Overhead transmission lines - Svenska kraftnät

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KRAFTNÄTSWEDISH NATIONAL GR1D

SVENSKA

UNIT, BUSINESS AREANTL Overhead Transmission Lines, Grid Technology

DATE9 March 2020

CONSULTATIONSNAL, NLB, NLP

>1 Jff jtfREVISION

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OUR REFERENCETR05-IOE

TECHNICAL GUIDELINE

APPROVEDTd

Overhead transmission linesInsulator set and overhead earth wire set

IntroductionThese guidelines describe the requirements on insulator sets and in applicable parts of earth wire sets and cover design, test and installation. The guidelines intend to guarantee satisfaetoiy performance of insulator sets and overhead earth wire set during the lifetime of the overhead line and shall be used at purchasing of insulator sets.

TECHNICAL GUIDELINE 9 March 2020 TR05-10E rev 4

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Revision Notes Change notes Date

1 (A) Revision of standards and new template 09 / 07 2010

2 Template changed.Clause. 10.5.1.4 support clamp inserted. Clause 10.5.4.2 creepage text revised. Clause 10.6.7 ”Dry” inserted in headline. Clause 10.6.8 ”Dry” inserted in headline. Clause 10.9.1 locking of bolt and nut inserted. Clause 10.9.2 installation conditions inserted. Clause 10.9.3.2 placement of transposition installation sets revised. 10.8,2.5 revised. 10.8.3 added.

02 / 04 / 2012

3 New template and change of clause numbers. Rev. clause 5.4.2, 6.1, 8.2.5, 9.2 installation requirements. Clause 9 inserted:” nuts in long direction be installed on the side towards lower tower number”. Inserted in clause 9.3 “in vertical direction shall bolt head be installed on the upper side and nuts underneath. Inserted: Transposition sets shall not be installed at crossings with roads.

27 / 06 / 2014

4 Totally reworked 09 / 03 / 2020

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Content

1 References ........................................................................................................... 6

2 Scope .................................................................................................................... 6

3 Definition ............................................................................................................ 6

4 Requirements ...................................................................................................... 7

4.1 General 7

4.2 Material 7

4.2.1 Insulators 7

4.2.2 Insulator fittings 7

4.2.3 Power arc protection devices 7

4.2.4 Suspension and support clamps 7

4.2.5 Tension clamps 7

4.3 Design 8

4.3.1 General 8

4.3.2 Insulation 8

4.3.3 Arching distance 10

4.3.4 Yokes 10

4.3.5 Arcing ring (Power arc protection device) 10

4.3.6 Counterweights 10

4.4 Mechanical requirements 11

4.5 Electrical requirements 11

4.5.1 General 11

4.5.2 Power frequency withstand voltage 11

4.5.3 Corona 11

4.5.4 Radio interference 11

4.5.5 Lightning overvoltage 11

4.5.6 Switching overvoltage 12

4.5.7 Short circuit current 12

5 Type test ............................................................................................................ 12

5.1 General 12

5.2 Dimensions 12

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5.3 Wet power frequency withstand voltage 12

5.4 Corona 13

5.5 Radio interference 13

5.6 Dry lightning impulse withstand voltage 14

5.7 Wet switching impulse withstand test 14

5.8 AC power arc test 14

6 Delivery ............................................................................................................. 14

6.1 Documentation 14

6.1.1 General 14

6.1.2 Assembly drawing 15

6.1.3 Reports 15

6.1.4 Transport and storage 15

7 Installation ........................................................................................................ 15

7.1 General 15

7.2 Installation of straight line, angle line and V-string insulator sets 15

7.2.1 General 15

7.2.2 Straight line suspension insulator sets 15

7.2.3 Angle line suspension insulator sets 16

7.2.4 V-string insulator sets 16

7.3 Installation of tension and transposition insulator sets 17

7.3.1 Tension insulator set 17

7.3.2 Transposition insulator sets 17

8 Tables................................................................................................................. 19

Tabell 1 Withstand voltage 19

9 Figures .............................................................................................................. 20

