SIST EN 50341-2-18:2018

SLOVENSKI STANDARD
01-februar-2018
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Overhead electrical lines exceeding AC 1 kV - Part 2-18: National Normative Aspects
(NNA) for Sweden (based on EN 50341-1:2012)
Lignes électriques aériennes dépassant 1 kV en courant alternatif - Partie 2-18 : Aspects
Normatifs Nationaux (NNA) pour la Suède (sur la base de l'EN 50341-1:2012)
Ta slovenski standard je istoveten z: EN 50341-2-18:2016
ICS:
29.240.20 Daljnovodi Power transmission and
distribution lines
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 50341-2-18

NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2016
ICS 29.240.20
English Version
Overhead electrical lines exceeding AC 1 kV - Part 2-18:
National Normative Aspects (NNA) for Sweden (based on EN
50341-1:2012)
Lignes électriques aériennes dépassant 1 kV en courant
alternatif - Partie 2-18 : Aspects Normatifs Nationaux (NNA)
pour la Suède (sur la base de l'EN 50341-1:2012)
This European Standard was approved by CENELEC on 2016-11-01. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2016 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 50341-2-18:2016 E
Sweden 2/85 EN 50341-2-18:2016
Foreword . 7
1 Scope . 8
2 Normative references, definitions and symbols . 8
2.1 Normative references . 8
2.2 Definitions . 11
2.3 Symbols . 11
3 Basis of design . 12
3.2 Requirements of overhead lines . 12
3.2.2 Reliability requirements . 12
3.6 Design values . 13
3.6.2 Design values of an action . 13
3.7 Partial factor method and design formula . 13
3.7.3.2 Design situations related to permanent and variable actions . 13
3.7.3.3 Design situations related to permanent, variable and accidental actions 14
4 Actions on lines . 14
4.1 Introduction . 14
4.3 Wind loads . 14
4.3.4 Turbulence intensity and peak wind pressure . 14
4.4 Wind forces on overhead line components . 14
4.4.1 Wind forces on conductors . 14
4.4.1.1 General . 14
4.4.1.2 Structural factor . 15
4.4.1.3 Drag factor . 15
4.4.2 Wind forces on insulator sets . 15
4.4.3 Wind forces on lattice towers . 15
4.4.3.1 General . 15
4.4.3.2 Method 1 . 15
4.4.3.3 Method 2 . 16
4.4.4 Wind forces on poles . 16
4.5 Ice load . 16
4.5.2 Ice forces on conductors . 16
4.6 Combined wind and ice loads . 18
4.6.2 Drag factors and ice densities . 18
4.6.3 Mean wind pressure and peak wind pressure . 18
4.6.4 Equivalent diameter D of ice covered conductor . 18
4.7 Temperature effects . 18
4.8 Security loads . 19

Sweden - 3/85 - EN 50341-2-18:2016
4.9 Safety loads . 19
4.9.1 Construction and maintenance loads . 19
4.12 Load cases . 19
4.12.2 Standard load cases . 19
4.13 Partial factors for actions . 24
5 Electrical requirements . 26
5.3 Insulation co-ordination . 26
5.4 Classification of voltages and overvoltages . 27
5.5 Minimum air clearance distances to avoid flashover . 28
5.6 Load cases for calculation of clearances . 30
5.8 Minimum internal clearances within the span and at the top of support. 34
5.9 External clearances . 39
5.9.1 General . 39
5.9.2 External clearances to ground in areas remote from buildings, roads, etc.
................................................................................................................. 40
5.9.3 External clearances to residential and other buildings . 43
5.9.4 External clearances to crossing traffic routes . 44
5.9.6 External clearances to other power lines or overhead telecommunication
lines. 46
5.9.7 External clearances to recreational areas (playgrounds, sports areas,
etc.) . 50
6 Earthing systems . 51
6.1 Introduction . 51
6.1.3 Earthing measures against lightning effects . 51
6.1.4 Transferred potentials . 51
6.2 Ratings with regard to corrosion and mechanical strength . 51
6.2.1 Earth electrodes . 51
6.2.2 Earthing and bonding conductors . 52
6.4 Dimensioning with regard to human safety . 52
6.4.3 Basic design of earthing systems with regard to permissible touch voltage
................................................................................................................. 52
6.4.4 Measures in systems with isolated neutral or resonant earthing . 54
7 Supports . 54
7.1 Initial design considerations . 54
7.2 Materials . 54
7.2.1 Steel materials, bolts, nuts and washers, welding consumables . 54
7.2.6 Wood . 54
7.3 Lattice steel towers . 55
7.3.1 General . 55

