Why EHV busbars are hallowed and circular?

Why EHV busbars are hallowed and circular?
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1 Answer

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Answer: To avoid corona effect
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Related questions

What is the first equipment of the substation connected to the incoming transmission line?

Description : What is the first equipment of the substation connected to the incoming transmission line?

Last Answer : Lightning arrestor is the first equipment of the substation connecting the incoming transmission lines. It protects other substation equipment from lightning and switching surges by suppressing them to ... between both the ends of major equipment such as power transformers for protection.

What are different Bus bar materials used in Substation?

Description : What are different Bus bar materials used in Substation?

Last Answer : Busbars are generally made of copper and Aluminum. Aluminim has the advantage of one third the weight of the copper and also Aluminum requires less maintenance and proper use of alloys provide necessary rigidity required for bus material. Aluminum is used widely in EHV and HV stations

What are the different electrical clearances in Substation?

Description : What are the different electrical clearances in Substation?

Last Answer : Ground Clearance: This is the minimum distance between any live conductor and the earth or ground. Phase Clearance: It is the clearance between the different phases in a circuit or same phases in different ... The limits of work section may be ground or the platform on which the person is working.

Factors on which material of station busbar depends?

Description : Factors on which material of station busbar depends?

Last Answer : Some of the factors on which station busbar depends are: Current Carrying capacity Short Circuit Stresses Establishing minimum electrical clearances

For distribution network which type of Switching scheme is employed?

Description : For distribution network which type of Switching scheme is employed?

Last Answer : For distribution network Ring Main busbar scheme is employed. It has the provision that if power interruption occurs to one bus section due to maintenance or fault, power can be fed the bus from other side of the power system.

Which type of bus arrangement is costlier and more reliable?

Description : Which type of bus arrangement is costlier and more reliable?

Last Answer : One and half breaker scheme is most reliable and costlier scheme. In one and half breaker scheme 3 circuit breakers are provided for 2 bus-bars. Hence the name is coined as One and half breaker scheme

What are different types of busbar arrangement Schemes in Substations?

Description : What are different types of busbar arrangement Schemes in Substations?

Last Answer : Different switching schemes or busbar arrangement scheme employed in switch-yard are: Single Bus Scheme Double bus single breaker scheme Main and Transfer busbar scheme Double bus single breaker scheme Breaker and half scheme Ring main bus scheme

What are the different substation components

Description : What are the different substation components

Last Answer : Circuit Breakers, Disconnecting switches, Grounding switches, Current Transformers, Potential Transformers or Capacitor voltage Transformers, Line Traps, Lightning Arrestors, Power Transformers, Shunt ... Station Buses and Insulators, Grounding system, Series capacitors and shunt capacitors.

What is the neutral point earthing and its advantages?

Description : What is the neutral point earthing and its advantages?

Last Answer : In substation all the neutrals of rotating machines, transformers, busbars and other equipment are connected to ground. Some of the advantages are: Earth fault protection is based on the method of ... , grounding of neutral helps to reduce the over-voltages which occur on the one healthy phases

What is the significance of Corona rings in substations?

Description : What is the significance of Corona rings in substations?

Last Answer : It is observed that corona discharge occurs mostly at sharp corners, edges near the conductor fixing points. Corona rings also called grading rings are hallow metallic rings having large diameter ... is reduced to much lower value Corona discharge is eliminated Dust deposition is also minimized

What are the disadvantages of corona?

Description : What are the disadvantages of corona?

Last Answer : Some of the disadvantages of corona are: Corona causes power loss Corona causes unacceptable noise Corona cause radio interference

What is Basic Impulse Level (BIL)?

Description : What is Basic Impulse Level (BIL)?

Last Answer : Basic Impulse Level (BIL) refer to the peak value of lightning impuse voltage withstand capability of the equipment

What is creepage distance?

Description : What is creepage distance?

Last Answer : Creepage distance is the shortest distance between two conducting points along the surface of the insulating material.

What are different insulators employed in substations?

Description : What are different insulators employed in substations?

