Revision of Wind Farm Certification Onshore Wind Power Plant Edition (NKRE-GL-WFC01)
Comparison Table for Previous and New Versions[After revision: Edition: March 2023  Before revision: July 2021 (October 2021 Error Correction Edition)]
March 31, 2023
NIPPON KAIJI KYOKAI (ClassNK)▪ The underlined parts of the provisions listed in the "Before revision" column shall be amended to the underlined parts of the corresponding provisions listed in the"After revision" column.
▪ Where a provision is marked with double lines in the "Before revision" column and there is no corresponding provision in the "After revision" column, that provision
shall be deleted.
▪ Where a provision is marked with double lines in the “After revision” column and there is no corresponding provision listed in the "Before revision" column, thatprovision shall be added.
< Main points of revision >1) Reflection of 20140328 Bureau of Commerce No. 1 "Interpretation of Technical Standards for Wind Power Generation Facilities" (Revision 20230310 Bureau No. 2).
-

Action for amendment effective December 26, 2022, and amendment effective March 20, 2023.

2) Revisions to respond to the following items in accordance with the amendment of the Electricity Business Act executed on March 20, 2023.
-

In connection with the abolition of the “Implementation procedures for the examination of construction plans for the installation or modification of wind power plants”(Ministry of Economy, Trade and Industry, No.20210518, Bureau No. 1, May 24, 2021), from the viewpoint of ensuring the continuity of examinations, the contents
written in those Implementation procedures were incorporated into this document.

-

In connection with the start of the system of registered conformity assessment bodies, as a response to this system, some items were added to address all of therequirements of Articles 4, 5 and 7 of the Ministerial Ordinance Prescribing Technical Standards for Wind Power Generation Facilities (Ministry of Economy, Trade andIndustry Ordinance of the Ministry of International Trade and Industry No. 53, final revision: Ordinance of the Ministry of Economy, Trade and Industry No. 32 of March
31, 2017).

3) Incorporation of requirements that have been generalizable in the course of performing the individual examinations for wind farm certification to date.
-Partial revision of contents of Annexes A, B, C and F.

-Foundation design requirements were added in Chapters 2, 3, 4 and 6, and Annex G was newly added.

4) The items are specified as requirements, which were often commented in the individual evaluations for wind farm certification performed in the past.
End
1 / 44

Cover and revision history
After revision

Before revision

New issue NKRE-GL-WFC01, Edition: July 2021

New issue NKRE-GL-WFC01, Edition: July 2021

July 31, 2021

July 31, 2021

Partial revision (document number unchanged) NKRE-GL-WFC01, Edition: July 2021

Partial revision (document number unchanged) NKRE-GL-WFC01, Edition: July 2021

October 1, 2021

October 1, 2021

Partial revision NKRE-GL-WFC01, Edition: March 2023

(added)March 31, 2023

Revision History

Revision History

I.

(Omitted)I.

II.

New issue dated March 31, 2023 (Document No.: NKRE-GL-WFC01, Edition: March 2023)(added)EFFECTIVE DATE and APPLICATION
1. These guidelines shall be enforced from April 1, 2023.
2. Notwithstanding the provisions of these guidelines, the provisions then in force shallremain applicable to power plants other than those falling under any of the following.
(1)

Power plants for which the application for examination pertaining to wind farm
certification is accepted on or after June 1, 2023

(2)

Power plants for which the initial certification document of wind farm
certification is issued on or after September 1, 2023

3. Regardless of 1 and 2 above, it should be noted that for provisions, etc., based on the requirements
shown below from Chapter 1, 1.1.1-3. of these Guidelines, the application shall be from theeffective date of that provision, etc.
1) 20140328 Bureau of Commerce No. 1 "Interpretation of Technical Standards for Wind Power
Generation Facilities" (revised 20230310 Bureau No. 2)
2 / 44(Omitted)After revision

Before revision

2) Annotations to the Ministerial Ordinance Prescribing Technical Standards for Wind Power
Generation Facilities and its Interpretation (Ministry of Economy, Trade and Industry, revisedon March 20, 2023)

3 / 44

Chapter 1 General
After revision
1.1

Before revision

General

1.1

General1.1.1 to 1.1.3 (Omitted)

1.1.1 to 1.1.3 (Omitted)

1.2

1.2

1.2.1
-1.

Normative References
General1.2.1

The following standards are the normative references for wind farm certification that are specified-1.

Normative References
GeneralThe following standards are the normative references for wind farm certification that are specified

in the "Sector-specific guidelines for ‘accreditation criteria’ - Wind power generation systems: windin the "Sector-specific guidelines for ‘accreditation criteria’ - Wind power generation systems: windfarms, projects -" (JAB PD366:2017) document produced by the Japan Accreditation Board, excluding

farms, projects -" (JAB PD366:2017) document produced by the Japan Accreditation Board, excluding

those for offshore and small wind turbines. Where an anno domini year is written for these cited

those for offshore and small wind turbines. Where an anno domini year is written for these citedstandards, the version of the year mentioned shall apply, and subsequent revised versions (including

standards, the version of the year mentioned shall apply, and subsequent revised versions (including

Supplements) shall not apply. If there is no anno domini year written for a cited standard, the most recent

Supplements) shall not apply. If there is no anno domini year written for a cited standard, the most recent

version (including Supplements) shall apply.

version (including Supplements) shall apply.

[J-01]JIS C 1400-1:2017 : Wind Energy Generation Systems-Part 1: Design requirements[J-01]JIS C 1400-1:2017 : Wind Energy Generation Systems-Part 1: Design requirements[J-02]IEC 61400-1:2019 : Wind energy generation systems - Part 1: Design requirements[J-02]IEC 61400-1:2019 : Wind energy generation systems - Part 1: Design requirements[J-03]

Ministerial Ordinance Prescribing Technical Standards for Wind Power Generation[J-03]

Ministerial Ordinance Prescribing Technical Standards for Wind Power Generation[J-04]

Facilities (Ministry of Economy, Trade and Industry, Ordinance of the Ministry ofFacilities (Ministry of Economy, Trade and Industry, Ordinance of the Ministry ofInternational Trade and Industry No. 53, final revision: Ordinance of the Ministry ofInternational Trade and Industry No. 53 of March 27, 1997, final revision: Ordinance of

Economy, Trade and Industry No. 32 of March 31, 2017)

the Ministry of Economy, Trade and Industry No. 32 of March 31, 2017)[J-04]

20140328 Bureau of Commerce No. 1 "Interpretation of Technical Standards for Wind
Power Generation Facilities" (Revision 20230310 Bureau No. 2)[J-05]

Economy, Trade and Industry, No. 20140328, Bureau of Commerce No. 1, April 1, 2014)

Guidelines for Design of Wind Turbine Support Structures and Foundation [2010[J-05]

version] (Japan Society of Civil Engineers)[J-06]-2.

Interpretation of Technical Standards for Wind Power Generation Facilities (Ministry of
Guidelines for Design of Wind Turbine Support Structures and Foundation [2010version] (Japan Society of Civil Engineers)

Germanischer Lloyd (GL) Guideline for the Certification of Wind Turbines 2010

[J-06]In order to meet the requirements of the standards listed in -1 above, the following standards-2.

Germanischer Lloyd (GL) Guideline for the Certification of Wind Turbines 2010

In order to meet the requirements of the standards listed in -1 above, the following standards

referenced by these guidelines shall form part of the provisions. Where an anno domini year is writtenreferenced by these guidelines shall form part of the provisions. Where an anno domini year is written

for these cited standards, the version of the year mentioned shall apply, and subsequent revised versions

for these cited standards, the version of the year mentioned shall apply, and subsequent revised versions(including Supplements) shall not apply. If there is no anno domini year written for a cited standard, the(including Supplements) shall not apply. If there is no anno domini year written for a cited standard, themost recent version (including Supplements) shall apply.

most recent version (including Supplements) shall apply.

[R-01]NKRE-SP-0003 Wind Farm Certification Procedures, Edition October 2021

[R-01]NKRE-SP-0003 Wind Farm Certification Procedures, Edition February 2021

[R-02]

Annotations to the Ministerial Ordinance Prescribing Technical Standards for Wind

[R-02]

Annotations to the Ministerial Ordinance Prescribing Technical Standards for Wind

Power Generation Facilities and its Interpretation (Ministry of Economy, Trade and4 / 44

Power Generation Facilities and its Interpretation (Ministry of Economy, Trade andAfter revision

Before revision

Industry, revised on March 20, 2023)

Industry, revised on June 21, 2021)[R-03](Deleted)

Implementation procedures for the examination of construction plans for the installation
or modification of wind power plants (Ministry of Economy, Trade and Industry,
No.20210518, Bureau No. 1, May 24, 2021)[R-03]

Recommendations for Design of Building Foundations (Architectural Institute of Japan,[R-04]

2019)[R-04]

2019)

Guidebook on Design and Fabrication of High Strength Bolted Connections[R-05](Architectural Institute of Japan, 2003)[R-05]

Structural Design Recommendation for Chimneys (Architectural Institute of Japan,
JIS C 1400-12-1:2010

Guidebook on Design and Fabrication of High Strength Bolted Connections(Architectural Institute of Japan, 2003)[R-06]

2007)[R-06]

Recommendations for Design of Building Foundations (Architectural Institute of Japan,

Structural Design Recommendation for Chimneys (Architectural Institute of Japan,
2007): Wind turbines - Part 12-1: Power performance[R-07]JIS C 1400-12-1:2010

measurements of electricity producing wind turbines

measurements of electricity producing wind turbines[R-07]JIS C 1400-24:2014: Wind turbines - Part 24: Lightning protection[R-08]JIS C 1400-24:2014: Wind turbines - Part 24: Lightning protection[R-08]IEC 61400-6:2020: Wind energy generation systems - Part 6: Tower and[R-09]IEC 61400-6:2020: Wind energy generation systems - Part 6: Tower andfoundation design requirements[R-09]IEC 61400-13:2015

foundation design requirements: Wind turbines - Part 13: Measurement of mechanical[R-10]IEC 61400-13:2015

loads

1.3

: Wind turbines - Part 13: Measurement of mechanicalloads[R-10]

ISO 273:1979: Fasteners - Clearance holes for bolts and screws[R-11]

ISO 273:1979: Fasteners - Clearance holes for bolts and screws[R-11]

ISO 4354:2009: Wind actions on structures[R-12]

ISO 4354:2009: Wind actions on structures[R-12]

EN 1993-1-9:2005: Design of steel structures - Part 1-9: Fatigue[R-13]

EN 1993-1-9:2005: Design of steel structures - Part 1-9: Fatigue[R-13]

fib Model Code for Concrete Structures 2010(CEB-FIP Model Code 2010)[R-14]

fib Model Code for Concrete Structures 2010 (CEB-FIP Model Code 2010)[R-14]

CEB-FIP Model Code 1990

[R-15]

CEB-FIP Model Code 1990

[R-15]DNVGL-ST-0126 Support structures for wind turbines, Edition April 2016

[R-16]DNVGL-ST-0126 Support structures for wind turbines, Edition April 2016

[R-16]MEASNET Evaluation of Site-Specific Wind Conditions, Version 2, April 2016

[R-17]MEASNET Evaluation of Site-Specific Wind Conditions, Version 2, April 2016

[R-17]IEC 61400-12-1:2017[R-18]IEC 61400-12-1:2017

Definitions and abbreviations: Wind energy generation system - Part 12-1: Powerperformance measurements of electricity producing

wind turbines

wind turbines
1.3

Definitions and abbreviations

1.3.1 to 1.3.3 (Omitted)

1.4

1.4

Wind farm certification
General: Wind energy generation system - Part 12-1: Powerperformance measurements of electricity producing

1.3.1 to 1.3.3 (Omitted)
1.4.1: Wind turbines - Part 12-1: Power performance

1.4.1
5 / 44Wind farm certification
GeneralAfter revision

Before revision-1. to -2. (Omitted)-1. to -2. (Omitted)

-3.

-3.

The purpose of wind farm certification is to assess whether the design of type-certified wind

The purpose of wind farm certification is to assess whether the design of type-certified windturbines (RNA) and support structure (towers and foundations) are in conformity with the externalturbines (RNA) and support structure (towers and foundations) are in conformity with the external

conditions and the requirements under the Electricity Business Act, specifically, to confirm complianceconditions and the requirements under the Electricity Business Act.

with Articles 4, 5 and 7 of the Technical Standards for Wind Power Generation Facilities[J-03].
-4.

