Reliability, availability and maintenance the development of offshore wind power has become a pressing modern energy issue in which the uk is taking a major. The offshore environment limits the accessibility to the wind turbines and subjects them to faster degradation processes than in onshore. Offshore wind turbines an overview sciencedirect topics. State of the art and technology trends for offshore wind.
Sand20080983 unlimited release printed february 2008. It is also a critical field to examine, as wind power experiences a high cost pressure, and the cost of service will raise as service moves further from shore. There is potential for more wind turbines to be erected in remote and offshore locations, to achieve a greater wind energy harvest, where the access to turbines for maintenance will be restricted. Wind turbine gearbox reliability database, condition. P j tavner, g j w van bussel, f spinato, machine and converter reliabilities in wts. Reliability, availability and maintenance the development of offshore wind power has become a pressing modern energy. Offshore availability reduces with wind speed 17 supergen wind training. The global wind industry has witnessed exciting developments in recent years. On maintenance optimization for offshore wind farms. Thus, operation and maintenance is more challenging and costly and represents a considerable share of the cost of energy. Reliability centered maintenance studies rcm codification systemising technical hierarchy for maintenance and spare parts. Their availability, reliability and the efficacy and costeffectiveness of the maintenance, needed to achieve that availability, are essential to improve offshore wind lifecycle costs and the future of this emerging industry. This depends upon the longevity of the wind turbines which make up offshore wind farms. Proceedings of ar2ts conference, loughborough, 2007.
A simply stated goal of this process is to better understand and to improve the operable reliability of wind turbine installations. Optimal redundancy and maintenance strategy decisions for. Windinlimits availability number of hours generating kw iv number of hours that the wind is between cutin and cutout3. In the present paper, the proven concept of reliabilitycentred maintenance rcm is applied to wind turbines.
Technical availability technical availability a tech is a variation of the timebased availability section2. Wind turbine technology for offshore locations availability, reliability and access. Availability, operation and maintenance costs of offshore. In section ii, the relevance of rcm in the context of databased maintenance management and the implemented analysis procedure are. Offshore wind turbines operate in a harsher environment than those onshore. In this paper, we propose an approach of joint redundancy and maintenance strategy optimization for offshore wind power converters, aiming to simultaneously determine the optimal allocation of redundant converters and the optimal threshold number of converters that are allowed to fail before sending a maintenance crew to the offshore platform.
Furthermore, access to offshore wind turbines is much more difficult. Introduction to wind turbines and their reliability. Nonetheless, a future offshore wind farm consisting of 200 turbines of 5 mw each will therefore need some 3000 offshore visits per year. An availability simulation is performed to compare the performance of the two service strategies. This thesis proposes decision models for cost efficient maintenance for offshore wind power systems. With rapid development of wind farms, many challenges have emerged with respect to the reliability and availability of the inservice equipment. This is heightening the need for accurate reliability predictions so that wind turbine availability and life can be predicted and reason. Our integrated ict monitoring system is an optimal solution for operating wind turbines. Additionally, with increasing size of wind turbine blades, both onshore and offshore, the serviceability and maintainability of the equipment poses its own unique challenge. Reliability, availability, maintainability ram for wind. In contrast, a wil form of calculation only considers the availability during times when the wind and temperature are within the turbines operating limits, and the grid and bop are available. Definitions of availability terms for the wind industry. Analysis of field failure data collected from various wind farm databases indicates that the power converters are among the most critical components in offshore wind turbines, since they suffer from a high failure rate. Review of design concepts, methods and considerations of.
