Balance Control Of The Semi-submersible Floating Turbine Based On Long-term Performance

Wind energy is a pollution-free renewable energy source.With the rapid development of wind power technology and equipment in the world,wind power generation has become a new energy technology with the most extensive development conditions and commercial development prospects.With a coastli ne of 18,000 kilometers and an ocean area of about 3 million square kilometers,huge amounts of wind energy are contained in China,so there is ample scope for the development of abundant offshore wind energy.Shenzhen,as a coastal developed city,can use its offshore wind energy very effectively in the development of the city.Therefore,the research work of this paper revolves around how to improve the long-term performance of offshore wind turbines and provide a reasonable long-term performance evaluation of offshore wind turbines.This article first carries out a statistical analysis of the surrounding oceanic data in Shenzhen.The source of the data is the Ocean Back Report data fo r the past 24 years supported by waveclimate.com.First of all,the accuracy of the data was analyzed and compared with the wind-wave data provided by the Shenzhen Ocean Bureau in the past 2 years to ensure the reliability of the data.Then explore which edge distribution the wind speed,significant wave height,and wave period follow.Finally,we use the Copula function to fit the three-dimensional joint distribution of wind speed,wave height,and wave period.Calculating the performace of the turbine under all the oceanic stituations takes a long time.This chapter aim at finding an effective long-term performance evaluation of offshore wind turbines.Firstly,using the MDA method(maximum dissimilarity algorithm)to select the most representative 1000 sets of data from the database for 24 years.The data includes five variables such as w ind speed,wind direction,significant wave height,wave direction,and wave period.Based on the selected 1000 different operating conditions,do the batch calculations on the basis of OC4 Deep Cwind platform in FAST to obtain 11 turbine responses,including the mean value and standard deviations of pitch,roll,surge and sway of the platform,as well as the nacelle acceleration,tower base bending moment and power generation.Finally,the RBF interpolation meth od was used to reproduce the turbine response under all operating conditions for 24 yea rs.And set two downtime thresholds of the turbine according to the turbine response: the nacelle acceleration and platform pitch.Then explore the relationship between the two thresholds and tower base fatigue and turbine power generation respectively.Designed a set of control system for the OC4 Deep Cwind semi-submersible turbine.Firstly,explored the relationship between the movement of the ballast water inside the platform and the pitch angle of the platform.In order to increase its long-term performance and reduce the downtime of the turbine,the system can guarantee the platform pitch with in a certain threshold under different wind directions and wind speeds thought the movement of the ballast water.The results show that the ballast system can significantly adjust the pitch angle of the platform and reduce the bending moment at the tower base of the turbine.