The prerequisites for the issuance of wind farm certification are the conditions that the wind turbine-4.

In principle, wind farm certification is not permitted for power plants that use wind turbines (RNA)(RNA) and tower must have obtained type certification, and that the manufacturing of the wind turbine

or towers that have not obtained type certification. However, in the case of a wind turbine which has(RNA) and tower and their main parts and components must have been carried out at a place specified

acquired a design evaluation conformity statement and is carrying out type testing for the acquisition ofin the type certification. The handling of deviations from these conditions is specified in Chapter 5 fortype certification, the wind farm certification may be issued on the condition that the acquisition of thethe wind turbines (RNA) and in Chapter 6 for the towers.

type certification is set as an outstanding issue and a time limit for the solution of that outstanding issue
is established.

-5.

-5.

(Omitted)(Omitted)

1.4.2 to 1.4.8 (Omitted)

1.4.2 to 1.4.8 (Omitted)

1.4.9

1.4.9

Certification subcommittee

Certification subcommittee-1. to -2. (Omitted)-1. to -2. (Omitted)(Deleted)-3.

In addition to -2. above, in cases where the requirements for general facilities do not apply as aresult of the Implementation procedures for the examination of construction plans for the installation or
modification of wind power plants[R-02], after the examination by ClassNK is completed, a place may beestablished where the requester directly explains the content of the construction plan to thesubcommittee/section meeting members based on the results of the examination by ClassNK. The only
language accepted for the materials used for explanation in the relevant subcommittee/section meetingshall be Japanese.
-3.

In principle, the format when the Support Structure Certification Subcommittee Foundation and-4.

In principle, the format when the Support Structure Certification Subcommittee Foundation and

Ground Section Meeting is held shall be that the requester directly explains the contents related to the

Ground Section Meeting is held shall be that the requester directly explains the contents related to theitems to be examined to the members of the section meeting. The only language accepted for the materials

items to be examined to the members of the section meeting. The only language accepted for the materials

used for explanation in the relevant section meeting shall be Japanese.

used for explanation in the relevant section meeting shall be Japanese.

Table 1-4 Certification subcommittee/section meeting
Certification subcommittee
Large Wind Turbine Certification

Table 1-4 Certification subcommittee

Items to be examined

Certification subcommittee
Large Wind Turbine Certification(Omitted)

Subcommittee

Subcommittee
6 / 44

Items to be examined(Omitted)After revision

Before revision

Support Structure Certification[M3] The Support structure design evaluation (Tower)

Support Structure Certification[M3] The Support structure design evaluation (Tower)

Subcommittee[including site conditions assessment, design basis evaluation

Subcommittee[including site conditions assessment, design basis evaluation

Tower Section Meetingand integrated load analysis] items that deviate from theTower Section Meetingand integrated load analysis] items that deviate from the

Guidelines for Design of Wind Turbine Support Structures

Guidelines for Design of Wind Turbine Support Structuresand Foundation[J-05]

and Foundation[J-05]*Among the items to be examined by the Tower Section(added)Meeting as deviations from the Guidelines for Design ofWind Turbine Support Structures and Foundation[J-05], theitems for which the corresponding design methods have been
established are summarized in Annex F. If there is deviationin an item not listed in Annex F, or if a method that is different
to the methods listed in Annex F is to be applied, therequirements shall be determined separately by the Tower
Section Meeting.
Support Structure Certification[M4] The Support structure design evaluation (Foundation)

Support Structure Certification[M4] The Support structure design evaluation (Foundation)

Subcommittee[including site conditions assessment, design basis evaluation

Subcommittee[including site conditions assessment, design basis evaluation

Foundation and Ground Section

and integrated load analysis] items that deviate from theFoundation and Ground Section

and integrated load analysis] items that deviate from theMeeting

Guidelines for Design of Wind Turbine Support Structures

Meeting

Guidelines for Design of Wind Turbine Support Structuresand Foundation[J-05]

and Foundation[J-05]*Among the items to be reviewed by the Foundation and(addhed)Ground Section Meeting as deviations from the Guidelines
for Design of Wind Turbine Support Structures andFoundation[J-05] the items for which the corresponding design
methods have been established are summarized in Annex G.
If there is deviation in an item not listed in Annex G, or if amethod that is different to the methods listed in Annex G is tobe applied, the requirements shall be determined separatelyby the Foundation and Ground Section Meeting.
1.5 Documents to be submitted

1.5 Documents to be submitted

1.5.1 to 1.5.3 (Omitted)

1.5.1 to 1.5.3 (Omitted)

1.5.4 Materials related to wind turbine (RNA) design evaluation

1.5.4 Materials related to wind turbine (RNA) design evaluation
7 / 44

After revision

Before revision-1. (Omitted)-1. (Omitted)(1) to (6) (Omitted)(1) to (6) (Omitted)(7) Of the items among the wind turbine structural drawings and strength calculation documents(added)(including details related to construction) to be attached to the construction plan notification based on
the Electricity Business Act, the items which are not included in (1) to (6) above.
(8) Materials summarizing the measures for safely stopping wind turbines specified in 5.5.2 and the(7) Materials summarizing the measures for safely stopping the wind turbine as specified in 5.5.1, andresults of the strength evaluation associated with those measures (It is acceptable for this to be thethe results of the strength evaluation associated with those measures (added)"Explanation of the measures for the safe and automatic stopping of the wind turbine when the rotational
speed has increased significantly, or when the functioning of the control equipment for the wind turbine
has significantly deteriorated," which is an explanation to be attached to the construction plan notification
based on the Electricity Business Act)
(9) Materials summarizing the measures taken to protect against lightning strikes specified in 5.5.3 (It is(8) Materials summarizing the measures taken to protect against lightning strikes as specified in 5.5.2

acceptable for this to be the "Explanation of the protection of the wind turbine against lightning strikes,"(added)which is to be attached to the construction plan notification based on the Electricity Business Act)
(10) Explanation of the power generation method, which is to be attached to the construction plan
notification based on the Electricity Business Act(added)1.5.5 Materials related to the support structure (Tower) design evaluation

1.5.5 Materials related to the support structure (Tower) design evaluation-1. (Omitted)-1. (Omitted)(1) to (4) (Omitted)(1) to (4) (Omitted)(5) Report including the results of consideration of the items specified in 6.2 (If there are items that(5) Report including the results of consideration of the items specified in 6.2 (added)

deviate from the Guidelines for Design of Wind Turbine Support Structures and Foundation[J-05], it must
include items for the contents of Annex F.)(6) (Omitted)(6) (Omitted)(7) Of the items among the support structure structural drawings and strength calculation documents(added)(including details related to construction) to be attached to the construction plan notification based on
the Electricity Business Act, the items which are not included in (1) to (6) above.
(8) Materials summarizing the details listed below for the tower manufacturing evaluation.
1) If a tower described in the type certification will be selected (including the selection of the
manufacturing plant described in the type certification), then the expected timing of thedecision on the manufacturing plant.
2) In cases other than 1) above, the policy related to the manufacturing evaluation, and the estimated
8 / 44

After revision

Before revision

timing of the decision on that policy.
-2. If no application for examination for the support structure (Foundation) design evaluation is made,(Deleted)

the following documents shall be submitted to ClassNK from among the examination materials specified
in 1.5.6-1.
(1)

Of the support structure strength calculation documents attached to the construction plan
notification based on the Electricity Business Act, a report that corresponds to the following
details-

Geotechnical investigation-

Seismic response analysis-

Work execution plan-

Special materials-

Foundation drawings around tower anchorage zone

1.5.6 Materials related to the support structure (Foundation) design evaluation

1.5.6 Materials related to the support structure (Foundation) design evaluation-1. (Omitted)-1. (Omitted)(1)

Support structure structural drawings and strength calculation documents (including details(1)

related to construction) to be attached to the construction plan notification based on the

Support structure strength calculation documents attached to the construction plan notification
based on the Electricity Business Act

Electricity Business Act
(2)

(2)

Explanatory materials for the following items related to the support structure design (in case theOverview materials on the support structure design (in case the Support Structure Certification

Support Structure Certification Subcommittee Foundation and Ground Section Meeting

Subcommittee Foundation and Ground Section Meeting specified in 1.4.9-4. is to be hold)specified in 1.4.9-3. is to be hold)(added)-Overview of the power plant plan-

Items that deviate from the Guidelines for Design of Wind Turbine Support Structuresand Foundation[J-05] related to foundation design, and details of the handling policy andstudy items related to them (including the details related to the applicable items in Annex
G.)-

Overview of structural design of support structure

1.6 Correspondence to the Technical Standards for Wind Power Generation Facilities [Reference]

1.6 Correspondence to the Technical Standards for Wind Power Generation Facilities [Reference]

1.6.1 General

1.6.1 General-1. (Omitted)-1. (Omitted)

Table 1 -5 Correspondence between the Technical Standards for Wind Power Generation Facilities andTable 1-5 Correspondence between the Technical Standards for Wind Power Generation Facilities and9 / 44

After revision

Before revision

the requirements of these guidelines

the requirements of these guidelines

Technical Standards for Wind Power Generation Facilities

Related items in these(Excerpts from the original text, and temporary translation)

guidelines(As left)(As left)(Scope)-(Scope)(added)(Omitted)(Deleted)(Omitted)

Chapter 1. General(Definitions)(Omitted)(Definitions)(Omitted)(Omitted)(Hazard prevention measures for persons other than operators)(Omitted)(Hazard prevention measures for persons other than operators)(Omitted)(Omitted)(Omitted)(Wind turbine)(Wind turbine)(Omitted)(Deleted)(Omitted)(Omitted)

2.Site conditions assessment
3. Design basis evaluation
4. Integrated load analysis
evaluation
5. Wind turbine (RNA) design
evaluation< Item (i) >(added)▪ [Interpretation] Article 3
Paragraphs 1 to 3
- 1.4.1-3., 1.5.2- 5.5.2< Item (ii) >▪ [Interpretation] Article 4
Paragraphs 1 to 2
- 2.1, 2.2, 2.3- Annex A- Annex B- Annex C▪ [Interpretation] Calculationof wind pressure in Article
4 Paragraph 1, and
10 / 44After revision

Before revision
Paragraphs 3 and 4- 3.2.2- 4.2- Chapter 5▪ [Interpretation] Article 4
Paragraph 5- Not covered< Item (iii) >▪ [Interpretation] Article 5- 5.5.2-2.
< Item (iv) >▪ [Interpretation] Article 6- 5.5.2-2.
< Item (v) >- 5.5.1(Ensuring the safety of wind turbines)(Omitted)(Ensuring the safety of wind turbines)(Deleted)(Omitted)

2.Site conditions assessment
5. Wind turbine (RNA) design
evaluation< Paragraph 1 >(added)▪ [Interpretation] Article 7
Paragraphs 1 to 3
- 5.5.2-1.
< Paragraph 2 >▪ [Interpretation] Article 7
Paragraphs 4 to 5
- Not covered< Paragraph 3 >▪ [Interpretation] Article 7
Paragraph 6
11 / 44After revision

Before revision- 2.5- 5.5.3(Prevention of dangers of oil pressure systems and compressed(Omitted)(Prevention of dangers of oil pressure systems and compressed

air devices)

air devices)(Omitted)(Structure to support the wind turbine)(Omitted)(Omitted)(Deleted)(Omitted)(Structure to support the wind turbine)

2.Site conditions assessment(Omitted)

3. Design basis evaluation
4. Integrated load analysis
evaluation
6. Support structure design
evaluation< Paragraph 1 >(added)▪ [Interpretation] Article 9
Paragraph 1- 2.1, 2.2, 2.3, 2.4, 2.6- 3.2.3- 4.3▪ [Interpretation] Article 9
Paragraph 2- Chapter 6▪ [Interpretation] Article 9
Paragraph 3- Chapter 6▪ [Interpretation] Article 10- 3.2.3▪ [Interpretation] Article 11- 3.2.3▪ [Interpretation] Article 12- 2.4, 2.6- 3.2.3- 4.3
12 / 44After revision

Before revision- Chapter 6▪ [Interpretation] Article 13- Chapter 6▪ [Interpretation] Article 14- Chapter 6▪ [Interpretation] Article 15- Chapter 6▪ [Interpretation] Article 16
Paragraph 1- 1.2.2▪ [Interpretation] Article 16
Paragraph 2- Not covered▪ [Interpretation] Article 17
Paragraph 1- Chapter 6▪ [Interpretation] Article 16
Paragraph 2- Not covered< Paragraph 2 >- Not covered(Prevention of pollution, etc.)(Omitted)(Omitted)(Prevention of pollution, etc.)(Omitted)

13 / 44(Omitted)

Chapter 2. Site conditions assessment
After revision

Before revision

2.1 General

2.1 General

2.1.1 General

2.1.1 General-1. to -2. (Omitted)-1. to -2. (Omitted)-3. The wind conditions shall be summarized in accordance with Annex C.4.

