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INSULATORS

BY:Raviteja Damerla

[email protected]

EEE. Department, B V C ENGG COLLEGE



Main component parts of the

overhead line



MAIN COMPONENTS

Support

Cross - arm and clamp

Insulator

Guys and stays

Conductor

Lighting arrestors

Fuses and Isolating switches

Continuous earth wire

Guard wire Bird guards

Vibration damper

Jumpers



1. SUPPORT

Support :

Pole, Tower, etc., which depends on the

size and height of the processing voltage.



SUPPORT – WOODEN, STEEL POLES

WOODEN POLES STEEL POLES



SUPPORT – RCC POLES



SUPPORT – TOWERS



2. CROSS ARM AND CLAMP



3. INSULATORS

Let we talk about this section in detail in upcoming slides



4. GUYS AND STAYS

Stays poll over his use of theguys and the Insulator.

guy wire clamp powertransmission line fittings



5. CONDUCTOR

copper, Aluminium, or A.C.S.R Through a line of electric coductor power one place to

another must be in place.

ACSR Aluminum conductor SteelReinforced conductor



6. LIGHTENING ARRESTORS



7. FUSES AND ISOLATING SWITCHES

They are different parts of the overhead system, the network can be isolated if necessary.

Disconnecting Switch (Isolator)

High-voltage fuse cutout applied to

alternating current system



8. CONTINOUS EARTH WIRE

Tower or the poll is over the top of the line along the entire Earth trait. The unusualcircumstances created by the additional voltage Discharge line to protect the soil easily.

Protective grounding jumper installation for two-pole and three-pole structures (grounded

structures). OGW denotes overhead ground wire. OGWs must be bonded to the worksite

grounding system if within reach of linemen. OGWs may be bonded to the cluster bars or to

the grounded phase conductors with protective grounds.

8 CONTINOUS EARTH WIRE



8. CONTINOUS EARTH WIRE

The most effective method of providing protection to transmission lines against direct

lightning strokes is by use of overhead ground wires as shown in Fig 6. For simplicity, one

ground wire and one line conductor are shown. The ground wires are placed above the lineconductors at such positions that practically all lightning strokes are intercepted by them (i.

e. ground wires). The ground wires are grounded at each tower or pole through a low

resistance as possible. Due to their proper location, the ground wires will take up all the

lightning strokes instead of allowing them to line conductors. The degree of protection

provided by the ground wires depends upon the footing resistance of the tower.

A lightning stroke hits an earth wire

9 GUARD WIRE



9. GUARD WIRE

When a power line, telephone or telegraph line crossing, and then find the

line that connects the top and bottom of the Earth Wire is used to guard.

10 BIRD GUARDS



10. BIRD GUARDS

It is created on the side of the saw teeth as long

ebonite basest plate, which is a cross - is prevented inthe presence of arm insulator. The birds of hokier

cross - in the arm and conductor Flash - Over inthe out .

11 VIBRATION DAMPER



11. VIBRATION DAMPER

vibration damper dimple shape in the presence of these

lines connect to the poll, that tremble down the line. The air

flow through the conductor is conductor vibration, thevibration is. The pressure on the conductor in the conductor

can be read off tear. The best way to protect against

damage from vibration induced arms rod is used. Bates is

one of the Stock Bridge damper .The shaking intensity isused to prevent damper betas.

12 JUMPERS



12. JUMPERS

jumpers connection is connected via thetwo conductor. Nevertheless, as part of the

phase plate, Danger plate, Barbed wire,

Cradle guard. Etc.

12 JUMPERS



12. JUMPERS

for easy handling of the jumper set by rubber gloves or hot-line tools



INSULATORS

Transmission and distribution system leak overhead line of the

by chance current can not flow, so that the line from the Earth, the

Insulator is used for the line. Insulator important role in system

operation.

Transmission line insulators are devices used to contain,

separate or support electrical conductors on high voltage electricity

supply networks. Transmission insulators come in various shapes

and types, including individual or strings of disks, line posts or long

rods. They are made of polymers, glass and porcelain--each with

different densities, tensile strengths and performing properties in

adverse conditions



TYPES OF INSULATORS

There are several types of insulators but the most commonly usedare pin type, suspension type, strain insulator and shackle insulator.



PIN TYPE INSULATORS

As the name suggests, the pin

type insulator is secured to the cross-

arm on the pole. There is a groove on

the upper end of the insulator for

housing the conductor. The

conductor passes through this groove

and is bound by the annealed wire of

the same material as the conductor.

