OceanAlpha explains how China General Nuclear Power Group used an OceanAlpha M80 USV and Echoscope 4G version of Coda Octopus’ real-time 3D sonar to detect wind power pile foundations and submarine cables at the Ruhai Wind Farm.
Operation details:
The mother ship carries the OceanAlpha M80 USV to the survey area and releases the USV. With 3D real-time sonar, the OceanAlpha M80 USV surveys and detects the pile foundation and cable routing according to the planned mission route. The operator can receive the detection data sent back from the USV in real time through the private network on the mother ship.
Background:
China General Nuclear Power Group (CGN)’s Ruhai Wind Farm is located in the Yellow Sea in the east of Rudong, Jiangsu Province. It was officially operated on September 8, 2016. As the pile foundation erosion of wind farms and the partial exposure and suspension of submarine cables may easily affect the safety production of offshore wind power, pile foundation and submarine cable erosion detection should be carried out regularly in wind farms.
The traditional survey using workboats is costly and the detection process is affected by the size and draft of the workboat. It is difficult to operate manually when surveying between wind turbines because of collision risks and lower work efficiency. Therefore, a new type of survey solution is needed to meet the demand for wind farm surveys.
Solution:
CGN group adopted a OceanAlpha M80 USV and Echoscope 4G version of Coda Octopus’ real-time 3D sonar to detect wind power pile foundations and submarine cables.
The advantages of USVs for pile foundation and submarine cable detection include:
- Smaller hull size is flexible and efficient
- Intelligent collision avoidance, which reduces the risk of collision
- Accurate line tracking and reliable data quality
- No human wading risk
Survey work:
The OceanAlpha M80 USV can sail from the wharf or operate with the mother ship (operation and maintenance boat). Real-time data is sent via public network, private network, satellite communication, or the communication link between the booster station and the land. The operator can effectively support the pile foundation and cable scour detection of the wind power plant on the shore or on the mother ship.
Operation diagram
Survey process flow chart
The OceanAlpha M80 USV can sail autonomously according to the position of the pile foundation and the route of the sea cable, and the maximum deviation of the position is less than 1m. At the same time, the mission line can be saved for future survey and historical data comparisons.
USV survey and observation around the pile foundation
Results:
Conclusion:
This project is the first case in China where USVs have been used to survey pile foundations and submarine cable scour in wind farms. The USV’s characteristics of maneuverability, flexibility, and high safety can make up for the limitations of conventional survey platforms operating in complex environments and harsh waters, and solve traditional operational problems.
Compared with the maintenance work of a conventional workboat, USVs have higher positioning and control accuracy, and the flexible turning radius of the hull is small, meaning a lower risk of collision. The accurate line tracking performance increases survey efficiency.
In addition, the use of USVs for cooperative surveys can greatly improve efficiency and reduce carbon emissions. Taking an offshore wind farm survey mission with an area of 50 square kilometers as an example, with one mother vessel and four USVs surveying in a cooperative way, the overall survey time could decrease by 75% and reduce fuel consumption and carbon emissions by 83%.
In the future, USVs will better utilize the characteristics of intelligence, efficiency, precision and safety, carry out various tasks by carrying different loads, replace traditional manpower for high-intensity, high-risk and repetitive offshore operations, and promote the offshore wind power industry. Enter the era of intelligence and unmanned.
