Bsi bs en 50341 2 6 2017

BS EN 50341-2-6:2017 BSI Standards Publication Overhead electrical lines exceeding AC kV Part 2-6: National Normative Aspects (NNA) for SPAIN (based on EN 50341-1:2012) BS EN 50341-2-6:2017 BRITISH STANDARD National foreword This British Standard is the UK implementation of EN 50341-2-6:2017 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 Code AT BE CH DE DK ES FI FR GB GR IE IS IT LU NL NO PT SE CZ EE PL SK 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 Czech National Committee Estonian National Committee Polish National Committee Slovak 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 50341-2-13:2017 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 50341-2-19:2015 BS EN 50341-2-20:2015 BS EN 50341-2-22:2016 BS EN 50341-2-23:2016 BS EN 50423-3:2005 and BS EN 50341-3:2001 will be withdrawn upon publication of the rest of the series The UK participation in its preparation was entrusted to Technical Committee PEL/11, Overhead Lines A list of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 97922 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 30 April 2017 Amendments/corrigenda issued since publication Date Text affected BS EN 50341-2-6:2017 EN 50341-2-6 EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM February 2017 ICS 29.240.20 English Version Overhead electrical lines exceeding AC kV - Part 2-6: National Normative Aspects (NNA) for SPAIN (based on EN 50341-1:2012) Lignes électriques aériennes dépassant kV en courant alternatif - Partie 2-13: Aspects normatifs nationaux (NNA)pour l'ESPAGNE (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 50341-2-6:2017 E BS EN 50341-2-6:2017 EN 50341-2-6:2017 -2- Spain Contents 1.1 Page SCOPE General 1.2 Field of application 2.1 NORMATIVE REFERENCES, DEFINITIONS AND SYMBOLS Normative references 2.3 Symbols 3.2 BASIS OF DESIGN Requirements of overhead lines 3.2.2 Reliability requirements 3.2.5 Strength coordination 3.6 Design values 3.6.2 Design value of an action 3.6.3 Design value of a material property 3.7 Partial factor method and design formula 3.7.2 Basic design formula 4.1 ACTIONS ON LINES Introduction 4.2 Permanent loads 4.3 Wind loads 4.3.1 Field of application and basic wind velocity 4.3.5 Wind forces on any overhead line component 4.4 Wind forces on overhead line components 10 4.5 Ice loads 10 4.5.2 Ice forces on conductors 10 4.7 Temperature effects 10 4.8 Security loads 10 4.8.1 General 10 4.8.2 Torsional loads 11 4.8.3 Longitudinal loads 11 4.12 Load cases 12 4.12.1 General 12 4.12.2 Standard load cases 12 4.13 5.2 Partial factors for actions 12 ELECTRICAL REQUIREMENTS 13 Currents 13 5.2.1 Normal current 13 5.3 Insulation co-ordination 14 5.4 Classification of voltages and overvoltages 17 Spain -3- 5.4.2 BS EN 50341-2-6:2017 EN 50341-2-6:2017 Page Representative power frequency voltages 17 5.5 Minimum air clearance distances to avoid flashovers 18 5.6 Load cases for calculation of clearances 19 5.6.1 Load conditions 19 5.8 Internal clearances within the span and at the top of support 19 5.9 External clearances 21 6.1 5.9.1 General 21 5.9.2 External clearances to ground in areas remote from buildings, roads, etc 22 5.9.3 External clearances to residential and other buildings 23 5.9.4 External clearances to crossing traffic routes 24 5.9.5 External clearances to adjacent traffic routes 25 5.9.6 External clearances to other power lines or overhead telecommunication lines 26 5.9.7 External clearances to recreational areas (playgrounds, sports areas, etc.) 29 EARTHING SYSTEMS 29 Introduction 29 6.1.2 Requirements for dimensioning of earthing systems 29 6.1.3 Earthing measures against lightning effects 30 6.2 Ratings with regards to corrosion and mechanical strength 30 6.2.2 6.3 Earthing and bonding conductors 30 Dimensioning with regard to thermal strength 30 6.3.1 General 30 6.3.2 Current rating calculation 31 Dimensioning with regard to human safety 31 6.4 6.4.1 Permissible values for touch voltage 31 6.4.3 Basic design of earthing systems with regard to permissible touch voltage 31 6.5 Site inspection and documentation of earthing systems 32 7.2 SUPPORTS 33 Materials 33 7.2.1 Steel materials, bolts, nuts and washers, welding consumables 33 7.2.5 Concrete and reinforced steel 33 7.2.6 Wood 33 7.3 Lattice steel towers 33 7.3.1 General 33 7.3.6 Ultimate limit states 34 7.3.8 Resistance of connections 34 7.3.9 Design assisted by testing 34 7.4 Steel poles 35 7.4.1 General 35 7.4.2 Basis of design (EN 1993-1-1:2005 - Chapter 2) 35 7.4.6 Ultimate limit states (EN 1993-1-1:2005 - Chapter 6) 35 7.4.8 Resistance of connections 35 BS EN 50341-2-6:2017 EN 50341-2-6:2017 7.4.9 7.5 -4- Spain Page Design assisted by testing 35 Wood poles 36 7.5.1 General 36 7.5.2 Basis of design 36 7.5.5 Ultimate limit states 36 7.6 Concrete poles 36 7.6.1 General 36 7.6.4 Ultimate limit states 36 7.6.5 Serviceability limit states 36 7.6.6 Design assisted by testing 36 7.7 Guyed structures 37 7.7.1 General 37 7.7.4 Ultimate limit states 37 7.8 Other structures 37 8.1 FOUNDATIONS 37 Introduction 37 8.2 Basis of geotechnical design (EN 1997-1:2004 - Section 2) 37 8.2.2 Geotechnical design by calculation 37 8.3 Soil investigation and geotechnical data (EN 1997-1:2004 - Section 3) 39 8.6 Interactions between support foundations and soil 40 CONDUCTORS AND EARTH-WIRES 40 9.2.4 Mechanical requirements 