Overhead electrical lines exceeding AC 1 kV - Part 2-2: National Normative Aspects (NNA) for Belgium (based on EN 50341-1:2012)

1 Scope
1.1 General
BE.1 Scope of Part 1 and Part 2-2
(ncpt) Part 1 and the present Part 2-2 are only applicable to completely new or completely replaced overhead lines between two points, A and B, as well as to new supports on new foundations with nominal voltages above AC 50 kV.
(A-dev) Overhead lines or supports with nominal voltages exceeding AC 1 kV up to and including AC 50 kV are treated as a high voltage of the first category in the General Regulations of the Electrical Installations (GREI) and follow completely the GREI for their dimensioning.
1.2 Field of application
(ncpt) BE.1 Application to telecommunication equipment
Part 1 and this NNA apply to telecommunication equipment mounted on the new supports (e.g. dishes, antennas), particularly with respect to wind assumptions.

Nadzemni električni vodi za izmenične napetosti nad 1 kV - 2-2. del: Nacionalna normativna določila (NNA) za Belgijo (na podlagi EN 50341-1:2012)

1. del in ta 2-2. del tega standarda se uporabljata samo za povsem nove ali zamenjane nadzemne vode med dvema točkama – A in B – ter za nove nosilce na novih temeljih z nazivno izmenično napetostjo nad 50 kV.

General Information

Status
Published
Publication Date
11-Nov-2019
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
22-May-2019
Due Date
27-Jul-2019
Completion Date
12-Nov-2019

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SLOVENSKI STANDARD
SIST EN 50341-2-2:2019
01-december-2019
Nadzemni električni vodi za izmenične napetosti nad 1 kV - 2-2. del: Nacionalna
normativna določila (NNA) za Belgijo (na podlagi EN 50341-1:2012)

Overhead electrical lines exceeding AC 1 kV - Part 2-2: National Normative Aspects

(NNA) for Belgium (based on EN 50341-1:2012)
Ta slovenski standard je istoveten z: EN 50341-2-2:2019
ICS:
29.240.20 Daljnovodi Power transmission and
distribution lines
SIST EN 50341-2-2:2019 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 50341-2-2:2019
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SIST EN 50341-2-2:2019
EUROPEAN STANDARD EN 50341-2-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2019
ICS 29.240.20
English Version
Overhead electrical lines exceeding AC 1 kV - Part 2-2: National
Normative Aspects (NNA) for BELGIUM (based on EN 50341-
1:2012)
This European Standard was approved by CENELEC on 2019-04-10.

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: Rue de la Science 23, B-1040 Brussels

© 2019 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.

Ref. No. EN 50341-2-2:2019 E
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SIST EN 50341-2-2:2019
EN 50341-2-2:2019 - 2/29 - Belgium
Contents

European foreword ................................................................................................................................. 6

1 Scope ............................................................................................................................................. 7

1.1 General ................................................................................................................................ 7

1.2 Field of application ............................................................................................................... 7

2 Normative references, definitions and symbols ....................................................................... 7

2.1 Normative references........................................................................................................... 7

2.3 Symbols ............................................................................................................................... 8

3 Basis of design ............................................................................................................................. 8

3.2 Requirements of overhead lines .......................................................................................... 8

3.2.2 Reliability requirements ........................................................................................... 8

4 Actions on lines ............................................................................................................................ 9

4.1 Introduction .......................................................................................................................... 9

4.3 Wind loads ........................................................................................................................... 9

4.3.1 Field of application and basic wind velocity ............................................................ 9

4.3.2 Mean wind velocity ................................................................................................10

4.3.3 Mean wind pressure ..............................................................................................11

