Why are overhead transmission lines not insulated?

Why are overhead transmission lines not insulated?
by
retagged

7 Answers

Answer :

When use insulted cable is so expensive. In term of weight with insulation maybe double or more heavy. Therefore Engineer choose non insulated cable..but maintain clearance and creepage of insulator or others device which support hv cable.
by

Answer :

Cost reduction & lighter weight for easy transportation & installation
by

Answer :

Because the insulation is depend on voltage/current level . Due to high voltage in transmission line insulation is not possible .if insulation is done the conductor will heavy and whole line will insulation will be burned
by

Answer :

Transmitting HV with insulated conductors will burnt out insulation and causing fire along the network infrastructure
by

Answer :

1. The transmission lines are at some decent height, so there is a very rare chance of anyone touching them.

2. And air acts as an insulator for the transmission lines and keeping that in mind the voltage and current through the lines are calculated.
by

Answer :

OH transmission lines is combination of ACSR & Steel so the weight of conductor is already high. So because of it's weight high pressure intense on tower
by

Answer :

Insulators are useful to help separate electrical conductors when they come into physical contact. Overhead Transmission Lines Are Not Insulated: The overhead transmission line is carrying extreme high voltage and it would require a whole lot of thick insulation to absorb the heat produced by such high voltage.
by

Related questions

A minimum clearance of 6.3 m to ground is required for overhead lines when operating voltages are :

Description : A minimum clearance of 6.3 m to ground is required for overhead lines when operating voltages are :  (A) less than 66 kV (B) lie between 66 kV and 110 kV (C) more than 165 kV (D) lie between 110 kV and 165 kV

Last Answer : A minimum clearance of 6.3 m to ground is required for overhead lines when operating voltages are : lie between 66 kV and 110 kV

Overhead lines for power supply to tramcars are at a minimum height of?

Last Answer : Overhead lines for power supply to tramcars are at a minimum height of 10 m.

Why ACSR conductor is used for overhead lines?

Description : Why ACSR conductor is used for overhead lines?

Last Answer : It has high tensile strength 

Differentiate between overhead transmission and underground transmission.

Description : Differentiate between overhead transmission and underground transmission.

Last 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 

State the effects of low power factor on efficiency and voltage regulation of short transmission lines.

Description : State the effects of low power factor on efficiency and voltage regulation of short transmission lines. 

Last 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) 

State the classification of transmission lines depending on length of transmission lines.

Description : State the classification of transmission lines depending on length of transmission lines. 

Last 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

In which of the following transmission lines, the value of the Shunt admittance should be

Description : In which of the following transmission lines, the value of the Shunt admittance should be approximated to zero ? (A) A 66 kV 35 km long line (B) A 132 kV 200 km long line (C) A 220 kV 300 km long line (D) A 400 kV 500 km long line

Last Answer : In which of the following transmission lines, the value of the Shunt admittance should be approximated to zero ? (A) A 66 kV 35 km long line (B) A 132 kV 200 km long line (C) A 220 kV 300 km long line (D) A 400 kV 500 km long line

The purpose of guard ring in transmission lines is to

Description : The purpose of guard ring in transmission lines is to  (1) reduce the earth capacitance of the lowest unit. (2) increase the earth capacitance of the lowest unit. (3) reduce the transmission lines losses. (4) reduce the reactance of the line

Last Answer : The purpose of guard ring in transmission lines is to reduce the earth capacitance of the lowest unit.

Corona loss in transmission lines can be reduced by

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

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.

Series capacitors on transmission lines are of little use when the load VAR requirement is?

Last Answer : Series capacitors on transmission lines are of little use when the load VAR requirement is small.

State properties of conductor material used for overhead conductor.

Description : State properties of conductor material used for overhead conductor. 

Last Answer : Following are the properties of conductor material:-   1. High conductivity :- Material should have high conductivity 2. High mechanical strength:- Material should have sufficiently high mechanical strength ... available & less costly. 9. Scrap Value: - Material should have high scrap value. 