40 9.6 General requirements 40 9.6.2 Partial factor for conductors 40 10 INSULATORS 40 10.2 Standard electrical requirements 40 10.7 Mechanical requirements 40 11 HARDWARE 41 11.6 Mechanical requirements 41 11.9 Characteristics and dimensions of fittings 41 Tables Table 5.2.1/ES.1 – Conductor current density Table 5.3.1/ES.1 – Standard insulation levels for range I (1 kV < Um ≤ 245 kV) Table 5.3.2/ES.1 – Standard insulation levels for range II (Um > 245 kV) Table 5.3.3/ES.1 – Recommended air clearances Table 5.4/ES.1 – Nominal voltages and highest grid voltages Table 5.5/ES.1 – Minimum air clearance distances, Del and Dpp, to avoid flashover Table 5.8/ES.1 – Coefficient K based on the oscillation angle Table 5.9.6/ES.1 – Additional clearances, Dadd, to other overhead power lines or overhead telecommunication lines Table 8.3/ES.1 – Indicative soil characteristics for the calculation of the foundation Table G.6/ES.1 – Fault duration related to touch voltage, UTp Spain -5- BS EN 50341-2-6:2017 EN 50341-2-6:2017 European foreword The Spanish National Committee (NC) is identified by the following address: Asociación Espola de Normalización (UNE) c/Génova, E 28004 Madrid Spain Tel nº: + 34 915 294 900 Fax nº: + 34 91 310 45 96 Email: info@une.org Name of the relevant technical body: AEN/CTN 207/SC 7-11 “Líneas eléctricas ắreas” (Overhead power lines) The Spanish NC and its technical body AEN/CTN 207/SC 7-11 “Overhead power lines” has prepared this Part 2-6 of EN 50341, listing the Spanish National Normative Aspects (NNA) under its sole responsibility, and duly passed it through the CENELEC and CLC/TC 11 procedures NOTE: The Spanish NC also takes sole responsibility for the technically correct co-ordination of this EN 50341-26 with EN 50341-1 It has performed the necessary checks in the frame of quality assurance/control However, it is noted that this quality control has been made in the framework of the general responsibility of a standards committee under the national laws/regulations This Part 2-6 is normative in Spain and informative in other countries This document shall be read in conjunction with Part (EN 50341-1) All clause numbers used in this NNA correspond to those of Part Specific sub-clauses that are prefixed “ES”, are to be read as amendments to the relevant text in Part Any necessary clarification regarding the application of this combined NNA in conjunction with Part shall be referred to the Spanish NC who will, in co-operation with CLC/TC 11, clarify the requirements When no reference is made in this NNA to a specific sub-clause, then Part applies In case of “boxed values” defined in Part 1, amended values (if any), which are defined in this NNA, shall be taken into account in Spain However, any “boxed value”, whether in Part or in this NNA, shall not be amended in the direction of greater risk in a Project Specification The national Spanish standards/regulations related to overhead electrical lines exceeding kV A.C are listed in sub-clause 2.1/ES.1 and ES.2 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 Spanish NC to be applicable and thus reported to the secretary of CLC/TC 11 The Spanish NC declares, in accordance with sub-clause 4.1 of Part 1, that “Approach 3” shall be used in Spain to stablish numerical values of actions BS EN 50341-2-6:2017 EN 50341-2-6:2017 Scope 1.1 General (ncpt) ES.1 -6- Spain General This NNA is applicable to any new line between two points, A and B, its modifications and extensions 1.2 Field of application (A-dev) ES.1 RD 223/2008, ITC-LAT 08, sub-clause 6.3.2 The design and construction of overhead lines with covered conductors and voltages greater than 45 kV shall respect the same electrical clearances as of overhead lines with bare conductors of the same voltage Normative references, definitions and symbols 2.1 Normative references (A-dev) ES.1 National normative regulations Royal Decree (RD) 223/2008, of 15th February 2008, approving the Regulation on technical and safety conditions for high voltage electrical lines and its Supplementary Technical Instructions ITCLAT 01 to 09 Royal Decree (RD) 337/2014, of 9th May 2014, approving the Regulation on technical and safety conditions for high voltage power installations and its Supplementary Technical Instructions ITCRAT 01 to 23 Royal Decree (RD) 614/2001, of 8th June 2001, establishing the minimum health and safety requirements for the protection of workers against the electrical risk Royal Decree (RD) 1955/2000, of 1st December 2000, regulating the activities of transmission, distribution, marketing and supply of electrical energy and the procedures for the authorization of installations (ncpt) ES.2 National normative standards UNE 207016 “HV and HVH type concrete poles for overhead electrical lines” UNE 207017 “Lattice steel towers for distribution overhead electrical lines” UNE 207018 “Plate metallic supports for overhead electrical lines” 2.3 Symbols (ncpt) ES.1 Additional symbols asom minimum insulator set discharge gap, defined as shortest distance in straight line between live parts and earthed parts wind exposed pole area projected in a wind direction perpendicular plane in m2 minimum security factor defined for each element and load case clearance between same or different circuits’ phase conductors in metres maximum sag in metres, for load cases defined in sub-clause 3.2.3 