BS EN 50341-2-16:2016 BSI Standards Publication Overhead electrical lines exceeding AC kV Part 2-16: National Normative Aspects (NNA) for NORWAY (based on EN 50341-1:2012) BS EN 50341-2-16:2016 BRITISH STANDARD National foreword This British Standard is the UK implementation of EN 50341-2-16:2016 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 Code AT BE CH DE DK ES FI FR GB GR IE IS IT LU NL NO PT SE SK CZ EE SK PL Origin Ref Austrian National Committee Belgian National Committee Swiss National Committee German National Committee Danish National Committee Spanish National Committee Finnish National Committee French National Committee British National Committee Greek National Committee Irish National Committee Iceland National Committee Italian National Committee Luxemburg National Committee Nederland’s National Committee Norwegian National Committee Portuguese National Committee Swedish National Committee Slovak National Committee Czech National Committee Estonian National Committee Slovak National Committee Polish National Committee BS EN 50341-2-1 BS EN 50341-2-2 BS EN 50341-2-3 BS EN 50341-2-4:2016 BS EN 50341-2-5:2017 BS EN 50341-2-6:2017 BS EN 50341-2-7:2015 BS EN 50341-2-8 BS EN 50341-2-9:2015 BS EN 50341-2-10 BS EN 50341-2-11 BS EN 50341-2-12 BS EN 50341-2-13 No NNA available BS EN 50341-2-15 BS EN 50341-2-16:2016 BS EN 50341-2-17 BS EN 50341-2-18 BS EN 50341-2-23:2016 BS EN 50341-2-19:2015 BS EN 50341-2-20:2015 BS EN 50341-2-21:2016 BS EN 50341-2-22:2016 BS EN 50423-3:2005 and BS EN 50341-3:2001 will be withdrawn upon publication of the rest of the series The UK participation in its preparation was entrusted to Technical Committee PEL/11, Overhead Lines A list of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 978 580 92260 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 28 March 2017 Amendments/corrigenda issued since publication Date Text affected BS EN 50341-2-16:2016 EUROPEAN STANDARD EN 50341-2-16 NORME EUROPÉENNE EUROPÄISCHE NORM December 2016 ICS 29.240.20 English Version Overhead electrical lines exceeding AC kV - Part 2-16: National Normative Aspects (NNA) for NORWAY (based on EN 50341-1:2012) Lignes électriques aériennes dépassant kV en courant alternatif - Partie 2-16 : Aspects Normatifs Nationaux pour la NORVEGE (Basé sur l'EN 50341-1:2012) This European Standard was approved by CENELEC on 2016-09-13 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 50341-2-16:2016 E BS EN 50341-2-16:2016 EN 50341-2-16:2016 EN 50341-2-16:2016 BS EN 50341-2-16:2016 – 2/31 – -2/31 - Contents Foreword Scope Normative references, definitions and symbols 2.1 NO.1 Normative references NO.1 Basis of design 3.2 Requirements of overhead lines 3.2.1 NO.1 Basic requirements Actions on lines 4.1 NO.1 Introduction 4.2 NO.1 Permanent loads 4.3 NO.1 Wind Loads 4.3.1 NO.1 Field of application and basic wind velocity 4.3.2 NO.1 Mean wind velocity 4.3.3 NO.1 Mean wind pressure 4.3.4 NO.1 Turbulence intensity and peak wind pressure 4.3.5 NO.1 Wind forces on any overhead line component 4.4 Wind forces on overhead line components 4.4.1 NO.1 Wind forces on conductors 4.4.1.1 NO.1 General 4.4.1.2 NO.1 Structural factor 4.4.1.3 NO.1 Drag factor 4.4.2 NO.1 Wind forces on insulator sets 4.4.3 NO.1 Wind forces on lattice towers 10 4.4.4 NO.1 Wind forces on poles 10 4.5 Ice loads 10 4.5.1 NO.1 General 10 4.5.2 NO.1 Ice forces on conductors 10 4.6 NO.1 Combined wind and ice loads 11 4.6.1 NO.1 Combined probabilities 11 4.6.2 NO.1 Drag factors and ice densities 11 Norway Norway – 3/31 – -3/31 - Norway Norway BS EN 50341-2-16:2016 BS EN 50341-2-16:2016 EN 50341-2-16:2016 EN 50341-2-16:2016 4.6.3 NO.1 Mean wind pressure and peak wind pressure 12 4.6.4 NO.1 Equivalent diameter D of ice covered conductor 13 4.6.5 NO.1 Wind forces on support for ice covered conductors 13 4.6.6 