Project No.: PD.19.09
NHON HOI WIND FARM PROJECT – PHASE I
TECHNICAL DESIGN
VOLUME 1
DESCRIPTION
VOLUME 1.1
DESCRIPTION OF POWER PLANT
(Version 03)
Khanh Hoa, January, 2021
VIETNAM ELECTRICITY
POWER ENGINEERING CONSULTING
JOINT STOCK COMPANY 4
Project No.: PD.19.09
NHON HOI WIND FARM PROJECT – PHASE I
TECHNICAL DESIGN
VOLUME 1
DESCRIPTION
VOLUME 1.1
DESCRIPTION OF POWER PLANT
(Version 02)
Deputy Director
: Ly Dinh Huy
Project Manager
: Nguyen Khanh Hoa
Khanh Hoa, January
EMPLOYER
BINH DINH FICO
ENERGY JOINT STOCK
COMPANY
EPC CONTRACTOR
POWERCHINA VIETNAM
LIMITED COMPANY
, 2021
CONSULTANT
POWER ENGINEERING
CONSULTING JOINT
STOCK COMPANY 4
ON BEHALF OF PECC4
Le Cao Quyen
Deputy General Director
Nhon Hoi Wind farm project – Phase I
Technical Design
CONTRIBUTORS
No.
Full Name
1.
Nguyen Tan Quang
Electrical design leader
2.
Vu Ha Linh
Civil design leader
3.
Duong Dinh Dieu
Road design leader
4.
Le Thanh Tri
Civil designer
Contributors
Responsibility
Signature
i
Nhon Hoi Wind farm project – Phase I
Technical Design
CONTENTS
Technical Design report of “Nhon Hoi Wind farm project – Phase I” is established
as following:
Volume 1
Volume 1.1
Volume 1.1A
Volume 1.2
Volume 1.3
Volume 2
Volume 2.1
Volume 2.1A
Volume 2.2
Volume 2.3
Volume 3
Volume 3.1
Volume 3.2
Volume 3.3
Volume 4
Volume 4.1
Volume 4.1A
Volume 4.2
Volume 4.3
Volume 5
Volume 5.1
Volume 5.1A
Volume 5.2
Volume 5.3
Volume 6
Volume 6.1
Volume 6.2
Volume 6.3
Volume 7
DESCRIPTION
Description of Power plant
Description of Turbine foundation
Description of Substation
Description of Transmission line
DRAWINGS
Drawings of Power plant
Drawing of Turbine foundation
Drawings of Substation
Drawings of Transmission line
CONSTRUCTION EXECUTION
Construction execution of Power plant
Construction execution of Substation
Construction execution of Transmission line
CALCULATION
Calculation of Power plant
Calculation of Turbine foundation
Calculation of Substation
Calculation of Transmission line
TECHNICAL SPECIFICATION
Technical specification of Power plant
Technical specification of Turbine foundation
Technical specification of Substation
Technical specification of Transmission line
CONSTRUCTION MAINTENANCE PROCEDURE
Construction maintenance procedure of Power plant
Construction maintenance procedure of Substation
Construction maintenance procedure of Transmission line
FIRE FIGHTING SYSTEM
This is the “Volume 1.1: Description of Power plant” (Version 03).
Version 03 is finalized according to Document no. 98/BQL-QLQHXD dated
January 20, 2021 of Binh Dinh Economic Zone Management Board announcing the
appraisal result of Technical Design of Nhon Hoi Wind Power Plant – Phase I.
This version is replaced for version 02 issued in December 2020 by Power
Engineering Consulting JS Company 4.
Contents
ii
Nhon Hoi Wind farm project – Phase I
Technical Design
INDEX
CHAPTER 1: OVERVIEW ................................................................................................. 1-1
1.1.
LEGAL BASIS .....................................................................................................................1-1
1.2.
MAIN PROJECT INFORMATION .....................................................................................1-4
1.3.
INPUT FOR TECHNICAL DESGIN .................................................................................1-11
CHAPTER 2: SPECIFICATION OF PROJECT AREA ................................................. 2-1
2.1.
PROJECT LOCATION ........................................................................................................2-1
2.2.
SITE CONDITIONS OF PROJECT AREA .........................................................................2-3
CHAPTER 3: SOLUTIONS FOR ELECTRICAL – TECHNOLOGY OF POWER
PLANT
....................................................................................................................... 3-1
3.1.
GENERAL LAYOUT SOLUTION ......................................................................................3-1
3.2.
TECHNICAL CHARACTERISTICS OF MAIN EQUIPMENT .........................................3-4
3.3.
LIGHTNING PROTECTION .............................................................................................3-27
3.4.
FIRE FIGHTING SYSTEM ...............................................................................................3-29
3.5.
AUXILIARY TRANSFORMER ........................................................................................3-32
CHAPTER 4: CONSTRUCTION SOLUTIONS FOR PLANT PART ........................... 4-1
4.1.
SELECTION OF CONSTRUCTION SITES/ITEM ELEVATION .....................................4-1
4.2.
IMPACT LOADS AND EARTHQUAKE-RESISTANT DESIGN REQUIREMENT .......4-1
4.3.
WIND TURBINE FOUNDATION ......................................................................................4-3
4.4.
TECHINCAL REQUIREMENT FOR HARDSTANDS ......................................................4-4
4.5.
O&M BUILDING AREA .....................................................................................................4-7
4.6.
TECHINCAL INFRASTRUCTURE ..................................................................................4-10
4.7.
SOLUTIONS FOR ROAD PART ......................................................................................4-10
4.8.
CIVIL SOLUTION FOR CABLE TRENCH .....................................................................4-15
APPENDIX: LIST OF EQUIPMENT AND MATERIAL
Index
iii
Nhon Hoi Wind farm project – Phase I
Technical Design
LIST OF TABLE
Table 1.1: Summary of land uasge demands of project ...............................................1-4
Table 2.1: Project coordinates ......................................................................................2-1
Table 2.2: Geological layer within the project scope...................................................2-7
Table 2.3: Results of standard penetration test SPT ....................................................2-8
Table 2.4: Physical mechanical properties of rock, soil layers ..................................2-12
Table 2.5: Recommended standard values and calculation of geological layer 1 .....2-13
Table 2.6: Recommended standard values and calculation of geological layer 2 .....2-13
Table 2.7: Recommended standard values and calculation of geological layer 3 .....2-14
Table 2.8: Calculation results according to Hoek – Brown Layer 3 ..........................2-14
Table 2.9: Calculation results according to Hoek – Brown Layer 3 ..........................2-14
Table 2.10: Recommended standard values and calculation of geological layer 4 ...2-15
Table 2.11: Calculation results according to Hoek – Brown Layer 4 ........................2-15
Table 2.12: Calculation results according to Hoek – Brown Layer 4 ........................2-15
Table 2.13: Recommended standard values and calculation of geological layer 5 ...2-16
Table 2.14: Calculation results according to Hoek – Brown Layer 5 ........................2-16
Table 2.15: Calculation results according to Hoek – Brown Layer 5 ........................2-16
Table 2.16: Table of converting ground acceleration to earthquake grade according to
TCVN 9386:2012 .......................................................................................................2-18
Table 2.17: Measured results of resistivity of rock and soil ......................................2-20
Table 2.18: Recommendations for grades of excavated soil and rock ......................2-24
Table 2.19: Characteristics of ambient temperature at Quy Nhon meteor station .....2-26
Table 2.20: Characteristics of ambient humidity at Quy Nhon meteor station .........2-27
Table 2.21: Ambient pressure at Quy Nhon meteor station .......................................2-27
Table 2.22: Frequency of wind occurrence at 8 directions in a year at Quy Nhon
meteor station .............................................................................................................2-28
Table 2.23: Frequency of wind occurrence at 8 directions at months of rainy season
(from September to December) - Quy Nhon meteor station ......................................2-28
Table 2.24: Frequency of wind occurrence at 8 directions at months of dry season
(from Jan – August) - Quy Nhon meteor station .......................................................2-28
List of Table
iv
Nhon Hoi Wind farm project – Phase I
Technical Design
Table 2.25: Average wind speed of months in a year at Quy Nhon meteor station ..2-30
Table 2.26:Frequency of average wind speed levels at Quy Nhon meteor station ....2-30
Table 2.27: Maximum wind speed of months in a year at Quy Nhon meteor station ...231
Table 2.28: Maximum wind speed correspond to frequencies at 8 directions and nondirection at Quy Nhon meteor station .......................................................................2-31
Table 2.29: Standard wind pressure with repeated cycle of wind 1 time in 10 years and
1 time in 20 years .......................................................................................................2-32
Table 2.30: Precipitation and number of rainy days at Quy Nhon and Phu Cat stations
....................................................................................................................................2-33
Table 2.31: Rainfall volume corresponding to frequencies at Quy Nhon and Phu Cat
stations ........................................................................................................................2-35
Table 2.32: Maximum daily precipitation at Quy Nhơn and Phù Cát stations ..........2-36
Table 2.33: Maximum rainfall volume at Quy Nhơn and Phù Cát stations...............2-37
Table 2.34: Maximum daily precipitation corresponding to frequencies at Quy Nhơn
and Phù Cát stations ...................................................................................................2-37
Table 2.35: Maximum rainfall volume at design period ............................................2-38
Table 2.36: Annual average evaporation volume at Quy Nhon meteor station ........2-38
Table 2.37: The average number of sunshine hours in many years recorded at Quy
Nhon meteor station ...................................................................................................2-39
Table 2.38: Number of days having thunderstorms in average month and year .......2-39
Table 2.39: Number of days having biggest thunderstorms in months and year at Quy
Nhon meteor station ...................................................................................................2-40
Table 2.40: Statistic results of storms hitting Binh Dinh-Ninh Thuan area during the
period of 1964 to 2017 ...............................................................................................2-41
Table 3.1: Coordinates of some main items of project ................................................3-1
Table 3.2: The operating frequency range of wind turbine........................................3-11
Table 3.3: Main specifications of wind turbines ........................................................3-12
Table 3.4: Specifications of the 0.69/22kV-5500kVA MV substation ......................3-15
Table 3.5: Specification of PPC device .....................................................................3-25
Table 4.1: Summary table of internal road lengths ....................................................4-12
List of Table
v
Nhon Hoi Wind farm project – Phase I
Technical Design
LIST OF FIGURE
Figure 2.1: Project boundary ........................................................................................2-2
Figure 2.2: Some pictures of project area ....................................................................2-3
Figure 2.3: Topography map scale 1:500 of project, used for Technical Design ........2-5
Figure 2.4: Geological and Mineral resources map of Viet Nam on 1:200000 ...........2-6
Figure 2.5: Earthquake zoning map of Vietnam territory ..........................................2-18
Figure 2.6: Temperature variation progress at Quy Nhon station .............................2-26
Figure 2.7: Wind rose of months and year in Quy Nhon station ...............................2-29
Figure 2.8: Rainfall variation progress at Quy Nhon station .....................................2-35
Figure 2.9: Rainfall variation progress of months in a year at Phu Cat station .........2-36
Figure 3.1: Project General layout ...............................................................................3-3
Figure 3.2: The main components of wind turbines ....................................................3-5
Figure 3.3: Principle of the control of blades angle (pitch) .........................................3-8
Figure 3.4: Typical SLD of turbine ............................................................................3-14
Figure 3.5: RMU configuration..................................................................................3-16
Figure 3.6: Typical SCADA single line diagram .......................................................3-21
Figure 3.7: Typical fiber optic connection of WTG ..................................................3-21
Figure 3.8: Typical fiber optic connection of WTG’s switch ....................................3-21
Figure 3.9: Typical control system of wind power plant ...........................................3-22
Figure 3.10: Wind SCADA configuration .................................................................3-23
Figure 3.11: Single line diagram of SCADA’s communication ................................3-24
Figure 3.12: Normal Configuration ...........................................................................3-26
Figure 3.13: Quick Configuration ..............................................................................3-26
Figure 3.14: Lightning and grounding system of turbine’s tower .............................3-28
Figure 3.15: Gas automatic fire extinguishing system installed in wind turbines .....3-32
Figure 4.1: Foundation type 1 ......................................................................................4-3
Figure 4.2: Foundation type 2 ......................................................................................4-4
Figure 4.3: Typical laydown for asembly and installation...........................................4-4
List of Figure
vi
Nhon Hoi Wind farm project – Phase I
Technical Design
CHAPTER 1: OVERVIEW
1.1.
LEGAL BASIS
Technical design document of project "Nhon Hoi wind power plant – Phase I" is
prepared on the following basis:
-
Law on Electricity No. 28/2004/QH11 dated December 3, 2004 of the National
Assembly; Law amending and supplementing a number of articles of the
Electricity Law No. 24/2012/QH13 dated November 20, 2012 of the National
Assembly;
-
Law amending and supplementing a number of articles of 11 laws related to the
National Assembly's Planning No. 28/2018/QH14 dated June 15, 2018;
-
Law on Construction No. 50/2014/QH13 dated June 18, 2014 of the National
Assembly;
-
Law on Environmental Protection No. 55/2014/QH13 dated June 23, 2014 of
the National Assembly;
-
Law on Investment No. 67/2014/QH13 dated November 26, 2014 of the
National Assembly;
-
Law on Planning No. 21/2017/QH14 dated November 24, 2017 of the National
Assembly;
-
Decree No. 46/2015/ND-CP dated May 12, 2015 on quality management and
construction maintenance.
-
Decree No. 59/2015/ND-CP dated June 18, 2015 of the Government on
management of construction investment projects.
-
Decree No. 42/2017/ND-CP dated April 5, 2017 of the Government amending
and supplementing a number of articles of the Government's Decree No.
59/2015/ND-CP dated June 18, 2015 on construction investment project
management;
-
Decision No. 37/2011/QD-TTg dated June 29, 2011 of the Prime Minister on
the mechanism to support the development of wind power projects in Vietnam;
-
Decision No. 2068/QD-TTg dated November 25, 2015 of the Prime Minister
approving the Strategy for development of renewable energy of Vietnam to
2030, with a vision to 2050;
-
Decision No. 428/QD-TTg dated March 18, 2016 of the Prime Minister
approving the adjustment of National Electricity Development Plan for the
period 2011-2020 with a vision to 2030;
-
Decision No. 39/2018/QD-TTg dated September 10, 2018 of the Prime Minister
amending and supplementing a number of articles of Decision No. 37/2011/QD-
Volume 1.1 – Chapter 1
1-1
Nhon Hoi Wind farm project – Phase I
Technical Design
TTg dated June 29, 2011 of Prime Minister on mechanism to support the
development of wind power projects in Vietnam;
-
Circular 02/2019/TT-BCT dated 15/01/2019 of the Ministry of Industry and
Trade on Regulations on implementing wind power project development and
Power Purchase Agreement for wind power projects;
-
Circular 03/2016/TT-BXD: Circular Regulating the decentralization of
construction works and guiding the application in the management of
construction investment activities;
-
Circular 07/2019/TT-BXD: Amending, supplementing and replacing a number
of provisions in Circular No. 03/2016/TT-BXD dated March 10, 2016 of the
Minister of Construction on levels of construction works and instructions for
application in construction management activities;
-
Decision No. 428/QD-TTg dated March 18, 2016 of the Prime Minister
approving the adjusted national electricity development planning for the period
2011-2020 with a vision to 2030.
-
Circular No. 39/2015/TT-BCT dated November 18, 2015 of the Ministry of
Industry and Trade on regulations on distribution power system.
-
Circular No. 30/2019/TT-BCT dated November 18, 2019 of the Ministry of
Industry and Trade on amending and supplementing a number of articles of the
Ministry's Circular No. 25/2016/TT-BCT dated November 30, 2016 The
Minister of Industry and Trade regulates the power transmission system and the
Circular No. 39/2015/TT-BCT dated November 18, 2015 of the Minister of
Industry and Trade regulating the distribution power system;
-
Decision No. 332/QÐ-BCT dated February 3, 2017 of the Ministry of Industry
and Trade approving “Power development planning of Binh Dinh province for
the period 2016-2025, with consideration of 2035 Master plan for 110kV
electric system ";
-
Investment policy Decision No. 30/QD-BQL dated February 7, 2020 of the
Management Board of Binh Dinh Economic Zone on approving the investment
policy for FICO Investment Joint Stock Company to invest in the project Nhon
Hoi 1 wind power plant in Nhon Hoi Economic Zone, Binh Dinh province;
-
Decision No. 76/QD-BQL dated 25/03/2020 of the Management Board of Binh
Dinh Economic Zone on adjustment of Decision No. 30/QD-BQL dated
February 7, 2020 of the Management Board of provincial economic zones Binh
Dinh (renamed the project "Nhon Hoi wind power plant - Phase 1)";
-
Document No. 1264/UBND-KT dated 04/3/3020 of the People's Committee of
Binh Dinh province agreeing the direction of the 110kV line connected, the
Volume 1.1 – Chapter 1
1-2
Nhon Hoi Wind farm project – Phase I
Technical Design
22kV power line for construction, self-use of Nhon Hoi 1 and Nhon Hoi wind
power plants 2; Document No. 5714/UBND-KT, dated 25/8/2020 on the
adjustment of some contents in Document No. 1264/UBND-KT dated
04/3/3020 of the Provincial People's Committee;
-
Agreement on connecting Nhon Hoi wind power plant - Phase 1 and Nhon Hoi
wind power plant - Phase 2 between Central Power Corporation and Fico Binh
Dinh Energy Joint Stock Company on June 19, 2020 ;
-
Agreement on technical design of SCADA Telecommunication system for
Nhon Hoi wind power plant project - Phase 1 No. 2435/ĐĐQG-CN dated
27/7/2020 between the National Load Dispatch Center and the Company FICO
Binh Dinh Energy Joint Stock Company;
-
Agreement on technical design of the protective and automatic relay system of
Nhon Hoi wind power plant project - phase 1 No. 41/2020/ĐĐQG-TTRL dated
August 7, 2020 between the National Load Dispatch Center and Fico Binh Dinh
Energy Joint Stock Company;
-
Agreement on technical design of power metering system and metering data
collection system for Nhon Hoi wind power plant - phase 1, Binh Dinh province
No. 4706/EPTC-KT & IT-KDBD dated September 14, 2020 between Power
Trading Company and Fico Binh Dinh Energy Joint Stock Company;
-
Document No. 286/TC-QC dated June 25, 2020 of the Department of Warfare
Ministry of General Staff approving the static altitude for construction of Nhon
Hoi wind power plant project - phase 1;
-
Decision No. 2025/QD-UBND dated May 26, 2020 of the People's Committee
of Binh Dinh province approving the detailed construction planning project of
1/500 scale of Nhon Hoi wind power plant - Phase 1, Nhon Hoi Economic zone;
-
Document No. 805/BQL-QLQHXD dated 18/6/2020 of Binh Dinh Economic
Zone Management Board on notification of results of basic design appraisal of
Nhon Hoi wind power plant project - Phase 1;
-
Document No. 1208/BQL-QLQHXD dated September 1, 2020 of the
Management Board of Economic Zone of Binh Dinh province confirming the
completion of basic design documents of Nhon Hoi 1 and 2 wind power plants;
-
Decision No. 11/2020/QD-BDE dated October 1, 2020 of FICO Binh Dinh
Energy Joint Stock Company approving the feasibility study report on
investment in construction of Nhon Hoi wind power plant project - Phase 1.
Volume 1.1 – Chapter 1
1-3
Nhon Hoi Wind farm project – Phase I
1.2.
Technical Design
MAIN PROJECT INFORMATION
1.2.1. Project scale
Nhon Hoi wind power plant - Phase I is invested by Binh Dinh FICO Energy Joint
Stock Company with a total installed capacity of 30 MW with the project scale as
follows:
-
Type of project: Industry and energy.
-
Grade of work: Class II.
-
Construction group: Group B.
-
The main items of the project:
+ Construction of wind power plants using horizontal axis wind turbine
technology, including 6 turbines, each with a capacity of 5.0MW.
+ Construction of internal 22kV power grid within the plant to connect wind
turbines, combining underground cable and overhead lines solutions.
+ Construction of 110kV substation of Nhon Hoi wind power plant, capacity
of 2x40MVA to share the same infrastructure connection for Nhon Hoi wind
power plant - Phase I and Nhon Hoi wind power plant - Phase II. Each project
is connected to 1 22/110kV - 40 MVA transformer.
+ Construction of dual-circuit 110kV transmission line, ACSR 240 conductor,
approximately 0.25km in length from the 110kV Nhon Hoi wind power plant
substation to transitional connect to 110kV Nhon Hoi - Dong Da transmission
line.
+ Construction of an O&M Building to serve the general operation of Nhon
Hoi wind power plant - Phase I and Nhon Hoi wind power plant - Phase II.
+ Construction of road infrastructure including access road connecting to
existing National Highway 19B and internal road for plant construction and
operation
1.2.2. Land usage demand
Summary of land usage demand of the project is as follows:
Table 1.1: Summary of land uasge demands of project
Area (ha)
No.
Item
I
1
Phase 1
Phase 2
Total
Long term land usage
10.28
7.43
17.71
Wind turbine and harstand area
1.32
1.38
2.70
Volume 1.1 – Chapter 1
1-4
Nhon Hoi Wind farm project – Phase I
Technical Design
Area (ha)
No.
Item
Phase 1
Phase 2
Total
2
110kV substation
0.70
-
0.70
3
Internal route (including MV cable)
7.81
6.05
13.86
4
O&M building
0.40
-
0.40
5
110kV transmission line foundation
0.05
-
0.05
6
22kV transmission line foundation
0.10
0.10
0.20
II
Temporary land usage
6.23
4.22
10.45
1
Site office
0.20
-
0.20
2
Storage area
1.40
-
1.40
3
Disposal area
4.63
4.22
8.85
Therefore, the land usage area of the project is fully compliant with the provisions
of Clause 2, Article 12, Circular 02/2019/TT-BCT: long term land usage of wind power
plant shall not exceed 0.35 ha/MW, the temporary land usage of wind power plan shall
not exceed 0.3 ha/MW.
1.2.3. Applied standard
1.2.3.1. Wind turbines standard
-
IEC 61400-1
: Wind Turbines – General design requirements;
IEC 61400-4
: Wind Turbines – Design requirements for wind turbine
gearboxes;
IEC 61400-11
: Wind Turbines – Acoustic noise measurement techniques;
IEC 61400-12-1
: Wind Turbines – Wind energy efficiency measurements;
IEC 61400-13
: Wind Turbines – Measurement of mechanical loads;
IEC 61400-21
: Wind Turbines – Measurement and assessment of power
quality characteristics of grid connected wind turbines;
IEC 61400-22
: Wind Turbines – Conformity testing and certification;
IEC 61400-23
: Wind Turbines – Full-scale structural testing of rotor
blades;
IEC 61400-25
: Wind Turbines – Communications for monitoring and
control of wind power plants;
IEC 61400-27-1
: Wind Turbines – Electrical simulation models – Generic
models
Volume 1.1 – Chapter 1
1-5
Nhon Hoi Wind farm project – Phase I
Technical Design
1.2.3.2. Wind turbine generator
-
IEC 60034-1 to 60034-11 – Rotating electrical machines
ANSI B 49.1/IEEE Std 810-1987 – Shaft Couplings
NEMA ANSI/IEEE Std 810-1987 – Shaft Alignment
ISO 10816 – Mechanical vibration — Evaluation of machine vibration by
measurements on non-rotating
ISO 10816-3 1998-05 Part 3 Industrial machine with capacity of over 15kW,
speed from 120 rpm to 15000 rpm when measured in the field.
