EN IEC 61400-24:2019/FprA1:2024

SLOVENSKI STANDARD
01-oktober-2023
Sistemi za proizvodnjo energije na veter - 24. del: Zaščita pred delovanjem strele -
Dopolnilo A1
Wind energy generation systems - Part 24: Lightning protection
Windenergieanlagen - Teil 24: Blitzschutz
Systèmes de génération d’énergie éolienne - Partie 24: Protection contre la foudre
Ta slovenski standard je istoveten z: EN IEC 61400-24:2019/prA1:2023
ICS:
27.180 Vetrne elektrarne Wind turbine energy systems
91.120.40 Zaščita pred strelo Lightning protection
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

88/965/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 61400-24/AMD1 ED2
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2023-08-11 2023-11-03
SUPERSEDES DOCUMENTS:
88/928/CD, 88/948A/CC
IEC TC 88 : WIND ENERGY GENERATION SYSTEMS
SECRETARIAT: SECRETARY:
Denmark Mrs Christine Weibøl Bertelsen
OF INTEREST TO THE FOLLOWING COMMITTEES: PROPOSED HORIZONTAL STANDARD:

TC 81
Other TC/SCs are requested to indicate their interest, if any, in
this CDV to the secretary.
FUNCTIONS CONCERNED:
EMC ENVIRONMENT QUALITY ASSURANCE SAFETY
SUBMITTED FOR CENELEC PARALLEL VOTING NOT SUBMITTED FOR CENELEC PARALLEL VOTING
Attention IEC-CENELEC parallel voting
The attention of IEC National Committees, members of
CENELEC, is drawn to the fact that this Committee Draft for Vote
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The CENELEC members are invited to vote through the
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be included should this proposal proceed. Recipients are reminded that the CDV stage is the final stage for submitting ISC clauses.
(See AC/22/2007 or NEW GUIDANCE DOC).

TITLE:
Amendment 1 – Wind energy generation systems – Part 24: Lightning protection

PROPOSED STABILITY DATE: 2026
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AMD1 © IEC 2023
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
WIND ENERGY GENERATION SYSTEMS –

Part 24: Lightning protection
AMENDMENT 1
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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rights. IEC shall not be held responsible for identifying any or all such patent rights.
Amendment 1 to IEC 61400-24:2019 has been prepared by IEC technical committee 88: Wind
energy generation systems.
The text of this Amendment is based on the following documents:
Draft Report on voting
XX/XX/XXXX XX/XX/XXX
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this Amendment is English.

IEC CDV 61400-24:2019/ – 3 –
AMD1 © IEC 2023
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications/.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under 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.
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AMD1 © IEC 2023
1 INTRODUCTION
2 This amendment to IEC 61400-24:2019 addresses an update of the content in Annex L
3 regarding monitoring systems for detecting lightning strikes on wind turbines.