4.3.4 Turbulence intensity and peak wind pressure.......................................................11

4.4 Wind forces on overhead line components .......................................................................11

4.4.1 Wind forces on conductors....................................................................................11

4.4.1.1 General ................................................................................................11

4.4.1.2 Structural factor ...................................................................................11

4.4.1.3 Drag factor ...........................................................................................12

4.4.2 Wind forces on insulator sets ................................................................................12

4.4.3 Wind forces on lattice towers ................................................................................12

4.4.3.1 General ................................................................................................12

4.4.3.2 Method 1 .............................................................................................12

4.4.4 Wind forces on poles .............................................................................................13

4.5 Ice loads .............................................................................................................................13

4.5.1 General ..................................................................................................................13

4.6 Combined wind and ice loads ............................................................................................13

4.6.1 Combined probabilities ..........................................................................................13

4.6.2 Drag factors and ice densities ...............................................................................13

4.7 Temperature effects ...........................................................................................................13

4.8 Security loads ....................................................................................................................13

4.8.1 General ..................................................................................................................13

4.8.4 Mechanical conditions of application ....................................................................14

4.9 Safety loads .......................................................................................................................14

4.9.1 Construction and maintenance loads ....................................................................14

4.9.2 Loads related to the weight of linesmen ...............................................................16

4.10 Forces due to short-circuit currents ...................................................................................16

4.11 Other special forces ...........................................................................................................16

4.12 Load cases .........................................................................................................................16

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4.12.2 Standard load cases .............................................................................................16

4.13 Partial factors for actions ...................................................................................................17

5 Electrical requirements ..............................................................................................................18

5.1 Introduction ........................................................................................................................18

5.2 Currents .............................................................................................................................18

5.2.1 Normal current ......................................................................................................18

5.3 Insulation co-ordination ......................................................................................................18

5.5 Minimum air clearance distances to avoid flashover .........................................................19

5.5.2 Application of the theoretical method in Annex E .................................................19

5.6 Load cases for calculation of clearances ...........................................................................19

5.6.2 Maximum conductor temperature .........................................................................19

5.6.3 Wind loads for determination of electric clearances .............................................19

5.6.3.2 Nominal wind loads for determination of internal and external

clearances ...........................................................................................19

5.6.3.3 Extreme wind loads for determination of internal clearances .............20

5.6.4 Ice loads for determination of electric clearances .................................................20

5.8 Internal clearances within the span and at the top of support ...........................................20

5.9 External clearances ...........................................................................................................20

5.9.1 General ..................................................................................................................20

5.9.2 External clearances to ground in areas remote from buildings, roads, etc. ..........21

5.9.3 External clearances to residential and other buildings .........................................21

5.9.4 External clearances to crossing traffic routes .......................................................21

5.9.5 External clearances to adjacent traffic routes .......................................................22

5.9.6 External clearances to other power lines or overhead telecommunication lines ..23

5.9.7 External clearances to recreational areas .............................................................23

5.10 Corona effect .....................................................................................................................23

5.10.1 Radio noise ...........................................................................................................23

5.10.1.3 Noise limit ............................................................................................23

5.10.2 Audible noise .........................................................................................................23

5.10.2.3 Noise limit ............................................................................................23

5.11 Electric and magnetic fields ...............................................................................................23

5.11.1 Electric and magnetic fields under a line ..............................................................23

6 Earthing systems .......................................................................................................................24

6.1 Introduction ........................................................................................................................24

6.1.3 Earthing measures against lightning effects .........................................................24

6.4 Dimensioning with regard to human safety .......................................................................24

6.4.1 Permissible values for touch voltages ...................................................................24

7 Supports ......................................................................................................................................24

7.2 Materials ............................................................................................................................24

7.2.1 Steel materials, bolts, nuts and washers, welding consumables ..........................24

7.3 Lattice steel towers ............................................................................................................25

7.3.5 Structural analysis .................................................................................................25

7.3.6 Ultimate limit states ...............................................................................................25

7.3.6.1 General ................................................................................................25

7.3.6.4 Buckling resistance of members in compression ................................25

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7.3.6.5 Buckling resistance of members in bending .......................................25

