Design of Mooring Lines of Floating Offshore Wind Turbine in Jeju Offshore Area

2014 ◽  
Author(s):  
Hyungjun Kim ◽  
Joonmo Choung ◽  
Gi-Young Jeon
Keyword(s):  
Wind Turbine ◽  
Limit State ◽  
Design Procedure ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Ultimate Limit State ◽  
Mooring Lines ◽  
Offshore Area ◽  
Floating Offshore Wind Turbine ◽  
Wind Turbine System

This paper presents a mooring design procedure of a floating offshore wind turbine. The offshore environment data of Jeju south sea collected from Korea Hydrographic and Oceanographic Administration (KHOA) are used as environmental conditions for hydrodynamic analysis. A semi-submersible floating wind turbine system is considered based on Offshore Code Comparison Collaborative Continuation (OC4) DeepCWind platform and the National Renewable Energy Laboratory (NREL) 5MW class wind turbine. Catenary mooring with studless chain is chosen as the mooring system. Important design decisions such as how large the nominal sizes are, how long the mooring lines are, how far the anchor points are located, are demonstrated in detail. Considering ultimate limit state and fatigue limit state based on 100-year return period and 50 year design life, respectively, long-term predictions of breaking strength and fatigue are performed.

Coupled Dynamic Analysis for Multi-Unit Floating Offshore Wind Turbine in Maximum Operational and Survival Conditions

2015 ◽  
Author(s):  
H. K. Jang ◽  
H. C. Kim ◽  
M. H. Kim ◽  
K. H. Kim
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Time Domain ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Random Waves ◽  
Mooring Lines ◽  
Floating Offshore Wind Turbine ◽  
Coupled Dynamic Analysis ◽  
Floating Offshore Wind Turbines

Numerical tools for a single floating offshore wind turbine (FOWT) have been developed by a number of researchers, while the investigation of multi-unit floating offshore wind turbines (MUFOWT) has rarely been performed. Recently, a numerical simulator was developed by TAMU to analyze the coupled dynamics of MUFOWT including multi-rotor-floater-mooring coupled effects. In the present study, the behavior of MUFOWT in time domain is described through the comparison of two load cases in maximum operational and survival conditions. A semi-submersible floater with four 2MW wind turbines, moored by eight mooring lines is selected as an example. The combination of irregular random waves, steady currents and dynamic turbulent winds are applied as environmental loads. As a result, the global motion and kinetic responses of the system are assessed in time domain. Kane’s dynamic theory is employed to formulate the global coupled dynamic equation of the whole system. The coupling terms are carefully considered to address the interactions among multiple turbines. This newly developed tool will be helpful in the future to evaluate the performance of MUFOWT under diverse environmental scenarios. In the present study, the aerodynamic interactions among multiple turbines including wake/array effect are not considered due to the complexity and uncertainty.

Study on the Dynamic Response for Floating Foundation of Offshore Wind Turbine

2011 ◽  
Author(s):  
Yougang Tang ◽  
Jun Hu ◽  
Liqin Liu
Keyword(s):  
Wind Turbine ◽  
Wind Farm ◽  
Dynamic Responses ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Wave Load ◽  
Mooring Lines ◽  
Floating Foundation ◽  
Wind Turbine System ◽  
Sea Area

The wind resources for ocean power generation are mostly distributed in sea areas with the distance of 5–50km from coastline, whose water depth are generally over 20m. To improve ocean power output and economic benefit of offshore wind farm, it is necessary to choose floating foundation for offshore wind turbine. According to the basic data of a 600kW wind turbine with a horizontal shaft, the tower, semi-submersible foundation and mooring system are designed in the 60-meter-deep sea area. Precise finite element models of the floating wind turbine system are established, including mooring lines, floating foundation, tower and wind turbine. Dynamic responses for the floating foundation of offshore wind turbine are investigated under wave load in frequency domain.