7.3.3 Materials . 55
7.3.6 Ultimate limit states . 55
7.3.6.1 General . 55
7.3.6.3 Tension, bending and compression resistance of members . 55
7.3.6.4 Buckling resistance of members in compression . 55
7.3.8 Resistance of connections . 56
7.4 Steel poles . 56
7.4.1 General . 56
7.4.6.1 Ultimate limit states, General . 56
7.4.8.1 Connections, Basis . 56
7.4.8.2 Bolts (other than holding-down bolts) . 56
7.5 Wood poles . 56
7.5.1 General . 56
7.5.3 Materials . 57
7.5.5 Ultimate limit states . 57
7.5.5.2 Calculation of internal forces and moments . 57
7.5.5.3 Resistance of wood elements . 57
7.5.5.4 Decay conditions . 58
7.5.7 Resistance of connections . 58
7.5.8 Design assisted by testing . 58
7.6 Concrete poles . 58
7.6.1 General . 58
7.6.2 Basis of design . 59
7.6.3 Materials . 59
7.6.4 Ultimate limit states . 59
7.6.5 Serviceability limit states . 59
7.6.6 Design assisted by testing . 60
7.7 Guyed structures. 60
7.7.3 Materials . 60
7.7.4.1 Ultimate limit states, Basis . 60
7.7.4.2 Calculation of internal forces and moments . 60
7.7.4.3 Second order analysis . 60
7.7.6 Design details for guys . 61
7.8 Other structures . 61
7.9 Corrosion protection and finishes . 65
7.9.2 Galvanising . 66
7.9.3 Metal spraying . 66
7.9.6 Use of weather-resistant steels . 66
7.9.7 Protection of wood poles . 66

Sweden - 5/85 - EN 50341-2-18:2016
7.10 Maintenance facilities . 67
7.10.3 Safety requirements. 67
8 Foundations . 67
8.1 Introduction . 67
8.2 Basis of geotechnical design . 68
8.2.2 Geotechnical design by calculation . 68
8.2.3 Design by prescriptive measures . 69
8.2.4 Load tests and tests on experimental models . 70
8.3 Soil investigation and geotechnical data . 71
8.4 Supervision of construction, monitoring and maintenance . 72
9 Conductors and earth-wires . 72
9.1 Introduction . 72
9.2 Aluminium based conductors . 73
9.2.1 Characteristics and dimensions . 73
9.2.3 Conductor service temperatures and grease performance . 73
9.2.5 Corrosion protection . 73
9.2.6 Test requirements . 74
9.3 Steel based conductors . 74
9.3.1 Characteristics and dimensions . 74
9.3.3 Conductor service temperatures and grease characteristics . 74
9.3.4 Mechanical requirements . 74
9.4 Copper based conductors . 74
9.5 Conductors and ground wires containing optical fibre telecommunication circuits
........................................................................................................................... 75
9.5.1 Characteristics and dimensions . 75
9.5.3 Conductor service temperatures . 75
9.5.4 Mechanical requirements . 75
9.6 General requirements . 76
9.6.2 Partial factor for conductor . 76
9.6.4 Sag - tension calculations . 76
9.8 Selection, delivery and installation of conductors . 79
10 Insulators . 79
10.2 Standard electrical requirements . 79
10.7 Mechanical requirements . 80
10.10 Characteristics and dimensions of insulators . 80
10.16 Selection, delivery and installation of insulators . 80
11 Hardware . 81
11.2 Electrical requirements . 81