7.3.8 Resistance of connections ....................................................................................26

7.4 Steel poles .........................................................................................................................26

7.4.3 Materials ................................................................................................................26

7.4.6 Ultimate limit states ...............................................................................................26

7.4.6.2 Resistance of cross section areas ......................................................26

7.4.7 Serviceability limit states .......................................................................................26

7.4.8 Resistance of connections ....................................................................................26

7.4.8.2 Bolts ....................................................................................................26

7.4.8.4 Flanged bolted connections ................................................................26

7.4.8.7 Base plate and holding-down bolts .....................................................26

7.5 Wood poles ........................................................................................................................26

7.5.1 General ..................................................................................................................26

7.6 Concrete poles ...................................................................................................................27

7.6.1 General ..................................................................................................................27

7.6.4 Ultimate limit states ...............................................................................................27

7.6.5 Serviceability limit states .......................................................................................27

7.7 Guyed structures ................................................................................................................27

7.7.1 General ..................................................................................................................27

7.8 Other structures .................................................................................................................27

7.10 Maintenance facilities.........................................................................................................27

7.10.1 Climbing ................................................................................................................27

8 Foundations ................................................................................................................................28

8.2 Basis of geotechnical design .............................................................................................28

8.2.1 General ..................................................................................................................28

8.2.2 Geotechnical design by calculation .......................................................................28

9 Conductors and earth-wires......................................................................................................28

9.1 Introduction ........................................................................................................................28

9.2 Aluminium based conductors .............................................................................................28

9.2.1 Characteristics and dimensions ............................................................................28

9.6 General requirements ........................................................................................................29

9.6.2 Partial factor for conductors ..................................................................................29

10 Insulators ....................................................................................................................................29

10.7 Mechanical requirements ...................................................................................................29

11 Hardware .....................................................................................................................................29

11.6 Mechanical requirements ...................................................................................................29

12 Quality assurance, checks and taking over ............................................................................29

Annex J (normative) – Angles in lattice steel towers .........................................................................29

J.4 Buckling resistance of angles in compression ...................................................................29

J.4.3 Slenderness of members ......................................................................................29

J.4.3.3 Primary bracing patterns .....................................................................29

J.4.3.3.1 General ................................................................................................29

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Figures

Figure 4/BE.1 – Basic wind velocities V according to NBN EN 1991-1-4 ANB ..................................10

b,0

Figure 4/BE.2 – Distance x to observe the terrain roughness ................................................................10

Figure 4/BE.3 – Application of the mobile load F on a cross-arm .....................................................14

mob

Figure 4/BE.4 – Loads on the cross-arm end in the case of a removed cable ......................................15

Figure 4/BE.5 – Loads on the cross-arm end in the case of a pulled cable ...........................................15

Figure 4/BE.6 – Loads on the cross-arm end in the case of a cable in a redoubled hole (pull-lift)........15

Figure 4/BE.7 – Base and quartering wind.............................................................................................17

Figure 7/BE.1 – Extreme fiber positions of an angle ..............................................................................25

Tables

Table 3/BE.1 – Return period for temporary lines/towers ........................................................................ 8

Table 3/BE.2 – Probability factor for temporary lines/towers ................................................................... 9

Table 3/BE.3 – Seasonal coefficient for temporary lines/towers .............................................................. 9

Table 4/BE.1 – Drag reduction factor for aerodynamic conductors .......................................................12

Table 4/BE.2 – Characteristics of slipping suspension clamps ..............................................................14

Table 4/BE.3 – Mobile load ....................................................................................................................15

Table 4/BE.4 – Standard load cases ......................................................................................................16

Table 4/BE.5 – Partial factors γ and combinations factors ψ for actions ................................................17

Table 5/BE.1 – Insulation co-ordination in Belgium ...............................................................................18

Table 5/BE.2 – Clearances Del and Dpp to withstand lightning overvoltages .........................................19