Why underground service connections are service connections are costly than overhead service connection

Description : Why underground service connections are service connections are costly than overhead service connection

Last Answer : Reason: Underground service connection is given by underground cable. This cable is costly than bare conductor. Sometimes cable trench is required for cable laying, which requires additional cost. So underground service connections are costly than overhead service connection.

Define service connection and state types connection and state types of overhead service connection

Description : Define service connection and state types connection and state types of overhead service connection

Last Answer : Service Connection:- It is the input conductor or wire which is carried out from supply company (authorities) pole to consumers' main board or premises. Types of overhead service ...  1. Overhead service connection with Bare conductor 2. Overhead service connection with weather proof cable  

lf a travelling-wave travelling along a loss-less overhead line does not result in any reflection after it has

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

Last 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

Overhead system can be designed for operation up to?

Last Answer : Overhead system can be designed for operation up to 400 kV.

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.

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

Most of the high voltage transmission lines in India are (a) underground (b) overhead (c) either of the above (d) none of the above

Description : Most of the high voltage transmission lines in India are (a) underground (b) overhead (c) either of the above (d) none of the above

Last Answer : (b) overhead

Why don't we burry power lines underground ?

Description : Why don't we burry power lines underground ?

Last Answer : Because conductor used for power transmission are not insulated and if we do so it create phase to ground fault causing interruptions to supply.

Define magnetic lines of force. Also draw and show magnetic lines of force of a bar type magnet.

Description : Define magnetic lines of force. Also draw and show magnetic lines of force of a bar type magnet.

Last Answer : Magnetic Lines of force- These are the imaginary lines (having no physical existence) introduced by Faraday for the pictorial representation of the distribution of a magnetic field.  OR  A line of ... that the tangent at any point gives direction of the resultant force at that point. 

Define magnetic lines of force. Show the magnetic lines of force for bar type magnet.

Description : Define magnetic lines of force. Show the magnetic lines of force for bar type magnet.

Last Answer : Magnetic linens of force is the imaginary lines for magnetic field of magnet around it. These magnetic lines of forces are introduced by Michael Faraday. The direction of lines of force is from N-pole to S-pole. The figure shows lines of force for bar type magnet.

In tuned power lines, on load :

Description : In tuned power lines, on load :  (A) the receiving end voltage is numerically equal to the sending end voltage  (B) the receiving end current is numerically equal to the sending end current  (C) there is no voltage drop  (D) all the above

Last Answer : In tuned power lines, on load :  (A) the receiving end voltage is numerically equal to the sending end voltage  (B) the receiving end current is numerically equal to the sending end current  (C) there is no voltage drop  (D) all the above

Which of the following is the name given to the lines of electric force which move so that its beginning traces

Description : Which of the following is the name given to the lines of electric force which move so that its beginning traces a closed curve on a positive surface and its end traces a corresponding closed curve on the negative surface? A) Tube of surface B) Tube of lines C) Tube of force D) Tube of electricity

Last Answer : Which of the following is the name given to the lines of electric force which move so that its beginning traces a closed curve on a positive surface and its end traces a corresponding closed curve on the negative ... A) Tube of surface B) Tube of lines C) Tube of force D) Tube of electricity

Find out number of data lines required to interface 16 LEDs arrange in the 4 x 4 matrix form.

Description : Find out number of data lines required to interface 16 LEDs arrange in the 4 x 4 matrix form.

Last Answer : 4+4=8, eight lines are required for 4x4 matrix of 16 LEDs

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!

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

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

In transmission lines the cross-arms are made of (a) copper (b) wood (c) R.C.C. (d) steel

Description : In transmission lines the cross-arms are made of (a) copper (b) wood (c) R.C.C. (d) steel

Last Answer : (d) steel

High voltage transmission lines use (a) suspension insulators (b) pin insulators (c) both (a) and (b) (d) none of the above

Description : High voltage transmission lines use (a) suspension insulators (b) pin insulators (c) both (a) and (b) (d) none of the above

Last Answer : (a) suspension insulators

Which of the following are the constants of the transmission lines ? (a) Resistance (b) Inductance (c) Capacitance (d) All of the above