1.2.3.3. Semiconductor Converters
-
IEC 60146-1-1: General requirements and line commutated converters – Part 11: Specification of basic requirements
IEC 60146-1-2: General requirements and line commutated converters – Part 12: Application guide
IEC 60146-1-3: General requirements and line commutated converters – Part 13: Transformers and Reactors
1.2.3.4. Control, protection and automatic
-
-
IEC 60870 - Telecontrol equipment and systems (WAN network);
IEC 61850 - Communication networks and systems for power utility automation
(LAN network);
IEC 61255 - Protective relays;
IEEE 1131/IEC 61131 - Programmable Controllers;
IEC 60794-1-31:2018 - Optical fibre cables;
IEC 60874 - Fibre optic interconnecting devices and passive components;
IEC 61508 – Functional safety of electrical/electronic/programmable electronic
safety-related systems;
ICCP - Central protocol link control;
IEEE 802 - Standards for local area networks;
IEC 60870-5-104 - Telecontrol equipment and systems – Part 5-104:
Transmission protocols – Network access for IEC 60870-5-101 using standard
transport profiles;
IEC 61158 - Industrial communication networks – Fieldbus specifications;
IEC 61784 - Industrial communication networks;
IEC 60870-5-101 - Telecontrol equipment and systems – Part 5-101:
Transmission protocols – Companion standard for basic telecontrol tasks;
IEC 60870-5-103 - Telecontrol Equipment and Systems - Part 5-103:
Transmission Protocols - Companion Standard for the Informative Interface of
Protection Equipment;
1.2.3.5. Mechanical structure and components
-
ISO 2394 General principles of structural reliability
Volume 1.1 – Chapter 1
1-6
Nhon Hoi Wind farm project – Phase I
-
Technical Design
ISO 76, Roller Bearing - Static load rating
ISO 281:2007, Roller Bearing - Rated dynamic load and rated service life
ISO 683 (all components), Heat-resistant steel, alloy steel and free-cut steel
ISO 1328-1, Cylindrical gear - ISO precision system - Part 1: Definition and
allowable deviation values relative to the rib of the respective gear
ISO 6336 (all components), Calculate the load capacity of helical gears
ISO 6336-1: 2006, Calculation the load supporting ability of helical gear and
volute gear - Part 1: Basic principles, introduction and general influence factors
ISO 6336-2: 2006, Calculation the load supporting ability of helical gear and
volute gear - Part 2: Calculation of surface strength (pitting)
ISO 12925-1, Lubricants, industrial oils and related products (type L). Family C
(Gears) - Part 1: Specifications for lubricants for enclosed gear systems
DIN 743: 2000: Shaft, calculation of load capacity, Sections 1,2, 3
DIN 3990-4: Calculate the load supporting ability of the cylinder gear: calculate
the load supporting ability
DIN 6885-2: Parallel keys, deep pattern for machine, dimensions and application
1.2.3.6. Electrical equipment standards
-
IEC 60076 : Power transformers.
IEC 60137 : Insulated bushings for alternating voltages above 1000 V.
IEC 60296 : Fluids for electrotechnical applications – Mineral insulating oils
for electrical equipment.
IEC 60156 : Insulating liquids - Determination of the breakdown voltage at
power frequency - Test method.
IEC 60085 : Electrical insulation – Thermal evaluation and designation.
IEC 60044-1 : Instrument transformers - Part 1: Current transformers;
IEC 60044-5 : Instrument transformers . Part 5: Capacitor voltage transformers;
IEC 60099-3 : Surge Arresters Part 3: Artificial Pollution Testing of Surge
Arresters;
IEC 60093-4 : Surge arresters – Part 4: Metal-oxide surge arresters without gaps
for a.c. systems;
IEC 60099-5 Surge arresters – Part 5: Selection and application
recommendations;
IEC 60071 : Insulation co-ordination;
IEC 60056 : High-voltage alternating-current circuit-breakers
IEC 62271-100: High-voltage switchgear and controlgear – Part 100:
Alternating-current circuit-breakers;
IEC 62271-110: High-voltage switchgear and controlgear - Part 110: Inductive
load switching;
IEC 60376 : Specification of technical grade sulphur hexafluoride (SF6) and
complementary gases to be used in its mixtures for use in electrical equipment;
Volume 1.1 – Chapter 1
1-7
Nhon Hoi Wind farm project – Phase I
-
-
-
Technical Design
IEC 62271-102: High-voltage switchgear and controlgear - Part 102: Alternating
current disconnectors and earthing switches;
ISA S18.1 : Annunciator Sequences and Specifications;
ISA S5.5
: Graphic Symbols for Process Displays;
ISA RP60 : Control Center Design Guide and Terminology;
ICCP : Central protocol link control;
NEMA PB1-197: Panelboards;
IEEE 1131 / IEC 61131: Programmable Controllers;
IEEE 802
: Standards for local area networks;
IEC 61000 : Electromagnetic compatibility (EMC);
IEC 61850 : Communication networks and systems for power utility
automation;
IEC 60870-5-104: Telecontrol equipment and systems – Part 5-104:
Transmission protocols – Network access for IEC 60870-5-101 using standard
transport profiles;
IEC 60870-5-101: Telecontrol equipment and systems – Part 5-101:
Transmission protocols – Companion standard for basic telecontrol tasks;
IEC 60794 : Optical fibre cables;
IEC 61158 : Industrial communication networks – Fieldbus specifications;
IEC 61784 : Industrial communication networks;
IEC 60255 : Measuring relays and protection equipement;
IEC 60870-5-103: Telecontrol Equipment and Systems - Part 5-103:
Transmission Protocols - Companion Standard for the Informative Interface of
Protection Equipment;
IEC 60189 : Low-frequency cables and wires with PVC insulation and PVC
sheath;
IEC 60227 : Polyvinyl Chloride Insulated Cables of Rated Voltages up to and
Including 450/750 V;
IEC 60228 : Conductors of Insulated Cables;
IEC 60230 : Impulse Tests on Cables and Their Accessories;
IEC 60287 : Electric cables – Calculation of the current rating;
IEC 60304 : Standard Colours for Insulation for Low-Frequency Cables and
Wires;
IEC 60331 : Fire-Resisting Characteristics of Electric Cables;
IEC 60332 : Tests on electric and optical fibre cables under fire conditions;
IEC 60391 : Marking of Insulated Conductors;
IEC 60423 : Conduit systems for cable management – Outside diameters of
conduits for electrical installations and threads for conduits and fittings;
IEC 60502 : Extruded Solid Dielectric Insulated Power Cables for Rated
Voltages from 1 kV up to 30 kV;
IEC 60793 : Optical fibres;
IEC 60794 : Optical fibre cables;
Volume 1.1 – Chapter 1
1-8
Nhon Hoi Wind farm project – Phase I
-
Technical Design
IEC 60811 : Electric and optical fibre cables – Test methods for non-metallic
materials;
IEC 60874 : Fibre optic interconnecting devices and passive components –
Connectors for optical fibres and cables;
Regulations on electrical equipment 11TCN–18–2006, 11TCN–19–2006,
11TCN–20– 2006, 11TCN–21-2006.
1.2.3.7. Civil standards
a. Standards for turbine foundation
- EN 1992-1 Eurocode 2 - Design of concrete structures.
-
CEB-FIB Model Code 2010 - Model code for concrete structures.
-
EN 1997-1 Eurocode 7 - Geotechnical design.
-
EN 206-1 Concrete: Specification, performance, production and conformmity
-
IEC 61400-1 Wind turbines – Part 1: Design requirement
b. Others civil standard
- TCVN 2682: 2009 Portland cements - Specifications
- TCVN 6260: 2009 Portland blended cement - Specifications.
- TCVN 6227 :1996 ISO standard sand for determination of cement strength.
- TCVN 7570:2006 Aggregates for concrete and mortar - Specifications.
- TCVN 7570: 2006 Aggregates for concrete and mortar - Specifications.
- TCVN 7572: 2006 Aggregates for concrete and mortar - Test methods.
- TCVN 4506: 2012 Water for concrete and mortar - Technical specification.
- TCVN 6884:2001 Ceramic tiles with low water absorption – Specification
- TCVN 5574:2018 Design of concrete and reinforced concrete structures.
-
TCVN 9340: 2012 Ready-mixed concrete - Specification and acceptance.
TCVN 8828 :2011 Concrete - Requirements for natural moist curing.
TCVN 9115:2019 Assembled concrete and reinforced concrete structures Practice for erection and acceptance.
TCVN 4453:95 Monlithic concrete and reinforced concrete structures - Codes
for construction, check and acceptance
TCVN 3118:93 Heavyweight concrete - Method for determinatien of
compressive strength
TCVN 3106:93 Fresh heavyweight concrete - Method for slump test.
TCVN 1651-1: 2018 Steel for the reinforcement of concrete - Part 1: Plain bars.
TCVN 1651:2-2018 Steel for the reinforcement of concrete - Part 2: Ribbed bars
TCVN 5709: 2009 Hot rolled carbon steel for building - Technical requirements
TCVN 197-1:2014 Metallic materials - Tensile testing - Part 1: Method of test at
room temperature
TCVN 198:2008 Metallic materials - Bend test.
TCVN 1765-75 Carbon steel - General structures, Steel grades and specifications
Volume 1.1 – Chapter 1
1-9
Nhon Hoi Wind farm project – Phase I
-
Technical Design
TCVN 5847:2016 Spun precast reinforced concrete poles
TCVN-134-77 Washers fechnical requirements
TCVN 130-77 Lock Washers
TCVN 170-2007 Steel structures – Fabrication, assembly, check and acceptance
– Technical requerements
1.2.3.8. Firefighting system standards
-
TCVN 2622: 1995 - Fire prevention and protection for buildings and structures Design requirements.
-
TCVN 4513 - 1988: Internal water supply – Design standard.
-
TCVN 5040: 1990 - Fire prevention and protection equipments - Graphical
symbols used for protection schemes – Specifications.
-
TCVN 3890: 2009 Fire protection equipments for construction and building –
Providing, installation, inspection, maintenance.
-
TCVN 7435-1:2004 - Fire protection – Portable and wheeled fire extinguishers Part 1: Selection and Installation.
-
TCVN 5738 – 2001 Fire detection and alarm system - Technical requirements.
-
TCVN 6100: 1996 (ISO 5923:1984) Fire protection - Fire extinguishing media –
carbon dioxide.
-
TCVN 6102:1996 ISO 7202:1987 Fireprotection– Fire extinguishingmedia–
Powder.
-
Gas fire extinguishing Novec 1230 system for wind turbines, according to NFPA
2001 standard.
-
Electrical equipment regulations: 11 TCN 18-2006; 11 TCN 19-2006; 11 TCN
20- 2006; 11 TCN 21- 2006.
-
TCVN 6160:1996: Fire protection - High rise building - Design requirements;
-
TCVN 5738: 2001: Automatic fire alarm system;
-
TCXD 218: 1998. Fire detection system and fire alarm.
-
TCVN 7568-1:2006. Fire alarm system. Part 1: General rules and definitions.
-
TCVN 7568-2:2013. Fire alarm system. Part 2: Fire alarm control panel.
-
TCVN 7568-3:2015. Fire alarm system. Part 3: Sound alarm equipment.
-
TCVN 7568-4:2013. Fire alarm system. Part 4: Power supply equipment.
-
TCVN 7568-5:2003. Fire alarm system. Part 5: Point-type fire detectors.
-
TCVN 7568-6:2013. Fire alarm system. Part 6: Carbon monoxide fire detector
use electrochemical battery.
-
TCVN 7568-7:2015. Fire alarm system. Part 7: Point type smoke detector using
light, scattering or ionizing light.
Volume 1.1 – Chapter 1
1-10
Nhon Hoi Wind farm project – Phase I
Technical Design
-
TCVN 7568-8:2015. Fire alarm system. Part 8: Point-type fire detectors that use
carbon monoxide sensors in combination with heat sensors.
-
TCVN 7568-9:2015. Fire alarm system. Part 9: Test fires for fire detectors.
-
TCVN 7568-10:2015. Fire alarm system. Part 10: Point-type fire detectors.
-
TCVN 7568-11:2015. Fire alarm system. Part 11: Fire alarm button box.
-
TCVN 7568-12:2015. Fire alarm system. Part 12: Transmission line smoke
detector using optical beam.
-
TCVN 7568-13:2015. Fire alarm system. Part 13: Assessment of compatibility
of components in the system.
-
TCVN 7568-14:2015. Fire alarm system. Part 14: Design, installation, operation
and maintenance of fire alarm systems in and around the building.
-
TCVN 7568-15:2015. Fire alarm system. Part 15: Point-type fire detectors that
use smoke and heat sensors
-
QCVN 06:2020/BXD National technical regulation on fire safety for houses and
buildings
1.3.
INPUT FOR TECHNICAL DESGIN
The input documents serving the Technical design of Nhon Hoi wind power plant
- Phase I include:
-
The legal bases of the project
-
Basic design documents have been evaluated and approved
-
Profile of the technical design survey by 23 Construction Consulting Joint Stock
Company done in November 2020, including:
+ Topographic survey report
+ Construction geological survey report
+ Meteorological - hydrological survey report
-
Employer Requirements for EPC Contractor
-
EPC contractor's technical proposal (Powerchina Vietnam Limited Company)
includes the following main contents:
+ Technical specifications and characteristics of wind turbines proposed for the
project
+ Design requirements and recommendations of the wind turbine manufacturer
+ Report on wind energy assessment and calculation of annual energy
production
+ Other related documents
Volume 1.1 – Chapter 1
1-11
Nhon Hoi Wind farm project – Phase I
Technical Design
CHAPTER 2: SPECIFICATION OF PROJECT AREA
2.1.
PROJECT LOCATION
2.1.1. Project location
Nhon Hoi wind power plant - Phase I is located on the western slope of Phuong
Mai mountain range, located in the wind power planning area of Nhon Hoi economic
zone, in the territory of Nhon Ly and Nhon Hoi communes, Quy Nhon city, Binh Dinh
province.
The project's geographic coordinates at center of project is 13°51'17.24”,
109°16'48.12”. The total area of about 175 ha which has the following boundaries:
-
The North borders: Adjacent to QNY - Korea Solar Power project
-
The South borders: Adjacent to Nhon Hoi wind power project- Phase II.
-
The East borders: adjacent to the sea and Ky Co tourist area.
-
The West borders: Adjacent to the 110kV route of Nhon Hoi - Dong Da
transmission line.
The project boundary has the following coordinates
Table 2.1: Project coordinates
Point
VN2000 coordinates, 3o projection,
108o15' central meridian
X (m)
Y (m)
Boundary of Nhon Hoi WPP – Phase I
Volume 1.1 – Chapter 2
M1
1533635.13
610619.67
M2
1532669.79
610677.22
M3
1532543.59
610781.54
M4
1532068.41
610826.06
M5
1531921.56
610922.25
M6
1531665.78
611220.99
M7
1531397.91
611349.07
M8
1531503.90
611550.30
M9
1531745.67
611423.98
M10
1531836.55
611627.93
M11
1531941.12
611581.01
M12
1532278.15
611603.54
2-1
Nhon Hoi Wind farm project – Phase I
Point
Technical Design
VN2000 coordinates, 3o projection,
108o15' central meridian
X (m)
Y (m)
M13
1532437.32
611456.50
M14
1532652.82
611357.23
M15
1532840.22
611397.08
M16
1533022.76
611767.92
M17
1533835.50
611602.17
Area: 175ha
Nhon Hoi WPP –
Phase I
Nhon Hoi WPP –
Phase II
Figure 2.1: Project boundary
Volume 1.1 – Chapter 2
2-2
Nhon Hoi Wind farm project – Phase I
Technical Design
2.1.2. Some pictures of project area
Figure 2.2: Some pictures of project area
2.2.
SITE CONDITIONS OF PROJECT AREA
2.2.1. Topography conditions
Nhon Hoi wind power plant - Phase I is located Nhon Hoi economic zone, in the
territory of Nhon Ly and Nhon Hoi communes, Quy Nhon city, Binh Dinh province
Terrain of the surveyed area is average low mountainous area with natural
elevation from hill top from 50m to 360m. The terrain surface is undulated with strongly
Volume 1.1 – Chapter 2
2-3
Nhon Hoi Wind farm project – Phase I
Technical Design
dissected level. Erosion, denudation developed strongly in hill sides. Accumulation
process occurs with slow rate at low depression areas and along watersheds.
In the project area, the terrain has a steep slope divided by streams and rocks, the
road is difficult, the land cover is mainly in the bush and thorn trees.
The topographical survey scope in the Basic Design stage measured 1:2000
topography of the project boundary. On that basis, the main items of the project were
basically designed.
The scope of topographic survey in the stage of Technical design, measuring and
drawing topographic maps of 1:500 of project area, which is enough to design the
following items:
-
Turbine foundation
-
Turbine hardstanding
-
Access road, site office and storage area
-
Internal road
-
MV grid: 22kV underground cable and Overhead line
-
110kV substation
-
O&M Building
-
110kV transmission line (particular for 110kV transmission line foundation,
surveyed topography map is 1:200)
Result of surveyed topography map as in Figure 2.3.
The detailed topographical survey results are shown in the topographic survey
report of Nhon Hoi wind power plant project - Phase 1 & Phase 2 performed by 23
Construction and Consulting Joint Stock Company implemented in November 2020.
Volume 1.1 – Chapter 2
2-4
Nhon Hoi Wind farm project – Phase I
Technical Design
Figure 2.3: Topography map scale 1:500 of project, used for Technical Design
Volume 1.1 – Chapter 2
2-5
Nhon Hoi Wind farm project – Phase I
Technical Design
2.2.2. Construction geological conditions
2.2.2.1. General Geological features
According the Geological and Mineral resources map of Viet Nam on 1:200000,
published by Department of Geological and Mineral of Viet Nam in 1997, locations of
the Nhon Hoi Wind Farm are within the distribution of rock, soil of Nha Trang formation
and Quaternary sediments. In addition, there is an an extrusive igneous rock of the Deo
Ca complex distributed in the east of the project.
CRETACEOUS
Nha Trang Formation (Knt)
The composition mainly includes rhyolite, dacite, andesite and their tuffs. 450600m thick. Nha Trang formation is distributed throughout the scope of the project.
QUATERNARY
Middle-Upper Holocene (mvQIV2-3)
The composition mainly includes yellow grey quartz sand, silt. 10-20m thick.
These sediments are mainly distributed in the western and northern extent of the project.
EXTRUSIVE IGNEOUS ROCKS
Deo Ca Complex - Phase 2 (-Kdc2)
The composition mainly includes coarse to medium-grained granite, biotite
(hornblende) granosyenite. Deo Ca Complex is distributed in the east, out of the project
area.
Figure 2.4: Geological and Mineral resources map of Viet Nam on 1:200000
Volume 1.1 – Chapter 2
2-6
Nhon Hoi Wind farm project – Phase I
Technical Design
2.2.2.2. Physical mechanical properties of rock, soil within the scope of project
construction area
2.2.2.2.1. Engineering geological layer within the project scope
Based on the drill core, the results of soil and rock mechanical samples testing and
assessment at the site, soil and rock are divided in the project area into 05 layers as
follows:
Table 2.2: Geological layer within the project scope
Lay
er
1
2
3
4
5
Layer name
mvQIV
Layer of marine
and wind deposit
edQ+IA1
Layer of eluvial deluvial and Zone
of complete
weathered rock
Reddish brown, brownish clay loam,
in hard state, mixed with gravel,
block stones. Most of them use a
shovel to dig
Medium
Zone of strongly
weathered rock
Bedrock is gray brown, soft to
medium hard, with particularly
strong fracture, mixed with some
clay loam. More than half of the rock
material becomes soft and exists
either as monolithic or completely
discolored rock cores compared to
fresh rock. Using a shovel to dig,
although sometimes difficult to dig,
using crowds or sometimes mines
High
Zone of medium
weathered rock
Bedrock is brownish gray, greenish
gray, from medium to hard, very
strong fracture. The rock stains or
has white streaks, no longer retains
its original color. Digging must use
mines
Very high
Zone of fresh rock
Bedrock is greenish gray, light gray,
the rock is hard to very hard,
strongly cracked. The rock is slightly
and locally discolored. Weathering
on the surface of crevices and other
defects, oxidation penetration up to
3mm. Digging must use mines.
Very high
IA2
IB
IIA
Description
Load
bearing
capacity
Symbols
Medium grain sand color is in
yellowish grey, tight structured
Well
Khá
2.2.2.2.2. Results of standard penetration test SPT
SPT is carried out in layer 1 and layer 2 of most boreholes, the results are as
follows:
Volume 1.1 – Chapter 2
2-7
Nhon Hoi Wind farm project – Phase I
Technical Design
Table 2.3: Results of standard penetration test SPT
No.
Borehole
Location
1
NH-1
WTG 1
2
NH-1A
WTG 1
3
NH-2
WTG 2
4
NH-2A
WTG 2
5
NH-3
WTG 3
6
NH-3A
WTG 3
Volume 1.1 – Chapter 2
Depth (m)
Layer
2
3
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
1
2
3
4
1
2
3
4
5
6
7
8
9
10
1
2
1
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
2
2
Value
SPT N30
47
96
25
21
24
24
27
26
22
23
22
25
26
30
33
32
32
34
34
Rock
23
34
31
Rock
9
11
10
14
16
21
23
21
25
27
25
27
27
2-8
Nhon Hoi Wind farm project – Phase I
No.
Borehole
Location
7
NH-4
WTG 4
8
NH-4A
WTG 4
9
NH-5
WTG 5
10
NH-5A
WTG 5
11
NH-7
WTG 7
Volume 1.1 – Chapter 2
Technical Design
Depth (m)
Layer
2
3
4
5
6
7
8
9
10
1
2
3
4
5
6
7
8
9
1
2
1
3
4
5
6
7
8
9
10
11
1
2
3
4
5
6
7
1
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Value
SPT N30
29
33
31
37
35
40
43
72
78
32
31
25
36
48
77
84
100
106
37
48
75/5cm
19
21
21
25
43
71
74
38-50/8cm
42-50/5cm
25
28
27
29
28
34
30
26
2-9
Nhon Hoi Wind farm project – Phase I
No.
Borehole
Location
12
NH-7A
WTG 7
13
NH-13
WTG 13
14
DVH-1
Road route
15
DVH-2
Road route
16
DVH-3
Road route
17
DVH-4
Road route
18
DVH-5
Road route
Volume 1.1 – Chapter 2
Technical Design
Depth (m)
Layer
2
1
2
2
3
4
1
2
3
4
5
6
7
8
9
10
1
2
3
4
5
6
7
8
9
10
1
2
3
4
5
6
1
2
3
4
5
2
2
2
2
2
2
2
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
1
1
1
1
2
2
Value
SPT N30
40
27
31
25
31
40
41
45
47
52
40
35
37
40
42
48
23
21
34
15
16
19
23
26
31
34
21
18
30
41
38
39
7
6
11
27
30
34
2-10
Nhon Hoi Wind farm project – Phase I
No.
Borehole
Location
19
DVH-7
Road route
20
DVH-9
Road route
21
DVH-11
Road route
22
DVH-12
Road route
23
DVH-13
Road route
24
TBA-1
Substation
25
TBA-2
Substation
26
TTB-1
Yard equipment
27
28
TTB-2
NQL-1
Yard equipment
Management house
29
NQL-2
Management house
Volume 1.1 – Chapter 2
Technical Design
Depth (m)
Layer
1
2
3
3
4
5
6
1
2
1
2
3
4
5
6
7
8
9
10
2
1
2
3
4
1
2
3
1
2
3
4
1
1
1
2
3
4
5
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
2
Value
SPT N30
21
30
58
24
27
26
28
30
31
26
26
23
25
29
27
28
25
29
28
Rock
31
37
37
46
30
34
28
31
30
34
31
Rock
33
20
44
58
60
Rock
2-11
Nhon Hoi Wind farm project – Phase I
No.
Borehole
Technical Design
Location
30
DZ-1
Transmission line
31
DZ-4
Transmission line
Depth (m)
Layer
2
3
4
1
2
2
2
2
Value
SPT N30
26
30
29
31
Average SPT value by layer (SPT N30):
- Layer 1
: 27.
-
Layer 2
: 35.