coefficient depending on the conductors’ wind oscillation, it shall be selected from Table 5.8/ES.1 coefficient depending on overhead lines nominal voltage K’ = 0,85 for special category lines and K’ = 0,75 for other overhead lines suspension set length in metres For conductors attached to the pole with strain or postinsulator sets L = AT CS D F K K’ L Spain -7VV BS EN 50341-2-6:2017 EN 50341-2-6:2017 reference wind velocity in km/h Basis of design 3.2 Requirements of overhead lines 3.2.2 Reliability requirements (A-dev) ES.1 RD 223/2008, clause 16 For private overhead lines, a competent licensed technician, with the authorization of overhead line’s owner, may adopt in emergency situations the recommended provisional steps, immediately advising to the competent Administration body, which shall set the period to restore the regulation conditions (ncpt) ES.2 Reliability levels The minimum reliability level shall be Actions for wind and ice are defined in section 3.2.5 Strength coordination (snc) ES.1 Strength coordination Strength coordination is obtained by matching the security factors (CS) associated to each component and system of the overhead line 3.6 Design values 3.6.2 Design value of an action (A-dev) ES.1 Design value of an action Actions shall not be affected by partial factors 3.6.3 Design value of a material property (A-dev) ES.1 Partial factor for a material property The partial factor for a material property shall be: Xd = XK / CS Where: Xd XK CS is the design value of the material property is the characteristic value of the material property is the minimum security factor for each element and load case defined in sub-clause 4.13/ES.1 3.7 Partial factor method and design formula 3.7.2 Basic design formula (snc) ES.1 Basic design formula When considering a limit state of rupture or excessive deformation of a component, element or connection, it shall be verified that: Rd / Ed ≥ CS Where: BS EN 50341-2-6:2017 EN 50341-2-6:2017 Ed Rd CS -8- Spain is the total design value of the effect of actions, such as internal force or moment, or a representative vector of several internal forces or moments, as defined in sub-clause 3.7.2 of the main body is the corresponding structural design resistance, as defined in sub-clause 3.7.2 of the main body is the minimum security factor for each element and load case defined in clause 4.13/ES.1 Actions on lines 4.1 Introduction (snc) ES.1 Introduction Due to the lack, in general, of official statistical data, in Spain Approach shall be used to stablish the numerical values of actions 4.2 Permanent loads (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 3.1.1 Vertical loads on account of own weight of each element shall be taken into account: conductors, insulators, fittings, ground wires – if they exist –, poles and foundations 4.3 Wind loads 4.3.1 Field of application and basic wind velocity (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 3.1.2 A minimum reference wind velocity of 120 km/h (33.3 m/s) shall be considered, except in lines with voltages of 220 kV and above, or lower voltages which are considered part of the transmission grid, in which a minimum reference wind velocity of 140 km/h (38.89 m/s) shall be considered This reference wind velocity (VV) shall mean horizontal, acting perpendicular to the areas concerned 4.3.5 Wind forces on any overhead line component (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 3.1.2.4 In the case of a flat surface, the wind force, QWx, shall be at least: V  QWx = 100 ⋅  V   120  ⋅ Ax daN Where: (A-dev) VV Ax is the reference wind velocity in km/h is the area of the flat surface projected in a perpendicular plane to the wind direction, in m2 ES.2 RD 223/2008, ITC-LAT 07, sub-clause 3.1.2.5 In the case of a cylindrical surface, the wind force, QWx, shall be, at least: QWx V  = 70 ⋅  V   120  ⋅ Ax daN BS EN 50341-2-6:2017 EN 50341-2-6:2017 - 32 - Spain Ra = Ra1 + Ra = 1000 + 1,5 ρ S These supports are those placed at locations where it can be reasonably assumed that people are wearing shoes, like pavements of public roads, parking places, etc b) Frequented supports without shoes: just the resistance to ground at the point of contact shall be considered as additional resistance, Ra2 Additional resistance of footwear, Ra1, is void Ra = Ra = 1,5 ρ S These supports are those placed at locations where people may gather with bare feet, such as gardens, swimming pools, camping sites, recreational areas • (A-dev) Unfrequented supports Those placed in locations where towers are not freely accessible or where access by people will be rare ES.3 RD 223/2008, ITC-LAT 07, sub-clause 7.3.4.3, Figure (3) However, the value of the earthing resistance shall be low enough to ensure the performance of the protections in the case of a earth fault (A-dev) ES.4 RD 223/2008, ITC-LAT 07, sub-clause 7.3.4.3, Figure (6)-(7) The earthing designer shall check by a calculation procedure sanctioned by the practice that the estimated touch voltage value, U’ca, a metre away from the structure, for the projected installation depending on the geometry of the same, on the earthing current and on the resistivity corresponding to soil, not exceed, in the most unfavorable conditions, the admissible values indicated in sub-clause 6.4.1 The calculation methods and values of touch voltages shall be specified in the project