SIST EN IEC 62858:2020

Lightning density based on lightning location systems (LLS) - General principles

IEC 62858:2019 is available as IEC 62858:2019 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.
 
IEC 62858:2019 introduces and discusses all necessary measures to make reliable and homogeneous the values of ground flash density, NG and ground strike point density, NSG, obtained from lightning location systems (LLSs) in various countries. Only parameters that are relevant to risk assessment are considered. This second edition cancels and replaces the first edition published in 2015. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
- Two informative annexes are introduced dealing with the determination of lightning density for risk calculation (Annex A) and ground strike point calculation methods (Annex B).

Blitzhäufigkeit basierend auf Blitzortungssystemen - Allgemeine Grundsätze

Densité de foudroiement basée sur des systèmes de localisation de la foudre (LLS) - Principes généraux

IEC 62858:2019 est disponible sous forme de IEC 62858:2019 RLV qui contient la Norme internationale et sa version Redline, illustrant les modifications du contenu technique depuis l'édition précédente.
L'IEC 62858:2019 décrit et étudie l'ensemble des mesures nécessaires pour rendre fiables et homogènes les valeurs de la densité de foudroiement au sol, NSG, et de la densité de points d'impact au sol, NSG, obtenues par des systèmes de localisation de la foudre (LLS) dans différents pays. Seuls les paramètres essentiels à l'évaluation du risque sont pris en compte. Cette deuxième édition annule et remplace la première édition parue en 2015. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
- Introduction de deux annexes informatives, traitant de la détermination de la densité de foudroiement pour le calcul du risque (Annexe A) et des méthodes de calcul concernant les points d'impact au sol (Annexe B).

Pogostost strele na osnovi sistemov za lokacijo strel (LLS) - Splošna načela

Standard EN-IEC 62858 uvaja in obravnava vse potrebne ukrepe za podajanje zanesljivih ter homogenih vrednosti glede gostote strel proti zemlji (NG) in gostote točk udarov strele proti zemlji (NSG), ki so pridobljene iz sistemov za lociranje strel (LLS) v različnih državah. Upoštevani so samo parametri, ki so pomembni za oceno tveganja.

General Information

• Status: Published
• Publication Date: 10-Dec-2019
• ICS: 91.120.40 - Lightning protection
• Technical Committee: STZ - Lightning protection
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 05-Dec-2019
• Due Date: 09-Feb-2020
• Completion Date: 11-Dec-2019
• Ref Project: EN IEC 62858:2019 - Lightning density based on lightning location systems (LLS) - General principles

Relations

• Replaces: SIST EN 62858:2016 - Lightning density based on lightning location systems (LLS) - General principles
• Effective Date: 01-Jan-2020

Overview

EN IEC 62858:2019 (IEC 62858:2019) defines general principles for deriving lightning density from Lightning Location Systems (LLS). The standard explains how to obtain reliable and homogeneous values of ground flash density (NG) and ground strike-point density (NSG) from LLS data for use in lightning risk assessment. This second edition (2019) replaces the 2015 edition and adds two informative annexes on determination methods for lightning density and ground strike-point calculations.

Key topics and technical requirements

• Primary focus: Parameters from LLS that matter for lightning protection and risk assessment (NG and NSG).
• Performance characteristics required for LLS data used in NG/NSG calculation:
  • Flash detection efficiency (DE): annual average DE for cloud-to-ground (CG) flashes should be at least 80% in the computation region.
  • Location accuracy (LA): median location error for CG strokes should be better than 500 m within the network interior.
  • Classification accuracy: at least 85% of CG flashes must be correctly classified (i.e., not misclassified as intra-cloud).
  • NG values with an error of ±20% or less are considered adequate for risk assessment.
• Data quality and processing topics covered:
  • Stroke-to-flash grouping (how strokes are combined into flashes)
  • Minimum observation periods and uptime considerations
  • Definition of observation area and grid cell size for spatial analysis
  • Edge-effect correction and validation of LLS performance
• Annexes added in this edition:
  • Annex A (informative): Practical procedures for determination of lightning density for risk calculation.
  • Annex B (informative): Explanations and methods for computing ground strike points (GSPs).

Applications and users

EN IEC 62858:2019 is practical for:

• Lightning protection engineers and risk assessors performing LN/NSG-based evaluations for buildings, infrastructure and utilities.
• LLS operators and network analysts who produce lightning climatologies and need to certify data quality for risk applications.
• Standards bodies, consultants and insurers requiring standardized, comparable lightning density inputs across regions. Practical benefits include consistent NG/NSG datasets for application in IEC 62305 risk calculations and improved comparability between national LLS outputs.