Figure 1 Straight line suspension insulator set 20

Figure 2 Angle suspension insulator set 22

Figure 3 V-string suspension insulator set 23

Figure 4 Tension insulator set 24

Figure 5 Transposition tension insulator set 26

Figure 6 Earth wire sets 27

Figure 7 Attachment of counterweight 28

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Figure 8 Straight line suspension insulator set bolt orientation 29

Figure 9 Tension insulator set bolt orientation 30

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1 References EN ISO 9001 Quality management systems - Requirements C.I.S.P.R 16-2-1 Specification for radio disturbance and immunity

measuring apparatus and methods - Part 2: Methods of measurement of disturbances and immunity

C.I.S.P.R 18 – 2 Radio interference characteristics of overhead power

lines and high-voltage equipment - Part 2: Methods of measurement and procedure for determining limits

IEC 61284 Overhead lines - Requirements and tests for fittings IEC 61467 Insulators for overhead lines with a nominal voltage

above 1 000 V- A.C. Power Arc Tests on insulator sets EN 50341-1 Overhead electrical lines exceeding AC 1 kV General

requirements – Common specifications SS-EN 50341-2-18 Overhead electrical lines exceeding AC 1 kV National

Normative Aspects (NNA) for Sweden IEC 60383-2 Insulators for overhead lines with a nominal voltage

above 1 000 V- Part 2: Insulator strings and insulator sets for a.c. systems - Definitions, test methods and acceptance criteria

TR05-01 Svenska kraftnät Teknisk riktlinje - Luftledningar

Anläggningsdokumentation TR05-04E Svenska kraftnät Technical guidelines - Conductors TR05-05E Svenska kraftnät Technical guidelines – Suspension

clamp and support clamp TR05-06E Svenska kraftnät Technical guidelines – Tension clamp TR05-11E Svenska kraftnät Technical guidelines – Insulators

TR05-12E Svenska kraftnät Technical guideline – Fittings for

insulator and overhead earth wire sets

2 Scope

These guidelines are applicable to suspension, tension and transposition insulator

sets and overhead earth wire set which are to be used on AC overhead lines with

alternating current and comprise design, testing and installation.

3 Definition

Technical terms and definitions used in these guidelines:

Insulator set

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Device for insulating conductors either in suspension or tension.

Insulator string

The insulating part of the insulator set consisting of one or more insulators joined

together.

Highest voltage for equipment

The highest value of phase-to-phase voltage for which the equipment is designed.

The highest voltage for equipment is designated Um in this document.

Corona extinction voltage

The voltage where no corona is visible when the voltage is reduced from a level with

visible corona.

Fault current

The greatest short duration current which is caused by either a short-circuit (Ik) or

an earth fault (3Io).

USCD

Creepage distance of an insulator divided by the r.m.s. value of the highest

operating voltage across the insulator.

4 Requirements

4.1 General The manufacturer shall have a quality system in accordance with at least EN ISO 9001.

4.2 Material

4.2.1 Insulators

Insulators shall conform to the requirements of Svk TR05-11E.

4.2.2 Insulator fittings

Insulator fittings shall conform to the requirements of Svk TR05-12E.

4.2.3 Power arc protection devices

Power arc protection devices shall conform to the requirements of Svk TR05-12E.

4.2.4 Suspension and support clamps

Suspension and support clamps shall conform to the requirements of Svk TR05-

05E.

4.2.5 Tension clamps

Tension clamps shall conform to the requirements of Svk TR05-06E.

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4.3 Design

4.3.1 General

Insulator set design shall conform to TR05-10E figure 1-5 with respect to fittings,

fitting orientation, and ability to pivot. In addition the overall length of the

insulator set shall be designed to be as short as possible.

Earth wire set design shall conform to TR05-10E figure 6 with respect to fittings,

fitting orientation, and ability to pivot.

Maximum length for individual extension links in tension set is 2 m. Joint between

extension links shall have the ability to pivot horizontally as well as vertically. See

example below.

4.3.2 Insulation

Creepage

Pollution classes for areas in Sweden shall be in accordance with the table below.