2.2.2.2.3. Physical mechanical properties of rock, soil layers
Determination of physical and mechanical properties of soil and rock was
conducted by sampling in boreholes and then transferred to the laboratory department
for analysing at LAS XD-641 Testing Center of Construction and Consulting Joint Stock
Company 23.
Each geological layer was carried out to take experimental samples. The data of
experimental samples at each WTG are shown in the "Summary of physical and
mechanical properties of soil and rock samples".
The samples were collected by layers, statistics and excluded raw errors according
to TCVN 9153: 2012
Statistics quantity of samples taken and tested by layer:
Table 2.4: Physical mechanical properties of rock, soil layers
Layer
Quantity of
sample
Notes
1
33
Disturbed soil samples
2
122
Undisturbed & Disturbed soil samples
3
0
Can not taken samples. All physical and
mechanical indicators referenced in the project are
similar and the proposed by experience
4
13
Rock samples
5
60
Rock samples
Recommended that standard values and calculation of geological layers within the
project scope are as follows:
Volume 1.1 – Chapter 2
2-12
Nhon Hoi Wind farm project – Phase I
Technical Design
a. Layer 1:
Table 2.5: Recommended standard values and calculation of geological layer 1
Parameters
Symbol
Unit
Values
Sand Graine (ASTM D422)
-
%
43.2
Humidity
W
%
41.3
Natural density (*)
w
g/cm3
1.68
Density

g/cm3
2.76
Viscosity (*)
e
-
0.623
Inner friction angle (*)

độ
33000’
Cohesion force (*)
C
kG/cm2
0.024
Total transformation module (*)
E0
kG/cm2
155.5
Conventional load capacity
R0
kG/cm2
3.0
(*) Recommended value
b. Layer 2:
Table 2.6: Recommended standard values and calculation of geological layer 2
Parameters
Symbol
Unit
Values
Clay Graine (ASTM D422)
-
%
18.7
Humidity
W
%
18.6
Natural density
w
g/cm3
1.76
Saturated state density (recommended value)
bh
g/cm3
1.85
Dry density
k
g/cm3
1.46
Density

g/cm3
2.71
Elasticity (ASTM D4318)
Ip
%
35.6
Viscosity
B
-
-0.18
Viscosity
e
-
0.857
độ
22003’
21006’
Natural inner friction angle (*)

Saturated state inner friction angle (recommended value)
bh
độ
20031’
18040’
Natural cohesion force (*)
C
kG/cm2
0.290
0.276
Volume 1.1 – Chapter 2
2-13
Nhon Hoi Wind farm project – Phase I
Technical Design
Parameters
Symbol
Unit
Values
Saturated state cohesion force (recommended value)
Cbh
kG/cm2
0.236
0.206
Compression coefficient
a1-2
cm2/kG
0.022
Total transformation module
E0
kG/cm2
166.2
Conventional load capacity
R0
kG/cm2
2.24
Standard value
Calculated value
(*)
c. Layer 3:
Table 2.7: Recommended standard values and calculation of geological layer 3
Parameters
Recommended
Symbol
Unit
Density

g/cm3
2.64
Natural density
O
g/cm3
2.49
Saturate density
H
g/cm3
2.54
Dry humidity
W0
%
0.49
Saturate humidity
WH
%
2.38
Porosity
n
%
6.06
Natural compressive strength
Rn
kG/cm2
110
Natural tensile strength
Rk
kG/cm2
8
values
Calculation results according to Hoek - Brown standard according to the following
tables
Table 2.8: Calculation results according to Hoek – Brown Layer 3
Uniaxial
compressive
GSI
strength
(Mpa)
Rock
stype
Layer
Bedrock
(Volcanic)
Layer 3
10
20
mi
D
MR
Ei
(Mpa)
25
0.5
400
8000
Stress
3max
(Mpa)
1.0
Table 2.9: Calculation results according to Hoek – Brown Layer 3
Targets of rock
The criteria index/calculated index
according to Hoek &
(According to Mohr- Coulumb)
Brown
Hoek & Brown
Model constant
mb
s
a
mb
s
a
mb
s
0.554
0.00002
0.544
0.554
0.00002
0.544
0.554
0.00002
Volume 1.1 – Chapter 2
2-14
Nhon Hoi Wind farm project – Phase I
Technical Design
Recommended value
d. Layer 4:
Table 2.10: Recommended standard values and calculation of geological layer 4
Parameters
Symbol
Unit
Values
Density

g/cm3
2.70
Natural density
O
g/cm3
2.65
Saturate density
H
g/cm3
2.67
Dry humidity
W0
%
0.26
Saturate humidity/
WH
%
0.81
Porosity
n
%
2.16
Natural compressive strength (*)
Rn
kG/cm2
335
270
Natural tensile strength (*)
Rk
kG/cm2
33
26
Standard value
Calculated value
Calculation results according to Hoek - Brown standard according to the following
tables
(*)
Table 2.11: Calculation results according to Hoek – Brown Layer 4
Rock
stype
Bedrock
(Volcanic)
Layer
Uniaxial
compressive
GSI
strength
(Mpa)
mi
D
Layer
33.5 (*)
27.0
25
0.4
30
MR
Ei
(Mpa)
Stress
3max
(Mpa)
400
13400 (*)
10800
1.0
Table 2.12: Calculation results according to Hoek – Brown Layer 4
Targets of rock
according to Hoek &
Brown
Hoek & Brown
Model constant
mb
s
a
1.098
0.0001
0.522
(*)
The criteria index/calculated index
(According to Mohr- Coulumb)
mb
s
a
1.098
0.0001
0.522
mb
1.098
s
0.0001
Standard value
Calculated value
Volume 1.1 – Chapter 2
2-15
Nhon Hoi Wind farm project – Phase I
Technical Design
e. Layer 5:
Table 2.13: Recommended standard values and calculation of geological layer 5
Parameters
Symbol
Unit
Values
Density

g/cm3
2.72
Natural density
O
g/cm3
2.70
Saturate density
H
g/cm3
2.71
Dry humidity
W0
%
0.12
Saturate humidity
WH
%
0.30
Porosity
n
%
0.78
Natural compressive strength (*)
Rn
kG/cm2
879
837
Natural tensile strength (*)
Rk
kG/cm2
88
83
Calculation results according to Hoek - Brown standard according to the following
tables
Table 2.14: Calculation results according to Hoek – Brown Layer 5
Rock
stype
Bedrock
(Volcanic)
Layer
Uniaxial
compressive
GSI
strength
(Mpa)
mi
D
Layer
87.9 (*)
83.7
25
0.3
75
MR
Ei
(Mpa)
Stress
3max
(Mpa)
400
35160 (*)
33480
1.0
Table 2.15: Calculation results according to Hoek – Brown Layer 5
Targets of rock
according to Hoek &
Brown
Hoek & Brown
Model constant
mb
s
a
8.745
0.0457
0.501
(*)
The criteria index/calculated index
(According to Mohr- Coulumb)
mb
s
a
8.745
0.0457
0.501
mb
8.745
s
0.0457
Standard value
Calculated value
2.2.2.3. Engineering geological kinetic phenomenon
2.2.2.3.1. Weathering phenomenon
The weathering process is depended on many factors such as: topographic,
geomorphological characteristics, climate, fractured level of bedrock... The weathering
process of forming weathering crust has different thickness causing the surface of
Volume 1.1 – Chapter 2
2-16
Nhon Hoi Wind farm project – Phase I
Technical Design
weathered cover is in undulated, serrated. The surveyed area in general and the scope of
the survey in particular, the weathering process developed strongly. Data of boreholes
show that the thickness of weathered cover is 1.0-18.0m. It’s expected that the
weathered cover to be much deeper compared to the depth mentioned above.
2.2.2.3.2. Sliding phenomenon
No natural sliding points have been detected within the project scope. At locations
where the turbine foundations are located on steep hillsides and placed on top of the soil
cover (layer 2), measures to protect the slope and foundation bottom should be taken to
avoid sliding.
2.2.2.3.3. Earthquake
The project is located between Quy Nhon city and Tuy Phuoc district.
-
According to the document "Earthquake zoning map of Vietnam territory" of
the Institute of Geophysics (picture below), the project area has tremor level
VII, maximum expected tremor level VII according to the MSK-64 scale.
-
According to the QCVN 02:2009/BXD Vietnam Building Code - Natural
Physical & Climatic Data for Construction, the construction area is located in
Quy Nhon city, Binh Dinh province with has peak ground acceleration of agR
= 0.9228m/s2 corresponding to earthquake intensity of VII grade according to
the MSK-64 scale.
-
According to the standard for designing earthquake-resistant works: TCVN
9386: 2012, the construction area is located in Quy Nhon city, Binh Dinh
province with peak ground acceleration of (g) ag = 0.0941 (Appendix H)
corresponding to earthquake intensity of VII grade (Appendix I) according to
the MSK-64 scale.
It is recommended to use earthquake level VII (scale MSK-64) for design.
Volume 1.1 – Chapter 2
2-17
Nhon Hoi Wind farm project – Phase I
Technical Design
Figure 2.5: Earthquake zoning map of Vietnam territory
Table 2.16: Table of converting ground acceleration to earthquake grade
according to TCVN 9386:2012
Scale MSK-64
Scale NM
Earthquake
level
Peak ground
acceleration (a) g
Earthquake
level
Peak ground
acceleration (a) g
V
0,012-0,03
V
0,03 - 0,04
VI
> 0,03 - 0,06
VI
0,06 - 0,07
VII
> 0,06 - 0,12
VII
0,10 - 0,15
VIII
> 0,12 - 0,24
VIII
0,25 - 0,30
IX
> 0,24 - 0,48
IX
0,50 - 0,55
X
> 0,48
X
> 0,60
Volume 1.1 – Chapter 2
2-18
Nhon Hoi Wind farm project – Phase I
Technical Design
In addition, there is no engineering kinetic geological phenomenon that affects to
construction work.
2.2.2.4. Hydrological geological features
The project's terrain is hilly and mountainous, so water is poor, the water table is
deep and fluctuates greatly according to seasons. At the time of the survey, only a few
boreholes with groundwater appeared quite deep, most of which did not have
groundwater. Surface water only appears when it rains.
In the study area, there are 2 following geotechnical stratigraphic unit of
hydrogeology as follow:
a. The aquifer in the cover:
The composition contains water in the cover layers 1 and 2. Water is contained in
the empty slot between rock particles. The source is rain water and surface water. The
drainage area is the rivers, sea and the aquifers below.
b. The aquifer in the bedrock:
Water contains and mobilizes mainly in the fissure of the rock. The applying
source is rain water, the aquifer above. Drainage areas are springs and sea.
04 water sample was taken at the borehole NH-1A, NH-5, NH-14A, TBA-2.
The result of water sample analysis is as follows:
HCO3- 69 Cl-23
pH 6.8
Ca2+ 58 Mg2+ 34
According to the standard TCVN 12041: 2017: Water is not corrosive. Water is
used for concrete use.
M 0.096
General, the underground water level is deep. Groundwater does not affect the
foundation. The turbine foundations are not corrosive.
2.2.2.5. Resistivity measurement of rock and soil
Resistivity was measured at 20 points at the borehole locations (12 points at
WTGs, 04 points at the transmission line, 02 points at the substaion, 02 points at the
yard equipment)
The C.A 6470N machine of France has been used to measure under the Wenner
pole system method, it is arranged in 4 symmetrical poles. Measuring distance a = 2, 4,
8, 16, 30m.
Resistivity measurement of rock and soil was conducted on 12nd to 19th of October,
2020.
Measurement season: Rain season.
The resistivity of rock and soil is calculated by the following formula:
Volume 1.1 – Chapter 2
2-19
Nhon Hoi Wind farm project – Phase I
Technical Design
= 2Ra (m)
Where:
: resistivity of rock and soil (m)
a: measured distance (m)
R: readings in machine ()
Measured results of resistivity of rock and soil see on after table:
Table 2.17: Measured results of resistivity of rock and soil
No.
Borehole
1
NH-1A
2
NH-2A
3
NH-3A
4
NH-4A
5
NH-5A
Volume 1.1 – Chapter 2
Distance
a (m)
2
4
6
8
16
30
2
4
6
8
16
30
2
4
6
8
16
30
2
4
6
8
16
30
2
4
6
8
16
Read
Resistivity
R ()
13.20
5.52
4.17
5.91
2.03
440.00
161.00
25.30
9.81
19.60
23.10
9.61
4.11
2.88
2.18
28.30
12.70
8.12
4.79
2.33
29.10
8.78
3.66
1.14
0.75
53.00
29.50
20.80
11.60
 (m)
165.8
138.7
209.5
593.8
382.5
5526.4
4044.3
1271.1
985.7
3692.6
290.1
241.4
206.5
289.4
410.7
355.4
319.0
407.9
481.3
439.0
365.5
220.6
183.9
114.5
141.3
665.7
741.0
1045.0
1165.6
Season
Weather
Rainy
season
Sunny
Rainy
season
Sunny
Rainy
season
Sunny
Rainy
season
Sunny
Rainy
season
Sunny
2-20
Nhon Hoi Wind farm project – Phase I
No.
Borehole
6
NH-7A
7
NH-8
8
NH-9
9
NH-10
10
NH-12
11
NH-13
12
NH-14A
Volume 1.1 – Chapter 2
Distance
a (m)
30
2
4
6
8
16
30
2
4
6
8
16
30
2
4
6
8
16
30
2
4
6
8
16
30
2
4
6
8
16
30
2
4
6
8
16
30
2
Technical Design
Read
Resistivity
R ()
7.01
23.30
10.90
7.36
5.45
3.72
31.10
15.20
10.10
7.81
10.30
46.00
32.40
22.20
11.60
6.06
23.80
13.80
8.81
5.90
3.12
33.60
18.50
7.92
4.60
2.80
79.20
32.50
14.50
6.69
5.35
13.20
5.52
4.17
5.91
2.03
440.00
161.00
 (m)
1320.7
292.6
273.8
369.8
547.6
700.8
390.6
381.8
507.4
784.7
1940.5
577.8
813.9
1115.3
1165.6
1141.7
298.9
346.7
442.6
592.8
587.8
422.0
464.7
397.9
462.2
527.5
994.8
816.4
728.5
672.2
1007.9
165.8
138.7
209.5
593.8
382.5
5526.4
4044.3
Season
Weather
Rainy
season
Sunny
Rainy
season
Sunny
Rainy
season
Sunny
Rainy
season
Sunny
Rain
season
Sunny
Rainy
season
Sunny
Sunny
2-21
Nhon Hoi Wind farm project – Phase I
No.
Borehole
13
DZ-1
14
DZ-2
15
DZ-3
16
DZ-4
17
TBA-1
18
TBA-2
Volume 1.1 – Chapter 2
Distance
a (m)
4
6
8
16
30
2
4
6
8
16
30
2
4
6
8
16
30
2
4
6
8
16
30
2
4
6
8
16
30
2
4
6
8
16
30
2
4
6
Technical Design
Read
Resistivity
R ()
25.30
9.81
19.60
23.10
9.61
27.90
6.97
3.55
1.84
1.01
240.00
116.00
59.30
29.80
14.70
119.00
71.70
38.10
22.70
13.90
27.90
6.97
3.55
45.60
30.70
18.40
9.52
4.14
45.60
20.40
6.67
2.13
1.47
0.97
19.70
9.71
3.32
1.65
 (m)
1271.1
985.7
3692.6
290.1
241.4
350.4
175.1
178.4
184.9
190.3
3014.4
2913.9
2979.2
2994.3
2769.5
1494.6
1801.1
1914.1
2280.9
2618.8
350.4
175.1
178.4
572.7
771.2
924.4
956.6
780.0
572.7
256.2
167.6
107.0
147.7
182.7
247.4
243.9
166.8
165.8
Season
Weather
Rainy
season
Rainy
season
Sunny
Rainy
season
Sunny
Rainy
season
Sunny
Rainy
season
Sunny
Rainy
season
Sunny
Rainy
season
Sunny
2-22
Nhon Hoi Wind farm project – Phase I
No.
Borehole
19
TTB-1
20
TTB-2
Distance
a (m)
8
16
30
2
4
6
8
16
30
2
4
6
8
16
30
Technical Design
Read
Resistivity
R ()
1.24
22.60
8.79
20.40
6.67
2.13
1.47
0.97
19.70
9.71
3.32
1.65
1.24
20.40
6.67
 (m)
233.6
283.9
220.8
256.2
167.6
107.0
147.7
182.7
247.4
243.9
166.8
165.8
233.6
256.2
167.6
Season
Weather
Rainy
season
Sunny
Rainy
season
Sunny
Note: The resistivity value of rock depends on many different factors such as
weather, rock composition, groundwater level... Therefore, during the construction
process, it is necessary to conduct tests. check back to suit the actual conditions.
2.2.2.6. Grade of excavated rock, soil for construction
Soil grade is classified basing on Vietnamese standard: TCVN 4447: 2012 - Soil
work - Construction and test & acceptance and content of boulder masses mixed in the
soil.
The grade of excavated rock is classified according to Vietnamese standard:
TCVN 11676: 2016 - Construction works - Classification of rock in construction, on the
basis of uniaxial compressive strength of rock samples, fracturing grade (RQD, Modulus
of joint).
73 rock samples for mechanic properties have been taken and synthesized (of
which 13 samples are in layer 4, 60 samples are in layer 5).
-
Compressive strength of layer 4 at saturated state: 117-510kG/cm2.
-
Compressive strength of layer 5 at saturated state: 487-1339kG/cm2.
Based on compressive strength of rock samples, combined with fracturing degree
of rock mass (through the criteria RQD, Modulus of joint etc.,), table for
recommendation of grades of excavated rock and soil corresponding to weathered zones
has been proposed.
Volume 1.1 – Chapter 2
2-23
Nhon Hoi Wind farm project – Phase I
Technical Design
This recommendation table is intended for orientation, serving for calculation of
the excavation quantity of soil and rock in the design stage. In construction stage, it is
necessary to describe geology of the foundation pit to make accuracy matching with the
reality.
The grades of excavated soil and rock for construction are proposed as follows:
Table 2.18: Recommendations for grades of excavated soil and rock
Layer
Description
Layer 1
Medium grain sand color is in yellowish grey,
tight structured.
Layer 2
Reddish brown, brownish clay loam, in hard
state, mixed with gravel, block stones
Layer 3
Bed rock is gray brown, soft to medium hard,
with particularly strong fracture, mixed with
some clay loam
Layer 4
Bed rock is brownish gray, greenish gray, from
medium to hard, very strong fracture
Layer 5
Bed rock is greenish gray, light gray, the rock is
hard to very hard, strongly cracked
Rock/soil grade
Percent
(%)
Soil grade II
100%
Soil grade III
20%
Soil grade IV
60%
Rock grade 4
20%
Soil grade IV
60%
Rock grade 4
40%
Rock grade 4
100%
Rock grade 4
10%
Rock grade 3
20%
Rock grade 2
50%
Rock grade 1
20%
2.2.2.7. Natural Materials
Natural construction materials include soil for making the foundation, aggregates
and sand used for concrete.
The survey process does not include exploration and searching for borrow pits. We
make recommendations.
2.2.2.7.1. Earthfill materials
Within the scope of the project area, earthfill is quite rare. The soil cover layer is
mixed with many blocks, boulders. However, there are many locations where the
covered layer is quite thick and the excavated soil could be used to make road routines
to make road base. If the demand for earthfill materials is large, it is necessary to search,
explore more soil borrow areas or buy soil from available adjacent soil borrow areas.
2.2.2.7.2. Aggregates, sand materials
Aggregates and sand are used as materials for concrete. It is recommended to buy
fresh concrete from the available concrete plants which are nearby the project site.
Volume 1.1 – Chapter 2
2-24
Nhon Hoi Wind farm project – Phase I
Technical Design
The detailed Geological survey results are shown in the Construction geological
survey report of Nhon Hoi wind power plant project - Phase 1 & Phase 2 performed by
23 Construction and Consulting Joint Stock Company implemented in November 2020.
2.2.3. Basic meteorological characteristics
Near the studied area, there is Quy Nhon meteorological station that fully
monitoring factors such as precipitation, wind, ambient temperature, ambient humidity,
number of rainy days, sunshine days, etc.
The monitored data series at Quy Nhon meteorological station used in the project
is managed and measured by Vietnam Meteorological and Hydrological Administration,
with good quality, reliable assurance for the calculation of design meteorological
characteristics.
Meteorological characteristics of the Nhon Hoi Wind Power Plant (WPP) project
are calculated by statistical method according to actual recorded data of Quy Nhon
meteorological station from 1976 to 2018. Particularly, rain characteristics
(precipitation, number of rainy days and intensity of rainfall) are taken according to
synthesized data of rainfall gauging stations in the basin. In addition, data from the
following standards, regulations and norms are also adopted in the report:
-
QCVN 02:2009/BXD: National technical regulation on data of Natural Physical
and Climatic Data for Construction, issued under Circular No. 29/2009/TTBXD dated August 14, 2009.
-
QP.TL. C-6-77:Norm on calculation of designed hydrological characteristics.
-
Hydro-meteorology Atlas of Vietnam.
2.2.3.1. Ambient temperature at the project area
This is the area with relatively high ambient temperature, the annual average value
of about 27.10C, the maximum ambient temperature measured at Quy Nhon
Meteorological Station was 40.70C (May 4, 1994), the lowest value measured at this
station is 13.00C (October 27, 1995). There is not much difference in heat regime
amongvarious months. The average temperature difference value between the lowest
month and the highest month is about 6,70C. The characteristics of the average,
maximum and minimum ambient temperature at Quy Nhon station are presented in the
table below. Please refer to appendices for more details.
Volume 1.1 – Chapter 2
2-25
Nhon Hoi Wind farm project – Phase I
Technical Design
Table 2.19: Characteristics of ambient temperature at Quy Nhon meteor station
Characteristics Jan Feb. Mar. Ap. May Jun. Jul Au. Sept Oct Nov Dec
Annual
mean
TmeanoC
23.4 24.1 25.7 27.7 29.3 30.1 30.1 30.0 28.7 27.0 25.6 24.0 27.1
TmaxoC
33.3 34.9 34.9 38.1 40.7 39.9 39.6 39.0 38.8 36.6 33.7 32.9 40.7
TminoC
16.6 16.8 15.8 21.3 23.0 22.7 23.1 22.8 22.6 13.0 19.0 15.5 13.0
Figure 2.6: Temperature variation progress at Quy Nhon station
2.2.3.2. Ambient humidity
The relative humidity in the project area according to Quy Nhon meteorological
station ranges from 70.6% to 83.3%, with the annual average value of 79%. From June
to September, the relative humidity of the ambient is low. The relative humidity of the
ambient increased in the rainy season’ months. The lowest ambient relative humidity
also varies as the average value does.
The annual variation of the relative humidity is similar to that of precipitation.
During the rainy season (from October to December), humidity in months varied from
81% -83.3%, the highest values in October and November are 82.3%-83.3%. During
dry season, the monthly humidity varied from 70% -77.7%. At the end of the rainy
season, humidity decreases continuously and reaches the minimum value in July and
August and then gradually increases until October.
Characteristics of average and minimum ambient humidity recorded at Quy Nhon
station are presented in the table below. Please refer to appendices for more details.
Volume 1.1 – Chapter 2
2-26
Nhon Hoi Wind farm project – Phase I
Technical Design
Table 2.20: Characteristics of ambient humidity at Quy Nhon meteor station
Month/characteristics Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Year
Ubp %
81.0 81.4 82.5 82.1 78.9 73.0 71.5 70.6 77.7 82.3 83.3 81.8 78.8
Umin %
42.0 36.0 45.0 45.0 34.0 33.0 34.0 37.0 39.0 46.0 46.0 38.0 33.0
2.2.3.3. Ambient pressure
The annual average value of ambient pressure reaches 1010 mbar. In general, the
mean value as well as the maximum and minimum values among months are slightly
different with minor amplitude of variation. The ambient pressure characteristics of Quy
Nhon meteorological station are given in the table below.