Related standards

• IEC 62305-1 - Protection against lightning - Part 1: General principles
• IEC 62305-2 - Protection against lightning - Part 2: Risk management EN IEC 62858:2019 is intended to be used alongside these standards to provide validated lightning density inputs for lightning protection design and risk management.

Keywords: lightning density, lightning location systems, LLS, ground flash density, ground strike-point density, EN IEC 62858:2019, IEC 62858, lightning protection, risk assessment.

Standards Content (Sample)

SLOVENSKI STANDARD
01-januar-2020
Nadomešča:
SIST EN 62858:2016
Pogostost strele na osnovi sistemov za lokacijo strel (LLS) - Splošna načela
Lightning density based on lightning location systems (LLS) - General principles
Blitzhäufigkeit basierend auf Blitzortungssystemen - Allgemeine Grundsätze
Densité de foudroiement basée sur des systèmes de localisation de la foudre (LLS) -
Principes généraux
Ta slovenski standard je istoveten z: EN IEC 62858:2019
ICS:
91.120.40 Zaščita pred strelo Lightning protection
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 62858

NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2019
ICS 91.120.40; 29.020 Supersedes EN 62858:2015 and all of its amendments
and corrigenda (if any)
English Version
Lightning density based on lightning location systems (LLS) -
General principles
(IEC 62858:2019)
Densité de foudroiement basée sur des systèmes de Blitzhäufigkeit basierend auf Blitzortungssystemen -
localisation de la foudre (LLS) - Principes généraux Allgemeine Grundsätze
(IEC 62858:2019) (IEC 62858:2019)
This European Standard was approved by CENELEC on 2019-11-13. 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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, 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 IEC 62858:2019 E
European foreword
The text of document 81/627A/FDIS, future edition 2 of IEC 62858, prepared by IEC/TC 81 "Lightning
protection" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2020-08-13
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2022-11-13
document have to be withdrawn
This document supersedes EN 62858:2015 and all of its amendments and corrigenda (if any).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.

Endorsement notice
The text of the International Standard IEC 62858:2019 was approved by CENELEC as a European
Standard without any modification.

Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
NOTE 1  Where an International Publication has been modified by common modifications, indicated by (mod), the relevant
EN/HD applies.
NOTE 2  Up-to-date information on the latest versions of the European Standards listed in this annex is available here:
www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 62305-1 -  Protection against lightning - Part 1: EN 62305-1 -
General principles
IEC 62305-2 -  Protection against lightning - Part 2: Risk EN 62305-2 -
management
IEC 62858 ®
Edition 2.0 2019-10
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Lightning density based on lightning location systems – General principles

Densité de foudroiement basée sur des systèmes de localisation

de la foudre (LLS) – Principes généraux

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.020; 91.120.40 ISBN 978-2-8322-7457-6

– 2 – IEC 62858:2019 © IEC 2019
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms, definitions, abbreviated terms and symbols . 6
3.1 Terms and definitions . 6
3.2 Abbreviated terms and symbols . 7
4 General requirements . 7
4.1 General . 7
4.2 Stroke-to-flash grouping . 8
4.3 Minimum observation periods . 9
4.4 Observation area . 9
4.5 Grid cell size . 9
4.6 Edge effect correction . 9
5 Validation of lightning location system performance characteristics . 10
Annex A (informative) Determination of lightning density for risk calculation . 12
Annex B (informative) Ground strike points (GSPs) explanations and calculation
methods . 13
Bibliography . 14

Figure A.1 – High resolution full climatology (HRFC) N data. 12
t
IEC 62858:2019 © IEC 2019 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LIGHTNING DENSITY BASED ON LIGHTNING LOCATION SYSTEMS –
GENERAL PRINCIPLES
FOREWORD
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9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 62858 has been prepared by IEC technical committee 81:
Lightning protection.
This second edition cancels and replaces the first edition published in 2015. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
Two informative annexes are introduced dealing with the determination of lightning density for
risk calculation (Annex A) and ground strike point calculation methods (Annex B).