Table 5/BE.3 – Clearances D and D to withstand the power frequency voltage ..............19

50Hz_p_e 50Hz_p_p

Table 5/BE.4 – Proximity zone clearance DV .........................................................................................20

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SIST EN 50341-2-2:2019
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European foreword
1 The Belgian National Committee (NC) is identified by the following address:
Belgian Electrotechnical Committee (BEC)
Diamant Building
Boulevard Reyerslaan, 80
B-1030 Brussels
Belgium
Contact The secretary of SC11
E-mail centraloffice@ceb-bec.be
Phone +32 2 706 85 70

2 The Belgian NC has prepared this Part 2-2 (EN 50341-2-2) listing the Belgian National Normative

Aspects (NNA), under its sole responsibility, and duly passed it through the CENELEC and

CLC/TC11 procedures.

NOTE The Belgian NC also takes sole responsibility for the technically correct co-ordination of this NNA 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.
3 This NNA is normative in Belgium and informative for 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 “BE”, 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 Belgian NC who will, in co-operation

with CLC/TC11, clarify the requirements.

Where no reference is made in this NNA to a specific subclause, then Part 1 applies.

5 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 Belgium.

However, any boxed value, whether in Part 1 or this NNA, shall not be amended in the direction of

greater risk in a Project Specification.

6 The national Belgian standards/regulations related to overhead electrical lines exceeding 1 kV (AC)

are listed in subclauses 2.1/BE.1 and BE.2.

Only significant extracts and summaries of the Belgian national regulations are presented in the A-

deviations. They must be read in conjunction with the Belgian national regulations identified in

2.1/BE.1 which is in any case the relevant document.

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 Belgian NC to be applicable and thus

reported to the secretary of CLC/TC11.

7 Supplementary requirements in this NNA in addition to the part 1 are indicated by preceding the

corresponding paragraphs by (snc) or (ncpt).

Paragraphs preceded by (A-dev) are required by national law: i.e. the General Regulations of the

Electrical Installations (GREI).
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1 Scope
1.1 General
BE.1 Scope of Part 1 and Part 2-2

(ncpt) Part 1 and the present Part 2-2 are only applicable to completely new or completely replaced

overhead lines between two points, A and B, as well as to new supports on new foundations

with nominal voltages above AC 50 kV.

(A-dev) Overhead lines or supports with nominal voltages exceeding AC 1 kV up to and including AC

50 kV are treated as a high voltage of the first category in the General Regulations of the

Electrical Installations (GREI) and follow completely the GREI for their dimensioning.

1.2 Field of application
(ncpt) BE.1 Application to telecommunication equipment

Part 1 and this NNA apply to telecommunication equipment mounted on the new supports

(e.g. dishes, antennas), particularly with respect to wind assumptions.
2 Normative references, definitions and symbols
2.1 Normative references
(A-dev) BE.1 National regulations

The General Regulations of the Electrical Installations (GREI) are given by the Belgian Royal

Decree of March 1981 (latest issue) which has been published in the Belgian Statute Book of

29 April 1981.

The installations for transmission and distribution of electrical energy are covered in Book 3

after the restructuring of the GREI in 2019. The articles as mentioned in this NNA must

therefore be translated to corresponding sections to find the relevant extracts.
(ncpt) BE.2 National standards
Reference Title
NBN B21-602 Poteaux préfabriqués en béton pour supports de lignes aériennes –
Spécifications d’application en complément à la NBN EN 12843:
Produits préfabriqués en béton – Mâts et poteaux
NBN C34-100 Solid and stranded conductors for overhead lines for power
transmission
NBN EN 1090-2 Execution of steel structures and aluminium structures – Part 2:
Technical requirements for steel structures
Hot rolled products of structural steels
NBN EN 10025-1 Part 1: General technical delivery conditions

NBN EN 10025-2 Part 2: Technical delivery conditions for non-alloy structural steels