Combination of wind velocities and ice loads 13 4.6.6.1 NO.1 Extreme ice load IT combined with a high probability wind velocity VIH13 4.6.6.2 NO.1 Nominal ice load I3 combined with a low probability wind velocity VIL13 4.7 NO.1 Temperature effects 13 4.8 Security loads 14 4.8.1 NO.1 General 14 4.8.2 NO.1 Torsional loads 14 4.8.3 NO.1 Longitudinal loads 14 4.8.4 NO.1 Mechanical conditions of application 14 4.9 Safety Loads 14 4.9.1 NO.1 Construction and maintenance loads 14 4.9.2 NO.1 Loads related to the weight of linesmen 15 4.10 NO.1 Forces due to short-circuit currents 15 4.11 Other special forces 15 4.11.1 NO.1 Avalanches, creeping snow 15 4.11.2 NO.1 Earthquakes 15 4.12 Load cases 16 4.12.1 NO.1 General 16 4.12.2 NO.1 Standard load cases 16 4.13 NO.1 Partial factors for actions 17 Electrical requirements 21 5.6 Load cases for calculation of clearances 21 5.6.1 NO.1 Load conditions 21 5.8 Internal clearances within the span and at the top of support 22 5.9 NO.1 External clearances 24 Earthing systems 24 6.2 Ratings with regard to corrosion and mechanical strength 24 6.2.2 NO.1 Earthing and bonding conductors 24 6.4 Dimensioning with regard to human safety 24 6.4.1 NO.1 Permissible values 24 Supports 25 BS EN 50341-2-16:2016 EN 50341-2-16:2016 EN 50341-2-16:2016 BS EN 50341-2-16:2016 7.1 – 4/31 – -4/31 - Initial design consideration 25 7.1.1 NO.1 Introduction 25 7.1.2 NO.1 Structural design resistance of a pole 25 7.1.3 NO.1 Buckling resistance 25 7.2 NO.1 Materials 25 7.3 NO.1 Lattice steel towers 25 7.3.6 NO.1 Ultimate limit states 26 7.3.6.1 NO.1 General 26 7.4 NO.1 Steel poles 26 7.5 Wood poles 26 7.5.5 Ultimate limit states 26 7.5.5.1 NO.1 Basis 26 7.5.7 NO.1 Resistance of connections 26 7.6 NO.1 Concrete poles 27 7.7 NO.1 Guyed structures 27 7.7.1 NO.1 General 27 7.7.4 Ultimate limit states 27 7.7.4.1 NO.1 Basis 27 7.8 Other structures 27 7.9 NO.1 Corrosion protection and finishes 27 Foundations 27 8.2 Basis of geotechnical design by (EN 1997-1:2004 – Section2) 27 8.2.3 Design by prescriptive measures 27 10 Conductors, earthwires and telecommunication cables 30 Insulators 30 10.7 11 Hardware 31 11.6 12 NO.1 Mechanical requirements 31 NO.1 Mechanical requirements 31 Quality assurance, checks and taking-over 31 Norway Norway Norway Norway – 5/31 – -5/31 - BS EN 50341-2-16:2016 BS EN 50341-2-16:2016 EN 50341-2-16:2016 EN 50341-2-16:2016 European foreword The Norwegian National Committee (NC) is identified by the following address: Norsk Elektroteknisk Komité Mustads vei 1, NO-0283 Oslo Phone no +47 67 83 31 00 E-mail: Nek@nek.no The Norwegian NC has prepared this Part 2-16 of EN 50341-1:2012, listing the Norwegian national normative aspects, under its sole responsibility, and duly passed it through the CENELEC and CLC/TC 11 procedures NOTE The Norwegian NC also takes sole responsibility for the technically correct coordination of this EN 50341-2-16 with EN 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 This EN 50341-2-16 is normative in Norway and informative for other countries This EN 50341-2-16 has to be read in conjunction with EN 50341-1:2012, hereinafter referred to as Part All clause numbers used in this Part 2-16 correspond to those of Part Specific subclauses, which are prefixed “NO”, are to be read as amendments to the relevant text in Part Any necessary clarification regarding the application of Part 2-16 in conjunction with Part shall be referred to the Norwegian NC who will, in cooperation with CLC/TC 11 clarify the requirements When no reference is made in Part 2-16 to a specific subclause, then Part applies In the case of “boxed values” defined in Part 1, amended values (if any) which are defined in Part 2-16 shall be taken into account in Norway However any “boxed values“, whether in Part or Part 2-16, shall not be amended in the