IEC CDV 61400-24:2019/ – 3 –
AMD1 © IEC 2023
4 Annex L
5 (informative)
7 Lightning detection and measurement systems
8 L.1 General
9 It is recommended that wind turbines are equipped with systems capable of detecting lightning,
10 measuring its current components, and processing the parameters of the lightning strikes. The
11 purpose of such systems is to:
12 • provide information to the operator on the occurrence of lightning strikes to the wind
13 turbine and to give input to operation and maintenance regimes;
14 • provide valuable data on lightning strikes to wind turbines thus allowing post-
15 assessment of the lightning magnitude/characteristics and contribution to the operator’s
16 risk assessment processes.
17 • enable the operator to compare the measured current parameters of lightning strikes to
18 the lightning protection level, LPL, used for designing the wind turbine lightning
19 protection system (e.g. for assessing if the lightning current intercepted by the LPS is
20 below or above the values defined in Table 1 of IEC61400-24)
21 • avoid hazardous activities such as maintenance when there is a risk of lightning strike.
22 L.1.1 Nomenclature
23 The following nomenclature apply for the current Annex.
24 1) Lightning detection systems
25 a) Thunderstorm warning systems (TWS), detecting lightning by monitoring the
26 electrostatic and electromagnetic fields
27 b) Lightning Location systems (LLS), locate individual cloud-to-ground and intra-cloud
28 discharges (e.g. return strokes, Intra-Cloud pulses) in lightning flashes based on
29 direction finding (magnetic or interferometry), difference of time of arrival or both.
30 2) Lightning measurement systems (LMS), measuring lightning events and their features with
31 devices installed on the turbine. These systems range from a combination of simple
32 electromechanical event counters to complex systems measuring and analyzing lightning
33 parameters.
34 L.2 Benefits of lightning detection and measurement systems
35 There are many benefits of measuring actual lightning exposure. Depending on the specific
36 stakeholder, a non-exhaustive list is included in Tables L.1 – L.3. The industry is encouraged
37 to share lightning data across all stakeholders (OEM/Owner/Insurance), to ensure benefits
38 across the entire value chain.
39 Table L.1 – Considerations and benefits for the OEM (Original Equipment Manufacturer)
Statement Value Aspect
For turbines delivered with long service contracts, the OEM (Original This enables condition-based
Equipment Manufacturer) with a service contract would like to know when maintenance or repair, lowering
the receptor/LPS has reached the design lifetime and needs to be downtime and unexpected damage
replaced. This can be achieved by monitoring the accumulated charge and costs significantly. Maintenance is
specific energy for each blade and correlating with test performance of the cheaper than repair.
receptor/LPS.
The OEM would like to know all information of strikes, to determine the This information is used to market
efficiency of the receptors/LPS (the observed number of strikes intercepted the OEM products, “with a field
correctly divided by the total number of strikes to the turbine/blade efficiency of XX%, our turbines
observed – section 3.12) comply fully with YY”.

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Every strike will be different, and cross correlating strike information with Get more information on the
other sensor signals can provide valuable information to the OEM to fully lightning susceptibility of the
understand the turbine operation and design performance. turbines, to enable stronger and
cheaper designs for future turbines.
Turbine LPS have developed intensively during the past 10-20 years, and OEMs By measuring all strikes in field,
are still following different paradigms for the design and verification air evaluating the strike parameters, and
terminations, down conductors and lightning coordination with additional comparing them to design performance
from laboratory tests and/or modelling
conductive components like CFRP.
verification, the consequence of specific
strikes can be assessed.
If a blade design, known from verification tests or modelling, is challenged by
certain features of the lightning current, an active monitoring of the lightning
exposure will allow targeted maintenance. By evaluating the consequence of each
lightning event, maintenance and
Not all lightning strikes exhibit the same strike parameters, hence the consequence inspections can be tailored and
optimized.
of strikes will differ.
In case lightning damages occur, the detailed measurements of the lightning Enable the discussion on splitting costs
parameters can be used to assign and split the cost of repair between OEM and of blade damages based on lightning
owner/operator. impact.
41 Table L.2 – Considerations and benefits for owner and/or operator
Statement Value Aspect
The operator would like to know if a lightning flash exceeded IEC LPL Lightning damage is paid by the
current parameters to which the turbine has been certified as this is useful responsible party.
information in relation to warranty and insurance.
The owner and/or operator would like to know if a lightning flash was In case the measurement can be
potentially dangerous to the turbine. used to identify a strike as
representing a risk, the turbine
could be checked (online or on site)
before it is restarted. This could
prevent further damage on the
turbine.
The Owner and/or Operator would like to know when the receptor and/or This enables condition-based
LPS has reached the design lifetime and needs to be replaced. This is maintenance/repair, lower downtime
performed by monitoring the accumulated charge and/or specific energy in and unexpected damage cost
each blade and correlating it with the receptor and/or LPS performance as significantly. Maintenance is
proven by testing according to Annex D. cheaper than repair.
Additionally, the collection of lightning exposure will enable a
determination of potential LPS performance degradation.
A correlation of lightning performance across large fleets with LMS, will Enable the Owner to select turbines
provide knowledge on the performance of a specific design, and enable with documented good experience
customisation of the LPS design to specific site conditions (altitude, on the lightning performance, as
lightning regime, number of WTs in the WF, etc required by the specific site.
Every
...