Table 2.21: Ambient pressure at Quy Nhon meteor station
Characteristic Jan Feb. Mar. Ap. May Jun. Jul Au. Sept Oct Nov Dec
Annual
mean
Mean
1015 1012 1012 1009 1007 1004 1005 1005 1006 1010 1011 1014 1009
Max
1004 1003 1003 1001 997 994 997 993 984 995 991 1005 984
Min
1023 1022 1026 1018 1014 1012 1012 1013 1015 1018 1021 1021 1026
2.2.3.4. Wind
In winter monsoon period, Binh Dinh province is influenced by the eastern Trade
Wind with the prevailing air mass of the Tropical Marine. This air mass affects Binh
Dinh and normally moves from the Southern edge of the Pacific subtropical high
pressure or the sea region at the Eastern of China, while from the latitude 16 onward,
the desaturated tropical polar air mass becomes prevailing in this period.
However, whenever the Asian Continental High Pressure strongly operates and
spreads to the Southward, over the mainland of China or across the Japanese ocean, the
Yellow Sea and the Eastern China Sea to our country, then the tropical marine air mass
is often interrupted. The polar air mass can reach Binh Dinh along the eastern side of
the Truong Son range or in the direction of East off-course across the ocean, but when
it affects Binh Dinh, it has changed its original properties a lot compared with that of
original characteristics.
2.2.3.4.1. Wind direction
The project area is located close to Quy Nhon meteorological station, so this station
should be used as the basis to determine the annually wind direction in the area.
According to wind monitoring data at Quy Nhon station, the most appearing is North
direction, then NW direction. The frequency of occurrence of wind directions in the year
is shown in the following table, wind rose of months and combined with wind rose are
given in the appendix.
Volume 1.1 – Chapter 2
2-27
Nhon Hoi Wind farm project – Phase I
Technical Design
Table 2.22: Frequency of wind occurrence at 8 directions in a year at Quy Nhon
meteor station
Wind
direction
N
NE
E
SE
S
SW
W
NW Windless
Frequency % 26.6
11.3
3.4
19.3
7.2
1.6
9.1
21.6
27.6
Like the whole year, wind directions in the rainy season’ months (September –
December) of the region that appear mostly are still the North and NW. The occurrence
frequency of wind directions in months of rainy season is stated in the table below.
Table 2.23: Frequency of wind occurrence at 8 directions at months of rainy
season (from September to December) - Quy Nhon meteor station
Wind
direction
N
NE
E
SE
S
SW
W
NW Windless
Frequency % 36.8
17.0
3.0
7.3
2.6
0.9
5.6
26.8
21.6
Unlike the rainy season, wind directions in the dry season’ months (January –
August) of the region that appear mostly are the Southeast and North directions. The
occurrence frequency of wind directions in months of the dry season is provided in the
table below.
Table 2.24: Frequency of wind occurrence at 8 directions at months of dry season
(from Jan – August) - Quy Nhon meteor station
Wind
direction
N
NE
E
SE
S
SW
W
NW Windless
Frequency % 21.5
8.4
3.6
25.2
9.5
1.9
10.9
19.0
30.6
Thus, it can be said that the wind regime in Binh Dinh shows two distinct seasons
clearly. The North wind direction prevails in Winter. The North and NW wind directions
prevail in summer. Wind roses illustrating wind direction in months of the year and
summarized wind rose for the whole year.
N
N
50.00
NW
40.00
January
40.00
NW
NE
30.00
30.00
N
Feb
30.00
NE
NW
20.00
20.00
10.00
10.00
E
0.00
W
5.00
E
0.00
SW
SW
SE
SE
S
S
Volume 1.1 – Chapter 2
March
NE
20.00
15.00
10.00
W
25.00
W
E
0.00
SW
SE
S
2-28
Nhon Hoi Wind farm project – Phase I
Technical Design
N
N
April
NE
40.00
NW
NW
30.00
20.00
20.00
W
E
NE
5.00
E
SW
W
SW
SE
S
N
30.00
N
July
30.00
25.00
25.00
NW
NE
20.00
15.00
10.00
10.00
5.00
5.00
W
E
0.00
SW
N
August
25.00
NW
NE
20.00
5.00
E
W
Octorber
SE
SW
SE
NW
30.00
S
N
November
N
50.00
NE
20.00
40.00
50.00
NW
NE
W
40.00
30.00
30.00
20.00
20.00
December
NE
10.00
10.00
10.00
E
0.00
S
40.00
NE
10.00
SW
S
Sept.
15.00
0.00
SE
N
S
20.00
15.00
E
0.00
SE
S
W
June
20.00
15.00
0.00
SE
NW
NW
10.00
SW
W
25.00
10.00
0.00
NW
30.00
May
NE
40.00
30.00
10.00
W
N
50.00
50.00
W
E
0.00
E
0.00
E
0.00
SW
SW
SE
SW
SE
S
S
S
N
NW
W
SE
30.00
25.00
20.00
15.00
10.00
5.00
0.00
Year
NE
E
SW
SE
S
Figure 2.7: Wind rose of months and year in Quy Nhon station
2.2.3.4.2. Wind velocity
a. Average wind velocity
In Binh Dinh province in general and Quy Nhon station in particular, the annual
average wind velocity is quite small, from 1.5-1.8m/s, the monthly average value ranges
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Technical Design
from 1.44-2.5m/s. The month with the highest and lowest average wind velocity are
2.5m/s and 1.44m/s, respectively. In the coastal area, the average wind velocity in the
winter monsoon period is higher than that in the summer monsoon period and reaches
the highest value. Below is the average wind velocity table recorded at the Quy Nhon
meteorological station which is close to the project area.
Table 2.25: Average wind speed of months in a year at Quy Nhon meteor station
Unit: m/s
Features
/month
Vtb
Jan Feb. Mar. Ap. May Jun. Jul Au. Sept Oct Nov Dec
Annual
mean
2.50 1.83 1.93 1.79 1.44 1.67 1.61 1.64 1.29 1.85 2.40 2.49 1.87
The monthly average wind velocity is shown in Table 2.7, reflecting only the most
relative average of wind strength in the region. Therefore, if it only cares at the monthly
average wind velocity, the usage of these data for calculating and evaluating the wind
potential as well as the harm in order to exploit smoothly and limit negative impacts will
face with many difficulties. More descriptions such as frequency of each wind grade,
wind velocity and prevailing direction shall be discussed. Wind velocity in Quy Nhon
from April to September from 0 to 1m/s usually accounts for the highest frequency.
From October to March, the velocity is higher than 2-5m/s, reaching the highest
frequency in the year, accounting for 52-72%. Below is a table of average wind velocity
frequencies and grades recorded at Quy Nhon meteorological station.
Table 2.26:Frequency of average wind speed levels at Quy Nhon meteor station
Unit: %
Speed/month
0-1 (m/s)
>1-5 (m/s)
Jan
34.0
63.7
2.3
Feb
43.7
54.6
1.6
Mar
45.5
53.2
1.3
Apr
50.5
49.1
0.4
May
65.1
34.7
0.2
Jun
57.1
40.8
2.0
Jul
51.8
47.6
0.6
Aug
51.6
47.0
1.3
0.1
Sept.
65.5
34.0
0.4
0.1
Oct.
44.8
51.8
3.3
Nov.
22.8
69.6
7.3
Volume 1.1 – Chapter 2
>5-10 (m/s) >10-15 (m/s) >15 (m/s)
0.1
0.1
0.2
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Nhon Hoi Wind farm project – Phase I
Technical Design
Speed/month
0-1 (m/s)
>1-5 (m/s)
XII
21.3
72.2
>5-10 (m/s) >10-15 (m/s) >15 (m/s)
6.2
0.2
Wind velocity from higher than 5 to 10m/s accounts for only 0.2-7.3%. In the
winter monsoon period, where the leeward is recorded, the wind velocity from higher
than 5 m/s to 10m/s only reaches the frequency of 0.1-5%. The velocity of over 10m/s
rarely happens with very low frequency, not more than 1% and usually occurs in strong
monsoons, or occurs with dangerous weather phenomena such as storms, whirlwind
turbulence, tropical depressions.
b. Maximum wind velocity
According to data recorded from 1976 to 2019, the strongest wind velocity in Quy
Nhon measured was 40m/s (grade 14), but according to available data, there was a strong
wind of 59m/s in September 1972. Strong winds usually occur during thunderstorms,
the influence of storms, tropical depressions, strong northeast or Southwest monsoons,
but generally the strongest wind velocity occurs in case of direct-influenced strong
storms. Below is a table of the monthly maximum wind velocity in a year at Quy Nhon
meteorological station.
Table 2.27: Maximum wind speed of months in a year at Quy Nhon meteor
station
Unit: m/s
Features
/month
Jan Feb. Mar. Ap. May Jun. Jul Au. Sept Oct Nov Dec
Annual
mean
Vmax
15.0 15.0 15.0 14.0 20.0 28.0 40.0 20.0 20.0 40.0 40.0 24.0 40.0
To determine the maximum wind velocity in 8 directions and non-direction
corresponding to frequencies, data from 1976 to 2019 are collected for calculation. The
results are shown in the table below:
Table 2.28: Maximum wind speed correspond to frequencies at 8 directions and
non-direction at Quy Nhon meteor station
Unit: m/s
P%/direction
N
NE
E
SE
S
SW
W
NW
Nondirection
1
44.1
44.0
39.2
35.8
27.8
19.9
42.0
44.5
51.8
2
36.9
37.0
32.6
30.5
23.7
18.4
35.3
37.5
44.5
3
31.8
32.2
28.1
26.9
20.9
17.6
30.8
32.6
39.8
4
29.8
30.2
26.2
25.4
19.7
16.7
28.9
30.5
37.3
5
27.0
27.5
23.7
23.5
18.1
16.2
26.4
27.9
34.5
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Technical Design
10
21.4
22.1
18.7
19.3
14.9
14.5
21.2
22.4
28.4
20
16.4
17.1
14.2
15.5
11.7
12.8
16.5
17.4
22.4
25
15.0
15.6
12.9
14.3
10.8
12.1
15.1
15.9
20.5
50
10.3
11.0
8.8
10.5
7.8
9.8
10.7
11.2
14.6
2.2.3.4.3. Wind pressure
According to the National technical regulation on data of Natural Physical and
Climatic Data for Construction, QCVN 02:2009/BXD and Vietnamese electrical code
11 TCN-19-2006, the wind pressure applied to the project area is as follows:
Table 2.29: Standard wind pressure with repeated cycle of wind 1 time in 10
years and 1 time in 20 years
District, city
Quy Nhơn
Region
Wo (kN/m2)
Wo (kN/m2)
Pressure
3 seconds, 10 years
3 seconds, 20 years
III,B
1.09
1.25
2.2.3.4.4. Land wind and sea wind
Another basic feature of the wind regime in a coastal area like Binh Dinh province
is that, in addition to the change in wind direction over seasons according to annual
cycle, there also appears a type of wind alternating with the night and day cycle, it is the
land wind and sea wind.
The primary cause of this wind is the heterogeneity in the heat absorption and
emission of the buffer surface. During the daytime, the ground absorbs solar radiation
stronger than the ocean surface, so the ground is heated up faster and the air above the
ground rises, the pressure decreases and a barometric gradient appears from the sea.
towards the mainland, producing the wind blowing from the ocean to the mainland. At
night time, the above process is reversed, the ground emits heat strongly and cools faster
than the ocean surface, there appears a barometric gradient from the mainland to the
ocean, so wind blows from the mainland to the sea.
The sea wind blowing to the mainland occurs after sunrise, gradually stronger and
reaches its peak at over noon time. At the sunset, the sea wind becomes weaker and it is
gradually replaced by the land wind (the wind blowing from the mainland to the sea).
The land wind maintains throughout the night and gets its maximum level in the early
morning until sunrise. After that, it becomes weak and is replaced by the sea wind. The
range of the sea wind blowing to the mainland in mountainous areas like Binh Dinh is
about 10-20km, while the land wind blowing to the ocean is about 20-30km and its
thickness is usually less than 1.5km.
The sea wind- land wind is clearly found during periods of relatively weak
monsoon circulation and a less cloudy sky. In the case of the strong monsoon circulation,
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either the land wind or sea wind will be overwhelmed. At that time, the land wind and
sea wind only play the role of increasing or decreasing the direction and velocity of
monsoon wind.
Land wind – sea wind partly contributes to climate regulation in coastal areas. For
example, in summer during the daytime, the hot weather is relieved by the sea wind that
brings cooler and moist air. On the other hand, the sea wind blows to the mainland due
to friction, so the wind velocity is reduced. According to the law of conservation, this
area is easy to form turbulent flow, sometimes combined with favorable thermodynamic
conditions, sea wind also can create precipitation in the form of showers.
2.2.3.5. Precipitation
Precipitation distribution in Binh Dinh is extremely uneven. The mountainous
region of Vinh Son and the northern mountainous region of the province are the two
regions with the highest precipitation in the province, with the total annual average
precipitation from 2200 to 3200mm, of which the highest precipitation center is in An
Lao mountainous district. The second heavy rain area is Vinh Kim mountain area in the
middle of Kon river, Van Canh district, upstream of Ha Thanh river and the northern
coastal districts of 2000 ÷ 2200mm. The remaining areas such as the Southern coastal
area of the province, Tay Son district, the East of Vinh Thanh mountainous district and
the downstream basin of Kon river, the annual average precipitation is 1600 ÷ 1900mm,
of which the lowest precipitation is in Tan An and communes in the East of Tuy Phuoc
district with annual precipitation more or less of 1600mm.
The rainy season in this area lasts only 4 months, from September to December,
the maximum precipitation is in October. The dry season is from January to August. In
the 4 months of the rainy season, precipitation accounts for about 70-78% of the annual
precipitation. The dry season is quite long but only accounts for 22-30% of the annual
precipitation. The number of rainy days in a year is about 120-140 days. The distribution
of precipitation and average number of rainy days in many years recorded by stations
near the project area are given in the table below:
Table 2.30: Precipitation and number of rainy days at Quy Nhon and Phu Cat
stations
Month
Jan Feb. Mar. Ap. May Jun. Jul Au. Sept Oct Nov Dec Year
Quy Nhơn station
Rainfall
volume
(mm)
70.2 25.6 30.5 30.2 90.3 65.7 45.2 80.3 239.1 522.0 488.6 203.6 1891
Number of
13
rainy days
6
Volume 1.1 – Chapter 2
5
4
9
7
7
10
16
21
21
19
138
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Nhon Hoi Wind farm project – Phase I
Month
Technical Design
Jan Feb. Mar. Ap. May Jun. Jul Au. Sept Oct Nov Dec Year
Phù Cát station
L Rainfall
volume 48.4 16.7 28.7 39.0 96.3 75.1 63.7 91.8 224.4 557.5 512.5 162.6 1917
(mm)
Number of
rainy days
4
1
2
3
5
5
4
5
11
15
15
11
79
As shown in the table above, the precipitation is distributed in the studied area in
months as follows: From January to April, the period between the Northeast monsoon
to the transition period of two monsoons, is a stable period and has the lowest
precipitation in a year. The average precipitation in the months is from 17-70mm.
However, there is also an unusual year, for example, January 2008, 2019 due to the
influence of strong cold air, the whole province had moderate rain to heavy rain, some
places with extreme heavy rain, total precipitation in January 2008 at Phu Cat station
reached 183.7mm; Quy Nhon station reached 258.3mm. In January 2019, Quy Nhon
station had precipitation of 303.8mm. From May to June, the Southwest monsoon begins
to take its effect, the lower equatorial strip elevates the north axis to operate in the South
and South Central, making the precipitation increase steadily. The monthly average
precipitation ranges from 66–96 mm in coastal areas, this is the period of Xiaoman (premature or minor) precipitation in Binh Dinh. In July and August, the precipitation
slightly decreases compared to the previous two months, with the total monthly average
precipitation from 45 to 92mm. In the middle of September, the Northeast monsoon
affects the South, combined with the activity of tropical convergence band as well as
disturbances such as storms, tropical depressions, the rainy season officially begins.
Precipitation in the beginning and ending months of the rainy season (September and
December) is 160-557mm on average. In October and November, the 2 months in the
middle of the rainy season, average precipitation is from 488 – nearly 600mm and is the
two main rainy months of the year. Below is the plot of the average precipitation
variation in months of the year at Quy Nhon and Phu Cat stations.
From the series of annual precipitation data from 1976 to 2019 at Quy Nhon
Meteorological Station and the series from 1976 to 2017 at Phu Cat rain gauging station,
the annual precipitation calculation corresponds to the frequencies as table below:
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Nhon Hoi Wind farm project – Phase I
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Table 2.31: Rainfall volume corresponding to frequencies at Quy Nhon and Phu
Cat stations
Unit: mm
Station/month Xtb Cv Cs
Rainfall corresponds to frequencies p%
1
5
10
20
25
50
75
85
90
95
Quy Nhơn
1981 0.25 0.5 3164 2731 2517 2273 2184 1851 1553 1407 1314 1183
Phù cát
1917 0.3 0.59 3502 2949 2679 2374 2265 1858 1501 1330 1221 1071
Please refer to the appendices for the results of annual precipitation frequency
curve.
Figure 2.8: Rainfall variation progress at Quy Nhon station
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Nhon Hoi Wind farm project – Phase I
Technical Design
Figure 2.9: Rainfall variation progress of months in a year at Phu Cat station
To serve the calculation of water drainage and design floods for the project, rainy
value is usually taken with a daily period (24 hours). Below is the statistics of the
maximum daily precipitation at the two stations, Quy Nhon and Phu Cat.
Table 2.32: Maximum daily precipitation at Quy Nhơn and Phù Cát stations
Unit: mm
Năm
Xmax_Quy Xmax_Phù
Nhơn
Cát
Năm
Xmax_Quy Xmax_Phù
Nhơn
Cát
1976
95.8
143.7
1998
224.4
211.2
1977
127.4
205.5
1999
169.1
264.9
1978
150.7
200.4
2000
93.6
92
1979
217.4
165.2
2001
106.7
107.8
1980
136.4
153.2
2002
127.7
186
1981
293.2
257.9
2003
174.3
198.5
1982
180.9
58.5
2004
288.2
130.1
1983
150.2
232
2005
153.4
238
1984
232.3
188.7
2006
139.5
84.9
1985
206.9
325
2007
193.8
154.8
Volume 1.1 – Chapter 2
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Nhon Hoi Wind farm project – Phase I
Năm
Technical Design
Xmax_Quy Xmax_Phù
Nhơn
Cát
Xmax_Quy Xmax_Phù
Nhơn
Cát
Năm
1986
164.5
154
2008
209.5
127.7
1987
231.7
213
2009
231.9
297.6
1988
337.8
239
2010
256.7
228.6
1989
76
98
2011
129.4
157.7
1990
234.5
191.2
2012
107.9
72.2
1991
274.1
137
2013
143.9
1992
208.2
275
2014
142.2
1993
327.4
185
2015
114.5
1994
82.4
75
2016
191.1
1995
136.6
130
2017
238.8
1996
151
390
2018
153.2
1997
181.7
161.5
2019
151.3
198.4
The highest precipitation recorded at Quy Nhon and Phu Cat are shown in the table
below:
Table 2.33: Maximum rainfall volume at Quy Nhơn and Phù Cát stations
Unit: mm
Station
Rainfall volume in 1 Rainfall volume in 1 Rainfall volume in 1
day
month
year
Rainfall
Rainfall
Rainfall
Occurrence
Occurrence
Occurrence
volume
volume
volume
Quy Nhơn
337.8
15-X-1988
1511.2
XI-2010
2990
1998
Phù Cát
390
17-XI-1996
1352.9
XI-1996
3176
1996
From the series of maximum daily precipitation data at Quy Nhon Meteorological
Station and Phu Cat rain gauging station, the designed daily precipitation with
frequencies in the below table is calculated:
Table 2.34: Maximum daily precipitation corresponding to frequencies at Quy
Nhơn and Phù Cát stations
Unit: mm
station/month Xmaxtb Cv
Cs
Rainfall volume corresponding to frequencies p%
0.1 0.2 0.3 0.5
1
3
5
10
20
50
Quy Nhơn
180.4 0.416 4.5Cv 640 576 535 493 438 355 320 274 228 165
Phù cát
182.3 0.46 4.0Cv 700 628 583 532 474 379 339 286 235 164
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Nhon Hoi Wind farm project – Phase I
Technical Design
Table 2.35: Maximum rainfall volume at design period
Unit: mm
Frequency P(%)
Period
1
2
4
5
10
20
50
15 minutes
48.1
45.5
41.2
39.6
35.9
31.9
25.1
30 minutes
84.7
77.7
67.9
65.2
57.1
49.8
38.2
60 minutes
122
112
98.2
94.2
83.2
72.2
57.0
120 minutes
157
146
130
124
110
96.0
73.6
1440 minutes
450
416
367
351
306
261
190
(According to the data of the report on hydro-meteorological investigation at FS stage of Nhon Hoi 1
Wind Power plant prepared by Power Engineering Consulting Joint Stock Company 4)
2.2.3.6. Evaporation
The total Piche possible evaporation volume in Binh Dinh is relatively stable, the
total possible annual amount of evaporation is likely to reach 789 ÷ 1317mm, unevenly
distributed in months. Evaporation variation progress are contrary to the rain variation
progress. In the dry season, the evaporation is significant and vice versa. According to
data recorded at Quy Nhon meteorological station, the monthly average evaporation
reaches 73 ÷ 150mm from January to August, the total monthly average evaporation
reaches 74 ÷ 100mm from September to December. The annual average evaporation
volume at Quy Nhon station is as follows:
Table 2.36: Annual average evaporation volume at Quy Nhon meteor station
Unit: mm
Month Jan Feb. Mar. Ap. May Jun. Jul Au. Sept Oct Nov Dec Year
Zpiche 81.7 73.1 79.6 77.8 93.0 127.2 144.8 150.1 99.6 78.6 73.8 78.4 1158
2.2.3.7. Sunshine
As located at low latitudes, with a long daytime length around all year, and a very
long time dry season with 5-6 months of clear sky, Binh Dinh is also one among
provinces having many sunny times. Total mean annual sunny hours ranges from 2,350
to 2,500 hours.
During 6 months from March to August, the average number of sunshine hours per
month ranges from 240-250 hours, with an average of 8 hours per day. April and May
are the two months with the highest sunshine time, with an average of 250-270 hours
per month. The months with low sunshine hours are those in rainy season; the average
number of sunshine hours every month is also about 100-200 hours, with an average of
5-6 hours per day. December, the month that has the lowest sunshine hours has an
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average of 100-115 hours of sunshine. Thus, the number of sunshine hours of the lowest
sunshine month is only approximately half of the number of sunshine hours of the
highest sunshine month. This difference in sunshine hours also clearly reflects the
contrast between the two seasons: dry season and wet rainy season.
The number of sunshine hours at Quy Nhon Meteorological Station is 2455 hours
per year in average. The month with the highest sunshine hours in the year is May with
272 hours, the month with the lowest sunshine hours is December with 109 hours. The
number of sunshine hours in the dry season is higher than that in the rainy season, 160269 hours in average, 7-9 sunshine hours per day. Months in the rainy season have 110193 hours of sunshine, 5-6 hours sunshine hours per day. The average number of
sunshine hours in many years recorded at Quy Nhon station is measured as below:
Table 2.37: The average number of sunshine hours in many years recorded at
Quy Nhon meteor station
Unit: hour
Month Jan Feb. Mar. Ap. May Jun. Jul Au. Sept Oct Nov Dec Year
Average 153 193 242 264 272 245 248 233 199 168 128 109 2455
The maximum number of sunshine hours observed at Quy Nhon station reaches
12.5 hours/day
2.2.3.8. Special weather phenomena
2.2.3.8.1. Thunderstorm
Thunderstorms start from March and end in November, mainly from May to
October. According to observed data in Binh Dinh province, the Southern delta of the
province has 30-52 thunderstorm days in average; while in the mountains, valleys and
the North of the province, the number of thunderstorm day is more than 70 days.