(added)2.2 Wind conditions during power production

2.2 Wind conditions during power production

2.2.1 Wind condition measurement

2.2.1 Wind condition measurement-1. to -2. (Omitted)-1. to -2. (Omitted)-3. As shown in Table 2.1, the observed height shall be not less than 2/3 of the planned hub height,-3. As shown in Table 2.1, the observed height shall be not less than 2/3 of the planned hub height,

regardless of the topography class. Also, in order to appropriately evaluate the wind shear, the principle

regardless of the topography class. The distance between the measurement point and the wind turbine

shall be to perform observation at three altitudes or more. In addition, the distance between theconstruction point must be within the representative radius corresponding to the topographic complexity

measurement point and the wind turbine construction point must be within the representative radius

as shown in Table 2.1.

corresponding to the topographic complexity as shown in Table 2.1.
-4. to -5. (Omitted)-4. to -5. (Omitted)-6. When measurement must be carried out in the vicinity of an existing wind turbine that is in operation,(added)a point which is not affected by the wake of the existing wind turbine must be selected. In addition,
Annex A.6 may be followed if observations are to be made at a point where the wake effect of an existing
wind turbine cannot be excluded.
-7. The results of the wind condition measurement must be summarized in accordance with Annex A.5.
2.2.2 Measurement data evaluation

2.2.2 Measurement data evaluation-1. to -4. (Omitted)-1. to -4. (Omitted)-5. Regarding wind condition measurement data, comparison with normal year values must be carried-5. Regarding wind condition measurement data, comparison with normal year values must be carriedout using reference data that have a correlation coefficient of 0.8 or higher with the wind conditionout using appropriate reference data such as reanalysis data by a meteorological model and long-term

measurement data, such as reanalysis data by a meteorological model and long-term measurement datameasurement data from a meteorological observatory close to the site, and appropriate corrections mustfrom a meteorological observatory close to the site, and appropriate corrections must be made.

be made.

-6. to -8. (Omitted)-6. to -8. (Omitted)-9. For measurement data from remote sensing equipment, it shall be kept in mind that appropriate(added)correction will be required according to the complexity of the topography and the characteristics of theobservation methods of the equipment used.
2.2.3 Evaluation of topographic complexity

2.2.3 Evaluation of topographic complexity-1. In order to select a model for airflow analysis and to evaluate the number of wind direction sectors,-1. In order to select a model for airflow analysis and to evaluate the number of wind direction sectors,

14 / 44After revision

Before revision

the turbulence structure correction parameters (hereinafter, 𝐶𝐶𝐶𝐶𝐶𝐶 ) must be calculated for the measurement

position (measurement mast and remote sensing equipment) and the wind turbine position in order tothe turbulence structure correction parameters (hereinafter, 𝐶𝐶𝐶𝐶𝐶𝐶 ) must be calculated for the measurement

judge the topographic complexity at each position. The specific method of judgment shall follow one of

The specific method of judgment shall follow one of the following.

mast position and the wind turbine position in order to judge the topographic complexity at each position.

the following.
(1) to (2) (Omitted)(1) to (2) (Omitted)-2. (Omitted)-2. (Omitted)

2.2.4 Airflow analysis

2.2.4 Airflow analysis-1. to -3. (Omitted)-1. to -3. (Omitted)

2.2.5 Calculation of the wind speed appearance frequency distribution

2.2.5 Calculation of the wind speed appearance frequency distribution-1. (Omitted)-1. (Omitted)(Deleted)-2. In addition to the appearance frequency by direction, the energy density by direction must also be
calculated.

-2. (Omitted)-3. (Omitted)

2.2.6 Calculation of turbulence intensity

2.2.6 Calculation of turbulence intensity-1. to -5. (Omitted)-1. to -5. (Omitted)

2.2.7 Evaluation of wind turbine wake effect from adjacent wind turbines

2.2.7 Evaluation of wind turbine wake effect from adjacent wind turbines-1. to -2. (Omitted)-1. to -2. (Omitted)-3. For the consideration of the effects of ambient turbulence and discrete turbulent wakes, it is possible-3. For the consideration of the effects of ambient turbulence and discrete turbulent wakes, it is possible

to use the effective turbulence intensity (hereinafter, 𝐼𝐼𝑒𝑒𝑒𝑒𝑒𝑒 ). This 𝐼𝐼𝑒𝑒𝑒𝑒𝑒𝑒 shall be calculated using the model

to use the effective turbulence intensity (hereinafter, 𝐼𝐼𝑒𝑒𝑒𝑒𝑒𝑒 ). This 𝐼𝐼𝑒𝑒𝑒𝑒𝑒𝑒 shall be calculated using the model

given in either of the following. Also, for the extreme turbulence intensity including the wake effects, it

given in either of the following. (added)

is acceptable to use the maximum turbulence at the center of the wake in the most severe direction.
(1)

JIS C 1400-1:2017[J-01], Annex D (IEC 61400-1 Ed.3.1, Annex D)(2)

IEC 61400-1:2019 [J-02], Annex E(1)

JIS C 1400-1:2017[J-01], Annex D (IEC 61400-1 Ed.3.1, Annex D)(2)

IEC 61400-1:2019 [J-02], Annex E-4. (Omitted)-4. (Omitted)(Deleted)-5. For the extreme turbulence including the wake effects, it is possible to use the maximum turbulenceat the center of the wake in the most severe direction.

2.2.8 Calculation of the wind shear exponent

2.2.8 Calculation of the wind shear exponent-1. to -3. (Omitted)-1. to -3. (Omitted)

2.2.9 Calculation of flow inclination angle

2.2.9 Calculation of flow inclination angle-1. to -3. (Omitted)-1. to -3. (Omitted)
15 / 44After revision

Before revision

2.2.10 Calculation of atmospheric density

2.2.10 Calculation of atmospheric density-1. to -2. (Omitted)-1. to -2. (Omitted)

2.3 Wind conditions during parked by storm

2.3 Wind conditions during parked by storm

2.3.1 Calculation of extreme wind speed and turbulence intensity

2.3.1 Calculation of extreme wind speed and turbulence intensity-1. to -2. (Omitted)-1. to -2. (Omitted)-3. If a typhoon simulation is used in the calculation in -1. above, the validity must be sufficiently(added)confirmed by comparing the simulation results (upper air winds due to the hypothetical typhoon) withthe measured values (upper air winds calculated from the atmospheric pressure in the typhoon database).
If the result of the comparison of the simulation results and the measured values is that the simulation
results are an underestimation, additional consideration must be given to the effects of uncertainty related
to the number of years of analysis and the number of years of atmospheric pressure measurement. In
addition, the validity of the setting of the wind direction to be verified must be sufficiently confirmed.
-4. (Omitted)-3. (Omitted)-5. (Omitted)-4. (Omitted)-6. (Omitted)-5. (Omitted)

2.3.2 Calculation of atmospheric density

2.3.2 Calculation of atmospheric density-1. (Omitted)-1. (Omitted)

2.4 Geotechnical and earthquake conditions

2.4 Geotechnical and earthquake conditions

2.4.1 General

2.4.1 General-1. (Omitted)-1. (Omitted)(1) (Omitted)(1) (Omitted)(2) Interpretation of Technical Standards for Wind Power Generation Facilities[J-04](added)(3) (Omitted)(2) (Omitted)-2. The following points shall be taken into consideration when setting the conditions in accordance with

-2. The following points shall be taken into consideration when calculating the conditions in accordance-1. above.

with -1. above.

(1) (Omitted)(1) (Omitted)

(2)

(2)

When setting the engineering base surface, as the conditions for applying one-dimensional wave

When setting the engineering base surface, it must be confirmed that the shear wave velocity is 400

theory, it must be confirmed that the shear wave velocity is 400 m/s or higher, the layer thickness

m/s or higher, the layer thickness is 5 m or higher, and the inclination is 5 degrees or less (conditions

is 5 m or higher, and the inclination is 5 degrees or less. If there is deviation from the aboveof application of one-dimensional wave theory). (added)

conditions, the effect must be examined, and the applicability of one-dimensional wave theory
must be confirmed.
16 / 44After revision(3)

Before revision

If the spread foundations are on sloping ground, the effect of the decreased ultimate bearing capacity(added)must be considered.
(4)

If the planned construction site is weak ground, it must be taken into consideration that negative(added)frictional forces may become significant.
(5)

If the planned construction site falls within the target area specified in the MLIT Housing Bureau(added)Building Guidance Division Notice No. 1111 of June 24, 2016, the existence of effects from longperiod ground motion must be examined.
(6) (Omitted)(4) (Omitted)(7) (Omitted)(5) (Omitted)(8)(added)When making a liquefaction judgment, it should be noted that the simplified method can only beapplied to a depth of up to 20 m. When making a liquefaction judgment when the liquefied layer is
continuous beyond a depth of 20 m, the cyclic shear stress must be calculated using ground response
analysis.

(9)

When the planned construction site is near the edge of water line and there is a risk of liquefaction,(added)the following points must be checked and the existence of effects from lateral flow must be checked.
In addition, if there is a possibility of lateral flow occurring, the amount of lateral flow (flow power,
residual deformation, etc.) must be appropriately considered.
- The inclination of the ground surface and the thickness and inclination of the liquefied layer.
(For the inclination, both the direction parallel to the edge of water line and the direction
perpendicular to it must be checked.)- Distance to the edge of water line.
- If the edge of water line has shore protection, the shape of it.
(10) (Omitted)(3) (Omitted)-3. (Omitted)-3. (Omitted)

2.5 Lightning environment conditions

2.5 Lightning environment conditions

2.5.1 General

2.5.1 General-1. to -2. (Omitted)-1. to -2. (Omitted)

2.6 Other environmental conditions

2.6 Other environmental conditions

2.6.1 General

2.6.1 General-1. (Omitted)-1. (Omitted)

17 / 44

Chapter 3. Design basis evaluation
After revision

Before revision

3.1 General

3.1 General

3.1.1 General

3.1.1 General-1. (Omitted)-1. (Omitted)

3.2 Design basis requirements

3.2 Design basis requirements

3.2.1 General

3.2.1 General-1. to -2. (Omitted)-1. to -2. (Omitted)

3.2.2 Wind turbine (RNA) design basis

3.2.2 Wind turbine (RNA) design basis-1. (Omitted)-1. (Omitted)(Omitted)(Omitted)(2) Site conditions(2) Site conditions• Wind conditions during power production-• Wind conditions during power production

Turbulence intensity correction parameter: 𝐶𝐶𝐶𝐶𝐶𝐶 (at measurement position / at wind-turbine position)

Turbulence intensity correction parameter: 𝐶𝐶𝐶𝐶𝐶𝐶 (at measurement mast position / at windturbine position)(Omitted)(Omitted)(Omitted)(Omitted)(10) Ultimate and fatigue design loads and response analysis(10) Extreme and fatigue design loads and response analysis(Omitted)(Omitted)

3.2.3 Support structure design basis

3.2.3 Support structure design basis-1. The document which shows the design basis for the support structure (tower) shall describe how the-1. The document which shows the design basis for the support structure (tower) shall describe how thefollowing matters were decided. For the design basis for the support structure (Tower), it should be noted

following matters were decided. (added)that there must be compliance with Articles 10, 11 and 12 of the Interpretation of Technical Standards
for Wind Power Generation Facilities[J-04].
(Omitted)(Omitted)-2. Regarding the design basis for the support structure (foundation), in principle, it is acceptable to-2. Regarding the design basis for the support structure (foundation), in principle, it is acceptable tofollow the regulations in the Guidelines for Design of Wind Turbine Support Structures and Foundation[J-follow the regulations in the Guidelines for Design of Wind Turbine Support Structures and Foundation[J-05]. For the design basis for the support structure (foundation), it should be noted that there must be05]. (added)

compliance with Articles 10, 11 and 12 of the Interpretation of Technical Standards for Wind Power
Generation Facilities[J-04].

