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Zhenhua Heavy Industry builds the world's largest offshore converter station for shipment

Zhenhua Heavy Industry builds the world's largest offshore converter station for shipment

Column:Industry News    Date:2021/7/9 10:25:48    Viewed:

On July 8th, Shanghai Zhenhua Heavy Industry Group (Nantong) Co., Ltd. (Nantong Zhenhua Heavy Industry) held a delivery ceremony for the world's largest and Asia's first offshore converter station built by Zhenhua Heavy Industries, the Three Gorges Rudong Offshore Converter Station. Liu Chengyun, Party Secretary, Chairman and President of Zhenhua Heavy Industry, Qian Suoming, Deputy Chief Economist of Three Gorges Group, Fan Qiang, Vice President of China Classification Society, and Wang Hongtao, Deputy Mayor of Nantong City attended the ceremony and delivered speeches. Li Ruixiang, chief economist of Zhenhua Heavy Industry and general manager of converter station project, presided over the ceremony.

This is the largest offshore converter station in the world and Asia’s first offshore converter station so far built by Three Gorges Energy, China General Nuclear Power New Energy Holdings Co., Ltd. and Shanghai Zhenhua Heavy Industry (Group) Co., Ltd., invested by Yangtze Three Gorges Group Co., Ltd. Months of land construction have provided solid equipment and technical support for my country's entry into the field of far-reaching offshore wind power development.


The offshore converter station of Jiangsu Rudong Offshore (H6, H8, H10) wind power flexible DC transmission project is the first ±400kV flexible DC offshore power transmission project in China. The offshore converter station is the key core equipment for offshore wind power DC transmission, which is divided into foundation piles, There are three parts: jacket and upper module. The upper module is a seven-story building with a height of about 44 meters and a total weight of about 20,000 tons. The volume is the largest in the country.

The Three Gorges Rudong Offshore Converter Station is responsible for concentrating 1,100 megawatts of electricity from the three nearby wind farms (H6, H8, H10), converting it into direct current with lower loss, and transmitting it to land via submarine cable. It is China's first plus or minus 400 kV flexible DC transmission offshore wind power project, with a DC submarine cable transmission distance of about 100 kilometers, which is currently the domestic DC transmission submarine cable with the highest voltage level and the longest transmission distance. After the project is put into operation as a whole, it can provide annual electricity consumption of approximately 1.36 million households, effectively contributing to the "3060" dual-carbon target.


Liu Chengyun said in his speech that the Three Gorges Rudong Offshore Converter Station project has very high social and economic value, and provides equipment support for the development and construction of the national new energy industry and environmental protection. Zhenhua Heavy Industry is willing to work with various partners to grasp the development trend of new energy, give full play to professional advantages, integrate multiple resources, and write a new chapter for the development of the country's new energy industry with the responsibility and responsibility of a "big country and heavy weapon".

In his speech, Qian Suoming praised the company's spirit of defying difficulties and taking responsibility in the project. He said that the successful delivery of offshore converter stations is not only the implementation of the specific actions of the Three Gorges Group and its partners in implementing the carbon peak and carbon neutral goals proposed by General Secretary Jinping, but also an important sign to promote the accelerated development of my country's offshore wind power industry.

Fan Qiang said that China Classification Society, as one of the leading classification societies in the field of offshore engineering business, has accumulated rich engineering experience through a large number of project practices and established a complete offshore wind power-related technical standard system. China Classification Society is willing to work together with the industry to build an offshore wind power safety chain, and contribute to the construction of a “quality power” and “marine power”.

In his speech, Wang Hongtao emphasized that the offshore converter station project is of great significance to the construction of a higher value-added and more competitive 100 billion offshore wind power industry cluster in Nantong. The Nantong Municipal Government is willing to further strengthen cooperation with various enterprises, as always, provide the best environment and policies for the development of enterprises, and promote the realization of win-win cooperation in wind power and other fields.

Bao Delin, Deputy Secretary of the Party Working Committee and Director of the Management Committee of Nantong Development Zone, relevant persons in charge of Nantong Maritime Safety Bureau, Nantong Branch of Yangtze River Public Security Bureau, persons in charge of China Three Gorges Group and related units, CGN New Energy Jiangsu Branch, Nantong The relevant person in charge of the branch, the relevant person in charge of China Classification Society, the vice president of Zhenhua Heavy Industry Shan Jianguo, the company's converter station project general consultant Huang Hongyu, and the relevant person in charge of Longyuan Zhenhua jointly witnessed the delivery ceremony.