Although the time of thunderstorms is not long, the intensity of rain is heavy, sometimes
thunderstorms develop violently, causing tornadoes and lightning, resulting to house
fires, trees and electric poles falling down and human damage.
Table 2.38: Number of days having thunderstorms in average month and year
at Quy Nhon meteor station
Unit: day
Month Jan Feb. Mar. Ap. May Jun. Jul Au. Sept Oct Nov Dec Year
Average 0.05 0.00 0.30 1.95 6.32 4.32 3.91 4.00 7.59 4.57 0.91 0.07 33.98
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Table 2.39: Number of days having biggest thunderstorms in months and year at
Quy Nhon meteor station
Unit: day
Month Jan Feb. Mar. Ap. May Jun.
Jul
Au. Sept Oct Nov Dec
Average
11
12
2
0
5
9
16
12
18
17
7
2
Lightning density at the project area: 8.2 times/km2/year.
2.2.3.8.2. Fog
Fog usually occurs in winter. Highland has more fog than lowland. In Quy Nhon,
there is very little fog, mainly radiation fog that appearing in the first months in the dry
season. The number of foggy days is only about 1-2 days.
2.2.3.8.3. Storms and tropical depressions
Especially in the Central provinces in general and Binh Dinh in particular, the
storm season occurs coincide with the operating period of the winter monsoon and the
tropical convergence band following the natural climate cycle also operates at this
latitude. Therefore, the combination of effects among storms, tropical depression and
other weather patterns such as cold air, tropical convergence band or tropical
disturbances are the cause of heavy rain and big floods.
In Binh Dinh area, the real storm season starts from September to December. In
average, there are 1-2 storms or tropical depressions annually affecting Binh Dinh.
Storms and tropical depressions mostly occur in October and November. Due to unusual
changes in weather, unseasonal storms and tropical depressions occur in some years
which may affect the area from very early time in June (Storm No. 2 on June 12, 2004,
Storm No. 2 on June 30, 1978 all landed in Binh Dinh). These storms and tropical
depressions often damage people and properties of the State and of the local people.
According to documents before 1975, the strongest storm velocity in Quy Nhon was
59.0 m/s in 1972. In Binh Dinh, it was not a storm that directly hit the province that
caused extreme weather phenomena, but many storms and tropical depressions landed
in the neighboring provinces also caused dangerous weather. For example, the storm
No. 10 (Kyle) on November 23, 1993 landed in Tuy Hoa, the strongest wind velocity
was measured at Qui Nhon 34m/s, An Nhon 40m/s and the whole province of Binh Dinh
had heavy rain to extremely heavy rain. Or the storm No. 7 on October 8, 1988 that hit
the mainland of Quang Ngai also caused heavy rain to extremely heavy rain in the whole
province.
Storms and tropical depressions hitting Binh Dinh most were in the 1984, 1988,
1990, 1992, 1995 but all of them did not exceed 2 storms and there were also no storms
or tropical depressions landed such as 1976, 1981, 1982, 1989, 1991, 1994, 1997, 2000,
2002, 2003. Considering the influence of storms and tropical depressions, 1990 has the
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Nhon Hoi Wind farm project – Phase I
Technical Design
most storms, up to 4 storms. In addition, there are two storms landed in the same
province, 5-12 days apart from each other, causing great damage to people and
properties of the State and people in 1984, 1992, 1995. Below is a statistic table of
storms hitting Binh Dinh and Ninh Thuan provinces.
Table 2.40: Statistic results of storms hitting Binh Dinh-Ninh Thuan area during
the period of 1964 to 2017
Coastal area
Time of
occurrence
Storm names
Storm grade
Binh Dinh - Ninh Thuan
11/6/1964
JOAN (No.14)
Grade 8 (62-74 km/h)
Binh Dinh - Ninh Thuan
11/12/1964
KATE (No. 15)
Grade 7 (50-61 km/h)
Binh Dinh - Ninh Thuan
11/7/1967
FREDA (No. 10)
Grade 9 (75-88 km/h)
Binh Dinh - Ninh Thuan
11/15/1968
MAMIE (No. 9)
Grade 10 (89-102 km/h)
Binh Dinh - Ninh Thuan
10/18/1970
KATE (No. 5)
Grade 9 (75-88 km/h)
Binh Dinh - Ninh Thuan
10/26/1970
LOUISE (No. 6)
Grade 7 (50-61 km/h)
Binh Dinh - Ninh Thuan
4/23/1971
WANDA (No. 1)
Grade 9 (75-88 km/h)
Binh Dinh - Ninh Thuan
12/4/1972
THERESE (No. 10) Grade 10 (89-102 km/h)
Binh Dinh - Ninh Thuan
10/4/1973
OPAL (No. 10)
Grade 8 (62-74 km/h)
Binh Dinh - Ninh Thuan
11/9/1973
SARAH (No. 13)
Grade 7 (50-61 km/h)
Binh Dinh - Ninh Thuan
11/13/1974
HESTER (No. 14)
Grade 6 (39-49 km/h)
Binh Dinh - Ninh Thuan
11/2/1975
HELLEN (No. 7)
Grade 8 (62-74 km/h)
Binh Dinh - Ninh Thuan
6/28/1978
SHIRLEY (No. 2)
Grade 7 (50-61 km/h)
Binh Dinh - Ninh Thuan
10/31/1978
NONAME (No. 10)
Grade 8 (62-74 km/h)
Binh Dinh - Ninh Thuan
10/4/1979
SARAH (No. 8)
Grade 8 (62-74 km/h)
Binh Dinh - Ninh Thuan
10/29/1980
CARY (No. 7)
Grade 7 (50-61 km/h)
Binh Dinh - Ninh Thuan
10/12/1981
FABIAN (No. 7)
Grade 9 (75-88 km/h)
Binh Dinh - Ninh Thuan
3/17/1982
MAMIE (No. 1)
Grade 7 (50-61 km/h)
Binh Dinh - Ninh Thuan
10/6/1983
HERBERT (No.8)
Grade 8 (62-74 km/h)
Binh Dinh - Ninh Thuan
10/15/1983
KIM (No.10)
Grade 9 (75-88 km/h)
Binh Dinh - Ninh Thuan
10/11/1984
SUSAN (No.8)
Grade 7 (50-61 km/h)
Binh Dinh - Ninh Thuan
10/23/1984
WARREN (No.9)
Grade 7 (50-61 km/h)
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Nhon Hoi Wind farm project – Phase I
Coastal area
Time of
occurrence
Technical Design
Storm names
Storm grade
Binh Dinh - Ninh Thuan
11/20/1985
GORDON (No.11)
Grade 8 (62-74 km/h)
Binh Dinh - Ninh Thuan
11/6/1986
HERBERT (No.9)
Grade 6 (39-49 km/h)
Binh Dinh - Ninh Thuan
11/14/1987
MAURY (No.6)
Grade 6 (39-49 km/h)
Binh Dinh - Ninh Thuan
10/7/1988
NONAME (No.7)
Grade 7 (50-61 km/h)
Binh Dinh - Ninh Thuan
10/1/1990
IRA (No.7)
Grade 6 (39-49 km/h)
Binh Dinh - Ninh Thuan
10/16/1990
LOLA (No.8)
Grade 6 (39-49 km/h)
Binh Dinh - Ninh Thuan
11/10/1990
NELL (No.3)
Grade 7 (50-61 km/h)
Binh Dinh - Ninh Thuan
10/15/1992
ANGELA (No.6)
Grade 8 (62-74 km/h)
Binh Dinh - Ninh Thuan
10/18/1992
COLLEEN (No.7)
Grade 7 (50-61 km/h)
Binh Dinh - Ninh Thuan
11/19/1993
KYLE (No.10)
Grade 13 (>133 km/h)
Binh Dinh - Ninh Thuan
12/2/1993
LOLA (No.11)
Grade 10 (89-102 km/h)
Binh Dinh - Ninh Thuan
10/17/1994
TERRESA (No.9)
Grade 6 (39-49 km/h)
Binh Dinh - Ninh Thuan
10/24/1995
YVETTE (No.10)
Grade 10 (89-102 km/h)
Binh Dinh - Ninh Thuan
11/1/1996
Tropical depression
Grade 6 (39-49 km/h)
Binh Dinh - Ninh Thuan
11/17/1998
DAWN (No.5)
Grade 7 (50-61 km/h)
Binh Dinh - Ninh Thuan
11/23/1998
ELVIS (No.6)
Grade 7 (50-61 km/h)
Binh Dinh - Ninh Thuan
12/9/1998
FAITH (No.8)
Grade 6 (39-49 km/h)
Binh Dinh - Ninh Thuan
11/4/1999
Tropical depression
Grade 6 (39-49 km/h)
Binh Dinh - Ninh Thuan
12/14/1999
NONAME (No.10)
Grade 7 (50-61 km/h)
Binh Dinh - Ninh Thuan
11/7/2001
LINGLING (No.8) Grade 11 (103-117km/h)
Binh Dinh - Ninh Thuan
6/9/2004
CHANTHU (No.2)
Grade 7 (50-61 km/h)
Binh Dinh - Ninh Thuan
9/11/2005
Tropical depression
Grade 8 (62-74 km/h)
Binh Dinh - Ninh Thuan
10/26/2006
Cimaron
Grade 13 (>133 km/h)
Binh Dinh - Ninh Thuan
8/2/2007
Tropical depression
Grade 8 (62-74 km/h)
Binh Dinh - Ninh Thuan
10/29/2007
Tropical depression
Grade 6 (39-49 km/h)
Binh Dinh - Ninh Thuan
11/22/2007
Hagibis
Grade 12 (118-133 km/h)
Binh Dinh - Ninh Thuan
11/11/2008
Tropical depression
Grade 6 (39-49 km/h)
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Coastal area
Time of
occurrence
Technical Design
Storm names
Storm grade
Binh Dinh - Ninh Thuan
11/15/2008
Noul
Grade 7 (50-61 km/h)
Binh Dinh - Ninh Thuan
9/3/2009
Tropical depression
Grade 6 (39-49 km/h)
Binh Dinh - Ninh Thuan
10/25/2009
MARINAE
Grade 6 (39-49 km/h)
Binh Dinh - Ninh Thuan
7/18/2010
Chan Thu
Grade 7 (50-61 km/h)
Binh Dinh - Phu Yen
10/2012
GAEMI
Grade 6 (39-49 km/h)
Da Nang - Quang Nam
10/2013
NARI
Grade 10 (89-117 km/h)
Khanh Hoa-Ninh Thuan
11/2013
PODUL
Grade 8 (62-74 km/h)
Binh Dinh - Phu Yen
11/2014
SINLAKU
Grade 9 (75-88 km/h)
Quang Nam-Quang Ngai
9/2015
Vamco
Grade 8 (62-74 km/h)
Quang Nam-Quang Ngai
9/2016
Rai
Grade 8 (62-74 km/h)
Quang Tri-Thua Thien Hue
10/2016
Tropical depression
Grade 6 (39-49 km/h)
Phu Yen - Khanh Hoa
11/2017
Damrey
Grade 9 (75-88 km/h)
Ninh Thuan-Binh Thuan
11/2017
Kirogi
Grade 6 (39-49 km/h)
Toraji (No. 8)
Cấp 8 (62-74 km/h)
Matmo (No. 5)
Grade 9 (75-88 km/h)
Ninh Thuan-Binh Thuan 17-18/11/2018
Binh Dinh-Phu Yen
28-30/10/2019
Phu Yen - Khanh Hoa
5-10/11/2019 Tropical depression
Grade 6 (39-49 km/h)
2.2.3.8.4. Dry and hot western wind
The main source of the dry and hot west wind in Binh Dinh is during the Southwest
monsoon period with the nature of the hot and moist air flowing from Bengan Bay
through the vast continent to Vietnam was blocked by the Truong Son range. As it
crosses the mountain range, the air mass leaves most of the moisture in the form of rain
on the West slope, then continues to slide down the eastern slope toward valleys and
coastal plains. By this time, the air mass becomes hotter and drier than the original
nature, which is often called the hot and dry west wind. The property of dry and hot west
wind weather is absolute daily maximum temperature ≥ 350C, combined with the daily
minimum relative humidity ≤ 50%.
Every year in Binh Dinh at the later weeks of April, hot and dry west wind appears
in the low valleys of the province. In the middle and end of May, it appears in most of
the rest of the province. However, dry and hot weather may appear so early in some
years in the middle of March in the North of the province and at the later weeks of April
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Technical Design
in the South of the province, but it is not the Southwest monsoon mentioned above, but
the southern circulation of the South China continent's depression suffered from the
puffeffect of the Truong Son range. Usually this is the prerequisite for the Southward
invasion of the cold air wave. The end date of this pattern of weather is also quite
different from year to year, normally in the later weeks of August in the North and the
coastal plain and early weeks of September in the South of the province. There was no
more dry and hot west wind phenomenon from the middle of August in some years but
in some other years dry and hot west wind phenomenon lasted until early October
(October 1st, 1976).
The dry and hot west wind does not happen continuously but is interrupted in many
times. From May to August, each month has 2 hot and dry west winds in average. The
month that has the most dry and hot west wind is 4-5 winds. Most of the dry and hot
west winds last for 2-3 days, accounting for 60%, 4-6 days accounting for about 2025%, the rest are those lasting for more than 6 days. From July to August, dry and hot
west wind phenomenon may last 10-15 days. The hot and dry west wind may last over
half of a month in year (in Quy Nhon, one time of 16 days in July, 1963; and 1 time of
25 days in August, 1982).
Hot and dry west wind days in Binh Dinh have the daily average temperatures of
27-300C, average wind velocity of 2-8m/s (Grade 2 to Grade 4).
2.2.3.8.5. Northeast monsoon
Every year, Binh Dinh, like the central provinces, is influenced by Northeast
monsoon. The first period is around October, November or until December in some
years, at this time the monsoon brings dry weather for the northern provinces, but the
moving process towards the South causes wet weather in the Central coastal provinces.
The later period,about from January to April or sometimes until May in some years, the
Northeast monsoon only brings a little and irregular precipitation and causes dry weather
pattern for the Central region in general and Binh Dinh in particular. Weather
characteristics under the effect of the Northeast monsoon is cloudy usually resulted in
precipitation, the wind direction changes North and getting stronger to Grade 3, Grade
4, breeze Grade 5, 6 or above Grade 6 in coastal areas; in particular, there are strong
winds of Grade 6, Grade 7, above Grade 7 in offshore area. In the early winter months,
the Northeast monsoon arrives, sometimes combined with other weather system leading
to heavy to extremely heavy rain, causing floods. In the last months of winter, the impact
of Northeast monsoon often causes thunderstorms, sometimes accompanied by
cyclones. In addition, in February and March, the Northeast monsoon comes, the daily
average temperature may drops below 200C and lasts for a few days.
The Northeast monsoon during the process of moving to the South has been altered
its characteristics quite a lot, so when it affects Binh Dinh, the Northeast monsoon
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Technical Design
standard is no longer clear. According to statistic data, under the influence of the
Northeast monsoon, it’s only wind to change its direction towards the North and getting
stronger to Grade 3, Grade 4, gales of grade 5, Grade 6 in the coastal area, barometric
pressure increases, most of daily average temperatures reduce only about 10C.
In average, every year, there are nearly 10 Northeast monsoon times affecting Binh
Dinh, accounting for 30% of the monsoon time arriving to Hanoi and 68% of the
monsoon times to Da Nang. The first Northeast monsoon time to Binh Dinh normally
from October, but there is also a year that the first Northeast monsoon time appears in
Binh Dinh in September or until November. The end time usually ends in April, but
sometimes till May in some years. In general, in the winter months from November to
March of the following year, on average, there is more than one monsoon affecting Binh
Dinh. Monsoon occurs in December accounts for about 20% of the number of monsoons
in a year.
2.2.3.8.6. Atmospherecontamination
Nhon Hoi wind power plant project is expected to be built in Nhon Hoi economic
zone, Nhon Hoi and Nhon Ly communes, Quy Nhon city, Binh Dinh province. The
project is on Den mountainous area where there is a lot of boulders, 5km far from the
sea. According to the electrical equipment code 11 TCN-19-2006, it is recommended to
design the insulation for heavily polluted environment, corresponding to the leakage line
standard of 31mm/kV.
The detailed meteo-hydrological survey results are shown in the meteohydrological survey report of Nhon Hoi wind power plant project - Phase 1 & Phase 2
performed by 23 Construction and Consulting Joint Stock Company implemented in
November 2020.
Volume 1.1 – Chapter 2
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Nhon Hoi Wind farm project – Phase I
Technical Design
CHAPTER 3: SOLUTIONS FOR ELECTRICAL – TECHNOLOGY OF POWER
PLANT
3.1.
GENERAL LAYOUT SOLUTION
The General layout was basicaly considered for implementation in the Basic Design
stage. Due to the project is located in hilly and steep terrain, the optimal locations for the
arrangement of wind turbines do not vary much between calculated scenarios, mainly in
areas of hilltop or top of watershed.
On the basis of the researches in the Basic Design stage, combined with the detailed
1:500 topographic map in the Technical Design stage, the wind turbines are micro sitting
to fit with the construction conditions, as well as ensuring the optimum in terms of energy
production. Accordingly, the positions will be adjusted about 15 ÷ 30m compared to the
Basic Design stage.
The General layout solution for other items is as follows:
-
110kV substation and 110kV transmission line: the position is maintained
according to Basic Design stage;
-
Access road and internal road: inheriting the results of basic design phase,
combined with detailed 1:500 topography map, the Technical design adjusts some
parts of road sections to facilitate road slope, intersections to suit transportation
and installation of wind turbines;
-
22kV underground cable and overhead line: adjusted to fit with internal routes and
topographic conditions (for the 22kV overhead line);
-
The O&M Building: The position of the O&M Building is shifted about 170m
from the Basic Design, located on the same main road leading to the project;
-
Disposal area: on the basis of locations of main disposal area in the Basic Design
stage, the Technical design readjust the area to suit the terrain conditions;
-
Temporary items such as construction offices, storage areas are arranged near the
access road to the project, on flat terrain.
The coordinates of some main items are as follows:.
Table 3.1: Coordinates of some main items of project
VN2000 coordinates, 3o projection,
108o15' central meridian
Point
X (m)
Y (m)
Turbine location – Phase I
NH1
1533584.51
610753.35
NH2
1533355.48
610894.33
NH3
1533210.33
611143.02
Volume 1.1 – Chapter 3
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Nhon Hoi Wind farm project – Phase I
Point
NH4
NH5
NH7
Q1
Q2
Q3
Q4
Volume 1.1 – Chapter 3
Technical Design
VN2000 coordinates, 3o projection,
108o15' central meridian
X (m)
Y (m)
1533094.29
611401.38
1533056.61
611663.47
1532228.71
611472.61
O&M Building Location
1532854.51
610841.51
1532791.17
610822.95
1532804.11
610778.81
1532867.45
610797.37
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Nhon Hoi Wind farm project – Phase I
Technical Design
Figure 3.1: Project General layout
Volume 1.1 – Chapter 3
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Nhon Hoi Wind farm project – Phase I
3.2.
Technical Design
TECHNICAL CHARACTERISTICS OF MAIN EQUIPMENT
3.2.1.1. Wind turbines
3.2.1.2. Applied standard
The wind turbine standard specifies requirements and considerations when designing
a wind turbine, as well as other related components, systems, and technologies that affect
the reliable functioning of wind turbines. The extended IEC 61400 covers related issues
such as overall inspection of the structure and acoustical noise metering, as well as a 6-part
information model for communication for monitoring and control. wind power plants, the
standardization of wind turbines is complemented by efforts from ISO, ANSI, and other
national standards. Together, these standards help ensure the design and manufacture of
wind turbines reliably and are conducive to ensuring the long service life of wind turbines
and both environment and economy. The typical standards that are widely used when
designing wind turbines as well as specific wind power plants are:
-
IEC 61400 for requirements in wind turbine design, from pre-construction
conditions to inspection of installation and commissioning;
-
IEC 60050-415 Wind turbine generator systems;
-
ANSI/AGMA/AWEA 6006-A03 (R2010) Design And Specification Of Gearboxes
For Wind Turbines;
-
IEC 60076 (All part) Power transformers in wind turbines;
-
EC 62305: 2006 and the GL standard for lightning protection;
-
IEC 62271 High-voltage switchgear and controlgear
-
IEC 60376 Specification of technical grade sulfur hexafluoride (SF6) and
complementary gases to be used in its mixtures for use in electrical equipment;
-
IEC 60815 Selection and dimensioning of high-voltage insulators intended for use
in polluted conditions;
-
IEC 60364-6 Low-voltage electrical installations - Part 6: Verification;
-
IEC 60364-1 (all parts) Low-voltage electrical installations
-
IEC 60502 ower cables with extruded insulation and their accessories for rated
voltages from 1kV (Um = 1,2kV) up to 30kV (Um = 36kV)
-
IEC 60044 Current transformers
-
IEC-60099 Surge arresters
3.2.1.3. Main equipment specifications of wind turbines
Wind turbines are composed of the main components as shown below:
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Nhon Hoi Wind farm project – Phase I
Technical Design
Figure 3.2: The main components of wind turbines
a. General requirements:
Wind turbines are constructed with safety grade not less than class III according to
IEC 61400-11 standard at wind speed at height.
Wind turbines are equipped with automatic control, monitoring and protection system
to meet the requirement of no operator.
b. Nacelle
The Nacelle is the place where most of the regulating equipment of wind turbines
such as control space, heat exchange system, cylinder rotation system, generator, power
converter ..., outside the shell is equipped with sensors wind. The Nacelle is made of
fiberglass, highly durable, lightweight. The turbine shell has space (operating floor) for
maintenance personnel.
c. Base Plate
The base plate is located in the turbine housing compartment, for the installation of a
driven train, gearbox, generator, transmitting wind turbine power to the tower and
foundation. Base plate is made from cold rolled steel.
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Nhon Hoi Wind farm project – Phase I
Technical Design
d. Rotor
Blade: The turbine uses 3 upwind type blades. Each wing has an independent pitch
control system. The wing is equipped with a lightning protection system, which conducts
lightning through the tower to the ground.
The blades material uses epoxy-reinforced fiberglass.
Lightning protectors and lightning arresters installed on the top of the blade, wire
cross-section and the temperature rise for the maximum lightning discharge current of
100kA does not exceed 250°C
Blades and turbines are certified according to IEC 61400-23, the surface roughness
is tested to comply with DNVGL-ST-0376 quality certification or equivalent.
Root Bulkhead is connected to the turbine bulb by planting a bolt. The structure
allows copper / electro-hydraulic transmission equipment to be arranged for the blades
angle adjustment system.
e. Cooling system
The wind turbine unit compartment is equipped with an indirect water cooling system
with blower and circulating water pump, heat dissipation for the bearing oil parts,
generators, and inverters.
Radiator fins made of copper or stainless steel.
f. Generator
Generator type DFIG is intended. Main components include stator, rotor, stator shaft,
rotor shaft and other auxiliary parts.
+ Type
: DFIG asynchronous
+ Rated power
: 5.000kW
+ Maximum capacity
: 5.150kW
+ Range of power factor
: 0.9 leading to 0.9 lagging
+ Rated speed
: 1120 rpm-6p (50Hz)
1344 rpm-6p (60Hz)
+ Insulation level
: Stator F/H
Rotor F/H
+ Cooling system
: Liquid cooling
+ Ventilation inside
: Air
+ Adjusted parameters
: Coil, liquid, bearing temperature
+ Rated frequency
: 50 or 60Hz
+ Minimum voltage
: 90% Rated
+ Maximum voltage
: 112% Rated
+ Minimum frequency
: 94% Rated
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Nhon Hoi Wind farm project – Phase I
+ Maximum frequency
Technical Design
: 106% Rated
With the 3-phase, 6-pole squirrel cage asynchronous generator type connected to the
22kV transformer via a full-power inverter. The inverter power is determined by the
manufacturer in accordance with the range of slip rates between the rotor frequency and
the grid frequency.
g. Inverter
The 3-phase inverter meets the grid connection requirements specified in Circular
39/2017 / TT-BCT.