18 / 44

Chapter 4. Integrated load analysis evaluation
After revision

Before revision

4.1 General

4.1 General

4.1.1 General

4.1.1 General-1. (Omitted)-1. (Omitted)

4.2 Requirements for load analysis for RNA and tower evaluation

4.2 Requirements for load analysis for RNA and tower evaluation

4.2.1 Comparison of the site conditions and the design values set in the type certification

4.2.1 Comparison of the site conditions and the design values set in the type certification-1. to -3. (Omitted)-1. to -3. (Omitted)

4.2.2 Load analysis

4.2.2 Load analysis-1. (Omitted)-1. (Omitted)-2. In the case of a wind turbine with a power back-up as a measure for use in the event of a loss of the-2. In the case of a wind turbine with a backup power supply as a measure for use in the event of a loss

electrical power network, evaluation must be carried out according to 5.4, and a design load case to beof the electrical power network, evaluation must be carried out according to 5.3, and a design load caseapplied in the ultimate load analysis must be decided.

to be applied in the ultimate load analysis must be decided.

-3. (Omitted)-3. (Omitted)-4. The definition of the site load to be calculated shall be clearly indicated, and the coordinate definition-4. The definition of the site load to be calculated shall be clearly indicated, and the coordinate definition

applied in that site load calculation shall be clearly indicated in a diagram. In principle, the definition

applied in that site load calculation shall be clearly indicated in a diagram. In principle, the definition

specified in IEC 61400-13:2015[R-09] shall be used for the coordinate definition.

specified in IEC 61400-13:2015[R-16] shall be used for the coordinate definition.

-5. to -7. (Omitted)-5. to -7. (Omitted)

4.3 Requirements for load analysis for support structure evaluation

4.3 Requirements for load analysis for support structure evaluation

4.3.1 General

4.3.1 General-1. (Omitted)-1. (Omitted)(1) (Omitted)(1) (Omitted)(2) Interpretation of Technical Standards for Wind Power Generation Facilities[J-04](added)(3) (Omitted)(2) (Omitted)

4.3.2 Support structure load analysis

4.3.2 Support structure load analysis-1. In addition to the load calculated in 4.3.1-1., the loading data for the foundation and the tower design-1. In addition to the load calculated in 4.3.1-1., the loading data for the foundation and the tower design

load at the site shall be set with appropriate consideration of the load applied to the tower at the time ofload at the site shall be set by following the provisions of Paragraphs 2.2 and 4.1.2 of the Guidelines forthe type certification, and the site load on the tower that was calculated based on the site conditions

Design of Wind Turbine Support Structures and Foundation[J-05], and appropriately considering the load

specified in 4.2.2.

applied to the tower at the time of the type certification, and the site load on the tower that was calculated
based on the site conditions specified in 4.2.2.

-2. to -4. (Omitted)-2. to -4. (Omitted)-5. The handling of wind and wind turbine control loads combined with the seismic loads obtained from(added)19 / 44After revision

Before revision

the results of seismic response analysis must follow the Appended Table 3 of the Interpretation ofTechnical Standards for Wind Power Generation Facilities[J-04]. Although the handling of the wind andwind turbine control loads shall be as described above, the specific method for combining the seismic
load and the wind and wind turbine control loads may be carried out in accordance with Paragraph 5.5.4of the Guidelines for Design of Wind Turbine Support Structures and Foundation[J-05]. When coupledanalysis simultaneously considering both the seismic and the wind and wind turbine control loads is
performed, this shall be approved as appropriate by ClassNK.
-6. In the case of pile foundations, if ground springs and attenuation are set using the thin layer method,-5. In the case of pile foundations, if ground springs are set using the thin layer method, etc., and not by

etc., and not by following the provisions of the Guidelines for Design of Wind Turbine Support Structures

following the provisions of the Guidelines for Design of Wind Turbine Support Structures andand Foundation[J-05], the validity of the setting should be appropriately indicated in accordance withFoundation[J-05], the validity of the setting should be appropriately indicated.

Annex G.4.

20 / 44

Chapter 5. Wind turbine (RNA) design evaluation
After revision

Before revision

5.1 General

5.1 General

5.1.1 General

5.1.1 General-1. The structural integrity of the wind turbine for the site conditions shall be indicated by comparing the-1. The structural integrity of the wind turbine for the site conditions shall be indicated by comparing thesite-specific loads obtained by the integrated load analysis with the design loads used in the typesite-specific loads obtained by the integrated load analysis with the design loads used in the typecertification. It is also a prerequisite that the main components of the RNA are composed of components

certification.

specified in the type certificate, and that they are manufactured at a manufacturing site specified in thecertification documents pertaining to the type certification.
-2. (Omitted)-2. (Omitted)-3. However, in the case of a wind turbine that has not obtained type certification, where the wind turbine-3. In the case of a wind turbine which has not acquired type certification, the handling shall be as judged

has acquired a design evaluation conformity statement and is carrying out type testing for the acquisition

appropriate by ClassNK.

of type certification, the wind farm certification may be issued on the condition that the acquisition of
the type certification is set as an outstanding issue and a time limit for the solution of that outstanding
issue is established. (However, it should be noted that conditional issuance is not acceptable in an
examination by a registered conformity assessment body.) In other cases, the handling shall be as judged
appropriate by ClassNK.
5.2 Wind turbine (RNA) design evaluation

5.2 Wind turbine (RNA) design evaluation

5.2.1 Comparison of site loads with design loads at type certification

5.2.1 Comparison of site loads with design loads at type certification-1. to -3. (Omitted)-1. to -3. (Omitted)

5.2.2 Strength evaluation of the components of the RNA based on the site load

5.2.2 Strength evaluation of the components of the RNA based on the site load

-1. If the site load exceeds the certified design load, the integrity of the affected components against the-1. If the site load exceeds the certified design load, the integrity of the affected components against thesite load must be verified. For the value obtained by dividing the site load by the certified design load insite load must be verified. (added)

the load comparison, when it can be confirmed that the value after the third decimal place does not affectthe checking value as a strength evaluation result, then if the value does not exceed 1.00 after rounding
off the third decimal place, it may be considered that the integrity against the site load has been
confirmed.
-2. to -4. (Omitted)-2. to -4. (Omitted)

5.3 Nacelle cover strength evaluation

5.3 Nacelle cover strength evaluation

5.3.1 General

5.3.1 General-1. (Omitted)-1. (Omitted)
21 / 44After revision

Before revision

5.3.2 Wind load on the nacelle cover

5.3.2 Wind load on the nacelle cover-1. to -3. (Omitted)-1. to -3. (Omitted)

5.3.3 Load cases

5.3.3 Load cases-1. to -2. (Omitted)-1. to -2. (Omitted)

5.3.4 Strength evaluation

5.3.4 Strength evaluation-1. to -2. (Omitted)-1. to -2. (Omitted)

5.4 Evaluation in the event of the electrical power network loss

5.4 Evaluation in the event of the electrical power network loss

5.4.1 General

5.4.1 General-1. to -3. (Omitted)-1. to -3. (Omitted)-4. When DLC6.2 is omitted from the design load cases applied to the integrated load analysis in(added)accordance with -3. above, a test showing that the system using a power back-up operates as assumed in
the design must be conducted before the start of operation, and a report must be made to ClassNK using
time-series data on the operation of related equipment such as the yaw control equipment and powerback-up. The test plan for this testing must be submitted to ClassNK for approval before the test is
conducted.
5.4.2 Backup power supply

5.4.2 Backup power supply-1. (Omitted)-1. (Omitted)-2. When setting design values for yaw misalignment, the following items (1) to (8) must be evaluated-2. When setting design values for yaw misalignment, the following items (1) to (8) must be evaluatedand confirmed under site-specific extreme wind speed conditions. In addition, the validity of theand confirmed under site-specific extreme wind speed conditions. In addition, the validity of theevaluation and confirmation of these items must be shown by measured data. If no measured data underevaluation and confirmation of these items must be shown by measured data. (added)

conditions corresponding to the site-specific extreme wind speed have been obtained at the time of thedesign, then in order to confirm after the start of operations that the operation control assumed in thedesign can be appropriately performed under conditions corresponding to the site-specific extreme windspeed, an environment should be prepared to enable the collection of measured data (the history of thewind conditions (wind speed and wind direction) near the wind turbine and the history of the wind turbine
operation control (nacelle orientation) and operating conditions corresponding to those wind conditions),
and when this data has been obtained, it must be reported to ClassNK.
(Omitted)(Omitted)

22 / 44After revision

Before revision

5.5 Evaluation to secure a safe state on the wind turbine

5.5 Evaluation to secure a safe state on the wind turbine

5.5.1 General(added)-1. A wind turbine must be equipped so as not to come into contact with other structures, plants, etc.,
during operation.
5.5.2 Safe and automatic shutdown of wind turbines

5.5.1 Safe and automatic shutdown of wind turbines-1. Even in the following cases, there shall be a function to stop safely and automatically, and also the-1. Even in the following cases, there shall be a function to stop safely and automatically, and also thesafe state after stopping shall be maintained. It should be noted that for these items, it is necessary tosafe state after stopping shall be maintained. (added)

conform to Article 7 of the Interpretation of Technical Standards for Wind Power Generation Facilities[J04].

(Omitted)(Omitted)-2. (Omitted)-2. (Omitted)

5.5.3 Protection against lightning strikes

5.5.2 Protection against lightning strikes-1. to -3. (Omitted)-1. to -3. (Omitted)-4. (Omitted)-4. (Omitted)(1) The lightning protection through which the current generated by a lightning strike can flow safely(1) The lightning protection through which the current generated by a lightning strike can flow safely

into the ground without damaging the structures that support the wind turbine must conform to JIS C

into the ground without damaging the structures that support the wind turbine must conform to JIS C

1400-24:2014[R-07].

1400-24:2014[R-08].

(2) (Omitted)(2) (Omitted)-5. (Omitted)-5. (Omitted)

23 / 44

Chapter 6. Support structure design evaluation
After revision

Before revision

6.1 General

6.1 General

6.1.1 General

6.1.1 General-1. The structural integrity of the support structure for the site conditions is confirmed by using integrated(added)load analysis to indicate that there is sufficient strength against the site-specific loads. In addition, for the
tower part of the support structures, the prerequisites are that the design has obtained type certification,and that the tower has been manufactured at a manufacturing site specified in the certification documents
pertaining to the type certification.
-2. The design of the support structure (tower and foundation) shall comply with the following ministerial-1. The design of the support structure (tower and foundation) shall comply with the following ministerial

ordinances and guidelines, etc.

ordinances and guidelines.

(1) (Omitted)(1) (Omitted)(2) Interpretation of Technical Standards for Wind Power Generation Facilities[J-04](added)(3) (Omitted)(2) (Omitted)(4) (Omitted)(3) (Omitted)-3. (Omitted)-2. (Omitted)-4. (Omitted)-3. (Omitted)-5. It should be noted that if -3. and -4. above apply, then it is necessary to conduct a separate(added)manufacturing evaluation for the tower in light of the prerequisites of -1. above.
6.2 Support structure (Tower)

6.2 Support structure (Tower)

6.2.1 General

6.2.1 General-1. In the design of the support structure (tower), if any item does not satisfy the provisions in 6.1.1-2.,-1. In the design of the support structure (tower), if any item does not satisfy the provisions in 6.1.1-1.,

then it shall be shown that the item satisfies the required criteria regarding safety that are defined by thethen it shall be shown that the item satisfies the required criteria regarding safety that are defined by theprovisions in 6.1.1-2.

provisions in 6.1.1-1.