11.2.2 Requirement applicable to current carrying fittings . 81
11.6 Mechanical requirements . 81
11.7 Durability requirements . 82
11.14 Selection, delivery and installation of fittings . 82
12 Quality assurance, Checks and taking-over . 83
12.2 Checks and taking-over . 83
Annex E Electrical requirements . 84
E.2 Insulation co-ordination . 84
Annex G Earthing systems . 84
G.2 Material constants . 84
Annex J Lattice steel towers . 84
J.5 Design resistance of bolted connections . 84
Annex K Steel poles . 84
K.6 Design of holding-down bolts - Table K.2 . 84
Annex M Geotechnical and structural design of foundations . 85
M.1 Typical values of the geotechnical parameters of soils and rocks . 85
M.2.3 Calculation of R . 85
S
M.2.4 Analytical evaluation of R . 85
d
Sweden 7/85 EN 50341-2-18:2016
European foreword
1 The Swedish National Committee (NC) is identified by the following address:
SEK Svensk Elstandard - TK11 Overhead Lines
Box 1284
SE-164 29 KISTA
Telephone no.: +46 8 444 14 00
Facsimile no.: +46 8 444 14 30
E-mail sek@elstandard.se
2 The Swedish NC has prepared this Part 2-18 of EN 50341, listing the Swedish national
normative aspects (NNA), under the sole responsibility, and duly passed it through the
CENELEC and CLC/TC 11 procedures.
NOTE The Swedish NC also takes the sole responsibility for the technically correct co-ordination of this
EN 50341-2-18 with EN 50341. It has performed the necessary checks in the frame of quality
assurance/control. It is noted however that this quality assurance/control has been made in the
framework of the general responsibility of a standard committee under the national laws/regulations.
3 This NNA is normative in Sweden and informative in other countries.
4 This NNA has to be read in conjunction with Part 1 (EN 50341-1). All clause numbers used
in this NNA correspond to those of Part 1. Specific subclauses, which are prefixed "SE", are
to be read as amendments to the relevant text in Part 1. Any necessary clarification
regarding the application of this NNA in conjunction with Part 1 shall be referred to the
Swedish NC who will, in co-operation with CLC/TC 11 clarify the requirements.
When no reference is made in this NNA to a specific subclause, then Part 1 applies.
5 In the case of "boxed values" defined in Part 1, amended values (if any), which are defined
in this NNA shall be taken into account in Sweden.
However, any boxed value, whether in Part 1 or in this NNA, shall not be amended in the
direction of greater risk in a Project Specification.
6 The national Swedish standards / regulations related to overhead electrical lines exceeding
1 kV (AC) are listed in subclause 2.1/SE
NOTE All national standards referred to in this NNA will be replaced by the relevant European Standards as
soon as they become available and are declared by the Swedish NC to be applicable and thus
reported to the secretary of CLC/TC 11.

