Under Ground Cables Ppt

7/22/2019 Under Ground Cables Ppt

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A FUTURE TRANSMISSION LINES

UNDERGROUND CABLES


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CONTENTS

INTRODUCTION

COMPARISION BETWEEN OVER HEAD LINES AND UNDER

GROUND CABLES

DIFFERENT IMAGES FOR CABLES

CLASSIFICATION OF CABLES TYPES OF CABLES

MERITS & DEMERITS

CONCLUSION


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INTRODUCTION

CABLE:A conductor for transmitting

electrical or optical signals or electric power

The electrical energy can be transmitted and

Distributed with the overhead transmission or by

Underground cables.

Among these two underground is more preferred than

Over head transmission.


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COMPARISION BETWEEN OVERHEAD LINES AND

UNDERGROUND CABLES

Electricity can be transmitted from one place to another through eitherthe overhead lines or underground cables.

OVERHEAD LINES:

Inductance plays predominant role in overhead lines.

The insulation cost is less in overhead lines.

The erection cost is also less .

UNDERGROUND CABLES

These cables give greater safety to the public and better out look to the city.

These are used in submarine crossings.

These cables provide less interference with amenities.


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Different images for cables


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CLASSIFICATION OF CABLES

Cables for underground service may classified into two ways ,accordingto

a) The type of insulating material used by the manufacturer.

b) The voltage for which they are used manufactured.

They are:

Low tension cables {L.T} up to 1000v.

High tension cables{H.T} up to 11kv.

Super tension cables{S.T} from 23kv to 33kv.

Extra high tension cables{E.H.T} from 33kv to 66kv.

Extra super voltage cables beyond 132kv.


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TYPES OF CABLES FOR THREE PHASE SERVICE

In practice underground cables are generally used to deliver 3-phase

power. For the purpose three core cable or three single core cables may

be used.

For voltage up to 66kv 3-core cable is preferred due to economicreasons.

The following cables are generally used for three phase service are :

a) Belted cables up to 11kv.

b) screened cables from 22kv to 66kv.

c) pressure cables beyond 66kv.


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BELTED CABLE


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THREE CORE H-TYPE CABLE


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THREE CORE S.L.TYPE CABLE


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THREE CORE FILLER SPACE CHANNEL OIL FILLED CABLE.


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OIL FILLED CABLES OF SINGLE CORE &

THREE CORE CABLE.


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IMPREGNTED PRESSURE CABLE


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ADVANTAGES AND DISADVANTAGES

ADVANTAGES:

Less subject to damage from severe weather conditions (mainly

lightning, wind and freezing).

Underground cables pose no hazard to low flying aircraft or to wildlife.

Much less subject to conductor theft, illegal connections, sabotage, and

damage from armed conflict.DISADVANTAGES:

Underground cable locations are not always obvious, which can lead to

unwary diggers damaging cables or being electrocuted.

Operations are more difficult since the high reactive power of

underground cables produces large charging currents and so makesvoltage control more difficult.

Undergrounding is more expensive, since the cost of burying cables at

transmission voltages is several times greater than overhead power

lines, and the life-cycle cost of an underground power cable is two to

four times the cost of an overhead power line


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CONCLUSION

Underground cables offer an affordable and

justifiable solution for critical parts, and in some

cases the entire length, of overhead high voltage

power lines.

With appropriate technology used in appropriate

places, the environmental impact of underground

cables can be minimised.


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BY:

M.SREENIVASULU

&

M.D.PAWAN KUMAR

Documents

Under Ground Cables Ppt