Description : Which of the following are the constants of the transmission lines ? (a) Resistance (b) Inductance (c) Capacitance (d) All of the above

Last Answer : (d) All of the above

For an overhead line, the surge impedance is taken as (a) 20-30 ohms (b) 70—80 ohms (c) 100—200 ohms (d) 500—1000 ohms (e) none of the above

Description : For an overhead line, the surge impedance is taken as (a) 20-30 ohms (b) 70—80 ohms (c) 100—200 ohms (d) 500—1000 ohms (e) none of the above

Last Answer : (c) 100—200 ohms

Overhead system can be designed for operation up to (a) 11 kV (b) 33 kV (c) 66 kV (d) 400 kV

Description : Overhead system can be designed for operation up to (a) 11 kV (b) 33 kV (c) 66 kV (d) 400 kV

Last Answer : (c) 66 kV

By which of the following systems electric power may be transmitted ? (a) Overhead system (b) Underground system (c) Both (a) and (b) (d) None of the above

Description : By which of the following systems electric power may be transmitted ? (a) Overhead system (b) Underground system (c) Both (a) and (b) (d) None of the above

Last Answer : (c) Both (a) and (b)

How do I make a simple aid to carry packages up flights of stairs?

Description : How do I make a simple aid to carry packages up flights of stairs?

Last Answer : A back pack is the most efficient way but would not work for furniture. Are there windows on the stairs where you could hoist things up on the end of a rope in a bag or basket?

When you're on line at a store and you have 10+ items, and you notice that the person behind you has only one item, do you let that person "cut" you?

Description : When you're on line at a store and you have 10+ items, and you notice that the person behind you has only one item, do you let that person "cut" you?

Last Answer : Do you mean cut in front of you in the line? If so, always. However, I would not be happy to let a person cut me.

effect of inductance and capacitance on performance of transmission line.

Description : effect of inductance and capacitance on performance of transmission line.

Last 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. 

While calculating performance of medium transmission line, what assumptions are made in case of (i) Nominal 'T' Method (ii) Nominal 'TT' Method.

Description : While calculating performance of medium transmission line, what assumptions are made in case of (i) Nominal 'T' Method (ii) Nominal 'TT' Method. 

Last 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 

HVDC transmission line in India:

Description : HVDC transmission line in India: 

Last 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 

effect of line parameter on performance of transmission line.

Description : effect of line parameter on performance of transmission line. 

Last 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. 

necessity of transmission of electricity.

Description : necessity of transmission of electricity.

Last Answer :  Because of following points there is necessity of transmission of power:   1. Electrical load on power system is not concentrated at one place but it is widely spread.  2. Load ... to the point of actual utilization of it (consumers) for this purpose transmission electricity is necessary. 

Why is AC better for long distance power transmission than DC ?

Description : Why is AC better for long distance power transmission than DC ?

Last Answer : ac is more economical to transmit for long distances . wires can be made smaller by step up transformer .. since major cost are wires to transmit .. then at the end of distance step down transformer is used for commercial use.

Why is transmission line 11kV, 33kV 66kV Not Is 10kV, 20kV, 30kV ?

Description : Why is transmission line 11kV, 33kV 66kV Not Is 10kV, 20kV, 30kV ?

Last 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.

i) State the significance of modulation index in AM transmission. ii) Explain the effect of modulation index on AM wave with waveforms.

Description : i) State the significance of modulation index in AM transmission. ii) Explain the effect of modulation index on AM wave with waveforms.

Last 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.

Compare characteristics of asynchronous and synchronous transmission mode.

Description : Compare characteristics of asynchronous and synchronous transmission mode (four points). 

Last Answer : Synchronous transmission Asynchronous transmission 1. Synchronous transmission are synchronized by an external clock. 1. Asynchronous transmission are synchronized by special signals along the transmission ... for transferring a small amount of data as it is simple and economical.

A 50Ω transmission line is terminated in an impedance of 20-j50. What will be the reflection coefficient?

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 

Last 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 

The sag of a transmission line is least affected by

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.

Last Answer : The sag of a transmission line is least affected by Current through the conductor.