1 Scope
(ncpt)
SE.1 Application to existing overhead lines
This Part 2-18 is applicable for new overhead lines only and not for existing lines.
(A-dev)
SE.2 Maintenance, rebuilding or extension of an overhead line
Measures related to maintenance of the electrical installation shall fulfill the legislation in force when it
was erected. In the case of a rebuilding or extension of an electrical installation (overhead line), the
regulations in force shall be applied for the rebuilding or extension. (ELSÄK-FS 2008:1)
(ncpt)
SE.3 Replacement
This Part 2-18 replaces the Swedish Standards SS-EN 50341-3-18, edition 1 and SS-EN 50423-3-18,
edition 3.
(ncpt)
SE.4 Optical ground wire (OPGW) and optical phase conductor (OPCON)
This Part 2-18 is applicable for installation of OPGW and OPCON, also known as OPPC, in overhead
lines in Sweden.
(ncpt)
SE.5 All dielectric self supporting optical cable (ADSS) and optical attached cable (OPAC)
This Part 2-18 is applicable for installation of ADSS and OPAC in overhead lines in Sweden.
NOTE The allowable electrical field for the ADSS cable should be taken into consideration when the conductor
configuration is determined.
2 Normative references, definitions and symbols
2.1 Normative references
(A-dev)
SE.1 National normative laws, government regulations
Reference Title
ELSÄK-FS 2008:1 Elsäkerhetsverkets föreskrifter om hur starkströmsanläggningar ska vara
utförda
The Swedish National Electrical Safety Board - Regulations regarding
design, and erection of electrical installations
ELSÄK FS 2008:3 Elsäkerhetsverkets föreskrifter om innehavarens kontroll av elektriska
starkströmsanläggningar och elektriska anordningar
The Swedish National Electrical Safety Board - Regulations regarding
supervision of the electrical installation by the possessor
SFS 2009:22 Starkströmsförordning
The Swedish Government - Ordinance concerning electrical installations
BFS 2011:10 - EKS Boverkets föreskrifter och allmänna råd om tillämpning av europeiska
konstruktionsstandarder (eurokoder)
Swedish National Board of Housing, Building and Planning: Application
of the European design standards
NOTE If there is associated amendment instructions to the documents listed above, they shall be included.

