4.3 Wind loads 4.3.1 DK.1 Field of application and basic wind velocity snc The basic wind velocity, Vb,0 can be taken as given in Table 4.3.1 below Table 4.3.1/DK.1 - Reference wind sp
Trang 1Overhead electrical lines exceeding AC 1 kV – Part 2-5:
National Normative Aspects (NNA) for DENMARK (based on
EN 50341-1:2012)
BSI Standards Publication
Trang 2NORME EUROPÉENNE
ICS 29.240.20
English Version
Overhead electrical lines exceeding AC 1 kV - Part 2-5: National
Normative Aspects (NNA) for DENMARK
(based on EN 50341-1:2012)
Lignes électriques aériennes dépassant 1 kV en courant alternatif - Partie 2-5: Aspects normatifs nationaux (NNA)pour le DANEMARK (basé sur l'EN 50341-1:2012) This European Standard was approved by CENELEC on 2017-02-01.
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, Serbia, 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
© 2017 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref No EN 50341-2-5:2017 E
National foreword
This British Standard is the UK implementation of EN 50341-2-5:2017
This standard, together with the following list of National Normative Aspect standards, supersedes BS EN 50423-3:2005 and
BS EN 50341-3:2001:
Country
BS EN 50423-3:2005 and BS EN 50341-3:2001 will be withdrawn upon publication of the rest of the series
The UK participation in its preparation was entrusted to Technical Committee PEL/11, Overhead Lines
A list of organizations represented on this committee can be obtained
on request to its secretary
This publication does not purport to include all the necessary provisions
of a contract Users are responsible for its correct application
© The British Standards Institution 2017
Published by BSI Standards Limited 2017 ISBN 978 0 580 97923 1
ICS 29.240.20
Compliance with a British Standard cannot confer immunity from legal obligations.
This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 March 2017
Amendments/corrigenda issued since publication
Trang 3NORME EUROPÉENNE
English Version
Overhead electrical lines exceeding AC 1 kV - Part 2-5: National
Normative Aspects (NNA) for DENMARK
(based on EN 50341-1:2012)
Lignes électriques aériennes dépassant 1 kV en courant
alternatif - Partie 2-5: Aspects normatifs nationaux
(NNA)pour le DANEMARK (basé sur l'EN 50341-1:2012)
This European Standard was approved by CENELEC on 2017-02-01
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, Serbia, 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
© 2017 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members
Ref No EN 50341-2-5:2017 E
Trang 4Contents
Page
European foreword 4
1 Scope 5
1.1 DK.1 Reliability levels 5
2 Normative references, definitions and symbols 5
2.1 DK.1 Normative references 5
2.3 DK.1 Symbols 5
3 Basis of design 6
3.2 Requirements of overhead lines 6
3.2.2 DK.1 Reliability levels 6
4 Actions on lines 6
4.1 DK.1 Introduction 6
4.3 Wind loads 6
4.3.1 DK.1 Field of application and basic wind velocity 6
Table 4.3.1/DK.1 - Reference wind speeds in Denmark 6
4.3.3 DK.1 Mean wind pressure 6
4.4 Wind forces on overhead line components 6
4.4.1 Wind forces on conductors 6
4.4.1.1 DK.1 General 6
DK.2 General 6
4.4.1.3 DK.1 Drag factor 7
4.4.3 Wind forces on lattice towers 7
4.4.3.1 DK.1 General 7
4.4.4 DK.1 Wind forces on poles 7
4.5 Ice loads 7
4.5.1 DK.1 General 7
4.5.2 DK.1 Ice forces on conductors 7
4.6 Combined wind and ice loads 7
4.6.6 Combination of wind velocity and ice loads 7
4.6.6.1 DK.1 Extreme ice load IT combined with a high probability wind velocity VIH 7
4.6.6.2 DK.1 Nominal ice load l3 combined with a low probability wind velocity VIL 7
4.7 DK.1 Temperature effects 7
4.8 Security loads 7
4.8.2 DK.1 Torsional loads 8
4.8.3 DK.1 Longitudinal loads 9
4.12 Load cases 9
4.12.1 DK.1 General 9
4.12.2 DK.1 Standard load cases 9
4.13 DK.1 Partial factors for actions 9
5 Electrical requirements 9
5.6 Load cases for calculation of clearances 9
5.6.1 DK.1 Load conditions 9
5.6.2 DK.1 Maximum conductor temperature 9
5.6.3 DK.1 Wind loads for determination of electric clearances 9