Area Pollution classes USCD (mm/kV)

Distance from the coast

West coast

E-Very heavy 53,7 0-0,5 km

D-heavy 43,3 0,5-15 km

C-Medium 34,7 15-30 km

East coast in Götaland C-Medium 34,7 0-10 km

Skåne C-Medium 34,7 -

Öland and Gotland C-Medium 34,7 -

Remaining areas AB-Light 25 -

It is recommended to increase the creepage distance one pollution class for

insulation placed within 50 m from roads with motorized traffic which is

salted in wintertime.

It could be a need to increase the creepage distance for insulation placed

nearby polluting industries.

Creepage distance on transmission lines and its substations should be

coordinated.

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In new built 400 kV transmission lines with conductor 3x910 Al59/phase shall the

number of insulators and type be as below:

Pollution class Suspension set Tension set

AB 16xU210B 14xU300B

2x14xU300B

C 16xU210BP (fog) 14xU300BP (fog)

2x14xU300BP (fog)

D-E Class C with RTV coating Class C with RTV coating

In new built 220 kV transmission lines shall the number and type of insulators be

as below:

When rebuilding existing transmission lines, insulators shall be selected so that

original creep distance is preserved.

Pollution class Suspension set Tension set

AB 14xU70BL

14xU120B

12xU210B

11xU300B

Strings shall have the same

quantity of insulators as for

suspension string. Insulator

type, single or double string are

depending on design load.

C 14xU70BL (fog)

14xU120B (fog)

12xU210B (fog)

11xU300B (fog)

D 14xU70BL (fog) 1)

14xU120BP (fog) 1)

12xU210BP (fog)

11xU300BP (fog)

1) With RTV coating

E Class D with RTV coating

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4.3.3 Arching distance

For new lines shall the distance between power arcing horns be as below:


kV

Arching distance

mm

245 1760 −20+35

420 2300 −20+50

In rare cases at line connection to station it can be necessary to increase arcing

horn distance for the adjacent line towers. This shall be decided together with

Svenska kraftnät.

When rebuilding existing transmission lines, original arching distance shall be

preserved.

4.3.4 Yokes

Yokes for twin and triple bundle conductors for new lines shall be so designed that

the distance between sub-conductors will be 450 mm up to and including a

conductor diameter of 32 mm and 600 mm for conductor diameter greater than 32

mm.

Yokes for twin and triple bundle conductors for exiting lines shall be so designed

that the distance between sub-conductors will be unchanged.

4.3.5 Arcing ring (Power arc protection device)

Power arc protection devices shall conform to the requirements of Svk TR05-12E.

Radiated heat from power arcs shall not damage insulator sets.

4.3.6 Counterweights

Straight line and angle suspension insulator sets for the suspension of single, twin

or triple conductors shall be so designed as to allow for the addition of

counterweights when necessary.

Counterweights shall conform to the requirements of Svk TR05-12E.

Attachment of counterweight shall conform to TR05-10E figure 7.

The transverse swing of suspension insulator sets, with counterweights fitted to

suspension clamps, shall be limited to 45°. See Svk TR05-05E.

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4.4 Mechanical requirements Insulator sets shall conform to the mechanical requirements of SS-EN 50341-2-18

Overhead electrical lines exceeding AC 1 kV National Normative Aspects (NNA) for

Sweden.

4.5 Electrical requirements

4.5.1 General

Electrical designing/dimensioning shall, in addition to what is stated in these

technical guidelines, be performed in accordance with SS-EN 50341-18-2 Overhead

electrical lines exceeding AC 1 kV National Normative Aspects (NNA) for Sweden .

The length of the insulator string for insulator sets intended for insulation between

phase and earth shall be such that the required arcing distance to achieve the

withstand voltages given in TR05-10E table 1 are obtained.

The length of the insulator string in insulator sets intended for insulation between

phases shall be such that minimum arcing distances of 130% and 137% of that for

phase to earth insulation are obtained for the highest voltages for equipment of 245

kV and 420 kV respectively

4.5.2 Power frequency withstand voltage

The power frequency withstand voltage of insulator sets, which are intended for

phase to earth insulation, shall be the minimum voltage stated in TR05-10E table 1

when tested in accordance with IEC 60383-2.