The inverter is equipped with frequency-based shedding protection and is capable of
maintaining grid-clinging operation within the specified frequency range.
The inverter capacity is determined by the manufacturer according to the wind turbine
generator configuration/type.
h. raking system
The wind turbine includes 2 brake systems: aerodynamic brake and mechanical brake.
The aerodynamic brake system is operated through 3 independent pitch angle control
systems of 3 blades. Thanks to that, the braking of wind turbines can be operated flexibly
without being affected even in the event of a system failure.
The mechanical brake system is often used to lock the generator rotor during
maintenance. This system works independently of the control and protection system of a
wind turbine.
3.2.1.4. Monitoring control system
a. Yawin
This system works to rotate the entire nacelle to direct wind turbines to the main wind
direction, thereby achieving the highest wind energy collection.
Uses multiple motors to rotate the shaft with its smooth torque property to optimize
rotation speed thereby minimizing the effects of fluctuating operating conditions.
The system uses hydraulic brakes to lock the nacelle when the wind turbine is not
operating. In addition, the yawing system also uses an electromagnetically operated safety
brake at the motor shaft in case of serious damage.
b. Pitch control
The pitch motor uses a two-way acting hydraulic system that adjusts the wing angle
according to the wind speed signal installed above the wind turbine compartment:
-
High charging current, short charging time.
-
No required charge/discharge circuit.
-
Long service life.
-
Compact …
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Nhon Hoi Wind farm project – Phase I
Technical Design
The blades adjustment system is arranged for each blade independently, the
adjustment angle is not set to 90 degrees.
The turbine is capable of adjusting maximum power as well as the speed of output
power change through the pitch control system. The plant system not only controls the
capacity of each wind turbine but also has the function of controlling the capacity of the
whole wind farm to ensure that it is consistent with the resource mobilization plan and
stable operation on the regional power grid. The control of the power increase rate of the
turbine is achieved by controlling the pitch angle change rate of the impeller to minimize
the effects of sudden increases in wind speed resulting in large fluctuations (pulses) wind
turbine output power.
Figure 3.3: Principle of the control of blades angle (pitch)
c. Wind gauge
Each wind turbine is equipped with a device that measures the wind speed and
direction above the turbine compartment, directly connected to the Pitch and Yaw control..
d. The system for continuous monitoring of wind turbines
The control system consists of the following main parts:
-
Main control cabinet;
-
Sensor signal reception box;
-
Inverter;
-
The controller pitch;
-
Yaw regulator;
-
Generator cooling system;
-
Water cooling system control;
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Nhon Hoi Wind farm project – Phase I
Technical Design
-
Operational control;
-
Monitoring system (voltage, frequency, current, power and power factor of
generators, wind speed ...).
The wind turbine generator control system together with the electrical system can
completely protect the turbine generator's electromechanical equipment from malfunctions
and failures, and together with ensuring the power generated when wind maximum speed.
This control system must be automated, operating unattended under regional conditions. The
main control board can be individually designed for each generator and installed at each generator.
The system should at least be able to shut down, display, and signal under the
following conditions:
-
Activate emergency stop
-
Grid breakdown: frequency breakdown, voltage breakdown, over current, phase
order breakdown, ground fault, phase loss symmetry
-
Rotor over speed
-
Generator over speed
-
Transient overload Pt (Pr + 25%) is exceeded
-
The maximum overload level, Pa (Pr + 50%), is exceeded.
-
Over wind speed
-
Overheating (generator, transmission oil, control panel, frequency converter Overheating (generator, transmission oil, control panel, frequency inverter)
-
Brake system failure
-
Nacelle vibration
-
The Yaw incident
-
Twisted cable
-
Control failure
-
Grid breakdown
-
Hydraulic system breakdown
-
Transformer overheating (phase 1: warning, phase 2: disconnect the circuit breaker
and cut off the load - transfer load MV)
The system can display and signal in case of wind sensor failure.
The control system can automatically restart the WTG after being turned off due to a
mesh malfunction, after the cable is untwisted, after the wind speed returns to normal after
the overheating in the system is caused by overheating transient and temporary overloads
after disappearing. The WTG must be manually restored in the event of all shutdowns and
failures unevaluated.
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Emergency shut-off switches are required for manual operation at least at the nacelle,
ground control, top control, spindle and yaw ring.
Surveillance system that is part of the WTG control system should at least display the
following:
-
Status of each WTG
-
The state of the wind farm
-
State of the wind farm substation
-
Status of the meteorological station
-
Power generated by WTG (kWh)
-
All phase voltages and phase currents
-
Harmonic output of each WTG
-
Wind speed (m/s) and wind direction
-
All incidents including wind farm grid failures (status messages, times and total
times, dates and or accumulated memory to provide more than 14 months of storage)
-
Active capacity (kW)
-
Reactive power (kVAR)
-
Power factor
-
Rotor speed (rpm)
-
Generator speed (rpm of high speed shaft)
-
Temperatures at nacelle, gearbox, generator, bearing, control panel and
environment.
If a certain value cannot be measured directly, the contractor has to offer an
alternative to obtain data at the central monitoring computer.
Central monitoring software monitoring system has the function of monitoring,
controlling alarms, reporting ..., remote monitoring system. The intranet is flexibly
designed according to network forms such as ring circuit configuration, tree shape, star
shape, and special forms depending on the wind turbine layout.
3.2.1.5. Converter
The procedure for starting and connecting is as follows:
-
Wind sensor detects the direction of the wind to adjust the nacelle to rotate in that
direction;
-
Generator turbines rotate, excitation current increases with wind speed.
-
When the wind speed is greater than the operating speed (cut in), the full converter
generates voltage equal to the grid voltage as well as frequency synchronous with
the frequency on the grid. At the same time, the phase difference between the
generator is the voltage at the connection point being measured. When this deviation
Volume 1.1 – Chapter 3
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Nhon Hoi Wind farm project – Phase I
Technical Design
is 0, the generator is connected to the grid through the converter's IGBT power
electronics.
Table 3.2: The operating frequency range of wind turbine
No.
Technical requirements
System frequency
(50Hz –60Hz)
1
Depending on the minimum frequency, the turbine
can operate normally
< 46Hz
2
The turbine can operate for as little as 0.2 seconds at
a time
46-47Hz
3
The turbine can operate for at least 2 seconds at a
time
47-47,5Hz
4
Continuous operation
47,5-52,5 Hz
5
The turbine can operate for at least 2 minutes at a
time
52,5-53 Hz
6
The turbine can operate for as little as 0.2 seconds at
a time
53-54 Hz
7
Depending on the maximum frequency, the turbine
can operate normally
>54 Hz
At high frequencies, the system is either turned off or deflated to 2% to 10% of rated
power.
The reactive power control system adopts a power converter.
3.2.1.6. Steel tube cylinder
Steel tube cylinders for wind turbines are usually divided into sections and connected
by flanges and bolts. Steel tube cylinders is made entirely of galvanized steel.
Steel tube pillars are installed on a reinforced concrete foundation with the foundation
bolts buried in the concrete foundation.
Inside the steel tube cylinders are equipped with ladders and landing sites as well as
a protection system against falling. The lift can also be fitted inside if applicable.
The electrical cabinets are located below the tower.
The grade design meets level II for bearing safety. The tower is equipped with a
ladder and protected against falling. An elevator is optional. The power cable and control
cable are located in the post with anti-twisting protection when rotating the nacelle. After
the nacelle rotates in the same direction, the cable is automatically twisted.
3.2.1.7. Main specifications
Volume 1.1 – Chapter 3
3-11
Nhon Hoi Wind farm project – Phase I
Technical Design
The main specifications of wind turbines will include the following:
Table 3.3: Main specifications of wind turbines
No.
Unit
Parameter
1.1 Type
-
3 blades, horizontal axis
1.2 Orientation
-
In the wind direction
1.3 Diameter
m
145
1.4 Scanning area
m2
16.513
1.5 Capacity adjustment
-
Adjust pitch and torque
with variable speed
1.6 Rotor inclination
-
6o
2.1 Type
-
Self-bearing
2.2 Blades length
m
71
2.3 Root chord
m
2,856
1
2
Part
Rotor
Blades
2.4 Material
3
Aerodynamic brake
4
Load support item
Epoxy reinforced
Fiberglass
4.1 Hub
-
nodular cast iron
4.2 Main shalf
-
forging steel
4.3 Frame shell
-
nodular cast iron
6.1 Type
-
Completely self-contained
6.2 Gloss of surface
-
Half Gloss, <30/ISO2813
6.3 Color
-
White, RAL 9018
7
Generator
-
Asynchronous generator,
DFIG
8
Connect (LV)
5
Mechanical brake
Nacelle
6
Volume 1.1 – Chapter 3
3-12
Nhon Hoi Wind farm project – Phase I
No.
Unit
Parameter
8.1 Basic rated capacity
MW
5.0
8.2 Voltage
V
690
8.3 Frequency
Hz
50 hoặc 60
9.1 Type
-
Stell tube
9.2 Hub
-
102,5
9.3 Anticorrosion
-
Paint
9.4 Gloss of surface
-
Half Gloss, <30/ISO-2813
9.4 Color
-
White, RAL 9018
9
Part
Technical Design
Turbine tower
3.2.2. MV switchgear in power plant
3.2.2.1. Voltage level
The generators of each wind turbine will generate 3-phase AC with an output voltage
of 690V, then through a MV transformer placed in the turbine nacelle to transform the
voltage up to 22kV. These turbines will be connected together by 22kV underground cable
combined with overhead line 22kV XLPE aluminum core type then connected to the 22kV
busbar at the 22/110kV Nhon Hoi WPP substation to transform the voltage up to 110kV,
then connected to the National grid via the 110kV Nhon Hoi – Dong Da transmission line.
3.2.2.2. Single line diagram
Newly building a 3-phase, 22kV medium voltage system combining underground
cables and OHL cables connecting from turbines to 22kV cabinets at 22/110kV Nhon Hoi
WPP substation.
Volume 1.1 – Chapter 3
3-13
Nhon Hoi Wind farm project – Phase I
Technical Design
Figure 3.4: Typical SLD of turbine
The Nhon Hoi WPP – Phase 1 project has 06 MV substations 0.69/22kV (1 MV
substation for each turbine), divided into three 22kV cable routes connected from the
0.69/22kV MV substation to 22/110kV Nhon Hoi WPP substation via 01 single OHL and
01 double OHL, using ACX-240mm² wire. The details are as belows:
- Circuit 1: Connecting NH7 turbine to 22/110kV Nhon Hoi WPP substation.
+ Connecting from NH7 turbine to overhead transmission line using
underground cable Al-22kV-3x120mm2, 220m long.
+ Connecting from the overhead transmission line to 22/110kV Nhon Hoi
WPP substation using ACX-240mm², 373m long.
- Circuit 2: Connecting the NH1-NH2 turbines one by one 22/110kV Nhon Hoi WPP
substation.
+ Connecting from NH1-NH2 turbine using Al-22kV-3x120mm2
underground cable with length of 400m.
+ Connecting from NH2 turbine to overhead transmission line using Al22kV-3x240mm2 cable with length of 129m.
+ Connecting from the overhead transmission line to 22/110kV Nhon Hoi
WPP substation using ACX-240mm², 1605m long.
- Circuit 3: Connecting the NH5-NH4-NH3 turbines one by one to 22/110kV Nhon
Hoi WPP substation.
+ Connecting from NH5-NH4 turbine using Al-22kV-3x120mm2
underground cable with the length of 513m.
Volume 1.1 – Chapter 3
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Nhon Hoi Wind farm project – Phase I
Technical Design
+ Connection from NH4-NH3 turbine using Al-22kV-3x240mm2
underground cable with length of 461m.
+ Connecting from NH3 turbine to overhead transmission line using
underground cable Al-22kV-2x(3x240mm2) with length of 274m.
+ Connecting from the overhead transmission line to 22/110kV Nhon Hoi
WPP substation using ACX-240mm², 1605m long.
The OHL 22kV No. 1 has 1 section about 1km length with 3 circuits, of which a
22kV OHL is used to supply electricity for auxiliary power for the O&M building.
The 22kV underground cable routes go out from the 0.69/22kV wind turbine’s MV
substation to the transited pole between underground cable - overhead line are laid
in the cable trench, put inside flexible plastic pipe HDPE with a suitable size,
protecting HDPE conduits via a brick tile layer with an underground cable warning
tape. Above the cable trench, there are poles signaling the cable line with a distance
of 50m/pile. The underground cables cross the road are protected by steel pipe.
3.2.2.3. 0.69/22kV MV substation
At each wind turbine tower, 01 MV substation of 0.69/22kV will be arranged. MV
substation include MV transformer, medium voltage switchgear and protection system, in
which the alternating current will be transformed up to 22kV using 5500kVA transformer.
The MV substation will be placed in the nacelle to minimize capacity loss. Specifications
of the 0.69/22kV-5500kVA MV substation are as follows:
Table 3.4: Specifications of the 0.69/22kV-5500kVA MV substation
No.
Item
Specification
Unit
1
Type
3 phases, dry transformer
2
Standard
3
Rated capacity
5500
kVA
4
LV Rated voltage (turbine side)
0.69
kV
5
Connection
Dyn11
6
MV Off-load tap changer
7
MV Rated voltage
8
Insulation level (AC/LI)
9
IEC60076
ECO Design Directive
± 2 x 2.5%
22
kV
50/125
kV
Frequency
50
Hz
10
Cooling method
AF
11
Temperature regulation
Volume 1.1 – Chapter 3
Winding, Magnetic core
3-15
Nhon Hoi Wind farm project – Phase I
No.
Technical Design
Item
Specification
12
Insulation
F
13
Impedance
8.31
Unit
%
3.2.2.4. RMU 22kV
To protect and operate the 0.69/22kV - 5500kVA transformer for maintenance and
repair working, using the RMU switchgear equipped with a MV circuit breaker which has
a rated current 630A at the MV side.
Beside, the RMU is equipped with LBS - Load breaking switch with the rated current
630A to protect the underground cable line to ensure continuous operation and for isolated
cutting the underground cable segment to maintenance and repair. These switches are
integrated in the RMU located in the working platform inside wind turbine tower.
Two type of RMU shall be used in Nhon Hoi – Phase 1 project:
-
Type 1: 1 transformer cabinet included circuit breaker and disconnecting switch,
1 feeder cabinet for cables come out (turbine no. NH1, NH5, NH7).
-
Type 2: 1 transformer cabinet included circuit breaker and disconnecting switch,
1 feeder cabinet included load breaker for cables come in, 1 feeder cabinet for
cables come out (turbine no. NH2, NH3, NH4).
RMU type 1
RMU type 2
Figure 3.5: RMU configuration
Specification of the 22kV medium voltage cabinet are as follows:
-
Metal-clad/metal-enclosure/Ring main unit 3 phases, SF6/vacumm insulation.
-
Rated frequency
: 50 Hz
-
Rated voltage
: 24 kV
-
Insulation level
:
o Lightning impulse
: 125 kV (peak)
o Industrial frequency impulse
: 50 kV (rms)
Volume 1.1 – Chapter 3
3-16
Nhon Hoi Wind farm project – Phase I
-
-
Technical Design
MV feeder bay
: Equip LBS
o Rated current
: 630 A
o Load breaking current
: 630 A
o Short-circuit breaking current
: 20 kA rms (1s)
o Transient breaking current
: 25 kA (peak)
Main transformer bay
: Equip ACB
o Rated current
: 630 A
o Short-circuit breaking current
: 25 kA rms (1s)
o Transient breaking current
: 62.5 kA (peak)
3.2.2.5. Measuring diagram
-
All measuring equipments have input or converter that communicates with SCADA
system.
-
The generator output: Measure A, V, W, Var, Wh, Varh, f, cos φ.
-
Auxiliary power source: Measure A, V AC and DC.
3.2.2.6. MV switchgear location
Medium voltage equipment and control equipment are planned to be located in the
foundation base of the wind turbine with the working platform and access ladder.
The distance between MV equipment and other equipment at the base of the wind
turbine is arranged to ensure a safety distance for the operator and equipment in accordance
with the current IEC regulations.
The MV equipment and the control device are fixed to the working platform by a
solid bolt connection, while allow to detach the damaged part and replace easy the new
part when a failure occurs. The electrical equipment is transported through the door at the
base of the wind turbine’s tower.
3.2.2.7. Specification of MV underground cable
No.
1
Item
Type
Rated voltage
2
Unit
kV
Specification
YJLY2318/30kV 3*120
YJLY23-18/30kV
3*240
18/30
18/30
Conductor
Manufacturer
Jiangsu Shangshang Cable Group
Co.,Ltd.
Material
Aluminum
Volume 1.1 – Chapter 3
Aluminum
3-17
Nhon Hoi Wind farm project – Phase I
No.
Item
Technical Design
Unit
Long term operating
temperature
℃
90
90
Short circuit temperature
℃
250
250
Nominal cross-section area
mm2
120
240
Approximate outer diameter
mm
13
18.3
Number / diameter of single
wire
mm
19/2.95
37/2.97
≤0.9
≤0.9
957
1924
Compression coefficient
Structural consumption
3
kg/km
Jiangsu Shangshang Cable Group
Co.,Ltd.
Insulation
Material
4
Specification
XLPE
XLPE
Thickness(nominal value)
mm
8.0
8.0
Outer diameter (approximate
insulation outer diameter
value)
mm
30.3
35.6
Structural consumption
(approximate weight of
insulation)
kg/km
1512
1867
inner covering
Anhui Kenuo New Material Co., Ltd.
Jurong Boyue Cable Material Co.,
Ltd. Liyang new century electrical
materials Co., Ltd
Manufacturer
filling material
PP rope
PP rope
Thickness(nominal value)
mm
2.0
2.2
Outer diameter (approximate
outer diameter of inner
sheath)
mm
75
87
Volume 1.1 – Chapter 3
3-18
Nhon Hoi Wind farm project – Phase I
No.
Item
Structural consumption
(indicated by classification)
(reference weight of inner
sheath)
5
Technical Design
Unit
kg/km
704
918
Armor layer (if any)
Manufacturer
Jiangsu Ruixin metal products
Technology Co., Ltd. Jiaozuo Haibo
metal products Co., Ltd
Material
Steel ribbon
Steel ribbon
Specification (nominal value)
mm
0.8
0.8
outer diameter
mm
78
90
1965
2273
Structural usage (approximate
kg/km
weight of armor)
6
Specification
Serving
Manufacturer
Jiangsu Shangshang New Material Co.
, Ltd.Linhai Yadong special cable
material factory
Material
PE plastic, anti
rodent, anti
water
PE plastic, anti
rodent, anti water
Thickness（nominal value）
mm
3.7
4.1
Outer diameter (approximate
outer diameter of outer
sheath)
mm
86.5
99.4
Structure dosage (outer
sheath reference weight)
kg/km
888.7
1142
7
Approximate weight of cable
kg/km
7902
10644
8
DC resistance of conductor at
20 ℃
Ω/km
0.153
0.0754
9
Resistance of metal screen at
20 ℃
μF/km
0.1760
0.2207
Volume 1.1 – Chapter 3
3-19
Nhon Hoi Wind farm project – Phase I
No.
Item
10
Capacitance of cable
11
Maximum allowable traction
force of cable
12
Allowable bending radius of
cable
13
Short circuit current of
conductor for 1 second
14
Standard
Technical Design
Unit
mH/km
Specification
0.3799
0.3360
14040N
28080N
mm
12D
12D
kA
11.4
22.6
IEC60502
IEC60502
3.2.3. SCADA system
3.2.3.1. SCADA configuration
Control, monitoring and data collection system (SCADA system) is located in the
central control room of Nhon Hoi wind power plant with the aim of controlling and
monitoring all equipment in the whole plant as well as processing data to create a complete
database for operational management. Through the establishment of the Control Center
and appropriate Gateway devices and terminals, the tasks are as follows:
-
Control wind turbines and collect data from wind power plants.
-
Analyze and report on the operation of the plant.
-
Simple operation, minimizing the down time of the power plant and the grid.
-
The power plant SCADA system includes optical switches connected in series
between the turbines to the central switch at the control room, through the router
and communication equipment equipped in the 22/110kV Nhon Hoi substation’s
scope. The SCADA signals are connected to a wide area network WAN.
-
Use Ethernet network cable to connect the switch of each turbine to the Wind
turbine monitoring device (SCADA monitoring device).
-
Use fiber optic cables in the conduit placed in the cable trench to connect the
switches of wind turbines, the optical cables follow the underground cable to the
overhead line connecting to the fiber optic terminal box hanging on the steel pole,
the fiber optic cable routes overhead wire to control room.
-
The information on the wind power plant control system in this document is for
reference and design coordination of data communication lines to the dispatching
center according to the required SCADA signals in the Information - SCADA
agreement.
Volume 1.1 – Chapter 3
3-20
Nhon Hoi Wind farm project – Phase I
-
Technical Design
SCADA system is equipped in the Nhon Hoi power plant project - Phase 1 and is
used for general control and supervision for both phases of the project. It means
the total generating capacity of all wind turbines of both phases is controlled
through the common PPC - Power Plant Control device, invested in phase 1 of the
project.
Figure 3.6: Typical SCADA single line diagram
Figure 3.7: Typical fiber optic connection of WTG
Figure 3.8: Typical fiber optic connection of WTG’s switch
Volume 1.1 – Chapter 3
3-21
Nhon Hoi Wind farm project – Phase I
Technical Design
3.2.3.2. Control system of wind power plant
The power plant control system is equipped with computer control, power controller
and working status monitoring of all wind turbines, generators, inverters and MV station
equipments.
The wind power plant model for control and supervision system is set up with a
control loop through two optical switches were invested in 22/110kV Nhon Hoi
substation’s scope.
Figure 3.9: Typical control system of wind power plant
The VOB server operation control computer has the function of controlling and
monitoring the operation of the whole plant.
The PPC – plant power controller performs the functions of automatically adjusting
active power, reactive power of each wind turbine according to the requirements of the
power system dispatching centers.
All functions of the turbines and 22kV stations are controlled by computer software
with remote control using the manufacturer's dedicated integrated control system for each
turbine and interconnection to the central SCADA system located in the central control
room of the 110/22kV substation.
Data is transmitted through the fiber optic communication system, beside, a local
control function in the control cabinets shall be equipped too. All equipments are arranged
in the turbine tower or in the cabin next to the turbine tower (in the project is being designed
the 0.69/22kV substation, RMU and low voltage equipment, protective controller located
in the turbine tower).
Volume 1.1 – Chapter 3
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Nhon Hoi Wind farm project – Phase I
Technical Design
The operation of the wind power plant is completely automatic, except when the
generator is actively stopped due to problems or due to periodic maintenance.
The wind power plant is equipped with WIND SCADA system meeting IEC 61400
standard to control wind turbines.
Figure 3.10: Wind SCADA configuration
The wind turbines and WIND SCADA server systems are interconnected via an
internal fiber optic network (SCADA Network).
WIND SCADA server supports connection to other SCADA systems according to
IEC 60870-5-104. From the Setpoints value received via the SCADA system at the
22/110kV substation. WIND SCADA server controls the response wind turbines according
to the value Setpoints received.
Volume 1.1 – Chapter 3
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Nhon Hoi Wind farm project – Phase I
Technical Design
Figure 3.11: Single line diagram of SCADA’s communication
3.2.3.3. Power generation prediction system
SCADA system shall be equipped with equipment, tools or software to predict output
power of solar power plant based on meteorological conditions. These data shall be
transmitted to National Load Dispatch Center (A0) to ensure grid safety operation.