5.6.3.2 DK.1 Nominal wind loads for determination of internal and external clearances 10
5.6.4 DK.1 Ice loads for determination of electric clearances 10
5.6.5 DK.1 Combined wind and ice loads 10
5.8 DK.1 Internal clearances within the span and at the top of support 10
5.9 External clearances 10
5.9.3 DK.1 External clearances to residential and other buildings 10
5.9.4 DK.1 External clearances to crossing traffic routes 10
5.9.7 DK.1 External clearances to recreational areas (playgrounds, sports areas, etc.) 10
6 Earthing systems 11
7 Supports 11
7.1 Initial design considerations 11
7.1.1 DK.1 Introduction 11
7.2.1 DK.1 Steel materials, bolts, nuts and washers, welding consumables 11
7.2.4 DK.1 Holding-down bolts 11
7.3.6 Ultimate limit states 11
7.3.6.1 DK.1 General 11
7.4.6.1 DK.1 General 11
7.4.8 Resistance of connections 11
7.4.8.3 DK.1 General 11
7.6.4 DK.1 Ultimate limit states 11
8 Foundations 12
8.2.2 DK.1 Geotechnical design by calculation 12
8.3 DK.1 Soil investigation and geotechnical data (EN 1997-1:2004 – Section 3) 12
9 Conductors and earth-wires 12
10 Insulators 12
10.1 DK.1 Introduction 12
10.7 DK.1 Mechanical requirements 12
11 Hardware 12
12 Quality assurance, checks and taking-over 12
Trang 5Contents
Page
European foreword 4
1 Scope 5
1.1 DK.1 Reliability levels 5
2 Normative references, definitions and symbols 5
2.1 DK.1 Normative references 5
2.3 DK.1 Symbols 5
3 Basis of design 6
3.2 Requirements of overhead lines 6
3.2.2 DK.1 Reliability levels 6
4 Actions on lines 6
4.1 DK.1 Introduction 6
4.3 Wind loads 6
4.3.1 DK.1 Field of application and basic wind velocity 6
Table 4.3.1/DK.1 - Reference wind speeds in Denmark 6
4.3.3 DK.1 Mean wind pressure 6
4.4 Wind forces on overhead line components 6
4.4.1 Wind forces on conductors 6
4.4.1.1 DK.1 General 6
DK.2 General 6
4.4.1.3 DK.1 Drag factor 7
4.4.3 Wind forces on lattice towers 7
4.4.3.1 DK.1 General 7
4.4.4 DK.1 Wind forces on poles 7
4.5 Ice loads 7
4.5.1 DK.1 General 7
4.5.2 DK.1 Ice forces on conductors 7
4.6 Combined wind and ice loads 7
4.6.6 Combination of wind velocity and ice loads 7
4.6.6.1 DK.1 Extreme ice load IT combined with a high probability wind velocity VIH 7
4.6.6.2 DK.1 Nominal ice load l3 combined with a low probability wind velocity VIL 7
4.7 DK.1 Temperature effects 7
4.8 Security loads 7
4.8.2 DK.1 Torsional loads 8
4.8.3 DK.1 Longitudinal loads 9
4.12 Load cases 9
4.12.1 DK.1 General 9
4.12.2 DK.1 Standard load cases 9
4.13 DK.1 Partial factors for actions 9
5 Electrical requirements 9
5.6 Load cases for calculation of clearances 9
5.6.1 DK.1 Load conditions 9
5.6.2 DK.1 Maximum conductor temperature 9
5.6.3 DK.1 Wind loads for determination of electric clearances 9
5.6.3.2 DK.1 Nominal wind loads for determination of internal and external clearances 10
5.6.4 DK.1 Ice loads for determination of electric clearances 10
5.6.5 DK.1 Combined wind and ice loads 10
5.8 DK.1 Internal clearances within the span and at the top of support 10
5.9 External clearances 10
5.9.3 DK.1 External clearances to residential and other buildings 10
5.9.4 DK.1 External clearances to crossing traffic routes 10
5.9.7 DK.1 External clearances to recreational areas (playgrounds, sports areas, etc.) 10
6 Earthing systems 11
7 Supports 11
7.1 Initial design considerations 11
7.1.1 DK.1 Introduction 11
7.2.1 DK.1 Steel materials, bolts, nuts and washers, welding consumables 11
7.2.4 DK.1 Holding-down bolts 11
7.3.6 Ultimate limit states 11
7.3.6.1 DK.1 General 11
7.4.6.1 DK.1 General 11
7.4.8 Resistance of connections 11
7.4.8.3 DK.1 General 11
7.6.4 DK.1 Ultimate limit states 11
8 Foundations 12
8.2.2 DK.1 Geotechnical design by calculation 12
8.3 DK.1 Soil investigation and geotechnical data (EN 1997-1:2004 – Section 3) 12
9 Conductors and earth-wires 12
10 Insulators 12
10.1 DK.1 Introduction 12
10.7 DK.1 Mechanical requirements 12
11 Hardware 12
12 Quality assurance, checks and taking-over 12
Trang 6European foreword
1 The Danish National Committee (NC) is identified by the following address:
Dansk Standard
Göteborg Plads 1
DK-2150 Nordhavn
