Codeofchina.com is in charge of this English translation. In case of any doubt about the English translation, the Chinese original shall be considered authoritative.
This standard is developed in accordance with the rules given in GB/T 1.1-2009.
This standard was proposed by the China Machinery Industry Federation.
This standard is under the jurisdiction of SAC/TC 50 National Technical Committee on Wind Power Machinery of Standardization Administration of China.
Offshore Wind Turbine Generator Systems - Specification for Corrosion Protection
1 Scope
This standard specifies corrosion environment control of offshore wind turbine generator systems and regular corrosion protection methods for primary structural members and components (equipment) as well as relevant technical requirements.
This standard is applicable to corrosion protection design, construction, acceptance and operating maintenance of offshore wind turbine generator systems (hereinafter referred to as "turbine generator systems") and components.
This standard is not applicable to structures and foundations below offshore wind turbine generator system tower.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 470 Zinc Ingots
GB/T 1732 Determination of Impact Resistance of Film
GB/T 1733 Determination of Resistance to Water of Films
GB/T 1740 Determination of Resistance to Heat and Humidity of Paint Films
GB/T 1768 Method of Test for Abrasion Resistance of Paint Films
GB/T 1771 Paints and Varnishes - Determination of Resistance to Neutral Salt Spray (Fog)
GB/T 1865 Paints and Varnishes - Artificial Weathering and Exposure to Artificial Radiation - Exposure to Filtered Xenon-arc Radiation
GB/T 2423.4 Environmental Testing for Electric and Electronic Products - Part 2: Test Method - Test Db: Damp Heat, Cyclic (12h+12h Cycle)
GB/T 2423.16 Environmental Testing - Part 2: Test Methods - Test J and Guidance: Mold Growth
GB/T 2423.18 Environmental Testing - Part 2: Test Methods - Test Kb: Salt Mist, Cyclic (Sodium Chloride Solution)
GB/T 2694-2010 Specification of Manufacturing for Transmission Line Tower
GB/T 4208 Degrees of Protection Provided by Enclosure(IP Code)
GB/T 5210 Paints and Varnishes - Pull-off Test for Adhesion
GB/T 5267.4 Passivation of Corrosion-resistant Stainless-steel Fasteners
GB/T 6742 Paints and Varnishes - Bend Test (Cylindrical Mandrel)
GB/T 8923.1 Preparation of Steel Substrates before Application of Paints and Related Products - Visual Assessment of Surface Cleanliness - Part 1: Rust Grades and Preparation Grades of Uncoated Steel Substrates and of Steel Substrates after Overall Removal of Previous Coating
GB/T 8923.3 Preparation of Steel Substrates before Application of Paints and Related Products - Visual Assessment of Surface Cleanliness - Part 3: Preparation Grades of Welds Edges and Other Areas with Surface Imperfections
GB/T 9258.3 Coated Abrasives - Grain Size Analysis - Part 3: Determination of Grain Size Distribution of Microgrits P240 to P2500
GB/T 9274 Paints and Varnishes - Determination of Resistance to Liquids
GB/T 9278 Temperatures and Humidity for Conditioning and Testing of Paint Specimens
GB/T 9793-2012 Thermal Spraying - Metallic and Other Inorganic Coatings - Zinc, Aluminium and Their Alloys
GB/T 10125 Corrosion Tests in Artificial Atmospheres - Salt Spray Tests
GB/T 12608 Thermal Spraying - Wires, Rods and Cords for Flame and Arc Spraying - Classification and Technical Supply Condition
GB/T 13288.2 Preparation of Steel Substrates before Application of Paints and Related Products - Surface Roughness Characteristics of Blast-cleaned Steel Substrates - Part 2: Method for the Grading of Surface Profile of Abrasive Blast-cleaned Steel - Comparator Procedure
GB/T 13452.2 Paints and Varnishes - Determination of Film Thickness
GB/T 13912 Metallic Coatings - Hot dip Galvanized Coatings on Fabricated Iron and Steel Articles - Specifications and Test Methods
GB/T 16545 Corrosion of Metals and Alloys - Removal of Corrosion Products from Corrosion Test Specimens
