Presentations

Abstract

Today there is an emerging trend where more offshore wind farms are moving further offshore into deeper waters, the bottom fixed offshore substations are less feasible technically, logistically, and economically. There are quite a few pilot floating wind turbine projects in the world while there are no floating offshore substations except for one small Fukushima floating substation in Japan. For large commercial size floating wind farm projects in deep water areas, such as USA west coast, large size floating offshore substation (FOSS) is necessary to make the project viable. GE has worked with Genesis to develop a semi-submersible FOSS solution (810MW, HVAC) for USA west coast with 1100-mter water depth. This concept design is based on the metocean data in Morro Bay Area, California. The 1100-meter water depth and swell metocean (long period wave) give rise to extra technical challenges for floating OSS design, especially for the dynamic cable design. In addition to HV substation equipment qualification tests, the design of the entire floating offshore substation solution needs to be confirmed by a system level qualification test that includes a wave basin model test. The numerical simulations can be verified and validated by the wave basin model test results. Certain behaviour or phenomena, which may not be able to be simulated by the software, can also be observed by the wave basin model tests. The whole concept design process was approached in two phases: numerical concept design and analysis, and wave basin model test confirmation and validation. Physical wave basin model tests have been performed at Oceanide wave basin in 2023. This paper gives details of the scaled floating platform, the model test set-up configuration and instrumentation, and test procedure for the semi-submersible FOSS solution. System Identification Test results and overall model test conclusion summary are presented in this paper.