Phone no +45 39 96 61 01
E-mail: dansk.standard@ds.dk
2 The Danish NC has prepared this Part 2-5 of EN 50341, listing the Danish national normative aspects,
under its sole responsibility, and duly passed it through the CENELEC and CLC/TC 11 procedures
NOTE The Danish NC also takes sole responsibility for the technically correct coordination of this EN
50341-2-5 with EN 50341-2-50341-1:2012 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 standards committee under the national laws/regulations
3 This EN 50341-2-5 is normative in Denmark and informative for other countries
4 This EN 50341-2-5 has to be read in conjunction with EN 50341-1:2012, hereinafter referred to as Part
1 All clause numbers used in this Part 2-5 correspond to those of Part 1
Specific sub clauses, which are prefixed “DK”, are to be read as amendments to the relevant text in
Part 1 Any necessary clarification regarding the application of Part 2-5 in conjunction with Part 1 shall
be referred to the Danish NC who will, in cooperation with CLC/TC 11 clarify the requirements
When no reference is made in Part 2-5 to a specific sub clause, then Part 1 applies
5 In the case of “boxed values” defined in Part 1, amended values (if any) which are defined in Part 2-5
shall be taken into account in Denmark
However any “boxed values“, whether in Part 1 or Part 2-5, shall not be amended in the direction of
greater risk in a Project Specification
6 The national Danish standards/regulations related to overhead electrical lines exceeding 1 kV (AC)
are identified in 2.1/DK1
NOTE All national standards referred to in this Part 2-5 will be replaced by the relevant European Standards as
soon as they become available and are declared by the Danish NC to be applicable and thus reported to the
secretary of CLC/TC 11
(snc)
This Part 2-5 is applicable for new permanent overhead lines only and generally not for existing lines in Denmark If some planning/design or execution work on existing lines in Denmark has to be performed, the degree of application of this Standard shall be agreed upon by the parties concerned and the authorities
1.1 DK.1 General
(ncpt)
Installations in the planning and construction stage may be completed adopting the standard edition valid at the beginning of planning
2 Normative references, definitions and symbols 2.1 DK.1 Normative references
(A-dev)
Lov nr 525 af 29/04/2015
Lov om sikkerhed ved elektriske anlæg, elektriske installationer og elektrisk materiel (Elsikkerhedsloven)
Act No 525 - 29/04/2015
Act on the Safety of Electrical Plants, Electrical Installations and Electrical Equipment (the Electrical Safety Act)
Bekendtgørelse nr 1114 af 18/08/2016 Bekendtgørelse om sikkerhed for udførelse af elektriske anlæg Executive Order no 1114 - 18/08/2016
Executive Order on Safety in connection with the Construction of Electrical Plants
2.3 DK.1 Symbols
(ncpt)
L Length of the intact span [m] 4.8.2/DK.1
E Modulus of elasticity of the conductor [N/mm2] 4.8.2/DK.1
γ Weight of the conductor including possible external 4.8.2/DK.1 Load divided by the cross-sectional area [N/m/mm2]
σ Tensile stress in the conductor prior to breakage [N/mm2] 4.8.2/DK.1
I Max movement of movable suspension in the direction 4.8.2/DK.1
of the line [m]
u Deflection of the support in the direction of the line at the 4.8.2/DK.1
attachment point of the insulator [m]
d Horizontal conductor swing [m] 5.6.3.2/DK.1
Trang 7European foreword
1 The Danish National Committee (NC) is identified by the following address:
Dansk Standard
Göteborg Plads 1
DK-2150 Nordhavn
Phone no +45 39 96 61 01
E-mail: dansk.standard@ds.dk
2 The Danish NC has prepared this Part 2-5 of EN 50341, listing the Danish national normative aspects,
under its sole responsibility, and duly passed it through the CENELEC and CLC/TC 11 procedures
NOTE The Danish NC also takes sole responsibility for the technically correct coordination of this EN
50341-2-5 with EN 50341-2-50341-1:2012 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 standards committee under the national laws/regulations