Sweden - 9/85 - EN 50341-2-18:2016

(ncpt)
SE.2 National normative standards referred to in this NNA
Reference Title
SS-EN 335:2013 Träskydd - Definitioner och tillämpning av användningsklasser - Massivt
trä och träbaserade produkter
Durability of wood and wood-based products — Use classes: definitions,
application to solid wood and wood-based products
SS-EN 351-1:2007 Träskydd – Träskyddsbehandlat massivt trä – Del 1: Klassificering och
upptagning av träskyddsmedel
Durability of wood and wood-based products – Preservative-treated solid
wood – Part 1: Classification of preservative penetration and retention
SS-ISO 965-4 Metriska ISO-gängor för allmän användning – Gängtoleranser - Del 4:
Gränsmått för varmförzinkade utvändiga gängor avsedda för användning
tillsammans med invändiga gängor gängade till toleranskvalitet H eller G
efter förzinkning
ISO general purpose metric screw threads - Tolerances - Part 4: Limits
of sizes for hot-dip galvanized external screw threads to mate with
internal screw threads tapped with tolerance position H or G after
galvanizing
SS-EN 1090-2:2008 Utförande av stål- och aluminiumkonstruktioner – Del 2:
Stålkonstruktioner
Execution of steel structures and aluminium structures – Part 2:
Technical requirements for steel structures
SS-EN 1999-1-1:2007 Eurokod 9 : Dimensionering av aluminiumkonstruktioner – Del 1-1:
Allmänna regler
Eurocode 9: Design of aluminium structures - Part 1-1: General
structural rules
SS-EN ISO 4892-3:2013 Plast - Metoder för exponering i artificiellt ljus - Del 3: UV lysrör
(ISO 4892-3:2013)
Plastics - Methods of exposure to laboratory light sources - Part 3:
Fluorescent UV lamps (ISO 4892-3:2013)
SS-EN 10164:2005 Stålprodukter med förbättrade deformationsegenskaper i
tjockleksriktningen - Tekniska leveransbestämmelser
Steel products with improved deformation properties perpendicular to
the surface of the product - Technical delivery conditions
SS-EN 10204:2005 Metalliska varor - Typer av kontrolldokument
Metallic products - Types of inspection documents
SS-EN ISO 10684:2004 Fästelement – Varmförzinkning av fästelement
Fasteners – Hot dip galvanized coatings
SS-EN 13670:2009 Betongkonstruktioner – Utförande
Execution of concrete structures
SS-EN 60060 Högspänningsprovning
High-voltage test techniques
SS 11 23 18 Aluminium och stål – Lina till friledning – Kontinuerlig krypprovning
Aluminium and steel – Stranded conductors for overhead lines – non-
interrupted creep testing
SS 424 05 02 Isolatorer – Stödisolatorer av pinntyp för friledningar
Insulators – Pin insulators for overhead lines
SS 424 05 21 Stödisolator av massiv typ för friledningar
Line post insulators
SS 424 05 31 Isolatorer - Stagisolatorer
Insulators - Stay insulators
Reference Title
SS 424 08 06 Linor av hård förzinkad ståltråd för luftledningar - Fe140-linor
Hard zinc-coated steel wire strands for overhead lines – Fe140 wire
strands
SS 424 08 11 Tråd av aluminiumlegering för linor för friledningar - AlMgSi-tråd
Aluminium alloy wire for stranded conductors for overhead line – AlMgSi
wire
SS 424 08 12 Linor av aluminiumlegering för friledningar – AlMgSi-linor
Aluminium alloy stranded conductors for overhead line – AlMgSi-
conductor
SS 424 08 13 Tråd av aluminiumlegering för linor för friledningar - Al 59-tråd
Aluminium alloy wire for stranded conductors for overhead line – Al 59
wire
SS 424 08 14 Linor av aluminiumlegering för friledningar - Al 59-linor
Aluminium alloy stranded conductors for overhead line – Al 59-conductor
SS 424 12 50 Najning
Ties
SS 424 12 51 Förformad najningsspiral
Preformed ties
SS 436 02 61 Luftledningskorsningar - Högspänningsledning (friledning), högst 52 kV,
över allmän väg
Overhead line crossings - High voltage overhead line for max 52 kV
above public road
SS 436 02 62 Luftledningskorsningar - Högspänningsledning (friledning), högst 52 kV,
över allmän väg - Trädsäkert korsningsspann
Overhead line crossings - High voltage overhead line for max 52 kV
above public road - Crossing span safe for falling trees
SS 436 02 63 Luftledningskorsningar - Högspänningsledning (friledning), högst 52 kV,
över järnväg - Trädsäkert korsningsspann
Overhead line crossings - High voltage overhead line for max 52 kV
above railway - Crossing span safe for falling trees
SS 436 02 65 Luftledningskorsningar - Högspänningsledning (hängspiralkabel utan
skärm), 1-24 kV, över allmän väg
Overhead line crossings - High voltage overhead line (self-supporting
aerial cable without shield) 1-24 kV above public road
SS 436 02 66 Luftledningskorsningar - Högspänningsledning (hängspiralkabel utan
skärm), 1-24 kV, över järnväg
Overhead line crossings - High voltage overhead line (self-supporting
aerial cable without shield) 1-24 kV above railway
SS 436 02 80 Luftledningskorsningar - Högspänningsledning (metallskärmad
hängkabel eller metallskärmad hängspiralkabel), 1-24 kV, över allmän
väg
Overhead line crossings - High voltage overhead line (suspension cable
with metal sheath) 1-24 kV above public road
SS 436 02 81 Luftledningskorsningar - Högspänningsledning (metallskärmad
hängkabel eller metallskärmad hängspiralkabel), 1-24 kV, över järnväg
Overhead line crossings - High voltage overhead line (suspension cable
with metal sheath) 1-24 kV above railway

