in the field flux (D) cause reduction of flash over between commutator segments

Last Answer : The magnetic neutral plane shifts in a dc machine in the direction of motion of generator

In a D.C. generator the magnetic neutral axis coincides with the geometrical neutral axis, when?

Last Answer : In a D.C. generator the magnetic neutral axis coincides with the geometrical neutral axis, when there is no load on|he generator.

If we conect a two bulbs in series And if we give double phase without neutral then bulb will glow or not??

Last Answer : Due to no potential difference between the ends of the circiut there is no existance of current 

Which color wire is neutral?

Description : Which color wire is neutral?

Last Answer : Black but I think it depends with the place.

Ungrounded neutral transmission system is not recommended because of system (a) insulation being overstressed due to over voltages (b) insulation overstress may lead to failure and subsequent phase to phase faults (c) being inadequately protected against ground fault (d) all of the above

Description : Ungrounded neutral transmission system is not recommended because of system (a) insulation being overstressed due to over voltages (b) insulation overstress may lead to failure and subsequent phase to phase faults (c) being inadequately protected against ground fault (d) all of the above

Last Answer : (d) all of the above

The voltage of transmission can be regulated by

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

Last 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

Transmission efficiency of a transmission line increases with the

Description : Transmission efficiency of a transmission line increases with the

Last Answer : Transmission efficiency of a transmission line increases with the increase in power factor and voltage

Which relay is preferred for phase fault on short transmission line?

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

When a wave propagates on a transmission line, it suffers reflection several times at?

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

The interaction between a transmission line and communication line is minimized by?

Last 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.

When a transmission line is energized, the wave that propagates on it is?

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

A transmission line is protected by?

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

In quadrilateral speed-time curve of electric traction system, the accelerations during successive time periods

Description : In quadrilateral speed-time curve of electric traction system, the accelerations during successive time periods are ______ respectively.  (A) positive, negative and negative (B) positive, zero and negative (C) positive, positive and negative (D) positive, negative and zero

Last Answer : In quadrilateral speed-time curve of electric traction system, the accelerations during successive time periods are positive, negative and negative respectively. 

A lightening arrester connected between the line and earth in a power system protects the terminal equipment

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

Last Answer : A lightening arrester connected between the line and earth in a power system protects the terminal equipment against travelling surges

For a 15-bus power system with 3 voltage controlled buses, the size of Jacobian matrix is

Description : For a 15-bus power system with 3 voltage controlled buses, the size of Jacobian matrix is

Last Answer : For a 15-bus power system with 3 voltage controlled buses, the size of Jacobian matrix is 25 x 25

With fault clearing time, the transient stability of a power system

Description : With fault clearing time, the transient stability of a power system

Last Answer : With fault clearing time, the transient stability of a power system decreases

In a single bus-bar system there will be complete shut down when?

Last Answer : In a single bus-bar system there will be complete shut down when fault occurs on the bus itself.

A balanced 3-phase system consists of?

Last Answer : A balanced 3-phase system consists of positive sequence currents.

The steady state stability of the power system can be increased by?

Last Answer : The steady state stability of the power system can be increased by connecting lines in parallel.

Air blast circuit breakers for 400 kV power system are designed to operate in?

Last Answer : Air blast circuit breakers for 400 kV power system are designed to operate in 50 millisecond.

The contacts of high voltage switches used in power system are submerged in oil. The main purpose of the oil is to?

Last Answer : The contacts of high voltage switches used in power system are submerged in oil. The main purpose of the oil is to extinguish the arc.

On a 4x4 if you have the FWD shifter in neutral will it hurt the vehicle?

Description : On a 4x4 if you have the FWD shifter in neutral will it hurt the vehicle?

Last Answer : It’s not gonna go anywhere if it’s in N.

Explain some of the methods to improve the strength of transmission system?

Description : Explain some of the methods to improve the strength of transmission system?

Last Answer :  Introducing or adding of new transmission lines in to the system to avoid the overloading of the existing lines  Application of devices such as series capacitors in the right location of ... system  Adoption of multi-voltage levels an multi-circuits in the existing ac transmission system

Constant voltage transmission entails the following disadvantage (a) large conductor area is required for same power transmission (b) short-circuit current of the system is increased (c) either of the above (d) none of the above

Description : Constant voltage transmission entails the following disadvantage (a) large conductor area is required for same power transmission (b) short-circuit current of the system is increased (c) either of the above (d) none of the above

Last Answer : (b) short-circuit current of the system is increased

A 3-phase 4 wire system is commonly used on (a) primary transmission (b) secondary transmission (c) primary distribution (d) secondary distribution

Description : A 3-phase 4 wire system is commonly used on (a) primary transmission (b) secondary transmission (c) primary distribution (d) secondary distribution

Last Answer : (d) secondary distribution

A feeder, in a transmission system, feeds power to (a) distributors (b) generating stations (c) service mains (d) all of the above