specifications (A-dev) ES.5 RD 223/2008, ITC-LAT 07, sub-clause 7.3.4.3, Figure (8) These measures may be included in the project specifications When additional security measures are used to prevent contact with metallic parts connected to earth (for example anti-climbing devices of brick factory) there is no need to calculate the value of touch voltages, but it will be needed fulfilling the maximum permissible step voltages 6.5 Site inspection and documentation of earthing systems (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 7.2.1 The type or model, dimensions and position (under the ground surface) of the earth electrodes must be clearly marked on a site plan that will be part of the execution project of the line, so that it can be approved by the competent authority of the administration (A-dev) ES.2 RD 223/2008, ITC-LAT 07, sub-clause 7.2.1 Once built the earthing system and to be more certain that its design is correct regarding people safety, on-site accurate verifications and testing shall be done In order to verify that the maximum values of applied touch voltage is less or equal than the maximum permissible values specified in sub-clause 6.4.1, these verifications will take place in unfrequented supports without automatic interrupting devices and in all frequented supports On the lines of third category the measure of touch voltages may be replaced by measures of the earthing resistance, provided that it has been established a correlation, sanctioned by experience, between the values of touch voltage and earthing resistance Spain - 33 - Supports 7.2 Materials 7.2.1 Steel materials, bolts, nuts and washers, welding consumables (A-dev) ES.1 BS EN 50341-2-6:2017 EN 50341-2-6:2017 RD 223/2008, ITC-LAT 07, sub-clause 2.4.2 The technical characteristics of their components (angles, plates, fasteners, galvanization, etc.) shall fulfil the appropriate UNE standards (as indicated in ITC-LAT 02, RD 223/2008) or, in their absence, other standards or renown technical specifications 7.2.5 Concrete and reinforced steel (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 2.4.3 The use of reinforced vibrated concrete poles is preferred, manufactured with highest quality materials, according to the types and characteristics indicated in the appropriate UNE standards according to ITC-LAT 02, RD 223/2008 7.2.6 Wood (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 2.4.4 Predominantly, pinewood from the species Pinus sylvestris, Pinus nigra and Pinus uncinata shall be used, according to their technical characteristics indicated in the appropriate UNE standards according to ITC-LAT 02, RD 223/2008 7.3 Lattice steel towers 7.3.1 General (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 2.4.2 For steel supports, as well as for metallic elements of supports of different nature, the use of open steel profiles with thickness thinner than four millimetres is not allowed Whether those profiles are hot dip galvanized, the previous limit may be reduced to three millimetres In the same way, for bolted construction it is not allowed the use of holes on leg angles with length shorter than 35 mm Whenever a member of the base of the tower is sunk into the ground without a concrete cover case of metallic foundations-, the thickness of the buried profiles shall not be thinner than six millimetres Screws with a diameter shorter than 12 mm are not allowed Water accumulation inside closed steel profiles shall be avoided Under these conditions, the minimum wall thickness shall not be thinner than three millimetres This limit may be reduced to two and a half millimetres whether steel profiles are hot dip galvanized Steel buried profiles without concrete cover shall be specially protected against corrosion, by using suitable protective agents, such as galvanization, bituminous solutions, tar, etc The use of corrosion protection of maximum duration is recommended, in response to the difficulties of subsequent necessary conservation treatments Towers at locations which are freely accessible to people and where the presence of outsiders to the electrical installation is common, shall incorporate the appropriate measures so that climbing the support to a minimum height of 2,5 m is prevented BS EN 50341-2-6:2017 EN 50341-2-6:2017 7.3.6 Ultimate limit states (A-dev) ES.1 - 34 - Spain RD 223/2008, ITC-LAT 07, clause 3.5, Ultimate limit states Structural analysis of supports, whatever their nature and their elements are, shall be made assuming that they stand the loads set in the following clauses and with the security coefficients mentioned in clause in every load case Ultimate limit states to consider in the structural analysis of supports are: a) Rupture (collapse) b) Creep (permanent deformation) c) Instability (buckling or general instability) d) Resilience (low-temperature resistance) (A-dev) ES.2 RD 223/2008, ITC-LAT 07, sub-clause 3.5.2, Structural properties of materials Main property of materials is the ultimate load or the yield point, as appropriate, with its minimum guaranteed value The yield point of steel shall be considered equal to the conventional elastic limit The members used shall be made of steel, whose conventional elastic limit shall be equal or greater than 275 N/mm2, according to EN 10025 For the calculation of the metallic elements of the supports, the designer shall use