3 This EN 50341-2-5 is normative in Denmark and informative for other countries
4 This EN 50341-2-5 has to be read in conjunction with EN 50341-1:2012, hereinafter referred to as Part
1 All clause numbers used in this Part 2-5 correspond to those of Part 1
Specific sub clauses, which are prefixed “DK”, are to be read as amendments to the relevant text in
Part 1 Any necessary clarification regarding the application of Part 2-5 in conjunction with Part 1 shall
be referred to the Danish NC who will, in cooperation with CLC/TC 11 clarify the requirements
When no reference is made in Part 2-5 to a specific sub clause, then Part 1 applies
5 In the case of “boxed values” defined in Part 1, amended values (if any) which are defined in Part 2-5
shall be taken into account in Denmark
However any “boxed values“, whether in Part 1 or Part 2-5, shall not be amended in the direction of
greater risk in a Project Specification
6 The national Danish standards/regulations related to overhead electrical lines exceeding 1 kV (AC)
are identified in 2.1/DK1
NOTE All national standards referred to in this Part 2-5 will be replaced by the relevant European Standards as
soon as they become available and are declared by the Danish NC to be applicable and thus reported to the
secretary of CLC/TC 11
(snc)
This Part 2-5 is applicable for new permanent overhead lines only and generally not for existing lines in Denmark If some planning/design or execution work on existing lines in Denmark has to be performed, the degree of application of this Standard shall be agreed upon by the parties concerned and the authorities
1.1 DK.1 General
(ncpt)
Installations in the planning and construction stage may be completed adopting the standard edition valid at the beginning of planning
2 Normative references, definitions and symbols 2.1 DK.1 Normative references
(A-dev)
Lov nr 525 af 29/04/2015
Lov om sikkerhed ved elektriske anlæg, elektriske installationer og elektrisk materiel (Elsikkerhedsloven)
Act No 525 - 29/04/2015
Act on the Safety of Electrical Plants, Electrical Installations and Electrical Equipment (the Electrical Safety Act)
Bekendtgørelse nr 1114 af 18/08/2016 Bekendtgørelse om sikkerhed for udførelse af elektriske anlæg Executive Order no 1114 - 18/08/2016
Executive Order on Safety in connection with the Construction of Electrical Plants
2.3 DK.1 Symbols
(ncpt)
L Length of the intact span [m] 4.8.2/DK.1
E Modulus of elasticity of the conductor [N/mm2] 4.8.2/DK.1
γ Weight of the conductor including possible external 4.8.2/DK.1 Load divided by the cross-sectional area [N/m/mm2]
σ Tensile stress in the conductor prior to breakage [N/mm2] 4.8.2/DK.1
I Max movement of movable suspension in the direction 4.8.2/DK.1
of the line [m]
u Deflection of the support in the direction of the line at the 4.8.2/DK.1
attachment point of the insulator [m]
d Horizontal conductor swing [m] 5.6.3.2/DK.1
Trang 8y0 Overhead line sag at 0°C [m] 5.6.3.2/DK.1
Ik Distance from the attachment point of the conductor 5.6.3.2/DK.1 and the turning point of the insulator string [m]
3 Basis of design
3.2 Requirements of overhead lines
3.2.2 DK.1 Reliability requirements
(ncpt)
One reliability level generally applies corresponding to level 3
4 Actions on lines
4.1 DK.1 Introduction
(snc)
For assessment of climatic data to determine numerical values for action approach 1 is applied
4.3 Wind loads
4.3.1 DK.1 Field of application and basic wind velocity
(snc)
The basic wind velocity, Vb,0 can be taken as given in Table 4.3.1 below
Table 4.3.1/DK.1 - Reference wind speeds in Denmark Part of the country Reference wind speed
The whole of Denmark, however with the exceptions mentioned below 24 m/s The west coast of Jutland 27 m/s From the west coast line of Jutland
and 25 km inland Linear declination from 27 m/s to 24 m/s Further information can be found in DS/EN 1991-1-4 DK NA
4.3.3 DK.1 Mean wind pressure
(snc)
Density of air of ρ=1.25 kg/m3 is used in Denmark This is independent of temperature and altitude
4.4 Wind forces on overhead line components
