Study On Mooring System Of Spar Floating Foundation For Offshore Wind Turbine

As the change of the global energy structure and the increasing depletion of thefossil fuels, in recent years, wind energy as a kind of renewable green energy hasgradually come into people’s life. The development and utilization of wind energy hasbeen a very important approach of energy policy around the world. As an effectivedevelopment mode of wind energy utilization，wind power generation has been studiedby scholars from all the countries，and the world wind turbine industry has developedrapidly. But in recent years, with the construction of onshore and offshore wind farm，the environmental impact and low development benefit has been gradually exposed.With the rapid development of Marine Engineering Technology, for a solution to theproblem，People take location of offshore wind farm to the deeper sea. But as the costof traditional wind turbine increases rapidly with the deeper of water depth,, it isdifficult to get a large-scale development. In recent years, the development andutilization of floating wind power is becoming a hot topic of the research.Currently，for deep sea wind power development, the ability to design a suitableinfrastructure and its mooring system in a cost as low as possible is a pretty importantproblem related to the large-scale development of the floating wind turbine industry.The scholars from home and abroad have already done large research in regard to this，but what they focus on are the structure designs and response analysis of infrastructure，the study of mooring system for floating wind turbine is relatively less. As a veryimportant part of floating wind power structure, Mooring system’s investment costoccupies a great proportion in the offshore floating wind power cost. So the design ofMooring system plays an important role and has practical engineering significance tothe research of the Mooring system performance when the floating Offshore WindTurbine is designed. A3.6MW Spar floating foundation for offshore wind turbine in100m is studied inthis paper. The performance of its structure and mooring system are studied in order toreduce the structure motion and mooring tension shock. The main works are asfollows:1. Establish a hydrodynamic model of the infrastructure and calculate itshydrodynamic characteristics and motion performance with the3D potentialtheory in frequency domain. Then obtain its additional mass，additional damping，excited wave force under first order and the motion response transfer function.2. Two different types of mooring systems，the tension type and the catenary type，are been studied and calculated characteristics in time domain. Make the startingpoint of reducing the structure motion and mooring tension shock to contrast theperformance of the two types mooring system in. The study shows that foroffshore floating wind turbine, the tension mooring system has a betterperformance than the Catenary mooring system.3. The response of structural movement and mooring system under tension mooringsystem are been computational analyses in time domain. According to the futuresof the taut mooring system and beginning with the reduce of the structure motionresponse and mooring tension shock, to comparatively analyze the impact onMooring system performance from different mooring angle, different location ofmooring point and different pre tension.4. Design and manufacture the Spar type floating wind turbine foundation and themodel of its Mooring system, and do the model test under the load of waves andthe ocean current in Wave flume. Analyzing the impact on the performance of tautmooring system made by different pre-tightening force settings from the testingview, and comparatively analyzing the test results and simulation results.