any method sanctioned by practice provided that it has a wide experience on its application, confirmed by tests The maximum allowable slenderness is: a) Leg members: 150 b) Bracing members: 200 c) Redundant members: 250 (A-dev) ES.3 RD 223/2008, ITC-LAT 07, sub-clause 3.5.4, Security coefficients Security coefficients of supports shall be different according to the nature of the load case In this respect, load cases are classified as normal and abnormal Metallic elements: the security coefficient regarding the yield point shall not be lower than 1,5 in normal load cases or 1,2 in abnormal load cases 7.3.8 Resistance of connections (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 3.5.2 For connections of the metallic elements, the ultimate failure limits of elements shall be as follows, regarding the yield point of the material: a) calibrated screws subjected to shear: 1,0 b) Angles subjected to bearing with calibrated screws: 2,5 c) Screws subjected to tension: 0,8 The minimum screws class shall be 5.6 according to EN-ISO 898-1 and EN 20898-2, with a yield point equal to 300 N/mm2 For welded connections, the ultimate failure limit shall be that established for each type of welding in the corresponding standard UNE 14035 “Weld bead calculation required by static charges” 7.3.9 Design assisted by testing (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 3.5.4 Spain - 35 - BS EN 50341-2-6:2017 EN 50341-2-6:2017 Metallic elements: the security coefficient regarding the yield point shall not be lower than 1,5 in normal load cases or 1,2 in abnormal load cases Whenever the calculated resistance of complete towers is experimentally validated by full-scale tests, the above values may be reduced to 1,45 and 1,15 respectively 7.4 Steel poles 7.4.1 General (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 2.4.2 The metal supports shall present adequate characteristics to the function performed The technical characteristics of their components (angles, plates, fasteners, galvanization, etc.) shall fulfil the appropriate UNE standards (as indicated in ITC-LAT 02, RD 223/2008) or, in their absence, other recognized standards or technical specifications 7.4.2 Basis of design (EN 1993-1-1:2005 - Chapter 2) (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 3.5.2 For the calculation of the metallic elements of the supports, the designer shall use any method sanctioned by practice provided that it has a wide experience on its application, confirmed by tests 7.4.6 Ultimate limit states (EN 1993-1-1:2005 - Chapter 6) (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 3.5.4 Metallic elements: the security coefficient regarding the yield point shall not be lower than 1,5 in normal load cases or 1,2 in abnormal load cases 7.4.8 Resistance of connections (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 3.5.2 For connections of the metallic elements, the ultimate failure limits of elements shall be as follows, regarding the yield point of the material: a) calibrated screws subjected to shear: 1,0 b) Angles subjected to bearing with calibrated screws: 2,5 c) Screws subjected to tension: 0,8 The minimum screws class shall be 5.6 according to EN ISO 898-1 and EN 20898-2, with a yield point equal to 300 N/mm For welded connections, the ultimate failure limit shall be that established for each type of welding in the corresponding standard UNE 14035 “Weld bead calculation required by static charges" 7.4.9 Design assisted by testing (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 3.5.4 Metallic elements: the security coefficient regarding the yield point shall not be lower than 1,5 in normal load cases or 1,2 in abnormal load cases Whenever the calculated resistance of complete towers is experimentally validated by full-scale tests, the above values may be reduced to 1,45 and 1,15 respectively BS EN 50341-2-6:2017 EN 50341-2-6:2017 7.5 Wood poles 7.5.1 General (A-dev) ES.1 - 36 - Spain RD 223/2008, ITC-LAT 07, sub-clause 2.4.4 Predominantly, pinewood from the species Pinus sylvestris, Pinus nigra and Pinus uncinata shall be used, according to their technical characteristics indicated in the appropriate UNE standards according to ITC-LAT 02, RD 223/2008 However, supports made in accordance with other standards and with similar characteristics may be used, after approval by the competent organs of the Public Administration 7.5.2 Basis of design (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 3.5.2 In case of not knowing their exact features, a failure load of 500 daN/cm2 for wood from conifers, and 400 daN/cm2 for wood from chestnut may be used as a basis for calculating their resistance, taking account the reduction with time of the wood section on the embedding (A-dev) ES.2 RD 223/2008, ITC-LAT 07, sub-clause 2.4.4 In all cases they should receive an effective preservative treatment against putrefaction 7.5.5 Ultimate limit states (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 3.5.4 The security coefficient regarding the ultimate failure load shall not be lower than 3,5 in normal load cases or 2,8 in abnormal load cases 7.6 Concrete poles 7.6.1 General (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 2.4.3 The use of reinforced vibrated concrete poles is preferred, manufactured with highest quality materials, according to the types and characteristics