NBN EN 10025-3 Part 3: Technical delivery conditions for normalized rolled weldable fine

grain structural steels
NBN EN 10027-1 Designation systems for steels – Part 1: Steel names
Structural steel equal and unequal leg angles
NBN EN 10056-1 Part 1: Dimensions
NBN EN 10056-2 Part 2: Tolerances on shape and dimensions
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NBN EN 1993-1-6 Eurocode 3 – Design of steel structures – Part 1-6: Strength and
stability of shell structures
(ncpt) BE.3 Other publications

[1] 1999/519/EC: “Council Recommendation of 12 July 1999 on the limitation of exposure

of the general public to electromagnetic fields (0 Hz to 300 GHz)”, Official Journal of the

European Communities L199, 30/07/1999.

[2] BBRI: “Guidelines for the application of the Eurocode 7 in Belgium according to NBN

EN 1997-1 ANB. Part 1: geotechnical design in the ultimate limit state (ULS) of axially

loaded piles based on cone penetration tests (CPT)”, Belgian Building Research
Institute, Report n° 19, 2016.
2.3 Symbols
Symbol Signification Reference
c Probability factor 3.2.2/BE.3
prob
D Proximity zone clearance 5.9.1/BE.1
F Mobile load 4.9.1/BE.2
mob
k Turbulence factor 4.3.4/BE.1
x Upstream distance 4.3.2/BE.3
3 Basis of design
3.2 Requirements of overhead lines
3.2.2 Reliability requirements
(ncpt) BE.1 Reliability of overhead lines

In Belgium overhead lines shall be designed such that they meet the requirements of the

reliability level 2 unless otherwise defined in the Project Specification.

There is an exception for 70 kV concrete poles where the reliability level 1 applies.

The Project Specification shall specify whether the reliability level 3 has to be applied in case

of overhead lines with very high consequences of failure (e.g. lines near Seveso companies,

lines connecting a critical power plant).
(ncpt) BE.2 Reliability of temporary lines/towers

The minimum return periods of the climatic actions to be taken into account for the design of

temporary lines/towers installed for a period of less than one year are given in Table 3/BE.1.

Table 3/BE.1 – Return period for temporary lines/towers
Duration Return period (years)
≤ 3 days 2
≤ 3 months (but > 3 days)
≤ 1 year (but > 3 months) 10
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(ncpt) BE.3 Load cases for temporary lines/towers

The standard load cases based on the reliability level 3 (see also Table 4/BE.4) apply.

Only in the normal and extreme wind load case, the basic wind velocity shall be multiplied by

the probability factor c in function of the reduced return period according to Table 3/BE.2.

prob
Table 3/BE.2 – Probability factor for temporary lines/towers
Return period (years) c (c )²
prob prob
2 0,78 0,60
5 0,85 0,72
10 0,90 0,81

When the temporary line/tower is installed outside the months November, December,

January, February and March, no wind & ice and winter loading have to be considered.

(ncpt) BE.4 Application of seasonal coefficient for temporary lines/towers

For temporary lines/towers installed less than 3 months, the wind loads (except for the

reduced wind) may be reduced by the seasonal coefficient c according to Table 3/BE.3.

season
The highest value of c of the considered months shall be used.
season
Table 3/BE.3 – Seasonal coefficient for temporary lines/towers
05-06-
Month 01-02 03 04 09 10 11 12
07-08
cseason 0,96 0,92 0,88 0,83 0,88 0,92 1,0 0,96
(cseason)² 0,92 0,85 0,77 0,69 0,77 0,85 1,0 0,92
4 Actions on lines
4.1 Introduction
(ncpt) BE.1 Climatic data

The stipulated wind loads are based on NBN EN 1991-1-4 ANB. The stipulations for ice

loads are based on long-term operational experience.
4.3 Wind loads
4.3.1 Field of application and basic wind velocity
(snc) BE.1 Basic wind velocity
The basic wind veloci
...

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