-2. In the case of -1. above, if the design is based on the method shown in Annex F, and it is confirmed-2. In the case of -1. above, if the design is based on the method shown in Annex F, and it is confirmedby the Support Structure Certification Subcommittee/Tower Section Meeting that the contents of it are

by ClassNK that the contents of it are satisfied, then it may be considered that the required criteria

satisfied, then it may be considered that the required criteria regarding safety that are defined by theregarding safety that are defined by the provisions in 6.1.1-1 are satisfied for the item.

provisions in 6.1.1-2 are satisfied for the item.
-3. If it is necessary to conduct a manufacturing evaluation for the tower, ClassNK will individually(added)specify when and how the results of the manufacturing evaluation shall be confirmed, based on thecontent indicated in 1.5.5-1. (8).

24 / 44After revision

Before revision

6.3 Support structure (Foundation)

6.3 Support structure (Foundation)

6.3.1 General

6.3.1 General-1. In the design of the support structure (foundation), if any item does not satisfy the provisions in 6.1.1--1. In the design of the support structure (foundation), if any item does not satisfy the provisions in 6.1.1-

2., then it shall be shown that the item satisfies the required criteria regarding safety that are defined by1., then it shall be shown that the item satisfies the required criteria regarding safety that are defined by

the provisions in 6.1.1-2.

the provisions in 6.1.1-1.

-2. In the case of -1. above, if the design is based on the method shown in Annex G, and it is confirmed(added)by the Support Structure Certification Subcommittee/Foundation and Ground Section Meeting that thecontents of it are satisfied, then it may be considered that the requirements regarding safety that are
defined by the provisions in 6.1.1-2 are satisfied for the item.
6.3.2 Strength evaluation for support structure (foundation)

6.3.2 Strength evaluation for support structure (foundation)-1. (Omitted)-1. (Omitted)(1) The bearing capacity of piles must be additionally evaluated by the formula prescribed in the(1) The bearing capacity of piles must be additionally evaluated by the formula prescribed in the

Recommendations for Design of Building Foundations[R-03].

Recommendations for Design of Building Foundations[R-06].

(2) (Omitted)(2) (Omitted)(3) The horizontal resistance of piles must be additionally evaluated by a method using the group pile

(3) The horizontal resistance of piles must be additionally evaluated by a method using the group pile

frame model specified in the Recommendations for Design of Building Foundations[R-03].

frame model specified in the Recommendations for Design of Building Foundations[R-06].

(4) to (5) (Omitted)(4) to (5) (Omitted)(6) When applying certified construction methods in the field of architecture, etc., it is necessary to(added)sufficiently confirm that the application of those methods is acceptable. (In particular, it may be that thescope of certification is limited to the primary design, so it must be checked whether it can be applied tothe secondary design, etc.)
6.3.3 Items to be considered in the design

6.3.3 Items to be considered in the design-1. (Omitted)-1. (Omitted)

25 / 44Annex A. Measurement data evaluation methods [normative]
After revision

Before revision

A.1 Selection of measurement points

A.1 Selection of measurement points-1. to -3. (Omitted)-1. to -3. (Omitted)(Deleted)-4. When measurement must be carried out in the vicinity of an existing wind turbine that is in operation,a point which is not affected by the wake of that wind turbine must be selected. If the separation distancefrom that wind turbine is 10D or more (D: Rotor diameter of the wind turbine in operation), the windturbine may be treated as one that is not affected by the wake.

A.2 Wind speed measurement by measurement mast

A.2 Wind speed measurement by measurement mast

-1. (Omitted)-1. (Omitted)-2. The cup type anemometer is calibrated before the measurement period, and the calibration value is-2. The cup type anemometer is calibrated before the measurement period, and the calibration value isused in the wind condition evaluation. The calibration of the cup-type anemometer shall be performed inused in the wind condition evaluation. The calibration of the cup-type anemometer shall be performed inaccordance with the procedure described in Annex F of JIS C 1400-12-1:2010[R-06] or in a procedureaccordance with the procedure described in Annex F of JIS C 1400-12-1:2010[R-07] or in a procedurejudged to be equivalent, and the calibration results shall be attached to the report.

judged to be equivalent, and the calibration results shall be attached to the report.

-3. (Omitted)-3. (Omitted)-4. The installation of a wind speed anemometer on a measurement mast shall be in a manner that

-4. The installation of a wind speed anemometer on a measurement mast shall be in a manner thatminimizes the effect on the anemometer from the mast and boom. It is desirable that the installation of aminimizes the effect on the anemometer from the mast and boom. It is desirable that the installation of awind speed anemometer on a measurement mast follows Annex G of JIS C 1400-12-1:2010[R-06]. It iswind speed anemometer on a measurement mast follows Annex G of JIS C 1400-12-1:2010[R-07]. It is

desirable that the boom installation is at an orientation that is 45° from the principal wind direction indesirable that the boom installation is at an orientation that is 45° from the principal wind direction in

the case of a cylindrical mast, and 90° from the principal wind direction in the case of a truss structure.

the case of a cylindrical mast, and 90° from the principal wind direction in the case of a truss structure.

When a lightning rod is installed, it is installed at a position where it will not affect the anemometer.

When a lightning rod is installed, it is installed at a position where it will not affect the anemometer.

-5. The 10 minute average and standard deviation of the wind speed are measured. It is desirable that the-5. The 10 minute average and standard deviation of the wind speed are measured. It is desirable that the

sampling frequency is 1 Hz or higher. In addition, MEASNET[R-16], [A1] can be used as a reference for the

sampling frequency is 1 Hz or higher. In addition, MEASNET[R-17], [A1] can be used as a reference for thecalibration, installation method, equipment configuration, and test method, etc.

calibration, installation method, equipment configuration, and test method, etc.

-6. (Omitted)-6. (Omitted)

A.3 Wind direction measurement by measurement mast

A.3 Wind direction measurement by measurement mast

-1. The wind direction measurement is carried out by using a vane type anemometer. It is desirable to-1. The wind direction measurement is carried out by using a vane type anemometer. It is desirable toinstall one at each altitude to form pairs with the wind speed anemometers described in A.2. The

install one at each altitude to form pairs with the wind speed anemometers described in A.2. The

installation of a wind direction anemometer on a measurement mast shall be in a manner that minimizes

installation of a wind direction anemometer on a measurement mast shall be in a manner that minimizes

the effect on the anemometer from the mast and boom. It is desirable that the installation of a windthe effect on the anemometer from the mast and boom. It is desirable that the installation of a winddirection anemometer on a measurement mast follows Annex G of JIS C 1400-12-1:2010[R-06].

direction anemometer on a measurement mast follows Annex G of JIS C 1400-12-1:2010[R-07].

-2. (Omitted)-2. (Omitted)
26 / 44After revision

Before revision

A.4 Measurement using remote sensing devices

A.4 Measurement using remote sensing devices-1. (Omitted)-1. (Omitted)-2. For the measurement heights, the essential measurement heights shall be the height of the anemometer-2. For the measurement heights, the essential measurement heights shall be the height of the anemometeron the measurement mast with which the correlation is being confirmed, and the hub height of the plannedon the measurement mast with which the correlation is being confirmed, and the hub height of the plannedwind turbine. Other heights shall be set appropriately up to close to the top of the rotor plane, with one

wind turbine. Other heights shall be set appropriately, with one every 10 m as the standard setting.

every 10 m as the standard setting.
-3. (Omitted)-3. (Omitted)-4. If the correlation between the measurement data of the remote sensing equipment and of the(added)measurement mast does not satisfy the requirements, the effect of the topographic complexity, and of thecharacteristics of the measurement method of the using equipment may be corrected using the results ofairflow analysis, etc.
A.5 Measurements and evaluation report of measurement results

A.5 Measurements and evaluation report of measurement results-1. (Omitted)-1. (Omitted)-2. (Omitted)-2. (Omitted)(1) to (2) (Omitted)(1) to (2) (Omitted)(3) Wind shear exponent:(added)a. The average value of the wind shear exponent, described in tabular form with a wind direction
sector width of 30° or less.
(4) (Omitted)(3) (Omitted)(5) (Omitted)(4) (Omitted)(6) (Omitted)(5) (Omitted)(7) (Omitted)(6) (Omitted)

A.6 Measurement at a point affected by the wake of an existing wind turbine(added)-1. When measurement must be carried out in the vicinity of an existing wind turbine that is in operation,a point which is not affected by the wake of the existing wind turbine should be selected, but, due tovarious constraints, there are cases where measurement must be carried out at a point where the wake
effect of an existing wind turbine cannot be eliminated. This paragraph summarizes the items that should
be considered in such cases.
-2. If the separation distance between the measurement mast and the existing wind turbine is 10D or more
(D: Rotor diameter of the existing wind turbine), the measurement data may be treated as data that is notaffected by the wake.
27 / 44After revision

Before revision-3. If the measurement data within the disturbed sector specified in IEC61400-12-1: 2017[R-17] is rejected
and the effective data rate of the remaining data satisfies the provisions of 2.2.2-2., the measurement data
may be treated as data that is not affected by the wake.
-4. If neither of the items -2. and -3. above is satisfied, consider performing simultaneous measurement
using a wind condition measurement mast and remote sensing equipment and then performing correction
for the wake effect of the existing wind turbine. [A2]
A.7 Reference documents

A.6 Reference documents[A1] (Omitted)[A1] (Omitted)[A2] Yoshida et al., Study on the method of wind turbine wake effect exclusion from wind condition(added)measurement data in an existing wind farm, Proceedings of the 44th Wind Energy Symposium, pp.
199-201, 2022.

28 / 44Annex B Airflow analysis and verification of its validity [normative]
After revision

Before revision

B.1 Airflow analysis

B.1 Airflow analysis

B.1.1 Topographic data and ground surface roughness data

B.1.1 Topographic data and ground surface roughness data

-1. to -3. (Omitted)-1. to -3. (Omitted)

B.1.2 Measurement region

B.1.2 Measurement region-1. to -3. (Omitted)-1. to -3. (Omitted)

B.1.3 Calculation grid and resolution

B.1.3 Calculation grid and resolution-1. to -2. (Omitted)-1. to -2. (Omitted)

B.1.4 Boundary conditions

B.1.4 Boundary conditions-1. to -2. (Omitted)-1. to -2. (Omitted)

B.1.5 Direction division

B.1.5 Direction division-1. to -2. (Omitted)-1. to -2. (Omitted)

B.2 Verification of airflow analysis validity

B.2 Verification of airflow analysis validity

B.2.1 Verification of validity of airflow analysis applied to the calculation of wind conditions during

B.2.1 Verification of validity of airflow analysis applied to the calculation of wind conditions during

power production

power production-1. to -2. (Omitted)-1. to -2. (Omitted)-3. The vertical profiles of the wind shear by wind direction are normalized by the wind speed at the-3. The vertical profiles of the wind shear by wind direction are normalized by the wind speed at thehighest point on the measurement mast, and then the comparison of the measurement data with thehighest point on the measurement mast, and then the comparison of the measurement data with theairflow analysis results must be conducted in a format following the example shown in Figure B.2.

airflow analysis results must be conducted in a format following the example shown in Figure B.2.

However, if there is measurement data by a vertical lidar, it should be normalized by the wind speed at

However, if there is measurement data by a vertical lidar, it should be normalized by the wind speed at

hub height in a format following the example shown in Figure B.3. The following points should be kept

hub height in a format following the example shown in Figure B.3. (added)

in mind when preparing figures.
-

In all cases, the horizontal axis should start at 0.

-

The airflow analysis results should be displayed to the horizontal axis 0 position.

-

An auxiliary line should be inserted at the position where the horizontal axis is 1.0.

-

If displacement height is taken into account, it should be clarified that the value is consistent withthe figure.