PIN TYPE INSULATORS



PIN TYPE INSULATORS

Pin type insulators are used for transmission and distribution of

electric power at voltages upto 33 kV. Beyond operating voltage of

33 kV, the pin type insulators become too bulky and hence

uneconomical.

PIN TYPE INSULATORS



PIN TYPE INSULATORS

Pin type insulators are used for the transmission of lower

voltages. A single pin type insulator is used to transmit voltages up to

11 kV (kilovolts) and higher voltages require two-, three- or four-

piece pin insulators. They are not economically feasible for 33 kV and

higher transmission lines.

Pin type insulators are secured with steel or lead bolts onto

transmission poles. These are typically used for straight-runningtransmission lines



SUSPENSION TYPE INSULATORS

For high voltages (>33 kV), it is a usual practice to use suspension

type insulators shown in Figure. consist of a number of porcelain

discs connected in series by metal links in the form of a string.




SUSPENSION TYPE INSULATORSThe conductor is suspended at the bottom

end of this string while the other end of the

string is secured to the cross-arm of the

tower. Each unit or disc is designed for low

voltage, say 11 kV. The number of discs in

series would obviously depend upon the

working voltage. For instance, if the workingvoltage is 66 kV, then six discs in series will be

provided on the string.

Suspension type transmission line insulators suspend and

support high voltage transmission lines. They are cost effective forhigher voltage transmission, typically replacing multiple pin type

insulators. Suspension type insulators have a number of

interconnected porcelain discs, with each individual unit designed to

support a particular voltage.




Together, a system of these discs is capable of effectively supporting

high voltages. There are three types of suspension insulators:cemented cap suspension insulators; interlinking or Hewlett

suspension insulators; and link or core suspension insulators.


ADVANTAGES OF SUSPENSION TYPE INSULATORS



ADVANTAGES OF SUSPENSION TYPE INSULATORS

1. Suspension type insulators are cheaper than pin type insulators for voltages

beyond 33 Kv.

2. Each unit or disc of suspension type insulator is designed for low voltage,usually 11 kV. Depending upon the working voltage, the desired number of discs

can be connected in series.

3. If any one disc is damaged, the whole string does not become useless because

the damaged disc can be replaced by the sound one.

4. The suspension arrangement provides greater flexibility to the line. Theconnection at the cross arm is such that insulator string is free to swing in any

direction and can take up the position where mechanical stresses are minimum.

5. In case of increased demand on the transmission line, it is found more

satisfactory to supply the greater demand by raising the line voltage than to

provide another set of conductors. The additional insulation required for theraised voltage can be easily obtained in the suspension arrangement by adding

the desired number of discs.

6. The suspension type insulators are generally used with steel towers. As the

conductors run below the earthed cross-arm of the tower, therefore, this

arrangement provides partial protection from lightning.

STRAIN TYPE INSULATORS




When there is a dead end ofthe line or there is corner or

sharp curve, the line is

subjected to greater tension. In

order to relieve the line ofexcessive tension, strain

insulators are used. For low

voltage lines (< 11 kV), shackle

insulators are used as strain

insulators.





However, for the high voltage

transmission lines, strain insulator consists of

an assembly of suspension insulators as

shown in Figure. The discs of strain insulators

are used in the vertical plane. When the

tension in lines is exceedingly high, at long

river spans, two or more strings are used inparallel.


http://en.wikipedia.org/wiki/Transmission_line



Strain type insulators are horizontally suspended suspension

insulators. They are used to handle mechanical stresses and take the

pressure off a conductor at the end of a transmission line, at a sharp

corner or curve or over long river crossings. Strain insulators are

typically used for higher voltage transmissions


SHACKLE TYPE INSULATORS




Shackle type insulators, similar to strain type insulators, are used on

sharp curves, end poles and in section poles.





However, unlike strain insulators,

shackle insulators are designed tosupport lower voltages. These insulators

are single, round porcelain parts that are

mounted horizontally or vertically. In

early days, the shackle insulators were

used as strain insulators.

But now a days, they are frequently used

for low voltage distribution lines. Suchinsulators can be used either in a

horizontal position or in a vertical position.

They can be directly fixed to the pole with

a bolt or to the cross arm





OTHER MODELS

STAY TYPE INSULATORS




STAY, GUY, AND

EGG

INSULATORS




Stay insulators, also called egg insulators, are primarily used to

prevent stay wires from becoming energized from accidentally

broken live wires. They, therefore, function to provide insulation

between stay clamps and transmission poles. Stay insulators are

mounted at a height of at least 3 meters (118 inches) from ground

level.




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