GB/T 17850.1 Preparation of Steel Substrates before Application of Paints and Related Products - Specifications for Non-metallic Blast-cleaning Abrasives - General Introduction and Classification
GB/T 18570.3 Preparation of Steel Substrates before Application of Paints and Related Products - Tests for the Assessment of Surface Cleanliness - Part3: Assessment of Dust on Steel Surface Prepared for Painting (Pressure-sensitive Tape Method)
GB/T 18570.6 Preparation of Steel Substrates before Application of Paints and Related Products - Tests for the Assessment of Surface Cleanliness - Part 6: Extraction of Soluble Contaminants for Analysis - The Bresle Method
GB/T 18570.9 Preparation of Steel Substrates before Application of Paints and Related Products - Tests for the Assessment of Surface Cleanliness - Part8: Field Method for the Conductometric Determination of Water-soluble Salts
GB/T 18684 Specifications of Zinc/Chromate Coatings
GB/T 18838.1 Preparation of Steel Substrates before Application of Paints and Related Products - Specifications for Metallic Blast-cleaning Abrasives - General Introduction and Classification
GB/T 18839.2 Preparation of Steel Substrates before Application of Paints and Related Products - Surface Preparation Methods - Abrasive Blast-cleaning
GB/T 18839.3 Preparation of Steel Substrates before Application of Paints and Related Products - Surface Preparation Methods - Hand- and Power-tool Cleaning
GB/T 19355 Protection against Corrosion of Iron and Steel in Structures - Zinc and Aluminium Coatings - Guidelines
GB/T 23987 Paints and Varnishes - Exposure of Coatings to Artificial Weathering - Exposure to Fluorescent UV Lamps and Water
GB/T 26110 Specification of Zinc-aluminium Flake Coatings
GB/T 30790.1 Paints and Varnishes - Corrosion Protection of Steel Structures by Protective Paint Systems - Part 1: General Introduction
GB/T 30790.2 Paints and Varnishes - Corrosion Protection of Steel Structures by Protective Paint Systems - Part 2: Classification of Environments
GB/T 30790.4 Paints and Varnishes - Corrosion Protection of Steel Structures by Protective Paint Systems - Part 4: Types of Surface and Surface Preparation
GB/T 30790.5 Paints and Varnishes - Corrosion Protection of Steel Structures by Protective Paint Systems - Part 5: Protective Paint Systems
ISO 20340 Paints and Varnishes - Performance Requirements for Protective Paint Systems for Offshore and Related Structures
3 Terms and Definitions
For the purposes of this document, the terms and definitions given in GB/T 30790.1, GB/T 30790.2, GB/T 30790.4 and GB/T 30790.5 and the following apply.
3.1
corrosion environment
environment where one or more corrosive media exist
3.2
corrosion environment control
control of environmental factors (corrosive medium content, temperature, relative humidity, solar radiation and precipitation) which have important influence on corrosion rate aiming to reduce the environment corrosivity
3.3
labyrinth seal
seal type for preventing leaking through throttling effect generated when sealing medium passes through labyrinthic gap formed between ring seal teeth which are set around the rotating shaft and arranged in sequence
3.4
micro positive pressure seal
seal type for preventing outside air intruding into the relatively closed housing in which the treated outside air is filled so that the air pressure is slightly higher than the outside air pressure
4 General Provisions
4.1 Corrosion Environment
4.1.1 Main structures (tower and the structure above) and components of the turbine generator system is located in marine atmosphere, and the relevant corrosion environment is classified into out-housing area, in-housing area and dry-clear area by the annual corrosion rate of low carbon steel in atmospheric environment according to the provisions specified in GB/T 30790.2, see Table 1.
4.1.2 Components in dry-clear area shall be subjected to corrosion protection as specified for that not inferior to Corrosion Grade C3.