indicated in the appropriate UNE standards according to ITC-LAT 02, RD 223/2008 7.6.4 Ultimate limit states (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 3.5.4 The security coefficient of the supports and reinforced concrete elements regarding the ultimate failure load in normal load cases shall fulfil as established in standard UNE 207016 In abnormal load cases, such a security coefficient may be reduced by 20% 7.6.5 Serviceability limit states (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 3.5.4 It shall be fulfilled as indicated in standard UNE 207016 7.6.6 Design assisted by testing (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 3.5.4 Spain - 37 - BS EN 50341-2-6:2017 EN 50341-2-6:2017 Experimental tests shall be made as indicated in standard UNE 207016 7.7 Guyed structures 7.7.1 General (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 2.4.6 The use of guys is allowed just in case of failure, replacement of supports and temporary detours of lines They must be metal rods or metallic cables that, in case of steel cables, shall be hot dip galvanized Guys whose failure load is lower than 1750 daN or cables formed by wires with diameter lower than mm are not allowed 7.7.4 Ultimate limit states (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 3.5.4 The security coefficient of cables or rod used as guys regarding the ultimate failure load shall not be lower than in normal load cases or 2,5 in abnormal load cases 7.8 Other structures (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 2.4.5 In order to be able to incorporate in the execution of overhead lines new supports that could be developed, it is allowed the use of support of different materials and compositions than those indicated in the preceding clauses of RD 223/2008 In any case, these types of supports shall be included in recognized standards or technical specifications in the field and their use shall be approved by the competent bodies of the Administration Foundations 8.1 Introduction (snc) ES.1 Introduction Preferential type of single foundations is monoblock footings 8.2 Basis of geotechnical design (EN 1997-1:2004 - Section 2) 8.2.2 Geotechnical design by calculation (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 3.6, Analytical method for calculation of separate footing foundations When separate footings are provided for each leg, they shall be designed to resist the compression and uplift forces that support´s transfer to the subsoil The calculation of these forces shall be based on the angle of earth cone method Also it should be checked the adhesion between the anchor and the foundation of each support leg Whether stability of foundations of supports is mainly entrusted to vertical reactions of soil, it shall be checked the security coefficient against overturning from the most loaded edge of the foundation and the greater tilter moment motivated by external actions The security coefficient will not be lower than the following values: Normal hypothesis: Abnormal hypothesis: 1,5 1,2 BS EN 50341-2-6:2017 EN 50341-2-6:2017 - 38 - Spain The security coefficient shall not be lower than 1,5 in normal load cases or 1,2 in abnormal load cases (A-dev) ES.2 RD 223/2008, ITC-LAT 07, sub-clause 3.6.2, Uplift resistance They shall be considered all the forces acting against the uplift of support: - Weight of the support - Self weight of the foundation - Weight of ground dragged by the block of concrete whether it is pulled out - Resistance loads of bolts in case of foundations on rock or mixed foundations The stability coefficient shall not be lower than 1,5 in normal load cases or 1,2 in abnormal load cases In case of not knowing the soil characteristics by mean of geotechnical investigation at the location of the line is recommended the use of an angle of 30º for the sides of the earth frustum in case of normal soil and an angle of 20º in case of non-cohesive soils For the earth cone method, it is recommended a value equal to 2/3 of the internal friction angle of the soil as angle of shearing resistance (A-dev) ES.3 RD 223/2008, ITC-LAT 07, sub-clause 3.6.3, Compression verification They shall be considered all the compression forces transmitted to the soil by foundation: - Weight support Self weight of the foundation The dead load of the soil resting vertically upon the foundation Compression load exerted by the support It shall be checked that all previous compression loads, divided by the foundation sub-face, does not exceed the permissible load of soil In case of not knowing the soil characteristics by mean of geotechnical investigation at the location of the line is recommended the use of daN/cm2 as admissible load for normal soil and daN/cm2 in case of non-cohesive soils In case of foundations on rock or mixed foundations, it is recommended the use of 10 daN/cm2 as admissible load for rocks (A-dev) ES.4 RD 223/2008, ITC-LAT 07, sub-clause 3.6.4, Interface between support and foundation verification For embedment of steel members and connections into the concrete, half the greater load transmitted to the foundation by the anchoring elements, usually a compression load, is considered to be resisted by the adhesion between anchor and foundation And the other half is supposed to be resisted by shear resistance of the connection bolts between sockets and anchor The security