Customized solutions empower construction

"Offshore converter station is the key core equipment for offshore wind power DC transmission. There is currently no construction experience in the country. It is the first construction in the country." said Li Ruixiang, general manager of Zhenhua Heavy Industry Offshore Converter Station Project. The project is a short-term project. In order to advance the project on schedule, ZPMC's construction team planned in advance and discussed the construction plan with the owner many times. Finally, it abandoned the conventional building-building construction strategy with one-by-one loading and innovatively proposed "modules". The construction plan of “carrying and building in layers” means that after the first floor is loaded, the second and third floors are assembled together, and then assembled together. "Through the reasonable division and combination of modules, not only can dual-line construction and low-altitude operations be realized, but also efficiency can be greatly improved, ensuring the efficiency, integrity and economy of module loading." Zhenhua Heavy Industry Offshore Converter Station Project Implementation Manager Li Shuqing said that the program has significant advantages, but to achieve the desired benefits, it is inseparable from meticulous and careful construction deployment. "This is like playing a Rubik's Cube. If one step is wrong, it is likely to overturn the original plan. Cause more trouble."


On February 21, 2020, the project officially started. Each layer of modules needs to go through processes such as CNC cutting, prefabrication, sheet production, bulkhead installation, segmented pre-outfitting, and segmented coating. Through the introduction of BIM and other technologies, the project team realized the informatization, integration, visualization and intelligence of construction management and control, effectively advancing the project, and officially ushered in the superstructure outfield on July 28, 2020, ahead of the original plan For 4 days.

Module "suite" streamlined construction

There are two 3-story valve halls in the offshore converter station, which are mainly equipped with a series of high-precision equipment-converter valves. The total height of each valve hall is about 22.5 meters. These devices must be kept in a constant temperature and humidity environment for a long time. “Compared with the outside installation, the interior decoration of the valve hall is more difficult, and the requirements for safe construction management are also higher.” Xu Jingjing, the project safety director, said that if you want to have constant temperature and humidity conditions, you must install special films for noise reduction and heat insulation on the four walls. , This will definitely involve a lot of construction work of scaffolding.


As early as the beginning of the project construction, the project team held meetings and discussions on the scaffolding issues many times. After research and demonstration by technical experts, the project team finally finalized the "modular" scaffolding construction plan, that is, cantilevered scaffolds and upside down scaffolds are used for high-altitude operations. "That is to say, during the construction of the workshop or before the installation of the segmented module, the overhanging scaffolding in the platform-free area and the equipment cabin roof area is carried out to realize the segmental modularization of the scaffolding," explained Ji Qiubing, deputy project manager. This scheme realizes the synchronization of the interior decoration of the valve hall and the placement of high-precision equipment, which effectively saves the construction period and costs.

"One Hundred Meters Red Carpet" Helps Sliding On Board

The offshore converter station is about 213.7 meters away from the front yard of the Nantong Zhenhua Heavy Equipment Wharf. It will need to slide another 106.5 meters after boarding the ship. The project team of Zhenhua Heavy Industry Haifu Group customized the "100-meter red carpet" for the converter station-5 slide rails. After the tire frame of the final assembly was removed, the hydraulic windlass and the wire relay were used to help the converter station "walk" Go to the designated location at the front of the dock to achieve smooth boarding. "After receiving the project, we were under great pressure." Li Hui, manager of the offshore transportation and installation design department of Zhenhua Heavy Industry Marine Service Research Institute, said frankly that the project team must design an integrated DSF and final assembly transportation solution in a short time, and solve the problem. A series of problems that may arise in the process of moving, such as towing capacity, slippage correction, wharf load, ship load, ship condition monitoring, ship load adjustment, mooring and wind protection of the transport ship after the cargo is on the ship.


At 8:48 on the evening of July 4th, with the efforts of all the staff, in the final 17 days, the Three Gorges Rudong Offshore Converter Station slipped aboard the ship smoothly. The follow-up plan is to be shipped on July 10 for offshore float-over installation.

After the Three Gorges Rudong Offshore Converter Station arrives at the offshore wind power construction area, the next stage of on-site installation and other construction operations will start. At that time, Zhenhua Heavy Industry Haifu Group will adopt the first domestic heavy equipment high-position floating installation method to carry out offshore The millimeter-level precise docking realizes the smooth transfer of 10,000 tons of load.

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