Riskbased operation and maintenance planning for o. For offshore wind turbines especially the support structures and the foundation contribute. The paper uses an approach in which the design process of an owt is divided into three steps. A parametric whole life cost model for offshore wind farms. This chapter has presented the personnel, infrastructure and data issues associated with improving the maintenance, availability and reliability of offshore wind farms. The key factors are shown to be the training of staff, the availability of appropriate access infrastructure and the presentation of appropriate data from the wind farms to those staff to allow that costly. Reliabilitycentred maintenance for wind turbines based on. Typically, the communications link is a relatively. Maintenance of offshore wind farms located far from the. The economical benefits of condition based maintenance strategies are evaluated for drive train and for blades of wind turbines. High availability is crucial for the economics of any wind farm. Any repair is subject to weather and sea conditions, and in winter it may take weeks to access an offshore wind turbine tong, 2010. Their availability, reliability and the efficacy and costeffectiveness of the maintenance needed to achieve that availability, are essential to improve offshore wind lifecycle costs and the future of this emerging industry.
Offshore wind turbine reliability durham university. Nowadays commercial onshore wind turbines show very high availability levels. Reliability, availability and maintenance aspects of large. One efficient approach to enhance the reliability and availability of the wind power systems is through using a redundant converter design, in which a set of power. The dowec projects aims at implementation of large wind turbines in large scale wind farms. Pdf assessing offshore wind turbine reliability and.
Not only the installation is more difficult and more expensive but also building wind turbines offshore has a major. The contractual availability the size of the wind farm the number of turbines. A model is presented to optimize the inspection interval for the blade. The availability of a wind farm, defined as the percentage of time it is able to produce electricity, is a function of the reliability, maintainability and serviceability of the hard and software used in the whole system 2. It reveals an equal performance level together with a positive. Overview brief update on uk offshore wind power what we know about wind turbine availability and reliability, onshore.
It facilitates the management of power generation, monitors the status of wind turbine. Depending on the purpose of the availability definition, turbine availability may include faults, maintenance, delayed maintenance due to impeded access, lightning, and cable unwrapping. Given this large base of installed wind turbines, nrel is increasingly researching ways to increase wind turbine reliability, with the goal of minimizing maintenance costs, improving capacity factors, and ultimately driving down the. Availability of offshore wind farms wind turbine or wind farm availability is a timebased ratio of the amount of time a wind turbinefarm is ready to operate in a given time period divided by the total time. This depends primarily on high system reliability and adequate maintenance capability, with both being achieved within economic constraints on capital and operational costs. Keysan, in electrical drives for direct drive renewable energy systems, 20. The future will be even brighter with further reductions in capital and operation and maintenance costs, which can be accomplished with improved turbine reliability, especially when turbines are installed offshore. Key issues to be addressed for good economics of an offshore wind.
These calculations consider only downtime that is attributable to the reliability of the turbine itself. General descriptions on reliability assessment of wind turbines concentrating mostly on the structural components and application of structural reliability methods can be found in e. Assessing offshore wind turbine reliability and availability. Renewable energy series offshore wind turbines reliability, availability and maintenance this book intends to address these issues headon and demonstrate clearly to manufacturers, developers and operators the facts and figures of wind turbine operation and maintenance in the inclement offshore environment, recommending how maintenance should be done to achieve. Report on wind turbine subsystem reliability a survey of. B hahn, m durstewitz, k rohrig, relia bility of wind turbines, experiences. A reduction with a factor of 2 with regard to the present state of the art seems fairly easy achievable. Indirectly, the acceptance of windgenerated power by the financial and developer communities as a viable enterprise is influenced by the risk associated with the capital equipment reliability. Their availability, reliability and the efficacy and costeffectiveness of. The availability of wind turbines and wind farms will determine the energy impact they are able to. These models offer strong reliability and availability, ease of maintenance and. Operation and maintenance costs of offshore wind farms and.
Modelling and simulation of the operation and maintenance. Rams engineering in the development of offshore wind. In situations where both limited access and limited availability of maintenance equipment are at stake. Reliability, availability and maintenance aspects of largescale offshore wind farms. Operation and maintenance of offshore wind turbines are more difficult. With a proper service organisation and by ensuring that regular maintenance actions are quick and can be performed in time the operators of modern wind turbines show actual availability levels of 98% or sometimes even beyond 2.