-4. With regard to the turbulence intensity by wind direction, use the turbulence energy k of the k-epsilon-4. With regard to the turbulence intensity by wind direction, use the turbulence energy k of the k-epsilonmodel, etc., in the airflow analysis and obtain the standard deviation of the wind speed fluctuation in themodel, etc., in the airflow analysis and obtain the standard deviation of the wind speed fluctuation in theprincipal wind direction that arises due to the terrain and surface roughness

𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠
𝜎𝜎𝑢𝑢

by using equation(B.1). Also, the wind speed 𝑈𝑈 obtained from the airflow analysis and equation (B.2) must be used to𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠

principal wind direction that arises due to the terrain and surface roughness 𝜎𝜎𝑢𝑢

by using equation(B.1). Also, the wind speed 𝑈𝑈 obtained from the airflow analysis and equation (B.2) must be used to

29 / 44After revision

Before revisioncalculate 𝐼𝐼𝑠𝑠𝑠𝑠𝑠𝑠 and then compare the result with the turbulence intensity obtained from measurement

data. In this case, in principle, the wind speed bin corresponding to 15 m/s shall be applied, but the windcalculate 𝐼𝐼𝑠𝑠𝑠𝑠𝑠𝑠 and then compare the result with the turbulence intensity obtained from measurement

data. In this case, in principle, the wind speed bin corresponding to 15 m/s shall be applied, but the windspeed bin may be changed depending on the measurement data (the number of measurement points per

speed bin may be changed depending on the measurement data (the number of measurement points perwind speed bin, etc.). However, the wind speed bin selected should be appropriately stated.

wind speed bin, etc.). (added)(Omitted)(Omitted)

Figure B.2 Measurement mast only

Figure B.3 Measurement mast + vertical lidar

Figure B.2 Measurement mast only

Figure B.3 Measurement mast + vertical lidar(Displacement height not set)

(Displacement height not set)

(added)(added)B.2.2 Verification of validity of airflow analysis applied to the calculation of wind conditions during

B.2.2 Verification of validity of airflow analysis applied to the calculation of wind conditions duringparked by storm

parked by storm-1. (Omitted)-1. (Omitted)

B.3 Report on airflow analysis and its validity

B.3 Report on airflow analysis and its validity

B.3.1 Report on the airflow analysis applied to the wind conditions during power production and its

B.3.1 Report on the airflow analysis applied to the wind conditions during power production and its

validity

validity-1. (Omitted)-1. (Omitted)

B.3.2 Report on the airflow analysis applied to the wind conditions during parked by storm and its

B.3.2 Report on the airflow analysis applied to the wind conditions during parked by storm and its

validity

validity-1. Reports on the airflow analysis applied to the calculation of the wind conditions during parked by-1. Reports on the airflow analysis applied to the calculation of the wind conditions during parked bystorm and on the verification of the validity of that analysis shall include at least the following items.

storm and on the verification of the validity of that analysis shall include at least the following items.
30 / 44After revision(1)

Before revision

Details of the airflow analysis (including the following content):(1)

Details of the airflow analysis (including the following content):

a. to c. (Omitted)

a. to c. (Omitted)

d. The following items when a method that considers the wind directional characteristics shown(added)in C.3.1-4. (2) is applied
1) Probability distribution function for typhoon parameters
2) Probability distribution chart for typhoon parameters from analysis results
(2)

(3)

Results of validity verification (including the following content):a.

Results of comparison of the airflow analysis with the measurement data regarding theResults of validity verification (including the following content):a.

average wind speed by wind directionb.

average wind speed by wind direction

Results of comparison of the airflow analysis with the measurement data regarding theb.

vertical profiles of wind shear by wind direction
c.

Results of comparison of the airflow analysis with the measurement data regarding thec.

Results of comparison of the airflow analysis with the measurement data regarding the
turbulence intensity by wind direction

The following items when a method that considers the wind directional characteristics
shown in C.3.1-4. (2) is applied
1) Figure comparing the typhoon simulation results (upper air winds due to the
hypothetical typhoon) with the measured values (upper air winds calculated from theatmospheric pressure in the typhoon database)2) Figure showing the non-exceedance probability distribution of the annual maximum
wind speed due to typhoons on flat terrain and on the actual terrain
3) Figure showing the validity of the setting of the wind direction to be verifiede.

Results of comparison of the airflow analysis with the measurement data regarding thevertical profiles of wind shear by wind direction

turbulence intensity by wind directiond.

Results of comparison of the airflow analysis with the measurement data regarding the

When the simulation results are an underestimation in d. above, the results of considerationof the effects of uncertainty related to the number of years of analysis and the number ofyears of atmospheric pressure measurement

31 / 44(added)Annex C Evaluation method for wind conditions [informative /partially normative]
After revision

Before revision

C.1 General

C.1 General-1. to -2. (Omitted)-1. to -2. (Omitted)

C.2 Wind conditions during power production

C.2 Wind conditions during power production

C.2.1 Wind speed appearance frequency distribution and average wind speed

C.2.1 Wind speed appearance frequency distribution and average wind speed-1. to -3. (Omitted)-1. to -3. (Omitted)

C.2.2 Calculation method for turbulence intensity

C.2.2 Calculation method for turbulence intensity-1. to -3. (Omitted)-1. to -3. (Omitted)

C.2.3 Calculation method for wind shear exponent

C.2.3 Calculation method for wind shear exponent-1. to -2. (Omitted)-1. to -2. (Omitted)

C.2.4 Calculation method for flow inclination angle

C.2.4 Calculation method for flow inclination angle-1. to -2. (Omitted)-1. to -2. (Omitted)

C.2.5 Calculation method for atmospheric density

C.2.5 Calculation method for atmospheric density-1. to -2. (Omitted)-1. to -2. (Omitted)

C.3 Wind conditions during parked by storm

C.3 Wind conditions during parked by storm

C.3.1 Calculation method for extreme wind speed (10 minutes average wind speed with a return period

C.3.1 Calculation method for extreme wind speed (10 minutes average wind speed with a return periodof 50 years)of 50 years)-1. (Omitted)-1. (Omitted)-2. The ground surface roughness classification at the wind turbine position is determined according to-2. The ground surface roughness classification at the wind turbine position is determined according to

the Ministry of Construction Notification No. 1454 in 2000 (Ministry of Land, Infrastructure, Transport

the Building Standards Act or by the situation of the ground surface around the wind power generation

and Tourism Notification No. 1437) according to Table C.1.

facility support according to Table C.1.

32 / 44After revision

Before revision

Table C.1 Categorization of ground surface roughness classifications

Table C.1 Categorization of ground surface roughness classifications

Roughness classI

II

Ground surface conditions around the construction site

Roughness class

Areas specified in a regulation by a Designated Administrative Agency as

Ibeing extremely flat and having no obstacles

Ground surface conditions around the construction site
Areas with few obstacles, such as the surface of a sea or lake

Of the areas other than the areas in the ground roughness classes I and IV, theAreas where the obstacles are only around the level of farm products, such as

areas where the distance to the shoreline or lake shoreline (This is limited topastoral areas and grasslands, areas where trees and low-rise buildings, etc.,

cases where the distance to the opposite shore is 1,500 m or more. The same

are scatteredshall apply hereafter.) is 500 m or less (Excluding in cases where the height ofIIthe building is 13 m or less, or the distance to the shoreline or lake shoreline
exceeds 200 m and the height of the building is 31 m or less.), or areas otherthan such areas which are specified in a regulation by a DesignatedAdministrative Agency as being extremely flat and interspersed with obstacles.

III
IV

III

Areas other than roughness class I, II or IV
Areas specified in a regulation by a Designated Administrative Agency asIVbeing extremely urbanized

Areas with many trees and low-rise buildings, or areas where medium-risebuildings (4 to 9 floors) are scattered
Urban areas mainly consisting of medium-rise buildings-3. (Omitted)-3. (Omitted)

Table C.2 Parameters to determine the altitude correction coefficient for average wind speed

Table C.2 Parameters to determine the altitude correction coefficient for average wind speed
Roughness class

I

II

III

IV

Roughness class

I

II

III

IV

𝑍𝑍𝑏𝑏

5

5

5

10

5

5

10

20

250

350

450

550

𝑍𝑍𝑏𝑏

250

350

450

550

0.10

0.15

0.20

0.27

0.1

0.15

0.2

0.27

𝑍𝑍𝐺𝐺
𝛼𝛼

𝑍𝑍𝐺𝐺
𝛼𝛼

-4. The topographic multiplier for the average wind speed 𝐸𝐸𝑡𝑡𝑡𝑡 and the wind direction to be verified 𝜃𝜃𝑑𝑑

-4. The topographic multiplier for the average wind speed 𝐸𝐸𝑡𝑡𝑡𝑡 and the wind direction to be verified 𝜃𝜃𝑑𝑑

are determined by either of the following methods (1) and (2).

are determined by either of the following methods (1) and (2).

(1) Method that does not consider the wind directional characteristics(1) Method that does not consider the wind directional characteristics(Omitted)(Omitted)

33 / 44After revision′ (𝜃𝜃 ),′ (𝜃𝜃 )′′
1) , 𝐸𝐸𝑡𝑡𝑡𝑡
𝐸𝐸𝑡𝑡𝑡𝑡 = 𝑚𝑚𝑚𝑚𝑚𝑚(𝐸𝐸𝑡𝑡𝑡𝑡
𝑑𝑑
𝑑𝑑 = 𝑚𝑚𝑚𝑚𝑚𝑚�𝐸𝐸𝑡𝑡𝑡𝑡 (𝜃𝜃)�, 𝐸𝐸𝑡𝑡𝑡𝑡 (𝜃𝜃) =Before revision
𝑈𝑈 (𝑥𝑥, 𝑦𝑦, 𝐻𝐻ℎ , 𝜃𝜃)
𝑈𝑈𝑃𝑃 (𝑥𝑥, 𝑦𝑦, 𝐻𝐻ℎ )′𝐸𝐸𝑡𝑡𝑡𝑡 = 𝑚𝑚𝑚𝑚𝑚𝑚(𝐸𝐸𝑡𝑡𝑡𝑡, 1) ,(C. 16)

𝑈𝑈 (𝑥𝑥, 𝑦𝑦, 𝐻𝐻ℎ , 𝜃𝜃)′
𝐸𝐸𝑡𝑡𝑡𝑡= 𝑚𝑚𝑚𝑚𝑚𝑚 � 𝑃𝑃�𝜃𝜃𝑈𝑈 (𝑥𝑥, 𝑦𝑦, 𝐻𝐻ℎ )(C. 16)(2) Method that considers the wind directional characteristics(2) Method that considers the wind directional characteristics

The topographic multiplier for the average wind speed 𝐸𝐸𝑡𝑡𝑡𝑡 is decided by the equation (C.17) based on

The topographic multiplier for the average wind speed 𝐸𝐸𝑡𝑡𝑡𝑡 is decided by the equation (C.17) based on

the results of typhoon simulations for the wind turbine construction site. Here, 𝑈𝑈50 (𝑥𝑥, 𝑦𝑦, 𝐻𝐻ℎ ) is the
expected annual maximum wind speed with a return period of 50 years at the hub height 𝐻𝐻ℎ at the wind

the results of typhoon simulations for the wind turbine construction site. Here, 𝑈𝑈50 (𝑥𝑥, 𝑦𝑦, 𝐻𝐻ℎ ) is the
expected annual maximum wind speed with a return period of 50 years at the hub height 𝐻𝐻ℎ at the windturbine construction site, which is obtained by statistical analysis from the result of the typhoon

turbine construction site, which is obtained by statistical analysis from the result of the typhoon

𝑃𝑃 (𝑥𝑥,𝑦𝑦, 𝐻𝐻ℎ ) is the expected annual maximum wind speed with a return period of 50
simulation, and 𝑈𝑈50

years at the hub height above flat terrain of the ground surface roughness classification. In addition, theyears at the hub height above flat terrain of the ground surface roughness classification. In addition, thewind direction to be verified 𝜃𝜃𝑑𝑑 shall be the wind direction corresponding to 𝑈𝑈50 (𝑥𝑥, 𝑦𝑦, 𝐻𝐻ℎ ) . The

𝑃𝑃 (𝑥𝑥,𝑦𝑦, 𝐻𝐻ℎ ) is the expected annual maximum wind speed with a return period of 50
simulation, and 𝑈𝑈50

validity of the simulation results must be sufficiently confirmed by comparing them with the measured

Furthermore, it must be sufficiently confirmed that there is no problem with the application of thevalues. Further, if the comparison of the typhoon simulation results (upper air winds due to thewind direction to be verified 𝜃𝜃𝑑𝑑 shall be the wind direction corresponding to 𝑈𝑈50 (𝑥𝑥, 𝑦𝑦, 𝐻𝐻ℎ ) .

