An opportunistic maintenance strategy for offshore wind turbine based on accessibility evaluation

2019 ◽  
Vol 44 (5) ◽  
pp. 455-468
Author(s):  
Xie Lubing ◽  
Rui Xiaoming ◽  
Li Shuai ◽  
Hu Xin
Keyword(s):  
Wind Turbine ◽  
Preventive Maintenance ◽  
Wind Farm ◽  
Weather Conditions ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Maintenance Strategy ◽  
Offshore Wind Farm ◽  
Opportunistic Maintenance ◽  
Operation And Maintenance

The maintenance costs of offshore wind turbines operated under the irregular, non-stationary conditions limit the development of offshore wind power industry. Unlike onshore wind farms, the weather conditions (wind and waves) have greater impacts on the operation and maintenance of offshore wind farm. Accessibility is a key factor related to the operation and maintenance of offshore wind turbine. Considering the impact of weather conditions on the maintenance activities, the Markov method and dynamic time window are applied to represent the weather conditions, and an index used to evaluate the maintenance accessibility is then proposed. As the wind turbine is a multi-component complex system, this article uses the opportunistic maintenance strategy to optimize the preventive maintenance age and opportunistic maintenance age for the main components of the wind turbine. Taking the minimum expectation cost as objective function, this strategy integrates the maintenance work of the key components. Finally, an offshore wind farm is taken for simulation case study of this strategy; the results showed that the maintenance cost of opportunistic maintenance strategy is 10% lower than that of the preventive maintenance strategy, verifying the effectiveness of the opportunistic maintenance.

scholarly journals An Optimal Number-Dependent Preventive Maintenance Strategy for Offshore Wind Turbine Blades Considering Logistics

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Mahmood Shafiee ◽  
Michael Patriksson ◽  
Ann-Brith Strömberg
Keyword(s):  
Wind Turbine ◽  
Preventive Maintenance ◽  
Wind Farm ◽  
Turbine Blades ◽  
Optimal Solution ◽  
Optimal Number ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Model Parameters ◽  
Maintenance Strategy

In offshore wind turbines, the blades are among the most critical and expensive components that suffer from different types of damage due to the harsh maritime environment and high load. The blade damages can be categorized into two types: the minor damage, which only causes a loss in wind capture without resulting in any turbine stoppage, and the major (catastrophic) damage, which stops the wind turbine and can only be corrected by replacement. In this paper, we propose an optimal number-dependent preventive maintenance (NDPM) strategy, in which a maintenance team is transported with an ordinary or expedited lead time to the offshore platform at the occurrence of theNth minor damage or the first major damage, whichever comes first. The long-run expected cost of the maintenance strategy is derived, and the necessary conditions for an optimal solution are obtained. Finally, the proposed model is tested on real data collected from an offshore wind farm database. Also, a sensitivity analysis is conducted in order to evaluate the effect of changes in the model parameters on the optimal solution.

Fatigue Life Analysis of Offshore Wind Turbine Support Structures in an Offshore Wind Farm

2018 ◽  
Author(s):  
Bryan Nelson ◽  
Yann Quéméner
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farm ◽  
The Body ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Analysis Tool ◽  
Support Structures ◽  
Offshore Wind Farm ◽  
Actuator Disk

This study evaluated, by time-domain simulations, the fatigue lives of several jacket support structures for 4 MW wind turbines distributed throughout an offshore wind farm off Taiwan’s west coast. An in-house RANS-based wind farm analysis tool, WiFa3D, has been developed to determine the effects of the wind turbine wake behaviour on the flow fields through wind farm clusters. To reduce computational cost, WiFa3D employs actuator disk models to simulate the body forces imposed on the flow field by the target wind turbines, where the actuator disk is defined by the swept region of the rotor in space, and a body force distribution representing the aerodynamic characteristics of the rotor is assigned within this virtual disk. Simulations were performed for a range of environmental conditions, which were then combined with preliminary site survey metocean data to produce a long-term statistical environment. The short-term environmental loads on the wind turbine rotors were calculated by an unsteady blade element momentum (BEM) model of the target 4 MW wind turbines. The fatigue assessment of the jacket support structure was then conducted by applying the Rainflow Counting scheme on the hot spot stresses variations, as read-out from Finite Element results, and by employing appropriate SN curves. The fatigue lives of several wind turbine support structures taken at various locations in the wind farm showed significant variations with the preliminary design condition that assumed a single wind turbine without wake disturbance from other units.

scholarly journals Maintenance Optimization of Offshore Wind Turbines Based on an Opportunistic Maintenance Strategy

Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2650 ◽  
Author(s):  
Lubing Xie ◽  
Xiaoming Rui ◽  
Shuai Li ◽  
Xin Hu
Keyword(s):  
Wind Turbines ◽  
Preventive Maintenance ◽  
Weather Conditions ◽  
Offshore Wind ◽  
Maintenance Optimization ◽  
Maintenance Strategy ◽  
Distribution Method ◽  
Opportunistic Maintenance ◽  
Maintenance Costs ◽  
Offshore Wind Turbines

Owing to the late development of offshore wind power in China, operational data and maintenance experience are relatively scarce. Due to the harsh environmental conditions, a reliability analysis based on limited sample fault data has been regarded as an effective way to investigate maintenance optimization for offshore wind farms. The chief aim of the present work is to develop an effective strategy to reduce the maintenance costs of offshore wind turbines in consideration of their accessibility. The three-parameter Weibull distribution method was applied to failure rate estimation based on limited data. Moreover, considering the impacts of weather conditions on the marine maintenance activities, the Markov method and dynamic time window were used to depict the weather conditions. The opportunistic maintenance strategy was introduced to cut down on the maintenance costs through optimization of the preventive maintenance age and opportunistic maintenance age. The simulation analysis we have performed showed that the maintenance costs of the opportunistic maintenance strategy were 10% lower than those of the preventive maintenance strategy, verifying the effectiveness of the proposed maintenance strategy.