Description : A feeder, in a transmission system, feeds power to (a) distributors (b) generating stations (c) service mains (d) all of the above

Last Answer : (a) distributors

Which of the following is the demerit of a 'constant voltage transmission system' ? (a) Increase of short-circuit current of the system (b) Availability of steady voltage at all loads at the line terminals (c) Possibility of better protection for the line due to possible use of higher terminal reactants (d) Improvement of power factor at times of moderate and heavy loads (e) Possibility of carrying increased power for a given conductor size in case of long-distance heavy power transmission

Description : Which of the following is the demerit of a 'constant voltage transmission system' ? (a) Increase of short-circuit current of the system (b) Availability of steady voltage at all loads at ... of carrying increased power for a given conductor size in case of long-distance heavy power transmission

Last Answer : (a) Increase of short-circuit current of the system

What are the building restrictions concerning power/transmission lines?

Description : What are the building restrictions concerning power/transmission lines?

Last Answer : There is none in North Carolina—- They just put in a transmission line right down the road with houses at 75 foot set-back from road on both sides of the road. The towers are taller than the driveways are long!

Transmission leaks?

Description : Transmission leaks?

Last Answer : Purple.

What are the factors that limit the maximum power transfer capability in a transmission line?

Description : What are the factors that limit the maximum power transfer capability in a transmission line?

Last Answer : Answer: Some of the factors which limits the maximum power transfer are: 1. Electrical phase shift 2. Voltage drop 3. Thermal effects in the line

What are the problems associated with EHV transmission?

Description : What are the problems associated with EHV transmission?

Last Answer : Answer: The problems associated with EHV transmission are corona loss and radio interference, requirement of heavy supporting structures and insulation requirments

What is the material used for overhead transmission lines?

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

Last Answer : Answer: ACSR conductors are employed.

What for series and shunt compensation provided in EHV transmission lines?

Description : What for series and shunt compensation provided in EHV transmission lines?

Last Answer : Answer: Series capacitance is provided in EHV lines to artificially reduce the series reactance of the line so as to improve stability, voltage regulation and transmission efficiency Shunt compensation ... reduce the line susceptance so as to improve the voltage regulation under light load condition

Series capacitors on transmission lines are of little use when the load VAR requirement is (a) large (b) small (b) fluctuating (d) any of the above

Description : Series capacitors on transmission lines are of little use when the load VAR requirement is (a) large (b) small (b) fluctuating (d) any of the above

Last Answer : (b) small

In the analysis of which of the following lines shunt capacitance is neglected ? (a) Short transmission lines (b) Medium transmission lines (c) Long transmission lines (d) Medium as well as long transmission lines

Description : In the analysis of which of the following lines shunt capacitance is neglected ? (a) Short transmission lines (b) Medium transmission lines (c) Long transmission lines (d) Medium as well as long transmission lines

Last Answer : (a) Short transmission lines

For transmission of power over a distance of 500 km, the transmission voltage should be in the range (a) 150 to 220 kV (b) 100 to 120 kV (c) 60 to 100 kV (d) 20 to 50 kV

Description : For transmission of power over a distance of 500 km, the transmission voltage should be in the range (a) 150 to 220 kV (b) 100 to 120 kV (c) 60 to 100 kV (d) 20 to 50 kV

Last Answer : (a) 150 to 220 kV

For transmission of power over a distance of 200 km, the transmission voltage should be (a) 132 kV (b) 66 kV (c) 33 kV (d) 11 kV

Description : For transmission of power over a distance of 200 km, the transmission voltage should be (a) 132 kV (b) 66 kV (c) 33 kV (d) 11 kV

Last Answer : (a) 132 kV

The voltage drop, for constant voltage transmission is compensated by installing (a) inductors (b) capacitors (c) synchronous motors (d) all of above (e) none of the above

Description : The voltage drop, for constant voltage transmission is compensated by installing (a) inductors (b) capacitors (c) synchronous motors (d) all of above (e) none of the above

Last Answer : (c) synchronous motors

Transmission voltage of ll kV is normally used for distances upto (a) 20—25 km (b) 40—50 km (c) 60—70 km (d) 80—100 km

Description : Transmission voltage of ll kV is normally used for distances upto (a) 20—25 km (b) 40—50 km (c) 60—70 km (d) 80—100 km

Last Answer : (a) 20—25 km

Which of the following characteristics should the line supports for transmission lines possess ? (a) Low cost (b) High mechanical strength (c) Longer life (d) All of the above

Description : Which of the following characteristics should the line supports for transmission lines possess ? (a) Low cost (b) High mechanical strength (c) Longer life (d) All of the above

Last Answer : (d) All of the above

Which of the following relays is used on long transmission lines ? (a) Impedance relay (b) Mho's relay (c) Reactance relay (d) None of the above

Description : Which of the following relays is used on long transmission lines ? (a) Impedance relay (b) Mho's relay (c) Reactance relay (d) None of the above

Last Answer : (b) Mho's relay

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

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