coefficients of both loads against sliding of anchor from the foundation shall not be lower than 1,5 (A-dev) ES.5 RD 223/2008, ITC-LAT 07, clause 3.6, Analytical method for calculation of monoblock foundations Whether stability of foundations of supports is mainly entrusted to horizontal reactions of soil, it is not allowed a rotation angle of the foundation with a tangent greater than 0,01 to meet the equilibrium between maximum tilting loads and soil reactions 8.2.3 Design by prescriptive measures (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 3.6.6, Direct embedded towers For wood or concrete poles that not require foundations, the embedment depth on the soil shall be not less than 1,3 metres for support with length lower than eight metres, increasing 0,10 metres each additional metre of pole length Spain BS EN 50341-2-6:2017 - 39 - EN 50341-2-6:2017 Whether wood and concrete supports require foundation, its resistance shall be not less than the support resistance In poor soils, a prism filled with gravel and stones shall surround the pole (A-dev) ES.2 RD 223/2008, ITC-LAT 07, sub-clause 3.6.1, Mixed foundations In case of soils with rocks on the surface or within a little depth, the foundation may be performed by attaching the support to the rock by bolts anchored to it (foundation in rock) Similarly, in those cases that foundation cannot be performed to the necessary deepness by usual mechanical means, and therefore, it must be reinforced, the reinforcement shall be made by attaching the foundation to the rock by bolts anchored to it (mixed foundation) 8.3 Soil investigation and geotechnical data (EN 1997-1:2004 - Section 3) (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 3.6.5 In case of not knowing the soil characteristics, the values shown in the table below may be used: Table 8.3/ES.1 – Indicative soil characteristics for the calculation of the foundation Type of soil I II III IV Rocks in good condition: isotropic Stratified (with some cracks Non-cohesive soils: a) Sandy-gravelly material (minimum 1/3 volume of gravel up to 70 mm in size) b) Sand, coarse (with particle diameters of mm to 0.2 mm) c)Sand, fine (with particle diameters of mm to 0.2 mm) Loose Non-cohesive soils: a) Sandy-gravelly b) Sand, coarse c) Sand, fine Cohesive soils (a): a) clay, stiff b) clay, semi-stiff c) clay soft d) clay fluid V Peaty mud and general marsh VI Uncompacted backfill soils Weight density Tn/m3 Angle of natural slope sexag Degrees Admissible load daN/cm2 Angle of shearing resistance º Compressive strength under m deepness daN/cm3 (b) 30-60 10-20 1,80-1,90 1,60-1,80 30º 1,50-1,60 1,70-1,80 1,60-1,70 1,40-1,50 1,80 1,80 1,50-2,00 1,60-1,70 0,60-1,1 1,40-1,60 4-8 20º-22º 2-4 20º-25º 8-20 1,5-3 30º 20º 30º-40º 3-5 2-3 1-1,5 8-12 - 20º-25º 22º 14º-16º 0º 10 6-8 4-5 2-3 (c) (c) 14º-20º (c) (c) (a) Stiff: Soils with its natural moisture are hardly breakable with the hand Usually of clear tone Semi-stiff: Soils with its natural moisture are hardly kneaded Usually of dark tone BS EN 50341-2-6:2017 EN 50341-2-6:2017 - 40 - Spain Soft: Soils with its natural moisture are easily kneaded, up to cylinders of mm in diameter Of dark tone Fluid: Soils with its natural moisture pressed in closed hand flow through fingers Usually of dark tone (b) May be assumed to be proportional to the depth at which the action is considered (c) It shall be established by soil investigation 8.6 Interactions between support foundations and soil (A-dev) ES.1 RD 223/2008, ITC-LAT 07, clause 3.6 Special attention shall be paid to protection of concrete foundations in aggressive soils or water Special attention shall be paid to protection of steel foundations, so as to ensure its duration Conductors and earth-wires 9.2.4 Mechanical requirements (ncpt) ES.1 Mechanical requirements The rated tensile strength of the high performance conductors of ACSS type shall be calculated according to EN 50540 and that of GAP type according to EN 62420 9.6 General requirements 9.6.2 Partial factor for conductors (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 3.2.1 Maximum tension applied to conductors and ground wires shall be no greater than their rated tensile strength divided by 2.5, for stranded conductors, or divided by 3, for single wire conductors, considering they are under the loading assumptions of table of ITC-LAT 07, regarding their location on A, B or C zone 10 Insulators 10.2 Standard electrical requirements (A-dev) ES.1 RD 223-2008, ITC-LAT 07, clause 4.4 The standard minimum isolation levels corresponding to the highest system voltage, are presented in Tables 5.3.1/ES.1 and 5.3.2/ES.1 For other values of the highest system voltage that not match with those shown on the table, standards EN 60071-1 and EN 60071-2 shall be fulfilled 10.7 Mechanical requirements (A-dev) ES.1 RD 223/2008, ITC-LAT 07, clause 3.4 The mean resistance characteristic of insulators is the minimum guaranteed electromechanical failing load, which likelihood of developing minor cases is less than 2%, average value of the distribution minus 2,06 times the standard deviation The mechanical resistance corresponding to a multiple string may be equal to the product of the number of its strings by the resistance of each single string, provided that, both in normal state as with a broken string, the load is shared equally among all intact