Feasibility study of offshore wind turbine substructures for southwest offshore wind farm project in Korea

2015 ◽  
Vol 74 ◽  
pp. 406-413 ◽  
Author(s):  
Wei Shi ◽  
Jonghoon Han ◽  
Changwan Kim ◽  
Daeyong Lee ◽  
Hyunkyoung Shin ◽  
...  
Keyword(s):  
Wind Turbine ◽  
Feasibility Study ◽  
Wind Farm ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Offshore Wind Farm

scholarly journals Research on a Comprehensive Maintenance Optimization Strategy for an Offshore Wind Farm

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 965
Author(s):  
Yang Lu ◽  
Liping Sun ◽  
Yanzhuo Xue
Keyword(s):  
Wind Farm ◽  
Wind Farms ◽  
Weather Conditions ◽  
Offshore Wind ◽  
Monte Carlo Algorithm ◽  
Maintenance Cost ◽  
Offshore Wind Turbine ◽  
Offshore Wind Farm ◽  
Proposed Model ◽  
Maintenance Activities

Offshore wind is considered a crucial part in the future energy supply. However, influenced by weather conditions, the maintenance of offshore wind turbine system (OWTs) equipment is challenged by poor accessibility and serious failure consequences. It is necessary to study the optimized strategy of comprehensive maintenance for offshore wind farms, with consideration of the influences of incomplete equipment maintenance, weather accessibility and economic relevance. In this paper, a Monte Carlo algorithm-improved factor is presented to simulate the imperfect preventive maintenance activity, and waiting windows were created to study the accessibility of weather conditions. Based on a rolling horizon approach, an opportunity group maintenance model of an offshore wind farm was proposed. The maintenance correlations between systems and between equipment as well as breakdown losses, maintenance uncertainty, and weather conditions were taken into account in the model, thus realizing coordination of maintenance activities of different systems and different equipment. The proposed model was applied to calculate the maintenance cost of the Dafengtian Offshore Wind Farm in China. Results proved that the proposed model could realize long-term dynamic optimization of offshore wind farm maintenance activities, increase the total availability of the wind power system and reduce total maintenance costs.

scholarly journals Assessing offshore wind turbine reliability and availability

2017 ◽  
Vol 233 (1) ◽  
pp. 267-282 ◽  
Author(s):  
Iraklis Lazakis ◽  
Maria A Kougioumtzoglou
Keyword(s):  
Wind Turbine ◽  
Wind Farm ◽  
Bayesian Belief Networks ◽  
Hazard Identification ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Operation And Maintenance ◽  
Integrated Risk Analysis ◽  
Main Components ◽  
Criticality Analysis

The renewables sector and particularly offshore wind energy is a fast developing industry over the last few years. Especially, activities related to the installation, and operation and maintenance of offshore wind turbines become a challenging task with inherent risks. This article assesses the risks related to the above stages of a wind farm lifecycle using the failure mode, effects and criticality analysis and hazard identification methods. All works, from installation to operation and maintenance, are considered together with the wind turbine main components. An integrated risk analysis methodology is presented addressing personnel Safety (S), Environmental impact (E), Asset integrity (A), and Operation (O). The above is supplemented by a cost analysis with the aid of Bayesian belief networks method to assist the decision-making process related to installation, and operation and maintenance tasks. All major risks and critical wind turbine components are identified as well as measures are suggested to prevent or mitigate them. Moreover, inspection and maintenance plans are elaborated in general for the mentioned activities.

Hydrodynamic and Aerodynamic Loads on the Behaviour of Offshore Wind Farm

2011 ◽  
Author(s):  
Wei Gong
Keyword(s):  
Wind Turbine ◽  
Wind Farm ◽  
Wave Theory ◽  
Wind Load ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Offshore Wind Farm ◽  
Wave Load ◽  
Aerodynamic Loads ◽  
Load Models

Renewable energy provides a solution for complex current and future social and environmental problems whereas offshore industry has a large potential for providing renewable energy for future. Currently, offshore technology making use of wind for energy generation purpose becomes a hot spot with highly advanced research and development going on on one side and complex and critical problems present and difficult to solve on the other. This paper is trying to study problems related to the quantification of the hydrodynamic and aerodynamic loads for the design of offshore wind turbine support structures in the offshore wind farm. Both the hydrodynamic and aerodynamic conditions in the offshore site are extremely complex resulting in the difficulty of reasonable determination for the external loads on the wind turbine support structures. However, due to the increasing global demands for future energy solution, the design, analysis and optimization of offshore wind turbine is nevertheless an important issue. The paper first gives an introduction of the offshore wind farm and the complexity of the offshore environment. Wave load is explored with introduction of existing wave load models, comparison of their characteristics while the focus is placed on the nonlinear wave load by means of the Stokes higher order wave theory. Properties of a single regular wave based on methods of linear wave theory and Stokes higher order wave theory are compared which lead to differences in the results of wave load models when these two different methods are used. Wind load model is introduced briefly, followed by the introduction of current methods for determination or approximation of combined wave and wind load and also recommendations for practice. Park effect of the wind load and wave load is also introduced at limited depth in the latter stage as a direction for future research. Conclusion and recommendations based on all the above are therefore given at the last section of the paper.

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