Zhoushan, Zhejiang: Intertidal Zone Submarine Cable Survey Enters the Era of Unmanned Operation

Unmanned Aerial Vehicles, Unmanned Surface Vessels and Multimodal Technology Jointly Build a Safety Defense Line

Recently, on the coast of Zhujiajian, Zhoushan, Zhejiang, an amphibious unmanned aerial vehicle (UAV) equipped with a multi-beam detection system has attracted attention. The scientific and technological research team of State Grid Zhoushan Power Supply Company has successfully used this UAV to quickly locate the position of intertidal zone submarine cables in the target area.

The intertidal zone – a special area that is submerged and exposed by seawater twice a day – is known as a “no-go zone” for submarine cable operation and maintenance due to its extremely complex environment. According to statistics, the total length of China’s submarine cables has exceeded 2,000 kilometers, which undertakes the important task of power supply for many key islands in China. However, the traditional operation and maintenance mode has long been restricted by the lack of reliable detection methods: ships cannot pass in areas with water depth less than 3 meters; manual inspection has to wait for the low-tide window period, which only occurs a few days a month; and sonar detection effect is poor due to sediment coverage.

Since this year, State Grid Zhoushan Power Supply Company has actively carried out technological upgrading and unmanned operation for intertidal zone submarine cable detection, taking the lead in applying aeromagnetic detection technology to intertidal zone submarine cable positioning. By equipping UAVs with high-sensitivity magnetometers to capture the differences in magnetic field signals of energized submarine cables, and combining with the “acoustic-optical-magnetic” multimodal information fusion algorithm, the system can penetrate the shallow sediment layer, display the cable position in real time and plan the detection path. Actual tests show that the operation time, which traditionally took several days, has been shortened to several hours, and the coverage efficiency has been greatly improved.

This detection work adopts the innovative method of using amphibious UAVs equipped with multi-beam detection equipment. The UAVs have functions such as one-click autonomous cruising, intelligent obstacle avoidance and remote control, which can effectively reduce the risk of manual operation and ensure equipment safety, and can scan the submarine cable path, burial depth and surrounding terrain in real time. The single inspection time has been significantly reduced, achieving a breakthrough in the operation and maintenance of intertidal zone submarine cables and providing a new solution for the safe operation of marine energy channels.

The technological innovation in the operation and maintenance of intertidal zone submarine cables is not only a breakthrough in the power industry, but also a key step in marine energy development. With the subsequent delivery and commissioning of “Tan Hai” (meaning “Exploring the Sea”), China’s first professional unmanned surface vessel for submarine cable detection, State Grid Zhoushan Power Supply Company will deeply integrate UAVs, unmanned surface vessels and multimodal technology, and reshape the submarine cable operation and maintenance system with the “Intelligence +” model, laying a solid safety foundation for national strategic projects such as offshore wind power and cross-sea power grids. In the future, this “unmanned fleet” will sail to deeper and farther sea areas to guard the energy arteries and light up thousands of households. (By Zhang Cifeng, He Xutao, Xu Beibei)