Fatigue Analysis for Mooring System of a Spar-Type Floating Offshore Wind Turbine

2020 ◽  
Author(s):  
Xutian Xue ◽  
Xiaoyong Liu ◽  
Nian-Zhong Chen ◽  
Xifeng Gao
Keyword(s):  
Wind Turbine ◽  
Fatigue Analysis ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Safety Factors ◽  
Mooring Lines ◽  
Hydrodynamic Analysis ◽  
Floating Offshore Wind Turbine ◽  
Different Diameters ◽  
Rainflow Counting

Abstract This paper aims to perform a time-domain mooring fatigue analysis for a Spar-type floating offshore wind turbine operated in the South China Sea. Tension ranges of mooring lines are achieved from a hydrodynamic analysis where the effects of wind, wave and current are considered. A rainflow counting method is used to calculate the number of mooring tension cycles with corresponding ranges. The fatigue lives of mooring lines are then predicted by Palmgren-Miner’s rule according to T-N & S-N curves. A comparison of fatigue lives predicted by T-N & S-N curves-based approaches with/without considering safety factors is made. The results show that the T-N curves-based approach is more conservative than the S-N curves-based approach if safety factors are not considered in the two approaches, while the fatigue lives predicted by both approaches are in general comparable when the safety factors suggested by API and DNVGL are applied in the two approaches. A comparative study of three kinds of R4 grade studless mooring chains with different diameters (2.5-inch, 4-inch, 5-inch) is also conducted and the results show that the design with the 2.5-inch chain does not meet the fatigue requirements.

Dynamic Response of Spar-Type Floating Offshore Wind Turbine in Freak Wave

2019 ◽  
Author(s):  
Yougang Tang ◽  
Yan Li ◽  
Peng Xie ◽  
Xiaoqi Qu ◽  
Bin Wang
Keyword(s):  
Dynamic Response ◽  
Wind Turbine ◽  
Offshore Wind ◽  
Modulation Method ◽  
Power Coefficient ◽  
Offshore Wind Turbine ◽  
Floating Structure ◽  
Mooring Lines ◽  
Freak Wave ◽  
Floating Offshore Wind Turbine

Abstract Simulations are conducted in time domain to investigate the dynamic response of a SPAR-type floating offshore wind turbine under the scenarios with freak wave. Towards this end, a coupled aero-hydro numerical model is developed. The methodology includes a blade-element-momentum model for aerodynamics, a nonlinear model for hydrodynamics, a nonlinear restoring model of SPAR buoy, and a nonlinear algorithm for mooring cables. The OC3 Hywind SPAR-type FOWT is chosen as an example to study the dynamic response under the freak conditions, while the time series of freak wave is generated by the Random Frequency Components Selection Phase Modulation Method. The motions of platform, the tensions in the mooring lines and the power generation performance are documented in different cases. According to the simulations, it shows that the power coefficient of wind turbine decreased rapidly at the moment when freak wave acted on the floating structure.

scholarly journals A synthesis of feasible control methods for floating offshore wind turbine system dynamics

2021 ◽  
Vol 151 ◽  
pp. 111525 ◽  
Author(s):  
Kamran Ali Shah ◽  
Fantai Meng ◽  
Ye Li ◽  
Ryozo Nagamune ◽  
Yarong Zhou ◽  
...  
Keyword(s):  
System Dynamics ◽  
Wind Turbine ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Control Methods ◽  
Floating Offshore Wind Turbine ◽  
Wind Turbine System

scholarly journals Dynamic Response for a Submerged Floating Offshore Wind Turbine with Different Mooring Configurations

2019 ◽  
Vol 7 (4) ◽  
pp. 115 ◽  
Author(s):  
Yane Li ◽  
Conghuan Le ◽  
Hongyan Ding ◽  
Puyang Zhang ◽  
Jian Zhang
Keyword(s):  
Dynamic Response ◽  
Wind Turbine ◽  
Dynamic Responses ◽  
Offshore Wind ◽  
Mooring Line ◽  
Offshore Wind Turbine ◽  
Intermediate Water ◽  
Mooring System ◽  
Mooring Lines ◽  
Floating Offshore Wind Turbine

The paper discusses the effects of mooring configurations on the dynamic response of a submerged floating offshore wind turbine (SFOWT) for intermediate water depths. A coupled dynamic model of a wind turbine-tower-floating platform-mooring system is established, and the dynamic response of the platform, tensions in mooring lines, and bending moment at the tower base and blade root under four different mooring configurations are checked. A well-stabilized configuration (i.e., four vertical lines and 12 diagonal lines with an inclination angle of 30°) is selected to study the coupled dynamic responses of SFOWT with broken mooring lines, and in order to keep the safety of SFOWT under extreme sea-states, the pretension of the vertical mooring line has to increase from 1800–2780 kN. Results show that the optimized mooring system can provide larger restoring force, and the SFOWT has a smaller movement response under extreme sea-states; when the mooring lines in the upwind wave direction are broken, an increased motion response of the platform will be caused. However, there is no slack in the remaining mooring lines, and the SFOWT still has enough stability.

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