Last Answer : Some of the insulators employed in substations are: Pin insulators Post insulators Strain insulators Suspension insulators Hallow apparatus insulators Dead-end insulators Solid core insulators

State the condition for selecting site for distribution substation.

Description : State the condition for selecting site for distribution substation. 

Last Answer : Following condition should be considered while selecting site for distribution sub-station:-  1. Near load center :  Sub-station should be located near load center to reduce cost of Transmission and ... free from earthquake :  To avoid damage to sub-station area should be free earth quake. 

State the classification of distribution substation.

Description : State the classification of distribution substation. 

Last Answer : The classification of distribution substation. 1. Pole mounted distribution substation 2. Plinth mounted distribution substation 3. Compact/prefabricated distribution substation 4. ... Indoor distribution substation 6. Outdoor distribution substation 7. Mobile distribution substation 

What is the purpose of auxiliary controller in substation?

Description : What is the purpose of auxiliary controller in substation?

Last Answer : The systems of substation auxiliaries ensure operation of substations providing internal consumers of substations with operating direct and alternating currents. Any breakdown (loss) of auxiliary systems ... whole substation, as well as serious problems during its subsequent putting into operation.

Classification of Substation According to Method of Construction

Description : Classification of Substation According to Method of Construction

Last Answer : Classification of Substation According to Method of Construction:- 1. Indoor Substation 2. Outdoor Substation 3. Gas insulated Substation 4. Underground Substation 5. Pole mounted substation 6. Plinth Substation 7. Compact/prefabricated substation

Isolator in substation is open under ___________ condition?

Description : Isolator in substation is open under ___________ condition?  (A) No load (B) Short circuit (C) Full load (D) None of the above

Last Answer : no load

What does a substation do?

Description : What does a substation do?

Last Answer : At  the  substations,  power  is  boosted  up  for  long  distance  transmission.

I’m trying to think of a movie/movie scene and all I can remember is a kid that is saying “our **** in heaven, hallowed be thy name.” And if I remember correctly it was said kind of jokingly and or sarcastic. It came into my head and is bugging me. Thanks?

Description : I’m trying to think of a movie/movie scene and all I can remember is a kid that is saying “our lord in heaven, hallowed be thy name.” And if I remember correctly it was said kind of jokingly and or sarcastic. It came into my head and is bugging me. Thanks?

Last Answer : What are you talking about!

The under voltage relay can be used for (a) generators (b) busbars (c) transformers (d) motors (e) all of the above

Description : The under voltage relay can be used for (a) generators (b) busbars (c) transformers (d) motors (e) all of the above

Last Answer : (e) all of the above

Explain differential protection scheme for busbars with neat sketch.

Description : Explain differential protection scheme for busbars with neat sketch.

Last Answer : Differential Protection Scheme for Bus bar:  Under normal conditions, the sum of the currents entering the bus bar zone is equal to those leaving it and no current flows through the relay ... of these currents will flow through the relay coil causing opening of circuit breaker of bus-bar.

Two 3-phase, Y-connected alternators are to be paralleled to a set of common busbars. The armature has a

Description : Two 3-phase, Y-connected alternators are to be paralleled to a set of common busbars. The armature has a per phase synchronous reactance of 1.7 Ohm and negligible armature resistance. The line voltage of the first machine is adjusted to ... will be  (A) 16.98 A (B) 29.41 A (C) 33.96 A (D) 58.82 A

Last Answer : Two 3-phase, Y-connected alternators are to be paralleled to a set of common busbars. The armature has a per phase synchronous reactance of 1.7 Ohm and negligible armature resistance. The ... instant they are paralleled. Under this condition, the synchronizing current per phase will be 16.98 A

D.C. generators are connected to the busbars or disconnected from them only under the floating condition?

Last Answer : D.C. generators are connected to the busbars or disconnected from them only under the floating condition to avoid sudden loading of the primemover, to avoid mechanicaljerk to the shaft, to avoid burning of switch contacts.

