detailed scientific and technical contents
offshore wind farm's offshore wind measurement and experimental research work mainly includes the following research contents:
(1) offshore wind measurement research: site selection, exploration, design, installation, operation and maintenance of one tidal flat anemometer tower and two offshore anemometers towers (all of which are 7m high), and wind measurement data collection, research and evaluation for 1.5 years.
(2) Geological survey and pile foundation test: conduct geological survey and data collection on the tower foundation site, draw up the survey plan, undertake geological drilling, conduct on-site technical guidance, data processing, sample analysis, map drawing, technical report writing, etc. Carry out the pile sinking process test of offshore pile foundation, obtain the relationship between the number of blows and penetration in different strata and depths, comprehensively study and analyze the bearing capacity of pile foundation, and the corresponding relationship between high strain bearing capacity detection and bearing capacity.
(3) Study on sea conditions: Through experiments, surveys and data analysis, study the hydrological conditions of Xiangshui offshore (including the study of shallow sea environment, waves, currents and tidal levels), and study the influence of sea conditions on offshore wind resource evaluation and wind farm construction in combination with the construction and wind measurement of offshore wind towers.
(4) research and summary of process methods and standards: summarize various process methods and experience in exploration, testing, testing, construction and operation and maintenance; Conduct a preliminary study on relevant standards, regulations and norms.
(5) analysis and arrangement of other data: collection, arrangement and analysis of existing meteorological, marine, topographic and geological data along the coast of Xiangshui, Jiangsu Province and the measured data of onshore wind farms.
(6) Build one tidal flat anemometer tower and two offshore anemometer towers: the tidal flat anemometer tower adopts the welded structure of equilateral triangle steel pipe with pull anchor, and the tower and the pull anchor fiber rope adopt independent concrete foundation, with the tower height of 7m. The offshore anemometer tower adopts steel pipe pile foundation (the pile diameter is 6mm, the wall thickness is 16mm, the pile length is 5m, the quadrilateral layout and it inclines outward at 1:7) and four-column gradual truss tower structure. The tower and the pile foundation are connected by steel caps, the bottom of the tower is a square section with a side length of 3.2m, the top of the tower is a square section with a side length of .82m, and the tower is 7m high. The whole tower and the pile foundation are protected from corrosion by parts. Wind speed sensors are installed at 1m, 25m, 4m, 5m, 6m and 7m positions for tidal flat anemometer tower and offshore anemometer tower, with 2 sensors on each floor; Wind direction sensors shall be installed at 1m, 5m and 7m positions, one for each floor. 2# anemometer tower is equipped with 1 set of marine data observation equipment.
inventions and innovations
this project has overcome the difficulties of no similar projects for reference and lack of on-site data, and combined with previous research results, made innovations in the following aspects, and achieved good results.
(1) The design concept of transforming offshore construction into onshore has been innovatively realized
Different from the design concept of domestic existing offshore anemometer tower with cast-in-place concrete pile caps, the offshore anemometer tower in Xiangshui adopts the structural type of steel pile caps. Compared with the conventional concrete pile caps, the processes of offshore formwork erection, steel bar binding, concrete pouring and curing can be omitted, and the steel pile caps can be processed on land, which can save the construction time and reduce the use of large ships (offshore concrete mixer, large crane ship, etc.), greatly reduce the workload of offshore operations, shorten the construction time and save the construction cost, and has obvious advantages.
(2) The connection technology of pile body and pile cap with high-strength grouting material is adopted.
The structural type of steel pile cap has high requirements for the connection section. Through indoor tests and a lot of calculations, the connection type is mainly filled with high-strength grouting material. Through the calculation of standard method, the verification of finite element method and the field operation test, the overall stress of the connection section is good, which can meet the stress requirements of different environmental loads. The grouting connection structure studied has obtained the national utility model patent.