Sweden - 11/85 - EN 50341-2-18:2016

(ncpt)
SE.3 National informative documents referred to in this NNA
Reference Title
NTR Dokument 3: 2013 Nordiska Träskyddsrådet – Nordiska regler för kvalitetskontroll av
impregnerat trä – Del 1: Furu och andra lätt impregnerbara barrträdslag
The Nordic Wood Preservation Council – Nordic requirements for quality
control of preservative treated wood – Part 1. Pine and other permeable
softwoods
Korrosionsinstitutet Riktlinjer för användning av rosttröga stål - Korrosionstekniska synpunkter
Bulletin nr 97 Guidelines for use of weathering steel - Corrosion technical aspects
Korrosionsinstitutet Rosttröga stål i byggnader
Bulletin No. 94 Weathering steel in buildings

2.2 Definitions
(A-dev)
SE.1.1 Reinforced lines type 1
Overhead lines so designed that the forces which according to experience is expected to occur do not
inflict damage which adversely will affect the capability of these lines or imply hazard to persons or
property. (Brottsäker ledning: 6 kap. 1 and 7 §§ together with 7 kap. 8 §, ELSÄK-FS 2008:1).
(A-dev)
SE.1.2 Reinforced lines type 2
Design of overhead line within the nominal voltage of 1-25 kV in urban area with reliability level 2, efficient
earth fault protection and particular measures to reduce the risk of falling trees. (Ledning i förstärkt
utförande: 5 kap. 4 § and 6 kap. 1, 7 and 8 §§, ELSÄK-FS 2008:1).
(ncpt)
SE.2 Similar conductors
Similar conductors are conductors which have the same cross section, material, sag and attachment, see
also Table 5.8/SE.1.
(ncpt)
SE.3 Demarcation span
Single spans which separate a line section build as a reinforced line type 1 with timber pole support and
with highest system voltage equal to or less than 55 kV. The demarcation span shall be supported by
demarcation supports which are timber pole supports without longitudinal guys.
2.3 Symbols
(ncpt)
SE.1
Symbol Signification Reference
E Modulus of elasticity, initial stage (before ice load) 9.6.4/SE.1
i
E Modulus of elasticity, initial lower 9.6.4/SE.1
iL
E Modulus of elasticity, initial upper 9.6.4/SE.1
iU
E Modulus of elasticity, final stage (after ice load) 9.6.4/SE.1
p
f Mean value of axial tensile strength of concrete 7.6.5/SE.1
ctm
g Dead weight of the conductor 4.5.2/SE.1 to SE.2
e
g Ice-load at no wind 4.5.2/SE.1 to SE.2
i0
Symbol Signification Reference
g Ice-load at normal wind 4.5.2/SE.1 to SE.2
iw
g Normal wind load at bare conductor 4.5.2/SE.1 to SE.2
w0
g Normal wind-load at conductor covered by ice load 4.5.2/SE.1 to SE.2
wi
H Horizontal clearance Table 5.8/SE.1 to SE.2
h Horizontal clearance at mixed conductor configuration, Table 5.8/SE.1 to SE.2, 4.3
height above ground
k Voltage coefficient for distances Table 5.8/SE.1 to SE.3
S Voltage dependent distance 5.9.1/SE.1
U Lightning impulse withstand voltage 5.5/SE.1 to SE.2.2
SK
U Switching impulse withstand voltage 5.5/SE.1 to SE.2.2
SL
U Short duration wet power frequency withstand voltage 5.5/SE.1 to SE.2.2
V
V Vertical clearance Table 5.8/SE.1 to SE.2
v Vertical clearance at mixed conductor configuration Table 5.8/SE.1 to SE.2
W Free space, from high water level, for sailing, Table 5.9.4/SE.2
given by the authorities
X Clearance between conductors, factor in conductor Table 5.8/SE.3, 9.6.4/SE.1
calculation
Strain elongation due to creep 9.6.4/SE.1
ε
c
Strain elongation due to stress 9.6.4/SE.1
ε
s
Stress value 9.6.4/SE.1
σ
9.6.4/SE.1
σ Stress value in conductor at 0 °C
Highest stress value at which E is valid 9.6.4/SE.1
σ
p iL
3 Basis of design
3.2 Requirements of overhead lines
3.2.2 Reliability requirements
(A-dev)
SE.1.1 Reliability level 2
Reliability level 2 with partial factors in accordance with 4.13 of this NNA shall be used for overhead lines
of class A in Sweden for which this NNA is applicable.
(ncpt)
SE.1.2 Reliability level 1
Reliability level 1 with partial factors in accordance with 4.13 of this NNA shall be used for overhead lines
of class B in Sweden for which this NNA is applicable.
(A-dev)
SE.1.3 Class A
Lines designed for the ice load in accordance with 4.5.2/SE.1.1, SE.1.2, SE.2 and 4.6.4./SE.1.1 and
fulfilling the fault current capacity requirements of 11.14/SE.1 Examples are reinforced lines and other
lines which are intended to be a part of systems which are used for transmission and distribution over the
entire country or which otherwise are of substantial importance. (5 kap. 4 § together with 6 kap. 1 and 7
§§, ELSÄK-FS 2008:1).
Sweden - 13/85 - EN 50341-2-18:2016