The power frequency withstand voltage of insulator sets, which are intended for

phase to phase insulation, shall be a minimum of 3 times the voltage stated in

TR05-10E table 1 when tested in accordance with IEC 60383-2.

4.5.3 Corona The insulator set shall have no visible corona at the test voltage defined by:

1,1*3

UgeTest volta m

Where Um is the highest voltage for equipment stated in TR05-10E table 1.

4.5.4 Radio interference

The radio interference level for insulator sets shall be less than 60 dB at the highest

voltage for equipment with 50 Hz alternating voltage (r.m.s. value) over 1V

interference voltage and 500 kHz measuring frequency

4.5.5 Lightning overvoltage

The lightning impulse withstand voltage for insulator sets intended for phase to

earth insulation shall be that stated in TR05-10E table 1 when tested in accordance

with IEC 60383-2.

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4.5.6 Switching overvoltage

The switching impulse withstand voltage for insulator sets intended for phase to

earth insulation shall be that stated in TR05-10E table 1 when tested in accordance

with IEC 60383-2.

The switching impulse withstand voltage for insulator sets intended for insulation

between phases shall be a minimum of 140% for 245 kV and 150% for 420 kV

highest voltages for equipment of that stated in TR05-10E table 1 when tested in

accordance with IEC 60383-2.

4.5.7 Short circuit current

Insulator sets shall be thermally designed to resist the stated fault current and fault

time so that the mechanical strength of fittings, which are subject to fault current,

is not weakened due to the heating caused by the fault current. In addition the zinc

layer of hot-dip galvanized steel fittings is not to be damaged. Welding due to

power arcs between fittings included in insulator sets shall be as far as possible

avoided.

5 Type test

5.1 General Unless otherwise agreed the type test is to be performed in accordance with TR05-

10E clause 5.2, on one test insulator set for each type and included all components.

On request of the client type test is to be performed in accordance with TR05-10E

clauses 5.32 - 5.8 with an agreed quantity of insulator sets.

The insulator set shall be installed in accordance with the relevant drawings and

simulate insulator set in service.

The tests shall be performed in such a way that neither the method nor the

equipment affects the result.

5.2 Dimensions The intention of this test is to check that the insulator set being in accordance with

the manufacturers drawings regarding measurements.

The test is performed by assemble all the components.

5.3 Wet power frequency withstand voltage The intention of this test is to establish the wet power frequency withstand voltage

of a complete insulator set.

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The insulator set is to be installed such that the clearance from live to earth given in

TR05-10E table 1 is obtained. The insulator set is then to be subjected to 50 Hz

alternating current. This test is to be performed as a wet test in accordance with

IEC 60383-2.

The wet power frequency withstand voltage of insulator sets, which are intended

for phase to earth insulation, shall be the minimum voltage stated in TR05-10E

table 1.

The wet power frequency withstand voltage of insulator sets, which are intended

for phase to phase insulation, shall be a minimum of 3 times the voltage stated in

TR05-10E table 1.

5.4 Corona The intention of this test is to establish the corona extinction voltage for a complete

insulator set and is to be performed in a fully-darkened room. During the corona

test the use of either field glasses with a minimum optical performance 7x50, or an

image intensifier with light amplification greater than 40 000 in accordance with

IEC 61284, is recommended.

The distance from the live phase to earth shall be as stated in TR05-10E table 1 and

the insulator set is to be subjected to 50 Hz alternating current.

The corona extinction voltage shall exceed the calculated test voltage in accordance

with TR05-10E clause 4.5.3.

The positive and negative corona extinction voltage is to be recorded. It shall be

documented by colour photographs, one with visible corona and another at the

corona extinction voltage level, with the voltage levels being indicated on the

photographs.

The test shall be performed in accordance with the applicable sections of IEC

61284.

5.5 Radio interference The intention of this test is to establish the level of radio interference for a complete

insulator set.