Output power prediction of solar power plant shall meet requirement of precision,
time range, to be consistent with load dispatch circle and exchange circle of Vietnam
Wholesale Electricity Market (VWEM), with considering to uncertainty of meteorological
factor.
Detail technical requirements are as following:
a. Prediction in operation day (intra day)
- Resolution: 15 minutes
- Time range: next 3 hours, with total 12 SCADA signals
- Update frequency: 15 minute/time, real time operation
- Acceptable mismatch: less than ± 7%. This mismatch will be decreased,
depended on real time operation requirement.
- Connection: measuring SCADA signal from power plant to National Load
Dispatch Center (A0).
b. Prediction of next day, next week (day ahead and month ahead)
- Resolution: 15 minutes
- Time range: next 7 days
- Update frequency: 1 time/day at 10h00
- Acceptable mismatch: less than ± 10%. This mismatch will be decreased,
depended on real time operation requirement.
Volume 1.1 – Chapter 3
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Nhon Hoi Wind farm project – Phase I
Technical Design
-
Connection: to website of Hydro-meteorological forecasting system for planing
and operation of power system (https://weather.nldc.evn.vn/KTTV).
c. Prediction of next month (month ahead)
- Resolution: 1 hour (typical daily chart)
- Time range: next month
- Update frequency: before 15th day of each month
- Connection: to website of Hydro-meteorological forecasting system for planing
and operation of power system (https://weather.nldc.evn.vn/KTTV).
3.2.3.4. Power plant controller - PPC
The power plant controller divides in two configurations: Normal and Quick
Configuration, available for installation in the wind farm depending on the reaction time,
response time, and accuracy to be achieved.
The main difference between both configurations is the reaction time and response
time which is summarized in the following table:
Table 3.5: Specification of PPC device
No.
Normal Configuration
Quick Configuration
Reaction time A-F (Active
power – Frequency)
1-2s
<200ms
1-2s
<200ms
Depending on turbine’s
transformation ratio
Depending on turbine’s
transformation ratio
2-3s
<1s
Solution
Yes
Yes
Hardware requirement
No
Yes
Reaction time Q-V
(Reactive power – Voltage)
Response time A-F
(Active power – Frequency)
Response time Q-V
(Reactive power – Voltage)
Volume 1.1 – Chapter 3
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Nhon Hoi Wind farm project – Phase I
Technical Design
Figure 3.12: Normal Configuration
Figure 3.13: Quick Configuration
The power control function can be divided into 3 main components:
-
Management system: Processes all external signals (regulating commands and
external control signals - Control commands and control signals) and forwards these
signals to the different internal regulators.
-
QVi: Module integrates algorithms to adjust reactive power / voltage.
-
PFi: Module integrates algorithms to adjust active power / frequency.
3.2.3.5. SCADA fiber optic cable specification
SCADA fiber optic cable has detailed structure as shown below:
Volume 1.1 – Chapter 3
3-26
Nhon Hoi Wind farm project – Phase I
3.3.
Technical Design
-
Minimum of 24 optical fibers (12 pairs) for each wind turbine connected to
SCADA system;
-
Fiber optic type Single mode 9/125 OS2;
-
Non-corrosive, meet IEC60754-2 and EN50267 standards;
-
Fire retardant, meet standards IEC60332-3-24 and EN50266-2-4;
-
Has reinforced flame retardant layer, does not generate halogen gas when burning;
-
No water ingress, meet IEC60794-1-2-F5 standard;
-
Non-metal fiber optic cable, no need for safe grounding;
-
Against rodent damage to optical fiber via anti-rodent chemical powder adding in
cable’s insulated cover;
-
Anti-bacteria and anti-UV;
-
Can be installed in cable conduit or buried directly in the ground;
-
Meet the regulations of RoHS;
-
Working temperature: -5°C to 50°C.
LIGHTNING PROTECTION
3.3.1. Strike lightning protection
Lightning protection system for each wind turbine: the receptors are located on the
turbine blades, the lightning arrester is arranged inside the blades to protect overvoltage
caused by direct lightning strikes.
3.3.2. Surge lightning protection
Protection against atmospheric overvoltage propagating from the strike lightning
protection to the wind turbine 22kV switchgear is carried out by lightning wire and surge
arresters installed at the both-end terminals of the 22kV underground cable and at the MV
side of MV transformer’s cable. Lightning arresters use non-gap metal oxides valve.
At the wind turbine nacelle, an anemometer installation area is equipped with a
lightning arrester to conduct lightning current through the grounding system to avoid the
lightning current spreading in the driven system.
Volume 1.1 – Chapter 3
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Nhon Hoi Wind farm project – Phase I
Technical Design
Figure 3.14: Lightning and grounding system of turbine’s tower
3.3.3. Grounding system
Wind turbine grounding grid consists of 02 parts, circular ground grid and additional
rod-bar grounding grid with D16 galvanized steel wire combined with D22 galvanized steel
rod 2.4m long.
Volume 1.1 – Chapter 3
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Nhon Hoi Wind farm project – Phase I
Technical Design
Arranging a circular ground grid in accordance with the shape of the concrete
foundation at the bottom of turbine tower, using bare copper wire with a minimum cross
section of 70mm² to perform a ring ground grid. The grounding grid directly placed in the
concrete foundation at bottom of the turbine tower. Combined arrangement of equipotential
rings in the bottom of reinforced concrete foundation and inside the turbine tower to form
a complete grounding grid.
The air-termination wire is from the air-termination unit on the top of the turbine
blade to the monopile foundation and the grounding system uses bare copper wire with
minimum cross section 50mm².
Main earthing electrical bonding (MEEB) is located at the back of the RMU mediumvoltage distribution cabinet to ground circuit breakers, load breakers, transformers,
electrical panel covers, steel ladders, cable trays, turbine platform, underground cable strip
steel cover and grounding for all equipment with metal shells in wind turbines.
The selection of the wind turbine grounding resistance value should meet the Vietnam
Electrical Equipment Regulation and recommendations of the turbine manufacturer.
Specifically, the whole turbine ground resistance should not exceed 5Ω. In accordance with
the technical requirements of the Regulation on Grounding for electrical equipment above
1kV of isolated neutral network, Article I.7.46, and at the same time meeting Article I.7.52
on Grounding for electrical equipment below 1kV of directly earthed neutral network (for
Wind Turbine Generator), combined with the turbine manufacturer's specifications for
lightning arresters for both of the medium and low voltage side that grounding resistance
value shall be equivalent and should be less than 10 Ω. Therefore, choosing the design of
the whole turbine earthing resistance not exceeding 5Ω is guaranteed in terms of technical
criteria and suitable for economic criteria.
3.4.
FIRE FIGHTING SYSTEM
The wind energy industry is one of the current leading industries in the field of
renewable energy, providing cheap and sustainable energy solutions. However, wind
power plants are facing the risk of fire and explosion. The elements of combustion are
always present in the body of the wind turbine. During a fire, it is difficult to extinguish
the fire because the height and location of these turbines are often located far from
residential areas, causing considerable damage to the wind industry. Therefore, it is
necessary to have an overview of the causes of fire for wind turbines to have an effective
fire protection solution.
3.4.1.1. Causes of fire in wind turbines
Some of the possible causes of fire in wind turbines are:
-
Lightning, electrical equipment failure, surface ignition and construction
maintenance. Of these reasons, lightning is the most common source of ignition,
especially for wind turbines at sea. The risk of fire is higher when wind turbines are
Volume 1.1 – Chapter 3
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Technical Design
not equipped with a lightning protection system or a lightning protection system that
is not maintained or maintained.
-
Another common cause of fire is breakdown of electrical / electronic equipment,
overload of electrical / electronic equipment. Short circuits, electrical arcs, and
improper protection of electrical equipment are also common causes of fires in wind
turbines.
-
“Hot” surfaces such as overheating bearings, actuators, and mechanical brakes can
present a high risk of fire if flammable materials come into contact with these
components.
-
In case of emergency, when the aerodynamic brake system fails to stop the turbine,
mechanical brake is used, and leads to a high risk of fire if the brake system is too
hot (especially if the lubrication is poor ), when very high temperatures are reached,
an arc can be ignited that can ignite combustible materials (for brakes without
protective covers). The phenomenon of overheating of the brake system can lead to
the breakdown and creation of brake disc fragments, which can cause hydraulic hose
to break in the engine body, resulting in hydraulic fluids at high pressure which are
very flammable in contact with "hot" surface.
-
Maintenance and repair activities such as cutting, welding, and grinding inside a
wind turbine can lead to a high risk of fire, especially in gear drive systems.
-
Flammable materials at a distance of 10m or more can be easily burned with a spark
from grinding, welding, and cutting.
3.4.1.2. Fire protection solutions for wind turbines
3.4.1.2.1. Passive solution
Passive fire prevention in wind turbines can be done in many ways, but is primarily
focused on flammable components that spread the flame to other components in the
turbine body. Passive fire prevention for wind turbines is implemented by several
solutions such as:
-
Installation of lightning protection systems;
-
Use hydraulic oil and non-flammable lubricating oil;
-
Using incombustible materials for wind turbine bodies;
-
Avoid performing maintenance and repair activities related to welding, "hot" cutting
inside the turbine body;
-
Use condition monitoring system (CMS) to monitor the working status of important
equipment and perform regular inspection and maintenance.
3.4.1.2.2. Active solution
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a. Smoke detector for wind turbine pillar
In the air intake detection system, the air is sampled from the protected area through
a network of pipes, actively sucking air towards the detection system using a highpressure suction fan.
Advantages of the system:
-
The sampling pipe used in the air intake system is more resistant to the harsh
environment than the standard point smoke detector.
-
Smoke detector system can typically provide much higher sensitivity than standard
smoke detectors, but at the cost of a conventional smoke detector.
-
This highly sensitive smoke detector is a device quality measuring device that
collects laser light scattered from smoke particles in a full 360 degree scan. The
result is an astonishing 0.001% obscure/meter sensitivity, 2000 times more
sensitive than a conventional smoke detector.
b. Fire fighting system in wind turbine pillars
Areas within a wind turbine with a high fire risk include:
-
Electric cabinets area
-
Converter cabinets area
-
Transformer room area
At the wind turbine pillars installed and equipped with automatic fire extinguishing
system NOVECTM 1230 installed fire protection for the areas inside the wind turbine.
Combined with the manufacturer's designed smoke detector integrated in the device of
the wind turbine.
The NOVECTM 1230 automatic gas fire extinguishing system includes:
-
Smoke detection system (smoke detector);
-
Control cabinet;
-
System of gas cylinders NOVECTM 1230;
-
Pipeline system of gas distribution and spray nozzle;
-
Push button activates the exhaust (on the cabinet);
-
Push button by manual action;
-
Push button to delay fire fighting;
-
Fire bell;
-
Horn / lamp;
-
Accessories included.
The number of Novec 1230 cylinders for a wind turbine pillar is 2 Novec 1230
cylinders for 1 wind turbine pillar (01 cylinder 11kg, 01 cylinder 2.7kg)
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Technical Design
Figure 3.15: Gas automatic fire extinguishing system installed in wind turbines
3.5.
AUXILIARY TRANSFORMER
-
Auxiliary power source of wind turbines is taken from a 0.69/0.4kV transformer
installed inside the turbine, combined with a UPS power source from a battery used
for control and protection systems.
-
Auxiliary power source of the O&M building is supplied from the 22kV OHL
from the 22/110kV substation, installed 01 new 22/0.4kV-200kVA substation near
the entrance of the O&M building.
-
During construction time, using diesel generator for auxiliary power supply.
-
Specifications of the auxiliary transformer of the O&M building are as follows:
+ Voltage
: 22±2x2.5%/0.4kV.
+ Capacity
: 200 kVA.
+ Connection
: Dyn-11.
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CHAPTER 4: CONSTRUCTION SOLUTIONS FOR PLANT PART
4.1.
SELECTION OF CONSTRUCTION SITES/ITEM ELEVATION
4.1.1. Principle of elevation calculation
The grading elevation of the plant shall be calculated to ensure conditions of
technical and consider the analysis of the economic factors of the project. The selection
of reasonable leveling will advance for the exploitation of natural land, reduction of
costs and construction time.
-
In accordance with the planning of infrastructure development and
transportation in Nhon Ly and Nhon Hoi communes – Nhon Hoi economic
zone, Quy Nhon city, Binh Dinh province.
-
Balancing cut-fill volume of the construction areas on the principle of ensuring
the technical requirements of the project.
-
In accordance with terrain and geological conditions of the areas.
-
Ensure surface drainage, avoiding local flooding in the rainy season.
-
Connecting traffic infrastructure from the plant internal transport system to
adjacent works/ items to ensure technical requirements.
4.1.2. Leveling solution
The leveling and preparation work of Nhon Hoi Wind power plant project – Phase
1 shall be constructed hardstand area, road, etc.
Before leveling, it is necessary to remove the surface organic soil layer with a
thickness of about 20cm, dismantle and move the stump, single rocks, etc. on the area
surface. Waste soil shall be storaged to reuse for backfilling. The leveling work shall
be carried out on the principle of digging at the location of high elevation and filling the
position of low elevation, refer to the slope ratio shown in the drawing.
Filling work: must remove the organic soil layer and make step on nature surface
to increase connection between soil layers, compaction ration requirement is K >0.95
4.2. IMPACT LOADS
REQUIREMENT
AND
EARTHQUAKE-RESISTANT
DESIGN
4.2.1. Impact loads
Depending on the characteristics, the scale of the structure, the technological
characteristics will have different special load types. However, basically the load
impacting on the construction includes the following types of loads.
4.2.1.1. Permanent loads (standard or design load)
These are the impact loads which do not change during construction and operation
stage. The permanent loads include:
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Nhon Hoi Wind farm project – Phase I
Technical Design
-
Weight of components and structures, weight of reinforcing structures and
cladding structures.
-
Weight and pressure of soil (backfilling and filling).
4.2.1.2. Long-term temporary loads include:
-
Weight of partitions, soil and concrete cushioned under the equipment;
-
Weight of fixed equipment;
-
Load applied to the floor by materials and equipment in rooms, warehouses, etc.
4.2.1.3. Short-term temporary loads include:
-
Weight of person, repaired material; accessories and tools;
-
Dynamic load by equipment in the stages of turn-on, cut-off, forwarding and
testing;
-
Load due to moving lifting equipment during construction and operation stage;
-
Load impact on the floor of houses, public houses, manufacturing storages.
-
Dynamic loads shall be accorded to TCVN 2737:1995.
4.2.1.4. Wind load:
The wind load will be determined according to the standard: TCVN 2737-1995
"Loads and Actions norm for design";
The plant is located in the region of medium wind forces (zone III.B according to
the wind pressure partition table) with standard wind pressure Wo = 125 daN/m2
W0 is determined from the wind speed v0 - wind speed at a height of 10m
compared to the benchmark (the average speed in a period of 3 seconds is exceeded by
the average one of once every 20 years) corresponding to the B-type terrain (surface
roughness z0 = 0.005).
4.2.1.5. Other loads and forces
Other loads and forces considered in the design include, but are not limited to, the
following loads and forces: Soil pressure, water pressure, environmental load, influence
of temperature change, influence due to shrinkage, settelment, etc.
4.2.2. Earthquake-resistant design requirements
The calculation of earthquake-resistant design for project items complies with
TCVN 9386: 2012 “Design of structures for earthquake resistances”.
According to Appendix H - TCVN 9386: 2012, the coefficient of peak ground
acceleration of the zone in Quy Nhon city, Binh Dinh province with the value of peak
ground acceleration is agR = 0.0941g, conversion from peak ground acceleration to
earthquake grade (Scale MSK-64) in Appendix 1 TCVN 9386:2012, the Nhon Hoi Wind
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Nhon Hoi Wind farm project – Phase I
Technical Design
farm project shall be calculated for earthquake level VII and must calculate seismic
resistance.
4.3.
WIND TURBINE FOUNDATION
4.3.1. Design of wind turbine foundation
The geotechnical and structural design is based on the principle of limit state
design, application of load components and the resistance coefficients in accordance
with the following standards:
-
EN 1992-1 Eurocode 2 - Design of concrete structures.
-
CEB-FIB Model Code 2010 - Model code for concrete structures.
-
EN 1997-1 Eurocode 7 - Geotechnical design.
-
EN 206-1 Concrete: Specification, performance, production and conformmity
-
IEC 61400-1 Wind turbines – Part 1: Design requirement
4.3.2. Structure of wind turbine foundation
Wind turbine foundation structure is a reinforced circular concrete slab structure,
in which:
-
Type 1 – NH1 to NH5: diameter 21.4 m; height of foundation base 2.6m; height
of pedestal 0.65m; total height of foundation 3.25m.
Figure 4.1: Foundation type 1
-
Type 2 – NH7: diameter 26.2 m; height of foundation base 2.6m; height of
pedestal 0.65m; total height of foundation 3.25m.
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Nhon Hoi Wind farm project – Phase I
Technical Design
Figure 4.2: Foundation type 2
Detail description shall be presented in “Volume 1.1A Description of turbine
foundation”
4.4.
TECHINCAL REQUIREMENT FOR HARDSTANDS
4.4.1. The load-bearing capacity of the internal roads, the crane hardstand and
the working ares
Figure 4.3: Typical laydown for asembly and installation
The crane hardstand areas must have a load capacity of 2 kg / cm², transmitted by
the main crane supports. All internal roads shall be constructed with a minimum
asphalted width of 4.5 m.
The requirements for access routes, internal roads and crane hardstand areas are
often intended to ensure that cranes and heavy vehicles can safely access and work at
wind turbine foundations. These requirements must be complied with in all weather
conditions.
4.4.2. Wind turbine foundation area
During installation of the crane boom and WTGS, distance between foundation
and crane is more than 24 m, depending on the WTGS and crane configuration. Where
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Nhon Hoi Wind farm project – Phase I
Technical Design
backfilling is required as part of the foundation design, such backfilling may in some
cases only be completed once the WTGS has been installed.
A gravel path shall be installed between the crane pad / interal road and the
foundation, around the tower in order to ensure safe access of the WTGS without any
danger.
4.4.3. Site office area
This area shall be leveled and constructed to a maximum slope of 2% and paved
with clean, fine gravel or equivalent. Construction contractor and supplier shall place
containers, toilets, equipment and parking in this area.
This area shall be located outside the crane working area to avoid the risk of falling
objects. If this is not possible, special procedures should be considered, such as
evacuation during crane lifting.
4.4.4. Crane pad
The crane hardstanding areas shall be constructed for both wheel-mounted and
crawlermounted cranes can be used.
The requirements of the crane hard standing / working areas are different due to
tower length and hub heights.
Any changes below are only allowed with the approval of the supplier's
representative:
-
The entire length and width of the crane hardstand surfaces shall be constructed
with slope 0% - maximum 0.5%.
-
Crane hardstand are must have loading capacity of 2 kg / cm² over the entire
yard area.
-
The Supplier points out that crane hardstands must be constantly monitored, in
particular during adverse weather conditions. Any required repairs must be
directly carried out during the installation phase of the project. he crane pads
will be required to be re-checked and repaired where necessary. Also the
levelness of for the crane pads will be required to be re-checked and re-instated
where necessary.
-
Top Soil and obstacles shall not be deposited around the crane pad and along
the site road. This area is required as working area and for assembly of the crane
boom. Also any overhanging tree branches or cables are to be removed from the
crane construction area.
-
In order to avoid contaminating the wind turbine equipment, a 2 m wide gravel
path must be constructed from the crane pad/site road to the WTGS and around
the tower.
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Nhon Hoi Wind farm project – Phase I
Technical Design
-
A working area on the right or left of the crane hard standings shall be used for
assembly of WTGS components and storage of the turbine components.
-
These areas shall be free and clear of obstacles that would prevent cranes
movement over them, to stage components and assemble WTGS.
-
The crane manual for the particular machine actually used on the project must
be consulted to verify dimensional and bearing requirements prior to the
performance of any move or lift. Compaction requirements must be checked
prior to mobilization of the crane.
Any additional design requirements such as working area for construction
machines; road or hardstand area; Drainage and reinforcement for roads and cranes are
added according to specific requirements and topographic situation.
4.4.5. Delivery and storage the turbine components
Tower sections: Delivery and storage will take place on the designated open
spaces next to the crane hard standing. This area should be prepared so that it is walkable
and can be used by an all-terrain forklift. The surface must absorb a surface pressure of
at least 2 kg/cm². The Supplier or the assigned assembly company will provide
appropriate plates for load distribution.
Naccle, hub, etc: Delivery and storage shall take place on the hardstand area next
to the interal road.
Blades, rotors: Delivery and storage shall take place on the hardstand area next to
the interal road.
4.4.6. Crane boom assembly requirements
This area needs to be accessible for the assisting crane which will always be
required. The assisting crane will also require a plain area beside the site road, or along
the direction chosen for the assembly of the main boom.
The requirements for crane boom assembly listed below. If the following
conditions cannot be met, the other options of the project must be discussed and
approval.
In general, the followings can be noted about the boom assembly area:
-
The assembly area must be accessible to all off-road forklifts.
-
In forestry areas the minimum dimensions must also be considered in the
vertical direction to ensure that all trees and cables shall be removed from the
crane working area.
-
All crane hardstand areas: Load capacity of the ground is not less than 2 kg /
cm².
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Nhon Hoi Wind farm project – Phase I
Technical Design
4.4.7. Crane boom assembly
The areas for the auxiliary crane shall be cleared and flat. This needs to be prepared
and serviceable by an off-road forklift.
Depending on the crane boom length, support surfaces to be used as abutments are
required underneath the crane mast. These surfaces and positions differ for each crane
mast configuration and can only be provided once the crane technology has been
determined. In general, the following does apply: the higher the abutment, the greater
the base area. Depending on the crane boom length, there are support surfaces for the
boom installation. These surfaces and locations of auxiliary crane differ for each crane
configuration and can only be correct once the crane technology has been approved. In
general, the following applies: the taller the crane boom, the larger the support area.
4.5.
O&M BUILDING AREA
4.5.1. Office house
This is one-storey house, plan dimension (17.5x13.7) m2. Office house include the
function room as follow: Meeting room, Technology room, Expert room, General
room…. Foundation structure shall isolated footing foudations. Columns, beams, roofs
shall reinforced concrete grade B20 (M250), aggregate size 1x2cm, casted in place. Wall
shall be made of un-burnt brick with cement mortar M75. External wall and internal
wall shall be plastered mastic, applied emulsion paint. Ceramic size 400x400 shall be
tiled on the floor. The door and window shall made of aluminium frame, glass thickness
5mm. Reinforced concrete roof floor with sheet metal heat resistant.
4.5.2. Canteen house
This is one-storey house, plan dimension (9.2x12.0) m2. Foundation structure shall
isolated footing foundations. Columns, beams, roofs shall be made of reinforced
concrete grade B20, aggregate size 1x2cm, casted in place. Wall shall be made of unburnt brick with cement mortar M75. External wall and internal wall shall be plastered
mastic, applied emulsion paint. Ceramic size 400x400 shall be tiled on the floor. The
door and window shall be made of aluminium frame, glass thichness 5mm. Reinforced
concrete roof floor with sheet metal heat resistant.
4.5.3. Tenement house
This is one-storey house, plan dimension (13.5x27.5) m2. Foundation structure
shall isolated footing foundations. Columns, beams, roofs shall be made of reinforced
concrete grade B20, aggregate size 1x2cm, casted in place. Wall shall be made of unburnt brick with cement mortar M75. External wall and internal wall shall be plastered
mastic, applied emulsion paint. Ceramic size 400x400 shall be tiled on the floor. The
door and window shall be made of aluminium frame, glass thichness 5mm. Reinforced
concrete roof floor with sheet metal heat resistant.