(ncpt)
SE.1.4 Class B
Lines designed for the ice load in accordance with 4.5.2/SE.1.3, SE.1.4, SE.2 and 4.6.4./SE.1.2.
Examples are distribution lines.
Deviation from this classification can be justifiable in special cases. However the requirements for class B
are the minimum requirements for all lines.
(A-dev)
SE.2.1 Reinforced lines type 1
Reinforced lines of type 1 shall fulfil the requirements of class A. Reinforced line of type 1 is demarcated
by terminal supports. For lines on timber poles with highest system voltage equal to or less than 55 kV
the terminal supports for a reinforced line type 1 can be replaced by demarcation spans. The demarcation
spans itself are not considered as a reinforced line.
The route and design of reinforced lines of type 1 shall be such that the risk of damage is prevented as
far as possible. Reinforced line of type 1 may thus not be routed over or in perilous vicinity of shooting
ranges, chemical industries which emit gas that is harmful to line materials, or locations where
combustible objects or inflammables exist to such an extent that a fire could be perilous for the line. Nor
may a reinforced line of type 1 or demarcation spans be routed close to buildings or structures of such
low structural strength that will not withstand occurring wind loads. It shall be guaranteed that falling trees
will not damage the line of type 1 or the demarcation span. (Brottsäker ledning: 6 kap. 1 and 7 §§
together with 7 kap. 8 §, ELSÄK-FS 2008:1).
(A-dev)
SE.2.2 Reinforced lines type 2
Reinforced lines of type 2 shall fulfil the requirements of class A. Lines with highest system voltage up to
and including 25 kV and routed over urban areas. Reinforced line of type 2 need not to be demarcated by
terminal poles or demarcation spans. However the requirements for reinforced line of type 2 shall also be
applied for minimum one span outside the border of the urban area for reinforced lines of type 2 routed in
forest. Lines routed in forests shall have a minimum clearance between tree trunk and phase of 3,5 m.
Exceptions for a few stray trees down to a clearance distance to 2 m may occur if an investigation state a
healthy tree with a solid root system. Remaining vegetation and twigs from trees shall for worst case have
a clearance of minimum 1 m (Ledning i förstärkt utförande: 5 kap. 4 § and 6 kap. 1, 7 and 8 §§, ELSÄK-
FS 2008:1).
3.6 Design values
3.6.2 Design values of an action
(ncpt)
SE.1
When calculating the effect of the action on the conductor tension, the partial factors γ shall be applied to
F
the difference in actual conductor tension and tension at 0 °C in bare conductor. The partial factors γ
F
shall not be applied to wind and ice loads for calculation of the conductor tension.
3.7 Partial factor method and design formula
3.7.3.2 Design situations related to permanent and variable actions
(ncpt)
SE.1
For all load cases and load combinations the basic design equation is:
E = Σ γ G + Σ γ Q
d G K Q nK
3.7.3.3 Design situations related to permanent, variable and accidental actions
(ncpt)
SE.1
For all load cases and load combinations the basic design equation is:
E = Σ γ G + Σ γ Q
d G K Q nK
4 Actions on lines
4.1 Introduction
The Swedish approach for calculation of climatic loads on transmission lines can be classified as an
approach 3 method. The value of the peak wind pressure is given directly.
4.3 Wind loads
4.3.4 Turbulence intensity and peak wind pressure
(snc)
SE.1
The characteristic wind pressure q (h) depends on the height h and the gust wind speed. Height h is the
p
vertical distance in metres from the ground or water surface to the centre of gravity of the wind exposed
surface. For a transmission line, which crosses over a single height on a plain or flat country, h is the
height to the centre of gravity over the plain.
Values given below are valid for Sweden in general. In mountainous regions and at exposed locations
along the coast line higher wind pressures may occur, which have to be considered.
(snc)
SE.1.1 For normal wind conditions the following formulas are valid
for h < 25 m q (h) = 500 (N/m )
p
for h > 25 m . (N/m )
q (h) = 500 + 6 (h - 25)
p
(snc)
SE.1.2 For extreme wind conditions the following formulas are valid
for h < 10 m q (h) = 800 (N/m )
p
for h > 10 m . (N/m )
q (h) = 800 + 6 (h - 10)
p
NOTE  For determining electrical clearances the formulas for normal wind conditions shall be used.
4.4 Wind forces on overhead line components
4.4.1 Wind forces on conductors
4.4.1.1 General
(ncpt)
SE.1
The recommended method for calculating the reference height of the conductor is proposal 1 from Table
4.3, but any of the other proposals can be selected to simplify the calculations.
For the calculation of the mechanical conductor tension in a line-section, a reference height of 25 m can
be assumed if no other value may be considered more appropriate.