typhoon simulation by conducting a comparison with measurement values, etc., in addition to checking

hypothetical typhoon) with the measured values (upper air winds calculated from the atmospheric

the validity of the simulation itself.

pressure in the typhoon database) indicates that the simulation results are an underestimation, additional
consideration must be given to the effects of uncertainty related to the number of years of analysis andthe number of years of atmospheric pressure measurement. In addition, the validity of the setting of thewind direction to be verified must be sufficiently confirmed.
C.3.2 Extreme wind speed (Calculation method for 3 seconds average wind speed)

C.3.2 Extreme wind speed (Calculation method for 3 seconds average wind speed)

C.3.2.1 Calculation method for turbulence intensity

C.3.2.1 Calculation method for turbulence intensity-1. to -2. (Omitted)-1. to -2. (Omitted)-3. The correction coefficient for the turbulence intensity due to the terrain 𝐸𝐸𝑡𝑡𝑡𝑡 is determined by the-3. The correction coefficient for the turbulence intensity due to the terrain 𝐸𝐸𝑡𝑡𝑡𝑡 is determined by the′consider the wind directional characteristics, then 𝐸𝐸𝑡𝑡𝑡𝑡(𝜃𝜃𝑑𝑑 ) is obtained by equation (C.16), and if theequation (C.21) based on the results of airflow analysis by wind direction on the actual terrain and on

equation (C.21). Here, 𝑈𝑈 (𝑥𝑥, 𝑦𝑦, 𝐻𝐻ℎ , 𝜃𝜃) is the average wind speed obtained by airflow analysis for winddirection θ at hub height 𝐻𝐻ℎ at the wind turbine construction site on the actual terrain, and 𝑈𝑈 𝑃𝑃 (𝑥𝑥, 𝑦𝑦, 𝐻𝐻ℎ )equation (C.20). Of the methods shown in C.3.1-4., if the method selected is (1) Method that does notmethod selected is (2) Method that considers the wind directional characteristics, then it is obtained bydirection θ at hub height 𝐻𝐻ℎ at the wind turbine construction site on the actual terrain, and 𝑈𝑈 𝑃𝑃 (𝑥𝑥, 𝑦𝑦, 𝐻𝐻ℎ )is the average wind speed at the hub height 𝐻𝐻ℎ at the wind turbine construction site that was obtainedby airflow analysis for flat terrain of ground surface roughness classification 𝑃𝑃.

′
is obtained by using
equation (C.20). Here, the topographic multiplier for the average wind speed 𝐸𝐸𝑡𝑡𝑡𝑡

flat terrain. Here, 𝑈𝑈 (𝑥𝑥, 𝑦𝑦, 𝐻𝐻ℎ , 𝜃𝜃) is the average wind speed obtained by airflow analysis for windis the average wind speed at the hub height 𝐻𝐻ℎ at the wind turbine construction site that was obtainedby airflow analysis for flat terrain of ground surface roughness classification 𝑃𝑃.

34 / 44After revision′(𝜃𝜃𝑑𝑑 ) , 1)
𝐸𝐸𝑡𝑡𝑡𝑡 = 𝑚𝑚𝑚𝑚𝑚𝑚(𝐸𝐸𝑡𝑡𝑡𝑡 (𝜃𝜃𝑑𝑑 )⁄𝐸𝐸𝑡𝑡𝑡𝑡′ (𝜃𝜃 )
𝐸𝐸𝑡𝑡𝑡𝑡𝑑𝑑 =𝑈𝑈 (𝑥𝑥, 𝑦𝑦, 𝐻𝐻ℎ , 𝜃𝜃𝑑𝑑 )𝑈𝑈𝑃𝑃 (𝑥𝑥, 𝑦𝑦, 𝐻𝐻ℎ )Before revision(C. 20)′, 1)
𝐸𝐸𝑡𝑡𝑡𝑡 = 𝑚𝑚𝑚𝑚𝑚𝑚(𝐸𝐸𝑡𝑡𝑡𝑡 ⁄𝐸𝐸𝑡𝑡𝑡𝑡(C. 20)(C. 21)𝑈𝑈 (𝑥𝑥, 𝑦𝑦, 𝐻𝐻ℎ , 𝜃𝜃)′
𝐸𝐸𝑡𝑡𝑡𝑡= 𝑚𝑚𝑚𝑚𝑚𝑚 � 𝑃𝑃�𝜃𝜃𝑈𝑈 (𝑥𝑥, 𝑦𝑦, 𝐻𝐻ℎ )(C. 21)-4. The correction coefficient for the fluctuating wind speed due to the terrain 𝐸𝐸𝑡𝑡𝑡𝑡 is determined byequation (C.22) regardless of whether the method selected is (1) Method that does not consider the winddirectional characteristics or (2) Method that considers the wind directional characteristics in C.3.1-4.
Here, 𝜎𝜎𝑢𝑢 (𝑥𝑥, 𝑦𝑦, 𝐻𝐻ℎ , 𝜃𝜃𝑑𝑑 ) is the standard deviation of the wind speed fluctuation in the principal winddirection at the hub height 𝐻𝐻ℎ in the wind direction to be verified on the actual terrain 𝜃𝜃𝑑𝑑 , and

𝜎𝜎𝑢𝑢𝑃𝑃 (𝑥𝑥, 𝑦𝑦, 𝐻𝐻ℎ ) is the standard deviation of the wind speed fluctuation in the principal wind direction at the
hub height 𝐻𝐻ℎ on flat terrain with a ground surface roughness classification 𝑃𝑃, which are obtained from

-4. The correction coefficient for the fluctuating wind speed due to the terrain 𝐸𝐸𝑡𝑡𝑡𝑡 is determined by theequation (C.22). Here, 𝜎𝜎𝑢𝑢 (𝑥𝑥, 𝑦𝑦, 𝐻𝐻ℎ , 𝜃𝜃𝑑𝑑 ) is the standard deviation of the wind speed fluctuation in theprincipal wind direction at the hub height 𝐻𝐻ℎ in the wind direction to be verified on the actual terrain𝜃𝜃𝑑𝑑 , and 𝜎𝜎𝑢𝑢𝑃𝑃 (𝑥𝑥, 𝑦𝑦, 𝐻𝐻ℎ ) is the standard deviation of the wind speed fluctuation in the principal winddirection at the hub height 𝐻𝐻ℎ on flat terrain with a ground surface roughness classification 𝑃𝑃, which

are obtained from airflow analysis.

airflow analysis.

𝐸𝐸𝑡𝑡𝑡𝑡 (𝜃𝜃𝑑𝑑 ) =𝜎𝜎𝑢𝑢 (𝑥𝑥, 𝑦𝑦, 𝐻𝐻ℎ , 𝜃𝜃𝑑𝑑 )𝜎𝜎𝑢𝑢𝑃𝑃 (𝑥𝑥, 𝑦𝑦, 𝐻𝐻ℎ )(C. 22)

𝐸𝐸𝑡𝑡𝑡𝑡 =𝜎𝜎𝑢𝑢 (𝑥𝑥, 𝑦𝑦, 𝐻𝐻ℎ , 𝜃𝜃𝑑𝑑 )𝜎𝜎𝑢𝑢𝑃𝑃 (𝑥𝑥, 𝑦𝑦, 𝐻𝐻ℎ )-5. (Omitted)-5. (Omitted)

C.3.2.2 Calculation method for 3 seconds average wind speed

C.3.2.2 Calculation method for 3 seconds average wind speed-1. (Omitted)-1. (Omitted)

C.3.2.3 Calculation method for wind shear for extreme wind speed

C.3.2.3 Calculation method for wind shear for extreme wind speed-1. (Omitted)-1. (Omitted)

C.3.3 Calculation method for 𝑈𝑈𝑒𝑒50 using wind condition measurement data [informative]-1. to -2. (Omitted)

C.3.3 Calculation method for 𝑈𝑈𝑒𝑒50 using wind condition measurement data [informative]

C.4 Reports on wind conditions

C.4 Reports on wind conditions

C.4.1 Report on wind conditions during power production

C.4.1 Report on wind conditions during power production-1. (Omitted)-1. (Omitted)

C.4.2 Report on wind conditions during parked by storm

C.4.2 Report on wind conditions during parked by storm-1. to -2. (Omitted)-1. to -2. (Omitted)

C.4.3 Other conditions

C.4.3 Other conditions-1. to -2. (Omitted)

35 / 44(C. 22)

After revision

Before revision-1. to -2. (Omitted)-1. to -2. (Omitted)

C.5 Reference documents

C.5 Reference documents(Omitted)(Omitted)

36 / 44Annex D Equivalent wind pressure coefficient for the nacelle cover [informative]
After revision

Before revision

D.1 General

D.1 General-1. to -2. (Omitted)-1. to -2. (Omitted)

D.2 Equivalent wind pressure coefficient [Wind direction: -15° to +15°]

D.2 Equivalent wind pressure coefficient [Wind direction: -15° to +15°]-1. to -2. (Omitted)-1. to -2. (Omitted)

D.3 Equivalent wind pressure coefficient [Wind direction: All wind directions]

D.3 Equivalent wind pressure coefficient [Wind direction: All wind directions]-1. to -2. (Omitted)-1. to -2. (Omitted)

D.4 Reference documents

D.4 Reference documents(Omitted)(Omitted)

37 / 44Annex E Measurement testing for fluctuating pressure characteristics acting on a nacelle surface [informative]
After revision

Before revision

E.1 General

E.1 General-1. (Omitted)-1. (Omitted)

E.2 Selection of wind tunnel

E.2 Selection of wind tunnel-1. (Omitted)-1. (Omitted)

E.3 Model and test conditions

E.3 Model and test conditions

E.3.1 Model

E.3.1 Model-1. (Omitted)-1. (Omitted)

E.3.2 Airflow similarity

E.3.2 Airflow similarity-1. (Omitted)-1. (Omitted)

E.3.3 Wind speed and wind direction in test implementation

E.3.3 Wind speed and wind direction in test implementation-1. (Omitted)-1. (Omitted)

E.3.4 Pressure measurement instrument

E.3.4 Pressure measurement instrument-1. (Omitted)-1. (Omitted)

E.3.5 Data processing and recording

E.3.5 Data processing and recording-1. to -2. (Omitted)-1. to -2. (Omitted)

E.3.6 Maximum/minimum peak wind pressure coefficientE.3.6 Maximum/minimum peak wind pressure coefficient-1. to -2. (Omitted)-1. to -2. (Omitted)

E.4 Reference documents

E.4 Reference documents(Omitted)(Omitted)

38 / 44Annex F Design methodologies for tower structures [normative]
After revision

Before revision

F.1 General

F.1 General

-1.

-1.

This Annex summarizes the tower structure-related items where the method has been establishedThis Annex summarizes the methods that meet the requirements for general facility, in 2. (3) [2]for items that deviate from the Guidelines for Design of Wind Turbine Support Structures andspecified in the Implementation procedures for the examination of construction plans for the installation

Foundation[J-05].

or modification of wind power plants[R-03].

-2.

(added)This Annex presents examples of methods based on past examination cases and does not deny theapplication of other methods.
F.2 Attenuation

F.2 Attenuation

-1.

-1.

For the first and second mode structural damping ratios for cylindrical steel structures, the values

For the first and second mode structural damping ratios for cylindrical steel structures, the values

obtained from equation (F.1) and equation (F.2)[R-08] [R-11] [F1] may be applied. When using values otherobtained from equation (F.1) and equation (F.2)[R-09] [R-12] [F1] may be applied. When using values otherthan this, it is necessary to explain the validity of the values. In addition, for the modal damping ratio

than this, it is necessary to explain the validity of the values. In addition, for the modal damping ratiothat consists of the structural damping and ground damping, evaluation is possible in the method shownthat consists of the structural damping and ground damping, evaluation is possible in the method shownin the reference document[F2]. Furthermore, in the time history response analysis using the SR model, thein the reference document[F2]. Furthermore, in the time history response analysis using the SR model, thesoil damping is considered as a dashpot[F2].

soil damping is considered as a dashpot[F2].

(Omitted)(Omitted)

F.3 Anchor bolt hole diameter

F.3 Anchor bolt hole diameter-1.

(Omitted)-1.

