The cost of underwater assets in offshore wind farms is relatively low compared with the total cost of offshore wind power projects

yet the quality of these assets is vital for safe and stable operation of the offshore wind farms. The quality issues that can arise with wind turbines

underwater steel structures and foundations of offshore substations

and submarine cables during the construction and operation and maintenance phases are analyzed. Based on cases from practical offshore wind power generation projects

the inspection requirements and methods stipulated by relevant standards are evaluated

and comprehensive and effective underwater inspection methods for various types of quality defects are put forward. These methods have been verified in real cases

forming industry standards and specifications

which provides significant technical guidance and reference value for quality control and operational maintenance of underwater assets in offshore wind farms.