4.4.1 Wind forces on conductors
4.4.1.1 DK.1 General
(ncpt)
Method 4 in Table 4.3 should be used for the determination of the reference height above ground, h of the conductors
DK.2 General
(ncpt)
For calculation of the mechanical tension in a section, the equivalent mean section length should be used as the span length
4.4.1.3 DK.1 Drag factor
(npct)
Method 1 or 2 shall be used for determination of the drag factor of the conductors
4.4.3 Wind forces on lattice towers 4.4.3.1 DK.1 General
(npct)
Method 1 should be used for determining the wind forces on the tower itself
4.4.4 DK.1 Wind forces on poles
(ncpt)
Method 2 is used for determination of the reference height for the pole
The reference height should be 60% of the total height
4.5 Ice loads 4.5.1 DK.1 General
(ncpt)
No ice loads apply on insulators or towers
DK.2 Characteristic ice load
(snc)
The characteristic ice load, I, on a conductor with the diameter d in mm is I = 12 + 0.9 d [N/m] The ice is considered as glaze ice For a 30 mm conductor the value reflects a 50-year return period load
Density of ice is 900 kg/m3
4.5.2 DK.1 Ice forces on conductors
(ncpt)
The vertical ice force on a support from each sub-conductor is QI = I (LW1+LW2)/2
4.6 Combined wind and ice loads 4.6.6 Combination of wind velocity and ice loads 4.6.6.1 DK.1 Extreme ice load I T combined with a high probability wind velocity V IH
(snc)
ΨW = 0.4 Only the extreme ice load combined with the reduced wind load have to be investigated, i.e
I = 0
4.6.6.2 DK.1 Nominal ice load l 3 combined with a low probability wind velocity V IL
(snc)
This situation should not be investigated in Denmark
4.7 DK.1 Temperature effects
(snc)
The following temperature effects should be considered:
a) A minimum temperature to be considered with no other climatic action: -20 °C b) A normal ambient reference temperature assumed for the extreme wind velocity condition:
5 °C c+d) Not relevant e) A temperature to be used for the combination of wind and ice: 0 °C
4.8 Security loads
Trang 9y0 Overhead line sag at 0°C [m] 5.6.3.2/DK.1
Ik Distance from the attachment point of the conductor 5.6.3.2/DK.1 and the turning point of the insulator string [m]
3 Basis of design
3.2 Requirements of overhead lines
3.2.2 DK.1 Reliability requirements
(ncpt)
One reliability level generally applies corresponding to level 3
4 Actions on lines
4.1 DK.1 Introduction
(snc)
For assessment of climatic data to determine numerical values for action approach 1 is applied
4.3 Wind loads
4.3.1 DK.1 Field of application and basic wind velocity
(snc)
The basic wind velocity, Vb,0 can be taken as given in Table 4.3.1 below
Table 4.3.1/DK.1 - Reference wind speeds in Denmark Part of the country Reference wind speed
The whole of Denmark, however with the exceptions mentioned below 24 m/s
The west coast of Jutland 27 m/s From the west coast line of Jutland
and 25 km inland Linear declination from 27 m/s to 24 m/s Further information can be found in DS/EN 1991-1-4 DK NA
4.3.3 DK.1 Mean wind pressure
(snc)
Density of air of ρ=1.25 kg/m3 is used in Denmark This is independent of temperature and altitude
4.4 Wind forces on overhead line components
4.4.1 Wind forces on conductors
4.4.1.1 DK.1 General
(ncpt)
Method 4 in Table 4.3 should be used for the determination of the reference height above ground, h of the conductors
DK.2 General
(ncpt)
For calculation of the mechanical tension in a section, the equivalent mean section length should be used as the span length
4.4.1.3 DK.1 Drag factor
(npct)
Method 1 or 2 shall be used for determination of the drag factor of the conductors
4.4.3 Wind forces on lattice towers 4.4.3.1 DK.1 General
(npct)
Method 1 should be used for determining the wind forces on the tower itself
4.4.4 DK.1 Wind forces on poles
(ncpt)
Method 2 is used for determination of the reference height for the pole
The reference height should be 60% of the total height
4.5 Ice loads 4.5.1 DK.1 General
(ncpt)
No ice loads apply on insulators or towers
DK.2 Characteristic ice load
(snc)