(Omitted)[1]

The hole diameter of anchor bolts shall not exceed the clearance based on the nominal bolt diameter[1]

The hole diameter of anchor bolts shall not exceed the clearance based on the nominal bolt diameter

specified in ISO273[R-10].

specified in ISO273[R-11].

[2]

[2]

Following the Guidebook on Design and Fabrication of High Strength Bolted Connections[R-04], if

Following the Guidebook on Design and Fabrication of High Strength Bolted Connections[R-05], if

the nominal bolt diameter exceeds 24 mm, the hole diameter may be the bolt diameter + 8 mm on thethe nominal bolt diameter exceeds 24 mm, the hole diameter may be the bolt diameter + 8 mm on thepremise that the slip resistance is reduced (reduction factor: 0.85). Therefore, in the most severer loading

premise that the slip resistance is reduced (reduction factor: 0.85). Therefore, in the most severer loading

conditions based on the site conditions, the horizontal force due to the shear force and torsional moment

conditions based on the site conditions, the horizontal force due to the shear force and torsional moment

acting on the tower base, and the frictional force (resistance friction force) on the underside of the baseacting on the tower base, and the frictional force (resistance friction force) on the underside of the baseplate should be compared considering the reduction factor of 0.85, and it must be confirmed that theplate should be compared considering the reduction factor of 0.85, and it must be confirmed that the"Resistance friction force considering horizontal force/reduction factor" is less than 1.0.

"Resistance friction force considering horizontal force/reduction factor" is less than 1.0.

F.4 Design applying the fatigue equivalent design method in structural calculations for anchor bolts

F.4 Design applying the fatigue equivalent design method in structural calculations for anchor bolts-1.

(Omitted)-1.

(Omitted)(1)(Omitted)(1)(Omitted)(2)(Omitted)(2)(Omitted)1)

Principle for conducting fatigue strength evaluation1)

Principle for conducting fatigue strength evaluation

39 / 44After revision2)

Before revision

According to the requirement by 7.4.1 in the Guidelines for Design of Wind Turbine
Support Structures and Foundation[J-05], the degree of fatigue damage shall be determinedby the cumulative fatigue damage rule.

The requirements for each item to be considered shall be as shown in Table F.1.



2)

The requirements for each item to be considered shall be as shown in Table F.1.
Table F.1 Items to be considered for fatigue strength evaluation and their requirements

Table F.1 Items to be considered for fatigue strength evaluation and their requirements
Items to be

Applicable specifications

consideredand standards

Anchor bolts

EN 1993-1-9: 2005[R-12]

Grout/Concrete

MC2010[R-13] (MC1990[R-This shall follow item 7.4.1 in the Guidelines for Design of Wind Turbine Support
Structures and Foundation[J-05], and the degree of fatigue damage shall be determined by the
cumulative fatigue damage rule.

Requirements

Items to be

Applicable specifications

consideredand standards(Omitted)

Anchor bolts

EN 1993-1-9: 2005[R-13](Omitted)(Omitted)

Grout/Concrete

MC2010[R-14] (MC1990[R-(Omitted)

14] is also possible)

Requirements

15] is also possible)*1: See the column of requirements for DC50 on Table 8.1 of EN 1993-1-9: 2005[R-12].

*1: See the column of requirements for DC50 on Table 8.1 of EN 1993-1-9: 2005[R-13].

(In addition, refer to the Guidance note in Paragraph 4.12.3.6 of DNVGL-ST-0126[R-15].)(In addition, refer to the Guidance note in Paragraph 4.12.3.6 of DNVGL-ST-0126[R-12].)(Omitted)(Omitted)

F.5 Lever ratio of flange joint

F.5 Lever ratio of flange joint

-1.

-1.

(Omitted)(Omitted)

F.6 Design applying the fatigue equivalent design method in structural calculations for flange joints

F.6 Design applying the fatigue equivalent design method in structural calculations for flange joints-1.

(Omitted)-1.

(Omitted)(1)(Omitted)(1)(Omitted)(2)(Omitted)(2)(Omitted)1)

Principle for conducting fatigue strength evaluation
 According to the requirement by 7.4.1 in the Guidelines for Design of Wind Turbine
Support Structures and Foundation[J-05], the degree of fatigue damage shall be determinedby the cumulative fatigue damage rule.

1)

Principle for conducting fatigue strength evaluation
 This shall follow item 7.4.1 in the Guidelines for Design of Wind Turbine Support
Structures and Foundation[J-05], and the degree of fatigue damage shall be determined by the
cumulative fatigue damage rule.

2)

The requirements for each item to be considered shall be as shown in Table F.2.

2)

The requirements for each item to be considered shall be as shown in Table F.2.
Table F.2 Items to be considered for fatigue strength evaluation and their requirements

Table F.2 Items to be considered for fatigue strength evaluation and their requirements
Items to be

Applicableconsidered

specifications andRequirements

Items to be

Applicableconsidered

specifications andstandards
Flange bolt

EN 1993-1-9: 2005[R-12]

Requirements

standards•

When considering only the axial force on

Flange bolt

the flange bolt and not bending, apply

EN 1993-1-9: 2005[R-13]•

When considering only the axial force on
the anchor bolt and not bending, apply

40 / 44After revision

Before revision

DC36* as the S-N diagram. *1•

DC36* as the S-N diagram. *1

The size effect reduction factor: ks shall be•considered.

The size effect reduction factor: ks shall beconsidered.

*1: See the column of requirements for DC50 on Table 8.1 of EN 1993-1-9: 2005[R-12].

*1: See the column of requirements for DC50 on Table 8.1 of EN 1993-1-9: 2005[R-13].

(In addition, refer to the Guidance note in Paragraph 4.12.3.6 of DNVGL-ST-0126[R-15].)(In addition, refer to the Guidance note in Paragraph 4.12.3.6 of DNVGL-ST-0126[R-12].)

F.7 Distance between flange bolt centers in circumferential direction(added)-1.

If the distance between the centers of the flange bolts in the circumferential direction does notsatisfy the dimensional specifications in 7.3.3 (1) 2) of the Guidelines for Design of Wind Turbine
Support Structures and Foundation[J-05], the following must be satisfied.
(1) For the tower flange connection, perform finite element analysis for each case where the distance
between the centers of the flange bolts in the circumferential direction is 1) and 2) below, andindicate the effect that the difference in the center-to-center distance has on bolt tension, stress, etc.,
against the site ultimate load (short-term, extremely rare earthquake, IEC load). In the case of 2),
also confirm from the results of the finite element analysis that the tower flange connection is
structurally safe.
1)

In the case of 2.0D (D: nominal bolt diameter), which is the dimensional specification in
7.3.3 (1) 2) of the Guidelines for Design of Wind Turbine Support Structures andFoundation[J-05]

2)

In the case where the planned distance between the centers of the flange bolts in thecircumferential direction is (< 2.0D)(2)The validity of the model and analysis method for the finite element analysis used in (1) above

must be verified by comparison with the results of structural experiments, or by reproducing thecontents of previous literature.
F.8 Tower opening-1.

(added)For the tower opening, in a case where the tower opening is not provided with a reinforcing material

that satisfies the dimensional provisions of 7.3.5 (2) 1) of the Guidelines for Design of Wind Turbine
Support Structures and Foundation[J-05], and the plate thickness around the opening is increased, thefollowing details must be satisfied in accordance with the provisions of 7.3.5 (2) 2) of those Guidelines.
(1) In accordance with 7.3.3 of the Structural Design Recommendation for Chimneys[R-05], the checkingof the strength of the opening in terms of bending moment and shear force must be performed foreach load of the site ultimate load (long-term, short-term, rare earthquake, extremely rare earthquake
and IEC load) calculated based on the site conditions. For the position of the cross-section check,41 / 44After revision

Before revisionperform finite element analysis for the opening and then the cross-section where the stressconcentration is confirmed to be the most severe must be selected and appropriate considerationmust be given to the stress concentration factor.
(2) Fatigue strength checks against the site fatigue loads calculated based on the site conditions mustbe performed for the welds at the opening end and around the opening.
F.9 Reference documents

F.7 Reference documents(Omitted)(Omitted)

42 / 44Annex G Design methodologies for foundations [normative]
After revision

Before revision

G.1 General-1.

(added)This Annex summarizes the foundation-related items where the method has been established for items that deviate fromthe Guidelines for Design of Wind Turbine Support Structures and Foundation[J-05].
-2.

This Annex presents examples of methods based on past examination cases and does not deny the application of othermethods.
G.2 Special earthwork such as ground improvement-1.

(added)When ground improvement is carried out, in principle, the Foundation and Ground Section Meeting of the Support

Structure Certification Subcommittee must conduct an examination according to the situation of each site.
-2.

When strength correction using rubble concrete is performed for the foundation floor, the item -1. above shall not apply

if the depth of that concrete is less than 3 m.
G.3 Handling of seismic response analysis for the ground-1.

(added)If the shearing strain exceeds 1% in the results of the seismic response analysis for the ground, then it is not permitted

to follow the response calculation flow for liquefied ground that is described in the Guidelines for Design of Wind Turbine
Support Structures and Foundation[J-05] (p. 170, Illustration 5.11), so at the subject point, it is not permitted to apply equivalentlinear analysis or simplified liquefaction analysis in which the equivalent stiffness of the liquefied layer multiplied by thestiffness reduction rate is set.
-2.

In the case of -1. above, the following analyses must be performed, depending on whether liquefaction is considered or

not.
(1)

When liquefaction is not considered: Sequential nonlinear - Total stress analysis(2)

When liquefaction is considered: Sequential nonlinear - Effective stress analysis (Time-history nonlinear analysis
considering the soil nonlinearity accompanying the increase in the shear strain and the increase in the excess porewater pressure)-3.

In a case where sequential nonlinear - effective stress analysis is performed in -2. above, the basis for setting the groundmodel (stress-strain model) and its validity must be shown.
-4.

If the shearing strain does not exceed 1% in the results of the seismic response analysis for the ground, but the response

calculation flow for liquefied ground that is described in the Guidelines for Design of Wind Turbine Support Structures andFoundation[J-05] (p. 170, Illustration 5.11) is not followed and sequential nonlinear - effective stress analysis is applied, thenthe validity of the analysis results must be shown. (Example: For representative cases, perform comparisons of the equivalentlinear analysis and simplified liquefaction analysis in which the equivalent stiffness of the liquefied layer multiplied by thestiffness reduction rate is set.)
43 / 44After revision-5.

Before revision

When the inclination of the engineering base surface is 5 degrees or more, the existence of effects from the inclinationof the engineering base surface must be checked. (Example: Perform seismic response analysis using the ground response at
the wind turbine site that was evaluated by finite element analysis (2-D), and then perform a comparison with the seismic
response analysis results evaluated using the ground response of a 1-D parallel stratified ground at the time of design.)
G.4 Handling related to time history response analysis-1.

(added)When setting ground springs and attenuation by using the thin layer method, the basis for that setting and its validity

must be shown. In particular, for attenuation, it must be clearly stated how the attenuation coefficient C was set in the formshown in Illustration 5.19 of the Guidelines for Design of Wind Turbine Support Structures and Foundation[J-05].
G.5 Pile design-1.

(added)When the pile response is calculated using a separated model in which the wind turbine and foundation response

analysis is performed separately to the pile response analysis, the value of the ultimate bending strength Mu of the pile
divided by the maximum bending moment M during extremely rare earthquakes should not be less than 1.2. However, thisdoes not apply when coupled analysis of the pile response is performed in an integrated model of the windturbine/foundation and pile, and it has been confirmed that the analysis is valid.
-2.

For the shear checks for piles during extremely rare earthquakes, the evaluation may be performed using the ultimate

strength rather than the short-term allowable value if the following items are satisfied.
(1)

The ultimate shear capacity of piles is evaluated based on each of the Pile Foundation Design Manual[G1] and Strengthand Deformation Capacity of Foundation Structural Members[G2], and it is confirmed to be within the allowable value.

(2)

The tolerance to shear based on the allowable value evaluated in (1) above exceeds the tolerance to bending, and it
has been confirmed that it is a failure mode where bending failure will occur first.

G.6 Reference documents(added)[G1] Pile Foundation Design Manual (Japan Road Association, September 2020)[G2] Strength and Deformation Capacity of Foundation Structural Members (Architectural Institute of Japan, 2022)

44 / 44