– 4 – IEC 62858:2019 © IEC 2019
The text of this International Standard is based on the following documents:
FDIS Report on voting
81/627A/FDIS 81/634/RVD
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
IEC 62858:2019 © IEC 2019 – 5 –
INTRODUCTION
International standards for lightning protection (e.g. IEC 62305-2) provide methods for the
evaluation of the lightning risk on buildings and structures.
The lightning ground flash density N , defined as the mean number of flashes per square
G
kilometre per year, and the ground strike point density N , defined as the mean number of
SG
ground strike points per square kilometre per year are the primary input parameters to
perform such an evaluation (see Annex A).
In many areas of the world data for risk evaluation are provided by lightning location systems
(LLSs), but no common rule exists defining requirements either for their performance or for
the elaboration of the measured data.

– 6 – IEC 62858:2019 © IEC 2019
LIGHTNING DENSITY BASED ON LIGHTNING LOCATION SYSTEMS –
GENERAL PRINCIPLES
1 Scope
This document introduces and discusses all necessary measures to make reliable and
homogeneous the values of ground flash density, N and ground strike point density, N ,
G SG
obtained from lightning location systems (LLSs) in various countries. Only parameters that are
relevant to risk assessment are considered.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their
content constitutes requirements of this document. For dated references, only the edition
cited applies. For undated references, the latest edition of the referenced document (including
any amendments) applies.
IEC 62305-1, Protection against lightning – Part 1: General principles
IEC 62305-2, Protection against lightning – Part 2: Risk management
3 Terms, definitions, abbreviated terms and symbols
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 62305-1 and
IEC 62305-2 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1.1
ground flash density
N
G
-2 -1
mean number of cloud-to-ground flashes per unit area per unit time (flashes x km x year )
3.1.2
ground strike-point density
N
SG
-2
mean of the number of strike-points to ground per unit area per unit time (strike-points x km
-1
x year )
3.1.3
lightning sensor
device that measures electromagnetic signals produced by lightning discharges

IEC 62858:2019 © IEC 2019 – 7 –
3.1.4
lightning location system
LLS
network of lightning sensors that work together to detect and geolocate lightning events within
the area of the system’s coverage
Note 1 to entry: This note applies to the French language only.
3.1.5
confidence ellipse
ellipse centred on the estimated ground strike-point, describing the degree of confidence of
the location estimation (e.g. 50 %, 90 %, 99 %) based on sensor measurement errors
Note 1 to entry: The confidence ellipse is described in terms of the lengths of the semi-major and semi-minor
axes as well as the bearing of the semi-major axis.
3.1.6
uptime
duration of fully functional operation of a lightning location system sensor, expressed as a
percentage of the total observation time
3.1.7
stroke detection efficiency
flash detection efficiency
percentage of strokes or flashes detected as a percentage of the total number of strokes or
flashes occurring in reality
3.1.8
median location accuracy
value of the distances between real stroke locations and the stroke locations given by the
lightning location system
3.2 Abbreviated terms and symbols
CG cloud-to-ground
DE detection efficiency
GSP ground strike point
IC intra-cloud and inter-cloud
LA location accuracy
LLS lightning location system
N ground flash density
G
N ground strike-point density
SG
4 General requirements
4.1 General
The performance characteristics of a lightning location system (LLS) determine the quality of
the lightning data available for calculating N [1] . A value of N with an error of ±20 % or
G G
less is deemed to be adequate for lightning risk assessment. Data from any LLS that is able
to detect CG lightning and accurately determine the point of strike of CG strokes can be used
for the purpose of N computation. The following LLS performance characteristics are
G
required for computation of N with adequate accuracy.
G
___________
Numbers in square brackets refer to the Bibliography.

– 8 – IEC 62858:2019 © IEC 2019
• Flash detection efficiency (DE): The value of the annual average flash detection efficiency
of an LLS for CG lightning shall be at least 80 % in the region over which N has to be
G
computed. This DE is usually obtained within the interior of the network. The interior of the
network is defined as the region within the boundary defined by the outermost adjacent
sensors of the network.
• Location accuracy (LA): The value of the median location accuracy of an LLS for CG
strokes shall be better than 500 m in the region over which N has to be computed. This
G
LA is usually obtained within the interior of the network.
• Classification accuracy: In a network with a flash DE meeting the criteria set for N
G
calculation, erroneously low or high values of N will be identified when too many CG
G
strokes are misclassified as cloud pulses (or vice versa). This is especially true for single-
.
stroke CG flashes. A classification accuracy (CG flashes not misclassified as IC) of at
least 85% is required.
These performance characteristics of an LLS can be determined using a variety of methods
including network self-referencing (using statistical analysis of parameters such
...