The characteristic ice load, I, on a conductor with the diameter d in mm is I = 12 + 0.9 d [N/m] The ice is considered as glaze ice For a 30 mm conductor the value reflects a 50-year return period load
Density of ice is 900 kg/m3
4.5.2 DK.1 Ice forces on conductors
(ncpt)
The vertical ice force on a support from each sub-conductor is QI = I (LW1+LW2)/2
4.6 Combined wind and ice loads 4.6.6 Combination of wind velocity and ice loads 4.6.6.1 DK.1 Extreme ice load I T combined with a high probability wind velocity V IH
(snc)
ΨW = 0.4 Only the extreme ice load combined with the reduced wind load have to be investigated, i.e
I = 0
4.6.6.2 DK.1 Nominal ice load l 3 combined with a low probability wind velocity V IL
(snc)
This situation should not be investigated in Denmark
4.7 DK.1 Temperature effects
(snc)
The following temperature effects should be considered:
a) A minimum temperature to be considered with no other climatic action: -20 °C b) A normal ambient reference temperature assumed for the extreme wind velocity condition:
5 °C c+d) Not relevant e) A temperature to be used for the combination of wind and ice: 0 °C
4.8 Security loads
Trang 104.8.2 DK.1 Torsional loads
(ncpt)
The β-method shall be applied and calculated in accordance with an accepted model, simulating the residual situation after a conductor breakage
Simplified β can be found using the diagram in Figure 4.8.2/DK.1
Figure 4.8.2/DK.1 - Tension reduction factor
where:
2
= σ
γ σ
L E
L
u I E
σ
L the length of the intact span [m]
E the modulus of elasticity of the conductor [N/mm²]
γ the weight of the conductor including possible external load divided by the
cross-sectional area [N/m/mm²]
σ the tensile stress in the conductor prior to breakage [N/mm²]
I the max movement of movable suspension in the direction of the line [m]
u the deflection of the support in the direction of the line at the attachment
point of the insulator [m]
NOTE The basis of the simplified method is reported in CIGRÉ paper 22-10, 1976
The number of released conductors is as follows:
- single and double circuit lines 1
- multiple circuit lines 2 The number of broken sub-conductors in a bundle conductor can be taken as half the sum of sub-conductors
The partial factor, γA1, to be 1.5, however for secondary parts of suspension supports, i.e tower peak and cross-arm peaks which do not support other conductors, the partial factor, γA1, may be reduced to 1.0
4.8.3 DK.1 Longitudinal loads
(ncpt)
The β-method shall be applied and calculated in accordance with an accepted model, simulating the residual situation after breakage of all conductors including all sub-conductors in bundle conductors, overhead ground wires, etc on one side of the support The simplified method as given in 4.8.2/DK.1 can be used
Derived β-values are multiplied by 0.80
4.12 Load cases 4.12.1 DK.1 General
(ncpt)
The same sub clauses shall apply for overhead lines exceeding a nominal system voltage AC 1
kV up to and including AC 45 kV as for overhead lines exceeding a nominal system voltage AC
45 kV
4.12.2 DK.1 Standard load cases
(ncpt)
The following reduction factors shall be used:
α = 0.0 α1 = 0.0 α2 = 0.5 on all spans α3 = 0.0
α4 = 0.0 NOTE Attention should be paid to the limited effect of unbalanced ice loads on suspension supports
as referred to in the note in 4.8.3
4.13 DK.1 Partial factors for actions
(snc)
Partial factors on Torsional security loads are given in section 4.8.2/DK.1
5 Electrical requirements 5.6 Load cases for calculation of clearances 5.6.1 DK.1 Load conditions
(ncpt)
Load cases for calculation of clearances Three different load cases have to be considered in Denmark:
- Maximum conductor temperature (given in 5.6.2/DK.1)
- Nominal wind load (given in 5.6.3.3/DK.1)
- Ice loads (given in 5.6.4/DK.1)
- Extreme Ice load
- Uneven Ice load
The load cases are detailed below
5.6.2 DK.1 Maximum conductor temperature
(ncpt)
The clearances should be based on the maximum continuous service temperature of the conductor specified in the Project Specification
5.6.3 DK.1 Wind loads for determination of electric clearances