Search results for "Shore"
showing 10 items of 263 documents
A framework for data integration of offshore wind farms
2013
Abstract Operation and maintenance play an important role in maximizing the yield and minimizing the downtime of wind turbines, especially offshore wind farms where access can be difficult due to harsh weather conditions for long periods. It contributes up to 25–30% to the cost of energy generation. Improved operation and maintenance (O&M) practices are likely to reduce the cost of wind energy and increase safety. In order to optimize the O&M, the importance of data exchange and knowledge sharing within the offshore wind industry must be realized. With more data available, it is possible to make better decisions, and thereby improve the recovery rates and reduce the operational costs. This …
Proactive maintenance of offshore wind turbine blades using knowledge-based force analysis
2013
The operation and maintenance (O&M) costs of wind turbines constitute approximately 10-15% of the lifecycle cost in onshore installations and up to 30% in offshore installations. The O&M costs for offshore wind power plants are higher than the onshore ones due to greater logistical challenges of maintaining and servicing, and the less mature state of offshore wind energy technology. Wind turbine blades suffer from various faults, for example, blade angle asymmetry, icing, and bends. These faults may cause wind turbines to a standstill. Replacement of rotor blades will normally result in a long downtime since the replacement process involves heavy transportation (vessel, crane) and dependenc…
Do small marinas drive habitat specific impacts? A case study from Mediterranean Sea.
2011
Many human activities add new structures to the marine landscape. Despite the fact that human structures cause some inevitable impacts, surprisingly little information exists on the effects of marina on natural marine assemblages. The aim of this paper is to assess habitat-specific response of benthic sessile organisms of rocky shores in relation to the presence of a small marina. Sampling was carried out at three coastal habitats (midshore, lowshore and subtidal) by means of visual censuses adopting an after-control-impact (ACI) experimental design. It appears that the marina affects the structure and composition of benthic communities of both the midshore and the lowshore. Little effect w…
Fault Diagnostics for Electrically Operated Pitch Systems in Offshore Wind Turbines
2016
This paper investigates the electrically operated pitch systems of offshore wind turbines for online condition monitoring and health assessment. The current signature based fault diagnostics is developed for electrically operated pitch systems using model-based approach. The electrical motor faults are firstly modelled based on modified winding function theory and then, current signature analysis is performed to detect the faults. Further, in order to verify the fault diagnostics capabilities in realistic conditions, the operating profiles are obtained from FAST simulation of offshore wind turbines in various wind conditions. In this way, the applicability of current signature analysis for …
A Two-Stage Fault Detection and Classification Scheme for Electrical Pitch Drives in Offshore Wind Farms Using Support Vector Machine
2019
Pitch systems are one of the components with the most frequent failure in wind turbines. This paper presents a two-stage fault detection and classification scheme for electric motor drives in wind turbine pitch systems. The presented approach is suitable for application in offshore wind farms with electric pitch systems driven by induction motors as well as permanent magnet synchronous motors. The adopted strategy utilizes three-phase motor current sensing at the pitch drives for fault detection and only when a fault condition is detected at this stage, features extracted from the current signals are transmitted to a support vector machine classifier located centrally to the wind farm. The …
An Exploratory Case Study of Offshore Outsourcing: Problems in Multicultural Settings
2014
Outsourcing means using factors which are external to an organization to perform its functions whereas offshore outsourcing relies on using foreign resources to perform those functions. We focus in this paper on offshore outsourcing of information systems (ISs). We have conducted an exploratory case study of outsourcing IS support services. The services have been outsourced by a supplier organization which has been based in Finland. Main parts of its customer support services have been allocated to so-called production centers, which have been located in three countries; Latvia, India, and the Philippines. We have gathered qualitative data from nine experts via theme-based interviews. The e…
Risk management in offshore outsourcing of software production using the ICT-supported unified process model: A cross-case study
2008
Successful execution of ICT-supported unified process of offshore outsourcing (ICT-SUPOO) of software development can offer various important benefits. However, ICT-SUPOO of software development is very complex and risky, and often fails. Almost no empirical studies are available on the risk factors that affect the ICT-SUPOO. The objective of this study is to investigate the key risk factors associated with ICT-SUPOO, understand how they create risks, and how the risks can be alleviated. We carry out a multiple case study from both of the vendorpsilas and clientpsilas sites, where professionals with extensive experience in managing offshore outsourcing of software development were interview…
H∞ static output-feedback control design with constrained information for offshore wind turbine system
2013
Abstract This paper deals with H ∞ static output-feedback control design with constrained information for offshore wind turbines. Constrained information indicates that a special zero–nonzero structure is imposed on the static output-feedback gain matrix. A practical use of such an approach is to design a decentralized controller for a wind turbine. This will also benefit the controller in such a way that it is more tolerant to sensor failure. Furthermore, the model under consideration is obtained by using the wind turbine simulation software FAST. Sufficient conditions to design an H ∞ controller are given in terms of Linear Matrix Inequalities ( LMI s ). Simulation results are given to il…
Wave Energy Assessment along Sicilian Coastline, Based on DEIM Point Absorber
2017
The use of renewable energy sources is one of the most relevant goals to be achieved in order to match the climate protection targets. As a case study, the paper shows the current electrical energy production by sources in the Sicilian context. Among the renewable energy sources, the paper investigates the wave energy potential along the Sicilian coasts, because of the favorable climate around the island. A point absorber is present in order to exploit this source. Two scenarios are presented, with two different levels of energy production.
Getting into the groove: Opportunities to enhance the ecological value of hard coastal infrastructure using fine-scale surface textures
2015
Concrete flood defences, erosion control structures, port and harbour facilities, and renewable energy infrastructure are increasingly being built in the world’s coastal regions. There is, however, strong evidence to suggest that these structures are poor surrogates for natural rocky shores, often supporting assemblages with lower species abundance and diversity. Ecological engineering opportunities to enhance structures for biodiversity conservation (and other management goals) are therefore being sought, but the majority of work so far has concentrated on structural design features at the centimetre–meter scale.\ud \ud We deployed concrete tiles with four easily-reproducible fine-scale (m…