(3) A feasible method for detecting the bearing capacity of offshore pile foundation is put forward
Compared with onshore pile foundation, there are two major problems in offshore pile foundation detection: ① The offshore conditions are harsh and greatly affected by wind and waves, so it is difficult and costly to carry out static load test. ② Large ships are needed for high-strain hammering, which leads to high cost and difficult organization. During the construction of offshore anemometer tower, the similar stratum conditions of tidal flat wind farm are fully utilized, and the static load test, buried osmometer and high strain detection in different periods are adopted. It is preliminarily concluded that under this geological condition, the high strain detection bearing capacity at initial driving is about 6% of the final bearing capacity of pile foundation, and the high strain detection during piling can be used to calculate the final bearing capacity of pile foundation.
(4) The research methods of offshore wind resources assessment are complete, and the results are highly reliable
① As for the experimental methods, one tower and two sets of wind measuring equipment are used, and marine observation equipment is set up;
② In terms of data richness, two offshore anemometers and one tidal flat anemometer were arranged. Together with the meteorological data of five tidal flat anemometers and weather stations for nearly 3 years, the density of anemometers in this area is high, and the wind data and environmental data are complete and complete.
③ In the research method, mathematical statistics, comparative study and numerical simulation are used, and the calculation program is independently developed according to the calculation model.
this project uses these measured data to carry out research on the influence of environmental factors on wind data, the corresponding relationship between wind speed and tidal level, the corresponding relationship between sea surface roughness and wave height, and the comparison of sea-land wind. The research methods, technical routes and research contents are all adopted for the first time in China. The research results are highly reliable and have been used in the design of offshore demonstration fans.
(5) Exploratory research on wind measurement means has been carried out
According to the characteristics of wind resource assessment and the difficulty of offshore construction, the concept of movable anemometer tower has been put forward, and the research on key technologies such as structural design, in-place fixing technology and floating movement of movable anemometer tower has been completed, which provides a new structural type for offshore anemometer tower, which can further reduce the cost of wind measurement and has a good promotion prospect.
comprehensive comparison with similar research and technologies at home and abroad
Jiangsu Xiangshui offshore anemometer tower built in this project is the first and second truly offshore anemometer towers in Jiangsu offshore area (the third and fourth in China). At present, of the six offshore anemometer towers built in China, only the Xiangshui offshore anemometer tower of this project adopts steel platform structure and corresponding grouting connection method, which greatly reduces the offshore construction time and dependence on large offshore construction equipment. After technical novelty, the technical features such as the structural form of steel bearing platform of offshore anemometer tower, the connection between bearing platform and pile foundation with cement-based high-strength grouting material, and the structural design of movable anemometer tower have not been mentioned in domestic literature.
the research methods, technical routes and research contents of this project, such as the influence of environmental factors on wind data, the corresponding relationship between wind speed and tidal level, the corresponding relationship between sea surface roughness and wave height, and the comparison of land-sea wind, are adopted for the first time in China.
application of achievements and social and economic benefits
The site selection and initial design of anemometer tower were completed in April 27, offshore exploration was completed in May, construction drawing design was completed in June, offshore pile foundation construction, tower hoisting and instrument installation were carried out in August, wind data were sent back in March 28, and ocean observation data were sent back in July 28. By October 29, wind measurement was completed for 1.5 years.
The research results of this project provide detailed wind resource data, marine data, geological data and construction experience for reference for offshore wind farm construction. At present, Changjiang New Energy Company has built a 2MW offshore test fan in this area, and Three Gorges Corporation is carrying out the feasibility study design of offshore wind farm with a capacity of 2MW.
Problems that need to be solved in the transformation, popularization or industrialization of achievements
At present, the Interim Measures for the Administration of Offshore Wind Power Development and Construction in China have been promulgated and implemented, and offshore wind measurement will be gradually carried out. In order to promote the application of the research results of this project, publicity should be strengthened. Workflow of wind farm: wind direction and speed detection, keeping in touch with dispatching during shift, starting power generation, inspection records, equipment inspection, lubrication maintenance, fault handling, voltage transformation and boosting, monitoring and adjustment of power distribution instruments, grid-connected power transmission and power generation statistics.