string The mechanical security coefficients shall not be lower than Spain - 41 - BS EN 50341-2-6:2017 EN 50341-2-6:2017 In case that minimum guaranteed electromechanical failing load were obtained by statistical control at reception, the security factor may be reduced to 2,5 11 Hardware 11.6 Mechanical requirements (A-dev) ES.1 RD 223/2008, ITC-LAT 07, clause 3.3 The security coefficient of fittings subjected to mechanical tension by conductors and ground wires or by insulators shall not be lower than regarding to their minimum failure load When the mechanic failure load is systematically tested, the security coefficient may be reduced to 2,5 The minimum failure load is that whose likelihood of being inferior is lower than 2% The minimum failure load can be estimated as the mean value of the failure loads minus 2,06 times the standard deviation Tension clamps for conductor must withstand a mechanical tension on clamp equal or greater than 95% of the failure load of conductor without slippage In case of special fittings, such as those used to limit the efforts transmitted to the supports, their characteristics as well as their permanence shall be fully justified 11.9 Characteristics and dimensions of fittings (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 2.2.6 The coupling dimensions of the fittings to insulators shall fulfil the standard UNE 21009 or UNE 21128 Annex G Calculation methods for earthing systems G.2 Minimum dimensions of earth electrodes (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 7.3.2 The different types of electrodes that may be used are: - Driven rods formed by vertical bars, tubes or profiles Horizontal buried conductors formed by cables, rods or bars and arranged radially, forming ring or mesh The dimensions of the driven rods shall fulfil the following specifications: - Copper rods or copper-clad steel rods, shall not be of a diameter lower than 14 mm Uncoated steel rods shall not be of a diameter lower than 20 mm The tubes shall neither be of a diameter lower than 30 mm nor a wall thickness lower than mm Steel angles shall not be of a thickness thinner than mm or a section lower than 350 mm2 Buried conductors, whether rod, cable or plates, shall have a minimum section of 50 mm2 if they are made of copper, and 100 mm2 if they are made of steel The minimum thickness of the plates and the minimum diameter of the wires shall not be lower than mm in case of copper and mm in case of steel G.4 Touch voltage and body current G.4.1 Equivalence between touch voltage and body current (A-dev) ES.1 RD 223/2008, ITC-LAT07, sub-clause 7.3.4.1, Table 18 Except justified cases, time duration of the fault current lower than 0,1 seconds are not considered BS EN 50341-2-6:2017 EN 50341-2-6:2017 - 42 - Spain To set the fault duration, the right operation of protection and switching devices shall be considered For installations with fast automatic reclosing (no more than 0,5 seconds), the time to consider will be the sum of the partial times of maintenance of the fault current Table G.6/ES.1 – Fault duration related to touch voltage, UTp Annex H Fault duration, tF Permissible touch voltage, UTp s V 0,05 735 0,10 633 0,20 528 0,30 420 0,40 310 0,50 204 1,00 107 2,00 90 5,00 81 10,00 80 >10,00 50 Installation and measurements of earthing systems H.3 Installation of earth electrodes and earthing systems H.3.1 Installation of earth electrodes H.3.1.1 Earth electrodes (A-Dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 7.2.1 An earthing system is usually composed of one or more horizontal or vertical earth electrodes, buried or driven into the ground by force and the earth line that connect the electrodes to the elements to be earthed H.3.1.2 Horizontal earth electrodes (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 7.2.2.1 Horizontal earth electrodes shall be placed at the bottom of a trench or excavation of a foundation, so that: a) they shall be surrounded with slightly tamped earth, b) stones or gravel shall not be in direct contact with buried earth electrodes, c) natural soil corrosive to the metal used in the electrode shall be replaced with a suitable backfill H.3.1.3 Vertical or inclined driven rods (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 7.2.2.2 Vertical or inclined driven rods shall be separated by a distance not shorter than 1,5 times the length of the rod H.3.1.4 Jointing the earth electrodes (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 7.2.2.3 Spain - 43 - BS EN 50341-2-6:2017 EN 50341-2-6:2017 Attachments will be made by appropriate bimetallic connection pieces to prevent the effects of galvanic corrosion H.3.2 Installation of earthing conductors H.3.2.1 General (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 7.2.3.1 Usually, the trace of the earthing conductors shall be as short as possible and shall avoid tortuous paths and small radius curves H.3.2.2 Installing the earthing conductors (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 7.2.3.1 In concrete foundations the conductors shall pass through it and not over it (A-dev) ES.1 RD 223/2008, ITC-LAT 07, sub-clause 7.2.3.1 Fuses and switching devices shall not be used in earthing conductors This page deliberately left blank This page deliberately left blank NO COPYING WITHOUT BSI PERMISSION EXCEPT 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