4.1.3 For hot and humid coastal areas, mass or thickness loss possibly exceed the limit for C5-M, thus special preventive measures shall be taken when coating protection system is selected for the structures used in such areas.
Table 1 Offshore Wind Turbine Generator Systems Corrosion Environment Area Division
Area name Environmental conditions Feature Example
Low carbon steel corrosion rate a
g/(m2·a) Corrosion grade
Dry-clear area ≤400 ≤C3 Not affected by natural climate, marine atmosphere and sea water; the moisture duration is short and the corrosive medium content is small Inside of the cabin where corrosion environment control measures are taken
In-housing area >400 and ≤650 C4 Connecting with marine atmosphere and free from the direct corrosion of sunshine, rain, snow, dew and other pollutants, and the moisture duration is long or/and the corrosive medium content is large Inside of wheel hub protected by housing, cabin and tower
Out-housing area >650 and ≤1,500 C5-M Exposed to marine atmosphere environment and directly corroded by sunshine, rain, snow, dew and other pollutants; temperature and humidity change greatly; the moisture duration is long and the corrosive medium content is large Outside of cabin and tower
a For the mass loss value of unit area after exposure for the first year, manufacture the low carbon steel standard specimen and determine the corrosion rate according to those specified Annex A.
4.2 General Corrosion Protection Measures
4.2.1 For corrosion protection system design service life, the design service life of turbine generator system shall be considered, and it should not be less than 25 years.
4.2.2 Sealing design shall be adopted for the overall structure of the turbine generator system, and corrosion environment control measures shall be taken inside of tower, cabin, wheel hub and generator (direct-drive turbine generator system) to maintain dry and clean air environment; the general corrosion protection measures are as follows:
a) For tower, the closed tubular structure should be adopted, and sealing treatment for flange connection surface such as coating sealant should be carried out during installation; sealing design shall be adopted for tower door, and isolating room should be arranged at inner side of the door to reduce outside air intrusion in door open/close process.
b) For cabin and hub, housing, which shall be designed to be a confined space as possible, made of corrosion resistant material should be adopted.
c) For direct-drive turbine generator system, its generator enclosure separately installed between cabin and wheel hub should be made of corrosion resistant material, and sealing design shall be adopted for generator body and cooling system.
4.2.3 For turbine generator system main structures and components, corrosion protection shall be carried out according to the corrosion grade of the areas they are located in; corrosion protection measures including but not limited to coating protection, thermal spraying metal protection, hot dip galvanizing protection, combined protection of metal coating and paint coating may be adopted.
4.2.4 The following measures shall be taken for structure and component design:
a) Reasonably select corrosion resistant material and painting protection according to the corrosion environment areas they are located in;
b) Use tubular members other than members of other shapes, and simplify the structure form;
c) Arrange drain hole and vent hole for space where water or moisture is possibly collected;
d) Minimize fitting surface and overlap surface, continuous weld shall be adopted for welded members and sealed by painting;
e) When shape and dimension change, arc transition shall be adopted, round angle design shall be adopted for edges and corners; stress corrosion shall be avoided and manufacturability for plating and painting shall be improved.
f) The same kind of metal material shall be selected for the same structure as possible to avoid galvanic corrosion.
Foreword i
1 Scope
2 Normative References
3 Terms and Definitions
4 General Provisions
4.1 Corrosion Environment
4.2 General Corrosion Protection Measures
5 Corrosion Environment Control
5.1 Measures
5.2 Requirements
6 Electrical Equipment Protection
6.1 Measures
6.2 Requirements
7 Steel Structural Member and Component Protection
7.1 Measures
7.2 Surface Treatment
7.3 Coating Material Protection
7.4 Thermal Spraying Metal Protection
7.5 Hot Dip Galvanizing Protection
7.6 Multi-coating Protection
8 Protection of Composite Material Parts
8.1 Protection of Blades
8.2 Protection of Cabin Cover and Air Deflector
9 Maintenance and Inspection
Annex A (Normative) Corrosion Rate Inspection
