Submarine cable laying for the second loop project

2022-07-24
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The power transmission capacity of Hainan Lianhe second loop project will be increased to 1.2 million KW

the power transmission capacity of Hainan Lianhe second loop project will be increased to 1.2 million KW

when the construction of Hainan pilot free trade zone and free trade port with Chinese characteristics is under way

Jinjiang, Hainan, February 3 (shaochangchun correspondent songyinguan, lipin, Zhuyu) on February 3, The second 500kV ultra-high voltage, long-distance and large capacity project in China with an average annual growth rate of 7% from 2015 to 2020 (hereinafter referred to as the Hainan secondary power connection project) has begun to lay submarine cables in the Qiongzhou Strait

it is reported that the project is expected to be completed and put into operation in April this year. At that time, Hainan Island and the mainland will realize double circuit road connection, further improve the power supply reliability of our province, and provide strong power support for the construction of Hainan free trade zone and free trade port

Hainan combined secondary circuit project is a key project in China. The project starts from Guangdong 500kV Zhanjiang Gangcheng substation and ends at Hainan 500kV Fushan substation. The most critical link of the project construction is to lay four ultra-high voltage submarine cables crossing the Qiongzhou Strait. The submarine cables are 500 kV oil filled paper insulated cables, with a single length of 32 km, a diameter of 14 cm, and no joint in the middle. It is the longest single 500 kV AC submarine cable in the world at present

it is reported that the submarine cable laying of Hainan Lianhe second loop project includes pre trenching, laying, flushing and burying, riprap protection and other links, and the laying operation is very complex. For the laying operation in the shoal section, the laying ship needs to stop at a place about 6km away from the shore to transfer part of the cables to another small barge, and then the small barge spits out the submarine cables from the stern of the ship and lays them along the pre dug trench to the shore. At a distance of about 1km from the coast, the submarine cables are hung on the floating ball, pulled ashore by the tractor on the shore, and then the floating ball is removed to make the cables sink into the cable trench for landfilling

the cable laying operation in the deep-sea section is much more difficult than that in the shoal. Due to the complex sea conditions and high winds and waves in Qiongzhou Strait, the average water depth is 44m, and the deepest reaches 110m. It is very difficult to safely lay the cable without joints to the seabed at one time

it is reported that the most advanced ship with dynamic positioning in the world is used for field operation in the deep-sea section, equipped with fully automated construction equipment such as underwater remote control robot and automatic positioning, to monitor the sailing speed of the ship, cable release speed and cable release position, and to control the water entry angle and laying tension of the cable, so as to avoid damaging the cable due to too small bending radius or too large tension

finally, after the submarine cable is placed at the established position, the stones are accurately thrown from the sea surface to the seabed to build a trapezoidal stone dam, such as wearing protective clothing and armor on the submarine cable to protect the submarine cable in an all-round way

the Hainan combined primary circuit project has ended the history of Hainan power island. On this basis, the Hainan combined secondary circuit project will increase the existing power transmission capacity from 600000 kW to 1.2 million KW, which will greatly reduce the risk of large-scale power outage in Hainan Island with frequent typhoons, and improve customers' sense of power acquisition and safe and reliable power use. Said chenkui, deputy general manager of Hainan lianerhui Project Management Co., Ltd

more importantly, the project will resolve the operation risks of Hainan electric power, meet the needs of safe and stable operation of multiple units of Changjiang nuclear power plant without smelling the pungent odor in the process of traditional plastic processing, further improve the interaction ability of clean energy in the five provinces and regions of southern electric power, continuously increase the consumption proportion of clean energy, support the construction of Hainan free trade zone and free trade port, and build a safe, green, intensive An efficient clean energy supply system provides strong power guarantee for the implementation of major strategies

it is understood that the project is jointly invested and constructed by Hainan provincial government, China Southern Power Corporation, China nuclear industry group and China Huaneng Group. In October 2015, the land part of the project broke ground in Chengmai, Hainan

according to the schedule, submarine cable laying and protection construction will be carried out from February 3 to April 30 this year, and continuous construction will be carried out during the Spring Festival

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