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Technical Design
4.5.4. Storage house
This is one-storey house, plan dimension (6.6x23.3) m2. Foundation structure shall
isolated footing foundations. Columns, beams, roofs shall be made of reinforced
concrete grade B20, aggregate size 1x2cm, casted in place. Wall shall be made of unburnt brick with cement mortar M75. External wall and internal wall shall be plastered
mastic, applied emulsion paint. The main door using automatic rolling steel door, width
4.6m and hight 5.0m. Reinforced concrete roof floor with sheet metal heat resistant.
Make ground floor slope i=2% to drain oil on both sides, to prevent oil from
spreading around when there is an incident.
In the storage house, electricity storage room area (3.1x6.2) m2. The room wall
shall be built with un-burnt brick cement mortar M75, the wall foundation shall be made
of stone, the roof shall be made of reinforced concrete. The floor of the house shall be
poured with reinforced concrete grade B25 (M350) aggregate size 2x4, 150cm thick,
with air-conditioning. The door and window shall be made of aluminium frame, glass
thichness 5mm.
4.5.5. Waste house
This is one-storey house, plan dismension (5.0x5.0) m2. Wall foundation and
reinforcing concrete bracing grade B20 (M250) agg. 1x2cm, steel columns shall be on
the concrete foundation. Cover fences wire B40 with height of 1.5m. Floor shall be mad
of concrete B20 (M250) agg. 1x2cm thickness 150mm.
Around the floor, wall with height of 100mm shall be built to prevent the soil from
spreading, and make slope of i=2% on floor.
4.5.6. Guard house
This is one-storey house, plan dimension (2.8x2.8) m2. Foundation structure shall
isolated footing foundations. Columns, beams, roofs shall be made of reinforced
concrete grade B20, aggregate size 1x2cm, casted in place. Wall shall be made of unburnt brick with cement mortar M75, wall foundation shall be made of stone. Ceramic
size 400x400 shall be tiled on the floor. The door and window shall be made of
aluminium frame, glass thichness 5mm.
4.5.7. Garage
This is one-storey house, plan dimension (4.0x2.8) m2. Foundation structure shall
isolated footing foundations casted in-place reinforced concrete with grade B20, agg.
1x2cm. Ground floor shall be made of reinforced concrete grade B25, agg. 2x4cm,
casted in place, thickness 150mm. Frame shall be made of galvanized tubular steel, with
painting layers include 02 primer layers and 01 finished coat layer, roof slope at on side
and using galvanised purlin.
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Nhon Hoi Wind farm project – Phase I
Technical Design
4.5.8. Water tank support structure
Foundation structure shall isolated reinforcing foundation grade B20 (M250) agg.
1x2cm. Upperstructure shall be made of galvanized steel. Plan dimension (4.0x5.0)m2,
height of structure is 8m.
4.5.9. Ground water reservoir
The tank shall be made of reinforcing concrete grade B20 (M250) agg. 1x2cm.
The capacity of tank is (2.1x2.6x1.1)m3.
4.5.10. Water supply and drainage system
-
Water supply system: Water for domestic use shall be provided from well
underground water. After discharged water from the domestic water system
shall be stored in the ground water reservoir and pumped to the inox water tank
to serve for the control house and guard house. Before use, water must be tested
for physicochemical and microbiological criteria according to QCVN 01 & 02:
2009/BYT.
-
Drainage system: Rainwater is spilled over the surface of the concrete yard
towards the back of the house.
-
Watsewater: Fertilizer drainage system + primary compartment of the toilet
compartment, domestic drainage system inlet to the tank of the toilet, The
dishwashing water system before flowing into the tank will be passed through
the grease extraction tank.
4.5.11. Gate – fence, internal roads
4.5.11.1. Gate – fences
-
Gate: The main gate shall be designed as a sliding door on steel rails, the width
of 7.5m, driven open and closed by electric motors. Gate shall be made of shape
steel and flat steel painted rust layer and color layer. Gate pillar shall be made
by reinforced concrete B20 (M250) agg. 1x2.
-
Fences: Column of fences shall be made by reinforced concrete B20 (M250)
agg. 1x2, size 150x150, array 2.5m. Wall of fences shall be made by steel wire
B40 thichness 3mm, height 2m.
-
The total length of the gate and fence: 200m.
4.5.11.2. Yard and internal roads
-
The structure of the yard and the internal road surface shall be made of concrete
B25, agg. 2x4cm, thichness 150mm, make slope i = 2%. Area of Yard and
internal road: 1301.26 m2.
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Nhon Hoi Wind farm project – Phase I
4.6.
Technical Design
TECHINCAL INFRASTRUCTURE
The main technical infrastructure of the project includes:
4.7.
-
The internal road system connects the O&M building area and the Substation
for the plant operation and maintenance. Designed to ensure a slope and a
curvature radius for the transport of materials and equipment. (i) The road
system connects the O&M building area with the local road; (ii) The internal
road system connect the O&M building and the turbine towers with the
alphalted width of 4.5m, the surface of the road is paved with asphalt concrete.
Details are referred to section 4.7.
-
Electricity supply system for construction and daily activities: Power source for
construction shall be taken from local power source and diesel generator of
contractor.
-
Water supply system for the plant: Water for construction and daily activies
shall be taken from the local water supply unit and by well underground water
in the substation and O&M building area. The water source on the site must
meet quality requirements consistent with the technical and hygiene standards.
Water for the construction work such as mixing concrete, mixing mortar,
washing stone and gravel, casting reinforced concrete structures, building
bricks, plastering, must be clean, must not contain grease and acids. Water for
living must be pure, clean, free of microorganisms, up to the standards of
domestic water prescribed by the Ministry of Health.
-
Other technical infrastructure includes: Access road to the area of the O&M
building and substation: A traffic route connecting from the area of the O&M
building and substation to the local traffic works.
SOLUTIONS FOR ROAD PART
4.7.1. Overview of the road system
4.7.1.1. Main features of the road system
The transport of concrete, wind turbine equipment, as well as the transport of
cranes, along with their attached components, need to be carried out by heavy trucks,
super-long vehicles, super-heavy vehicles. Therefore, the road system needs to meet the
minimum requirements related to the transportation of materials and equipment such as
the load of the road, the width of the road, the curve radius of the road, ... transportation
and installation work at each wind turbine location as well as operation and maintenance
after the plant is put into operation.
4.7.1.2. Standard apply
Current design standards for highways in Vietnam.
Volume 1.1 – Chapter 4
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Nhon Hoi Wind farm project – Phase I
Technical Design
-
Highway − Specifications for design
: TCVN 4054-2005
-
Calculation of flood flow characteristics
: TCVN 9845:2013
-
Flexible pavement - Requirements and guidelines designed
-
Temporary regulations on the design of regular concrete pavement with joints in
: 22 TCN 211-06
the construction of transport works is issued together with Decision
No.3230/QĐ-BGTVT dated 14/12/2012 of the Ministry of Transport.
-
Bridge design standard
: 22 TCN 272-05; TCVN 11823:2017
-
National Technical Regulation on Traffic Signs and Signals: QCVN
41:2019/BGTVT.
4.7.1.3. Scale of design
The internal road system is designed with a scale equivalent to that of the
mountainous grade VI road according to the TCVN 4054-2005 standard, with the
following main parameters:
-
Speed of design: V = 20 km/h.
-
Width of the roadbed: 6.0 m; inside:
+ Width of pavement: 2 sides x 2. 5 m = 5.00 m (with widening in the curve,
ensuring vehicle width requirements as recommended by some equipment
suppliers, refer to some projects that have been implementing).
+ Width of shoulder: 2 sides x 0.5 m = 1.00 m (land shoulder).
-
Minimum radius Rmin = 30 m (ensure shipping equipment).
-
Maximum longitudinal gradient of imax = 10%; limited difficulty imax = 15% (due
to difficult terrain).
-
Pavement structure design load: 12T for vehicles with single axle.
-
Modular elasticity required of the pavement structure: Eyc  100 MPa.
-
Construction load design: HL93.
-
Frequency of designing roadbeds and drainage Constructions: 4%.
4.7.2. Design Solutions
4.7.2.1. Design the layout
Nhon Hoi Wind Farm Project – Phase 1 is connected to NH19B (at the existing
intersection of the planned route to Nhon Ly), the route (Road D1) basically follows the
planned route to Nhon Ly.
The layout of the route is designed on the principle of ensuring design standards
according to the procedures, rules and scale of the project, ensuring the vehicle runs
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Technical Design
safely and smoothly, minimizing the volume of construction and construction on road
and secure requests from the equipment carrier and supplier.
The roads in service of super-long and super-heavy vehicles for transporting
turbine construction equipment should ensure that the route ground must ensure that
these vehicles change smoothly at curved positions, following natural terrain to avoid
excavation deep and deep embankment, minimize the sections with large longitudinal
slope for convenient transportation.
Nhon Hoi Wind Farm Project – Phase 1, it is expected to use a vehicle with a Lift
truck to transport Blades with length L = 71m, so the internal roads are subject to the
minimum radius Rmin = 30 m is guaranteed to be eligible for shipping.
4.7.2.2. Profile design
Based on the results of hydrological survey and calculation, the longitudinal design
ensures that the shoulder height of the road is at least 0.5m higher than the water level
before the culvert (for terrain culverts):
-
Designing the maximum vertical slope of 15% to meet the transport
requirements (it is necessary to ensure the requirements of the type of road
surface for the large slope segments as recommended by some equipment
suppliers);
-
Design profile along the terrain to reduce the volume of earthwork;
-
The connection is consistent with the existing roads;
-
Ensure convenient transportation;
-
Ensure design elevation at drainage culverts.
Table 4.1: Summary table of internal road lengths
road
Length of
road (km)
Width of
roadbed
(m)
Width of
pavement
(m)
1
Road D1
2.16
6.0
4.5
2
Road D2
1.85
6.0
4.5
Internal road
3
Road D3
2.23
6.0
4.5
Internal road
4
Road D4
0.68
6.0
4.5
Internal road
5
Road D5
0.18
6.0
4.5
Internal road
Total
7.10
No.
Name of
Notes
Access road (Road
connecting with NH19B)
4.7.2.3. Cross section design
Volume 1.1 – Chapter 4
4-12
Nhon Hoi Wind farm project – Phase I
Technical Design
Scale of cross section are proposed as follows:
-
Part of vehicle passed: 2 x 2. 5 m = 5.00 m (with superelevation design
and expansion in the curves, ensuring the transport of super-long and superweight equipment).
-
Part of the land shoulder:2 x 0.5 m = 1.00 m.
-
Total:
= 6.00 m.
4.7.2.4. Roadbed design
Based on the geological survey data, the roadbed design solution is proposed as
follows:
- Embankment:
+ When the natural ground has a horizontal slope <20%, organic layer about 20cm
thick must be excavated before embankment.
+ When the natural ground has a horizontal slope ≥20%, it is required to dig the
grade about 2m wide before embankment.
+ The slope of the soil embankment is 1/1.5 (with turfing to protect the slope); the
stone embankment is 1/1.0.
+ Compacted requires Kyc ≥ 0.95.
- Excavation:
+ The slope of the excavation in layer 1:
1: 1.00.
+ The slope of the excavation in layers 2, 3, 4:
1: 0.75.
+ The slope of the excavation in layers 5:
1: 0.50.
+ Compacted requires Kyc ≥ 0.95.
4.7.2.5. Design of pavement structures
Nhon Hoi Wind Farm Project – Phase 1 uses 02 types of pavement structures to
meet the requirements of the type of road surface depending on the longitudinal slope
the recommendations of some equipment suppliers:
A. Structure A1 (applicable to segments with a longitudinal slope on the
straight line >10%, and on the curve >7%): top-to-bottom pavement
structure is as follows:
Concrete pavement is calculated with a design single-shaft load of 10 tons (of
which the heaviest shaft is designed to be 15 tons). The structure of the pavement from
top to bottom is as follows:
-
Cement concrete M300, 1x2 stone, thickness 22cm.
-
Oil paper lining.
Volume 1.1 – Chapter 4
4-13
Nhon Hoi Wind farm project – Phase I
Technical Design
-
Graded aggregate of class I, thickness 18cm, Dmax = 25 mm, designed to be 30cm
wider than the concrete pavement on each side.
-
Separation layer made of geotextile, using the type with tensile strength ≥
25kN/m (separating Graded aggregate of class I layer with sandy base, only for
segments passing sand base).
-
Capping layer K≥ 0.95.
B. Structure A2 (applicable to segments with a longitudinal slope on the
straight line ≤10%, and on the curve ≤7%): top-to-bottom pavement
structure is as follows:
The pavement is of Graded aggregate and Bituminous penetration, calculated for
single-axle vehicles with axle load of 12T, minimum required elastic modulus: Eyc ≥100
MPa. The structure of the pavement from top to bottom is as follows:
-
Bituminous penetration 2 layer, standard 4.0kg/m2 (including penetration and
stick bituminous standard 1.0 kg/m2).
-
Graded aggregate of class I (Dmax = 25mm), thickness 17cm (K≥ 0.98).
-
Graded aggregate of class II (Dmax = 37.5mm), thickness 18cm (K≥ 0.98).
-
Separation layer made of geotextile, using the type with tensile strength ≥
25kN/m (separating Graded aggregate of class I layer with sandy base, only for
segments passing sand base).
-
Capping layer K≥ 0.95.
4.7.2.6. Drainage works
4.7.2.6.1. Longitudinal ditch design
-
At the segments of excavation roads with vertical slope i ≤ 3%: design of
trapezoidal longitudinal drainage ditches with dimensions: 0.40m deep; face
above 1.20m; the bottom of 0.40m is not reinforced.
-
At the segments of excavation roads with vertical slope 3% < i ≤ 6% or the
segments excavation through the sandy ground: design of trapezoidal
longitudinal drainage ditches with dimensions: 0.40m deep; face above
1.20m; the bottom of 0.40m is reinforced with concrete B12.5 (M150),
thickness 15cm.
-
At the sections of excavation roads with vertical slope i > 6%: design of
trapezoidal longitudinal drainage ditches with dimensions: 0.40m deep; face
above 1.20m; the bottom of 0.40m is reinforced with concrete B12.5
(M150), thickness 15cm. In these ditch segments, there are staggered energy
Volume 1.1 – Chapter 4
4-14
Nhon Hoi Wind farm project – Phase I
Technical Design
dissipation edges 2m / location, energy dissipation edges with a thickness of
20cm.
4.7.2.6.2. Culvert design
Design solutions for drainage culvert across roads are as follows:
-
Culvert is permanently designed with design load HL93.
-
The culvert aperture is based on hydrological data and area's topography.
-
Structure of pipe culvert: culverts are made by centrifugal rotation technology
combined with vibration, culverts are made of reinforced concrete B22.5
(M300), the length of each culvert segments is from 2-4m. Culvert foundation,
head walls is made of concrete B15 (M200); wing walls, reinforced of culvert
yard by of mortared stonework B7.5 (M100).
-
Box culvert structure: culvert body is made of reinforced concrete M300.
Culvert heads and foundation are made of concrete B15 (M200); wing walls,
reinforced of culvert yard made of mortared stonework B7.5 (M100).
4.7.2.7. Intersection design
At these positions, only the design of linked claws connecting the pavement;
length, slope and radius of linked claws to ensure technical requirements and traffic
safety; pavement structure made with the main road structure.
4.7.2.8. Traffic safety design
Picket systems, signs, ... have the effect of guiding traffic and ensuring traffic
safety. The shape, specifications, size, color and location of the traffic safety system are
designed according to the “National Technical Regulation on Traffic Signs and Signals
QCVN 41:2019/BGTVT”.
4.8.
CIVIL SOLUTION FOR CABLE TRENCH
The 22kV underground cable is connected from the turbine to the poles of 22kV
overhead line. 22kV underground cable is arranged along the internal road, under the
road shoulder. Underground cable warning pickets are arranged along the cable route
and at the road crossings according to regulations.
Medium voltage underground cables and communication cables are put in HDPE
pipes of suitable cross section for protection.
The structure of the cable trench includes sand layer, brick layer, warning tape,
compacted soil layer K ≥ 0.95.
At cable trenches crossing the road, underground cables and communication cables
are put in steel pipes of suitable cross-sections and poured with concrete for mechanical
protection outside.
Volume 1.1 – Chapter 4
4-15
Nhon Hoi Wind farm project – Phase I
Technical Design
APPENDIX: LIST OF EQUIPMENT AND MATERIAL
NO.
ITEM
A
ELECTRICAL MATERIAL
I
WTG
1.
WTG 5MW and full of accessories:
UNIT
QUANTITY
Set
3
Set
3
NOTE
- 0.69/22kV – 5.5MVA transformer;
- RMU 22kV type 2 cabinets: 1
transformer cabinet, 1 feeder out;
- Auxiliary systems: Controlprotection, communication, SCADA,
auxiliary power, fire and fighting
system, lightning and grounding
system…
2.
WTG 5MW and full of accessories:
- 0.69/22kV – 5.5MVA transformer;
- RMU 22kV type 3 cabinets: 1
transformer cabinet, 1 feeder in, 1
feeder out;
- Auxiliary systems: Controlprotection, communication, SCADA,
auxiliary power, fire and fighting
system, lightning and grounding
system…
II
WTG’s grounding system
1.
Annealed bare copper wire 70mm2
m
1020
2.
Galvanized steel wire 16
m
2700
3.
Copper-plated steel rod
Rod
144
4.
Exothermic welding
Pcs
240
5.
Electric welding
Pcs
300
6.
Connecting steel bar
Pcs
300
III
Cable and fiber optic system
Volume 1.1 – Appendix
L=2.4m,
D=0.022
PL-1
Nhon Hoi Wind farm project – Phase I
Technical Design
NO.
ITEM
UNIT
QUANTITY
1.
Underground cable – 22kV – Al
3x120mm2
m
1133
2.
Underground cable – 22kV – Al
3x240mm2
m
1138
3.
1 phase 22kV terminal cable for
1x120mm2
Pcs
18
Cable
termination
4.
1 phase 22kV terminal cable for
1x240mm2
Pcs
24
Cable
termination
5.
Fiber optic 24 core singlemode
m
2000
6.
HDPE 260/200 conduit
m
1960
for
22kV
underground
cable
7.
HDPE 65/50 conduit
m
1960
for fiber optic
cable
8.
200 Steel conduit
m
40
for
22kV
underground
cable across road
9.
50 Steel conduit
m
40
for fiber optic
cable across road
IV
Power plant’s SCADA system
1.
Power plant control - PPC
System
01
2.
Fiber optic switch
System
02
3.
SCADA’s computer
System
01
4.
Power generation prediction system
System
01
B
EQUIPMENT AND MATERIAL OF CONSTRUCTION PART
I
Hardstand area part
1.
Volume of cutting organic layer
m3
7280.09
2.
Total volume of soil and rock
excavation
works:
leveling,
aggregates, drainages…
m3
63593.22
3.
Total volume of soil filling work
m3
15551.66
Volume 1.1 – Appendix
-
NOTE
Installed
in
110kV substation
PL-2
Nhon Hoi Wind farm project – Phase I
Technical Design
NO.
ITEM
UNIT
QUANTITY
4.
Gravel size Dmax=2.5cm spread the
hardstand area, storage area,…
m3
4472.31
5.
Cement concrete grade M150 for
drainage work
m3
112.5
II
O&M BUILDING PART
(i)
Infrastructure work
1.
Leveling work: excavation volume
m3
1612.8
2.
Leveling work: filling volume
m3
933.5
3.
Reinforcement of slope by stone
m3
323.0
4.
Drainage work: trench excavation
m3
1049.55
5.
Drainage work: length of filter pipe
PVCD60
m
191.0
6.
Drainage work: geotextile
m2
546.0
7.
Gravel size 1x2
m3
50.0
8.
Drainage ditch
m3
43.2
(ii)
Main structures in O&M building
area
9.
Office house
house
1
10. Canteen house
house
1
11. Tenement house
house
1
12. Storage house
house
1
13. Garage
house
1
14. Guard house
house
1
15. Water tank support structure
set
1
16. Ground water reservoir
tank
1
17. Gate, fence
system
1
18. Flower parterre
set
1
19. Waste house
house
1
20. Water supply system
system
1
21. Lighting and electrical supply system system
1
C
NOTE
INTERNAL ROAD
Volume 1.1 – Appendix
PL-3
Nhon Hoi Wind farm project – Phase I
NO.
ITEM
Technical Design
UNIT
QUANTITY
m
7,063
I
LENGTH
1
Length of road
II
ROADBED
1
Road excavation
m3
1.1
Excavation layer 1
m3
46,621
1.2
Excavation layer 2
m3
136,626
1.3
Excavation layer 3
m3
901
1.4
Excavation layer 4
m3
2,737
1.5
Excavation layer 5
m3
504
2
Ditch excavation
m3
-
2.1
Excavation layer 1
m3
944
2.2
Excavation layer 2
m3
1,310
2.3
Excavation layer 3
m3
33
2.4
Excavation layer 4
m3
89
2.5
Excavation layer 5
m3
63
3
Road shaping excavation
m3
-
3.1
Excavation layer 1
m3
3,891
3.2
Excavation layer 2
m3
6,320
3.3
Excavation layer 3
m3
95
3.4
Excavation layer 4
m3
355
3.5
Excavation layer 5
m3
70
4
Stripping, earth class of 2
m3
2,499
5
Stepped excavation, earth class of 3
m3
2,512
6
Roadbed earthfill; K≥ 0.95
m3
7
Roadbed rockfill; γ≥ 1.9 T/m3
m3
314
8
Compacted subgrade, thickness of
30cm; K≥0.95
m2
28,574
9
Sodding on embankment slope
m2
11,110
10
Clearance
m2
98,893
III
PAVEMENT STRUCTURE
Volume 1.1 – Appendix
NOTE
28,210
PL-4
Nhon Hoi Wind farm project – Phase I
Technical Design
NO.
ITEM
UNIT
QUANTITY
1
Concrete M300, 1x2 stone, thickness
22cm
m3
4,269
2
Oil paper lining
m2
21,540
3
Graded aggregate of class I, thickness
18cm, K≥ 0.98
m3
3,877
4
Bituminous penetration 2 layer,
standard
4.0kg/m2
(including
penetration and stick bituminous
standard 1.0 kg/m2)
m2
17,207
5
Graded aggregate of class I, thickness
17cm, K≥ 0.98
m3
2,925
6
Graded aggregate of
thickness 18cm, K≥ 0.98
II,
m3
3,097
7
Separation layers by Geotextile (on
sand base)
m2
13,488
IV
CULVERT
1
Reinforced concrete pipe culvert
Ø0.80m
pcs/m
11/137.5
2
Reinforced concrete pipe culvert
Ø1.00m
pcs/m
4/58
3
Reinforced concrete box culvert
2x2.5x2m
pcs/m
1/10
VI
LINING DRAINAGE DITCH
1
Shaping excavation of ditch, earth
class of 3
m3
2,646
2
Concrete M200 of longitudinal ditch,
stone 2x4
m3
2,732
3
Concrete M200 of energy dissipation
edge, stone 2x4
m3
27
VII
LINING STEPS DITCH
1
Shaping excavation of ditch, earth
class of 3
m3
90
2
Concrete M200 of ditch, stone 2x4
m3
98
class
-
-
-
VIII WATER STEPS
1
Shaping excavation of steps, earth
class of 3
Volume 1.1 – Appendix
NOTE
m3
198
PL-5
Nhon Hoi Wind farm project – Phase I
NO.
ITEM
Technical Design
UNIT
QUANTITY
2
Mortared stonework M100
m3
139
4
Blinding stone, thickness 10cm
m3
13
IX
TRAFFIC SAFETY
1
Picket
pcs
1,580
2
Traffic signs (triangle)
pcs
54
3
Direction signs
pcs
3
4
Auxiliary signs
pcs
24
Volume 1.1 – Appendix
NOTE
PL-6