direction of greater risk in a Project Specification The national Norwegian standards/regulations related to overhead electrical lines exceeding kV (AC) are identified in 2.1/NO1 NOTE All national standards referred to in this Part 2-16 will be replaced by the relevant European Standards as soon as they become available and are declared by the Norwegian NC to be applicable and thus reported to the secretary of CLC/TC 11 BS EN 50341-2-16:2016 EN 50341-2-16:2016 EN 50341-2-16:2016 BS EN 50341-2-16:2016 Clause (snc) – 6/31 – - 6/31- Norway Norway National regulation Scope This Part 2-16 is applicable for new permanent overhead lines only and generally not for existing lines in Norway If some planning/design or execution work on existing lines in Norway has to be performed, the degree of application of this Standard shall be agreed upon by the parties concerned and the authorities Normative references, definitions and symbols 2.1 NO.1 Normative references (A-dev) These references shall be added to the list: Act No of 24 May 1929 of Supervision of Electrical Installations and Electrical Equipment Regulations for Electrical Installations – system for generating, transmission and distribution The Norwegian Regulations FEF 2006 Guidelines to the Norwegian Regulations FEF 2006 If newer acts and regulations are issued, the ones mentioned above shall be replaced with the valid version (snc) NO.1 Basis of design Unless mentioned below, the clauses 3.1 - 3.7.4 may be considered as informative 3.2 Requirements of overhead lines 3.2.1 NO.1 Basic requirements (snc) Generally minimum 50 year return periods shall be applied as basic loads Actions on lines 4.1 NO.1 Introduction (snc) May be considered as informative (snc) NO.2 Types of load Permanent loads include self-weight of supports, insulator sets, other fixed equipment and of the conductors from the adjacent spans Aircraft warning spheres and similar elements are also to be considered as permanent loads Climatic loads include wind, ice and combined wind and ice loads on conductors, insulator sets, lattice towers and poles – 7/31 – - 7/31- Norway Norway Clause BS EN 50341-2-16:2016 BS EN 50341-2-16:2016 EN 50341-2-16:2016 EN 50341-2-16:2016 National regulation Security loads include wire breakage Safety loads take the safety to the linesmen into consideration and also prevent collapse of the support by including load cases that may occur during construction and maintenance Other loads may include forces that occur due to short-circuit currents, avalanches, creeping snow, earthquakes etc 4.2 (snc) NO.1 Permanent loads Mentioned in clause 4.1 NO.2 4.3 (snc) NO.1 Wind Loads The text in Main Body may be considered as informative 4.3.1 NO.1 Field of application and basic wind velocity (snc) EN 1991-1-4 should normally be applied, alternatively wind velocities and their return periods may be asessed by an experienced meteorologist, and include effects of gust, height above ground, topography and the direction of the power line relative to that of the wind 4.3.2 NO.1 Mean wind velocity (snc) EN 1991-1-4 should normally be applied The wind velocity of 10 m above ground may be considered constant up to 20 m above ground In fjords or valleys the given wind velocities in EN 1991-1-4 apply for a line direction parallel to the main direction of the fjord or valley If the line direction is perpendicular to the fjord/valley direction, or if the line along a fjord/valley passes the mouth of a branch fjord/valley, the calculated wind velocity shall be multiplied by 1,2 The calculated values may generally be deviated from if separate evaluations are made by meteorologist In areas where strong winds are known to occur or may be expected, it is recommended that a meteorologist should be consulted 4.3.3 NO.1 Mean wind pressure (snc) EN 1991-1-4 should