The test shall be performed with the highest voltage for equipment, 50 Hz

alternating voltage (r.m.s. value) over 1 V interference voltage and 500 kHz

measuring frequency. Testing is to be in accordance with C.I.S.P.R publication 16-

SER and the results evaluated in accordance with C.I.S.P.R publication 18-2.

The distance from the live phase to earth shall be as stated in TR05-10E table 1.

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The level of interference at the highest voltage for equipment shall fulfil the

requirements of TR05-10E clause 4.5.4.

5.6 Dry lightning impulse withstand voltage The intention of this test is to establish the lightning impulse withstand voltage for

a complete insulator set.


the insulator set is to be subjected to a lightning impulse withstand voltage test in

accordance with IEC 60383-2.

The lightning impulse withstand voltage shall exceed the voltage stated in TR05-

10E table 1.

5.7 Wet switching impulse withstand test The intention of this test is to establish the switching impulse withstand voltage for

a complete insulator set.


the insulator set is to be subjected to a wet switching impulse withstand voltage test

in accordance with IEC 60383-2.

The switching impulse withstand voltage shall exceed the voltage stated in TR05-

10E table 1.

5.8 AC power arc test The intention of this test is to establish the capacity of a complete insulator set to

withstand flash-over with a power arc.

Complete insulator set with clamps and conductors is to be installed and tested in

accordance with IEC 61467 test series X and test circuit A (In = 0,5 Isys and two tn=

0,2 s and one of tn=1 s).

The insulator set shall fulfill the acceptances criteria in accordance with IEC 61467.

6 Delivery

6.1 Documentation

6.1.1 General

All documentation shall be written in English.

Complete documentation according to TR05-10E clauses 6.1.2 - 6.1.3 shall be

available to the client before delivery.

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6.1.2 Assembly drawing

Assembly drawing shall have a minimum of two views at an appropriate scale

according to TR05-01. On each drawing shall be given:

Type and/or catalogue number

Principal dimensions

Arcing distance

Creepage distance

Breaking load

Fault current

Weight, with and without insulators

List of materials

6.1.3 Reports

Complete reports, with all measured values reported, from all controls according to

TR05-10E clause 5.

6.1.4 Transport and storage

The insulator sets shall be packed up in such a way that they will not be damaged or

fouled at transport, construction and storing.

7 Installation

7.1 General Installation of insulator sets shall be performed in accordance with the relevant

drawings. The arching ring nuts shall be locked with two punches.

7.2 Installation of straight line, angle line and V-string insulator sets

7.2.1 General

Suspension sets shall be installed vertical to the direction of the line. Maximum

allowed deviation to the vertical plane at the suspension clamp is L/40, where L=

length of the insulator set.

7.2.2 Straight line suspension insulator sets

Arching horn on suspension insulator sets shall be installed in such a way that any

power arc will have a predestined direction transverse to the direction of the line

and outwards away from the insulator set and the support.

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With a horizontal phase arrangement arching horn for the middle phase shall be

installed in such a way that the power arc will have a predestined direction to the

right transverse to the direction of the line when looking towards higher support

numbers.

The pivot bolt nut and the eye of the split pin in a socket are to be installed facing

the support. For the middle phase the nut and the eye of the split pin are to be

installed facing left when looking towards higher support numbers. See TR05-10E

figure 8a.

The pivot bolt nuts in fittings between the conductors and the yoke plate are to be

installed facing each other in twin bundle conductor arrangements and similarly

for the upper two conductors in triple bundle conductor arrangements. See TR05-

10E figures 8b and 8c respectively.

In longitudinal direction shall the nuts be installed facing against lower support

number.

7.2.3 Angle line suspension insulator sets

Power arc protection devices on angle suspension insulator sets shall be installed in

such a way that any power arc will have a predestined direction upwards.

In inclined suspension insulator sets the pivot bolt nut and the eyes of split pins in

sockets are to be installed facing downwards.