Sweden - 15/85 - EN 50341-2-18:2016

For covered and insulated conductors the diameter of the conductor (d) is to be taken as the overall
diameter including the thickness of insulation.
4.4.1.2 Structural factor
(ncpt)
SE.1
The structural factor for the conductor is:
for spans G = 0,5
C
for jumpers G = 1,0
C
4.4.1.3 Drag factor
(ncpt)
SE.1
Method 1 is recommended.
4.4.2 Wind forces on insulator sets
(ncpt)
SE.1
The structural factor, the drag factor and the area of the insulator can be simplified to
G · C · A = 0,16 · L (m )
ins ins ins ins
where
L is the length of one insulator string (m).
ins
The formula for wind forces on insulator sets can therefore be written
Q = q (h) · 0,16 · L
Wins p ins
4.4.3 Wind forces on lattice towers
4.4.3.1 General
(ncpt)
SE.1
The wind forces on a tower can be determined with method 1 or with method 2.
Reference height of each tower section or each tower member is the height above ground of the
geometrical centre of the tower section or the tower member being considered.
4.4.3.2 Method 1
(ncpt)
SE.1
The structural resonance factor is G = G = 1,0
t tc
(ncpt)
SE.2 For lattice support the drag factor is:
rectangular cross section with flat sided members
C = 3,95 – 5,79 · χ + 3,86 · χ
t
rectangular cross section with cylindrical members
C = 2,30 – 3,24 · χ + 2,94 · χ
t
triangular cross section with flat sided members
C = 3,40 – 4,71 · χ + 3,37 · χ
t
triangular cross section with cylindrical members
C = 1,95 – 2,68 · χ + 2,76 · χ
t
where χ is the solidity ratio, see Figure 4.2.
(ncpt)
SE.3 For tower body or portal leg with triangular cross section the wind load is:
Q = q (h) · G · A · C (N/m)
Wt p t t t
4.4.3.3 Method 2
(ncpt)
SE.1
The structural resonance factor is G = 1,0
m
The
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