Load analysis and comparison of different jacket foundations

As a country mostly surrounded by water, Korea plans to build a massive offshore wind farm off the west coast by 2019. Due to the different seabed condition, wind turbine with jacket foundation is considered as a suitable choice for the intermediate water depths so far. And preliminary work is necessary for the wind turbine manufactures. In this work, a 3-blade upwind, pitch controlled, variable speed 5 MW offshore baseline model is used. Two different Jacket foundations are designed for the water depth of 30 m. Using several load cases, the dynamic response of two kinds of jacket structures, are compared by modal analysis and dynamic analysis. The analysis results of the system natural frequencies, significant loads of different jacket members for both models are given in detail. This research gives a good knowledge of large scale offshore wind turbine in Korea for intermediate water depth.

► Two different types of jacket foundations are designed for Korean offshore wind farm.
► A fully coupled dynamic analysis is conducted based on Korean environmental conditions.
► Modal analysis and dynamic analysis are carried out to compare the dynamic response of two jacket foundations.
► Jacket support structure with Z-braces has a comparable dynamic properties w.r.t. X-braces for offshore wind turbine.