normally be applied BS EN 50341-2-16:2016 EN 50341-2-16:2016 EN 50341-2-16:2016 BS EN 50341-2-16:2016 Clause – 8/31 – - 8/31- Norway Norway National regulation 4.3.4 NO.1 Turbulence intensity and peak wind pressure (snc) EN 1991-1-4 should normally be applied In such case the wind velocity shall include the effects of gust For wind on the conductors an average direction factor of 0,9 may be applied to reduce the wind velocity when EN 1991-1-4 is applied This reduction factor does not apply for wind pressure on the towers or any of their components 4.3.5 NO.1 Wind forces on any overhead line component (snc) The value of the wind force, QW due to wind blowing horizontally at reference height above ground, h, perpendicular to any line component, is given by: QW = 0,5ρ(VT)² C A ρ = The air density Normally considered constant as 1,292 kg/m3 VT = The wind velocity with return period T C A = The drag factor (or force coefficient) depending on the shape of the line component being considered = The area of the line component being considered, projected on a plane perpendicular to the wind direction To arrive at the actual design values according to the reliability class, the values of wind velocity or wind pressure have to be factored with their respective conversion factor given in Table 4.3.5/NO.1 Table 4.3.5/NO.1 Return period T Conversion factor VT/V50 50 150 500 0,763 1,000 1,087 1,182 4.4 Wind forces on overhead line components 4.4.1 NO.1 Wind forces on conductors (snc) Conversion factor qT/q50 0,58 1,00 1,18 1,40 Wind pressure on conductors gives forces transversal to the direction of the line as well as higher tension in the conductors In addition to the components from the BS EN 50341-2-16:2016 EN 50341-2-16:2016 EN 50341-2-16:2016 BS EN 50341-2-16:2016 Clause T1 – 20/31 – - 20/31- Norway Norway National regulation T2 gs2 gs1 gs1 gs1 gs1 gs1 gs1 gs1 S3 T2 S3 S2 T1 S2 S1 gs2 gs2 gs2 gs1 gs1 gs1 gs2 gs1 gs2 gs1 gs1 gs1 gs1 S1 S3 T2 S2 T1 gs2 gs2 gs2 gs2 gs2 gs1 gs1 gs1 S1 T gs1 S3 S6 S2 S5 S1 S4 gs1 gs1 gs1 gs1 S4,5,6 T gs2 gs2 gs2 gs2 gs1 gs1 gs1 gs1 gs2 gs1 gs1 gs1 gs1 S1,2,3 S4,5,6 T gs2 gs2 gs2 gs2 gs2 S1,2,3 Figure 4.12.2 / NO.3 Unbalanced ice loads giving torsion The values of the ice loads are: gs1 = 0,7 IT, gs2 = 0,3 IT – 21/31 – - 21/31- Norway Norway Clause National regulation Electrical requirements 5.6 Load cases for calculation of clearances 5.6.1 NO.1 (snc) BS EN 50341-2-16:2016 BS EN 50341-2-16:2016 EN 50341-2-16:2016 EN 50341-2-16:2016 Load conditions Load case Specification Conductor temperature Min 50 °C Earth wire temperature Min 50 °C Ice load on all conductors Min 50 year return period Ice load train 1) Min 50 year return period Wind load on all conductors Min 50 year return period 1) To be placed in the most unfavourable span in each section More conservative values may be specified in the Project Specification - 22/31- Dpp I50 k1 Del Del Del Phase conductor earth-wire k1 Dpp Dpp Dpp Between phases and/or circuits Del k1 Del Del Del Between phase conductors and earthed parts At the top of support Overvoltage The factor k1 is dependent on mechanical loading conditions, but should not be less than 0,6 Load conditions in still air Load conditions in still air Remarks Norway If lines with similar conductors (same cross-sectional area, material, construction and sag) are to be considered there are approximation methods to calculate the required clearance within the span in still air to ensure that clearances are not infringed in windy conditions (see Annex F.1) NOTE: EN 50341-1 is to be used for voltage ≥ 275 kV 0,55 V50 V50 V3 k1 Dpp Dpp Maximum conductor temperature V50 Phase conductor phase conductor Load Case Within the span Clearance cases (m) Table 5.8 NO.1 Minimum internal clearances within the span and at the top of support for bare conductors