Nuts on horizontally orientated pivot bolts and the eyes of split pins in sockets are

to be installed facing the support. For the middle phase the nut and the eye of the

split pin are to be installed facing left when looking towards higher support

numbers.



for the upper two conductors in triple bundle conductor arrangements. See TR05-



number.

7.2.4 V-string insulator sets

Arching horn on V-string suspension insulator sets shall be installed in such a way

that any power arc will have a predestined direction upwards.

For inclined insulator sets the pivot bolts nuts, the eyes of split pins in sockets and

power arc protection device attachment arms, are to be installed facing downwards.

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Nuts in horizontally orientated pivot bolts and the eyes of split pins in sockets are

to be installed facing the support. For the middle phase the nut and eyes of the

split pins are to be installed facing left when looking towards higher support

numbers.



for the two upper conductors in triple bundle conductor arrangements.


number.

7.3 Installation of tension and transposition insulator sets

7.3.1 Tension insulator set

Power arc protection devices on tension insulator sets shall be installed in such a

way that any power arc will have a predestined direction upwards.

Nuts on vertical orientated pivot bolts, the eyes of split pins in sockets and power

arc protection device attachment arms, are to be installed facing downwards.


to be installed facing the support. For the middle phase the nuts and eyes of the


numbers. See TR05-10E figure 9a.

The pivot bolt nuts on fittings between the conductors and the yoke plate are to be


for the upper conductors in triple bundle conductor arrangements. See TR05-10E

figures 9b and 9c respectively.

For bolts in vertical direction shall the bolt head be on the upper side and the nut

underneath.

7.3.2 Transposition insulator sets

Transposition tension sets are not allowed in spans that cross traffic routes,

railways and transmission lines, nor in the adjacent spans.

Power arc protection devices on transposition insulator sets shall be installed in

such a way that any power arc will have a predestined direction upwards.

Nuts on vertically orientated pivot bolts, the eyes of pins in sockets and power arc

protection device attachment arms, are to be installed facing downwards.

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to be installed facing the support. For the middle phase the nuts and the eyes of


numbers. See TR05-10E figure 9a.

The pivot bolts nuts on fittings between the conductors and the yoke plate are to be


for the two upper conductors in triple bundle conductor arrangements. See TR05-


For bolts in vertical direction shall the bolt head be on the upper side and the nut

underneath.

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8 Tables

Tabell 1 Withstand voltage


kV

Rated withstand voltage

kV

Distance

m

Um, phase – phase Lightning impulse

Switching impulse

Power frequency

Phase to earth

245 850 650 360 3

420 1175 950 - 4

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9 Figures

Figure 1 Straight line suspension insulator set

Figure 1a Single string, triplex conductor

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Figure 1b Single string for dropper attachment, triplex conductor

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Figure 2 Angle suspension insulator set

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Figure 3 V-string suspension insulator set

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Figure 4 Tension insulator set

Figure 4a Single string, simplex conductor

Figure 4b Single string, duplex conductor

Figure 4c Double string, duplex conductor

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Figure 4d Long, double string, duplex conductor

Figure 4e Double string, triplex conductor

Figure 4f Long, double string, triplex conductor

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Figure 5 Transposition tension insulator set

Figure 5a Single string, simplex conductor

Figure 5b Single string, duplex conductor

Figure 5c Double string, triplex conductor

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Figure 6 Earth wire sets

Figure 6a Suspension set

Figure 6b Tension set

Figure 6c Insulated tension set

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Figure 7 Attachment of counterweight

Figure 7a Counterweight installation, single conductor

Figure 7b Counterweight installation, duplex conductors

Figure 7c Counterweight installation, triplex conductors

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Figure 8 Straight line suspension insulator set bolt orientation The arrows indicate the direction bolts must face when looking towards higher

support numbers.

Figure 8a Straight line support

Figure 8b Twin bundle conductor Figure 8c Triple bundle conductor

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Figure 9 Tension insulator set bolt orientation The arrows indicate the direction bolts must face.

Figure 9a Terminal support

Figure 9b Twin bundle conductors

Figure 9c Triple bundle conductors

Towards higher support numbers

Overhead transmission lines - Svenska kraftnät

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