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 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

In order to switch-off and EHV circuit for maintenance, the following sequence is adopted:

Description : In order to switch-off and EHV circuit for maintenance, the following sequence is adopted: (1) Open the circuit breaker, open the isolator, operate the earth switch (2) Operate the earth switch, ... open the circuit breaker (4) Open the isolator, open the circuit breaker, operate the earth switch 

Last Answer : 1

For enhancing the power transmission in along EHV transmission line, the most preferred method is to

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

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

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

HVDC transmission is preferred to EHV AC because

Description : HVDC transmission is preferred to EHV AC because  (a) HVDC terminal equipments are inexpensive  (b) VAR compensation is not required in HVDC systems  (c) System stability can be improved  (d) Harmonic problem is avoided 

Last Answer : C- system stability can be improved

Shunt compensation in an EHV line is used to

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.

Series capacitive compensation in EHV transmission line is used to

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

Last Answer : To maintain voltage stability 

The insulation strength of EHV lines is mainly governed by

Description : The insulation strength of EHV lines is mainly governed by   (a) Switching overvoltages (b) Lightning overvoltages (c) Power frequency overvoltages (d) Dynamic overvoltages 

Last Answer : 1 P

The insulation of modern EHV lines is designed based on?

Description : The insulation of modern EHV lines is designed based on?

Last Answer : The insulation of modern EHV lines is designed based on switching voltage.

A bus bar is 3 inches wide and 0.375 inches thick. What size of round conductor (in circular mils) is necessary to carry the same current as the bus bar? A. 1,125,000 circular mils B. 1,250,000 circular mils C. 1,432,000 circular mils D. 1,547,000 circular mils

Description : A bus bar is 3 inches wide and 0.375 inches thick. What size of round conductor (in circular mils) is necessary to carry the same current as the bus bar? A. 1,125,000 circular mils B. 1,250,000 circular mils C. 1,432,000 circular mils D. 1,547,000 circular mils

Last Answer : Answer: C

A conductor with a cross-sectional area of one circular mil would have a diameter of _____________. A. 0.1 inches B. 0.01 inches C. 0.001 inches D. 0.0001 inches

Description : A conductor with a cross-sectional area of one circular mil would have a diameter of _____________. A. 0.1 inches B. 0.01 inches C. 0.001 inches D. 0.0001 inches

Last Answer : Answer: C

The standard measuring unit of wire by its cross-sectional area, as used in American wire tables is the _____________. A. AWG B. circular mil C. square millimeter D. cubic inch

Description : The standard measuring unit of wire by its cross-sectional area, as used in American wire tables is the _____________. A. AWG B. circular mil C. square millimeter D. cubic inch

Last Answer : Answer: B

The vertical dotted line connecting the small circular symbols at coordinates '05L', '09L', '13L', '21L', '25L', etc., shown in the illustration, indicate that all _______________. EL-0100 A. contacts are operated by the same relay coil B. screw connections are on terminal board 'TB2' C. wires are grounded at both ends of the line D. wires have a common shield

Description : The vertical dotted line connecting the small circular symbols at coordinates '05L', '09L', '13L', '21L', '25L', etc., shown in the illustration, indicate that all _______________. EL-0100 A. contacts are ... board 'TB2' C. wires are grounded at both ends of the line D. wires have a common shield

Last Answer : Answer: B

The small circular symbols to which wire '52N57E' is connected at coordinates '57L' and '57P' shown in the illustration represent ___________________. EL-0100 A. relay contact solder points B. wire wrap connections C. terminal board screws D. switch contact terminals

Description : The small circular symbols to which wire '52N57E' is connected at coordinates '57L' and '57P' shown in the illustration represent ___________________. EL-0100 A. relay contact solder points B. wire wrap connections C. terminal board screws D. switch contact terminals

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The cross-sectional area of shipboard electrical cable is expressed in _____________. A. millimeters B. gage numbers C. centimeters D. circular mils

Description : The cross-sectional area of shipboard electrical cable is expressed in _____________. A. millimeters B. gage numbers C. centimeters D. circular mils

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ECE Board Exam March 1996 An antenna that is circularly polarized is the ____________. A. parabolic reflector B. helical C. Yagi-uda D. small circular loop

Description : ECE Board Exam March 1996 An antenna that is circularly polarized is the ____________. A. parabolic reflector B. helical C. Yagi-uda D. small circular loop

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