Query: "acoustic emission location" and "cable"

title: A Mixed Integer Linear Programming approach to wind farm layout and inter array cable routing
abstract: A Mixed Integer Linear Programming (MILP) approach is proposed to optimize the turbine allocation and inter array offshore cable routing. The two problems are considered with a two steps strategy, solving the layout problem first and then the cable problem. We give an introduction to both problems and present the MILP models we developed to solve them. To deal with interference in the onshore cases, we propose an adaptation of the standard Jensen's model, suitable for 3D cases. A simple Stochastic Programming variant of our model allows us to consider different wind scenarios in the optimization. For the inter array cable routing, we propose a new MILP model able to deal with different constraints arsing in practical application, such as capacity limitations, substation limitations and non crossing constraints. Computational results on real world instances prove the practical viability of the approach.

title: Levelised cost of energy for offshore floating wind turbines in a life cycle perspective
abstract: This report presents a comprehensive analysis and comparison of the levelised cost of energy (LCOE) for the following offshore floating wind turbine concepts: Spar Buoy (Hywind II) Tension Leg Spar (SWAY) Semi Submersible (WindFloat) Tension Leg Wind Turbine (TLWT) and Tension Leg Buoy (TLB) The analysis features a generic commercial wind farm consisting of 100 five megawatt turbines, at a far offshore site in a Life Cycle Analysis (LCA) perspective. Data for existing bottom fixed turbines, both jacket and monopile concepts are used as reference values for adaptation to the generic wind farm parameters. The results indicate that LCOE values are strongly dependent on depth and distance from shore, due to mooring costs and export cable length, respectively. Based on the findings, depth is the dominant parameter to determine the optimal concept for a site. Distance to shore, Load Factor and availability are amongst the significant factors affecting the LCOE. The findings also indicate that LCOE of floating turbines applied in large scale and in intermediate depths of 50 150 m is comparable to bottom fixed turbines. Floating turbines for increasing depths generally experience increased LCOE at a lower rate than bottom fixed turbines. An optimal site, situated 100 km offshore would give LCOE in the range of EUR 82.0 EUR 236.7 per megawatt hour for the conceptual designs in this paper.

title: Sheath Loss Factors Taking Into Account the Proximity Effect for a Cable Line in a Touching Flat Formation
abstract: This paper presents the development of a correction coefficient for the International Electrotechnical Commission (IEC) Standard 60287 1 1 formula for the sheath loss factor of the middle cable in a touching flat formation. The solid sheaths are bonded and earthed at both ends of an electrical section. The reason for this correction is to take into account a nonuniform distribution of the losses within each sheath arising from the proximity effect. The coefficient is developed by using the filament method as well as the stochastic optimization algorithm based on differential evolution. The IEC formulae for the sheath loss factors of the outer cables, forming a part of the touching formation, do not need to be modified in order to consider the proximity effect.

title: Finite element formulation of the self excited forces for time domain assessment of wind induced dynamic response and flutter stability limit of cable supported bridges
abstract: In this paper it is shown how unsteady self excited aerodynamic forces modelled by rational functions can be introduced into a finite element beam model, using the nodal displacement degrees of freedom of the element to characterize the aeroelastic system. The time dependent part of the self excited forces is obtained introducing additional degrees of freedom in each node, the so called aerodynamic degrees of freedom. The stability limit and buffeting response obtained in the time domain, using different shape functions to discretise the self excited forces, are compared with results predicted by a traditional multimode approach. It is concluded that both the stability limit and the buffeting response can be obtained using this aeroelastic element, which implies that structural nonlinearities may be more easily introduced in time domain analysis of the wind induced buffeting response.

title: Time domain modeling of self excited aerodynamic forces for cable supported bridges: A comparative study
abstract: Prediction of the wind induced dynamic response of suspension bridges, emphasizing self excited forces, is discussed in this paper. The self excited forces have been modeled by two commonly applied unsteady models and an unsteady model introduced and explained in this article. A novel frequency independent approximation of the self excited forces, which for the suspension bridge considered provides results as accurate as those from the unsteady models, is also presented. An integration method that may reduce the number of time steps necessary to avoid amplitude and phase distortion of the self excited forces has been introduced and applied successfully in a comprehensive case study.

title: Power Cable Rating Calculations A Historical Perspective [History]
abstract: The thermal rating of power cables and wiring installations has received much attention since the advent of electricity in the late 19th and the early 20th centuries and today is still the subject of numerous scientific investigations. The first observations on this subject were made while the first electric telegraph systems and distribution lines for electric lighting were being developed by early pioneers in the 1820s and 1880s, respectively  One of the first publications on this subject was by Forbes in 1884  and by Kennelly in 1889 with his conference paper "Heating Conductors by Electric Currents"  Some years later, Kennelly published another paper, "On the Carrying Capacity of Electric Cables, Submerged, Buried, or Suspended in Air,"   and a book addressing the heating effects in currentcarrying conductors  During the same period, in 1894, Jenks coauthored a book, Electricity as a Fire Hazard  where he presents the state of the art on the development of design rules and guidelines for electric installations and also several definitions for the safe current carrying capacity of conductors on the basis of the publications of various authors such as A.E. Kennelly and E. Atkinson.

title: Short term monitoring of a cable stayed timber footbridge
abstract: Alvsbacka cable stayed timber bridge was built in 2010, over Skelleftea River in Sweden. Sensors were integrated at strategic locations of the bridge during the construction process. This paper explores the bridges' synchronized structural health monitoring system that consists of GNNS, force transducers, a weather station and wireless accelerometers. The initial results from short term monitoring are reported and correlation between deformation of the bridge and effect of temperature changes is emphasized. It is planned to perform long term monitoring for complete understanding of structural behaviour of the bridge.

title: Health monitoring of a cable stayed timber footbridge
abstract: This paper presents a structural health monitoring system to a timber bridge that will be built in Skelleftea during 2011. The bridge is a cable stayed timber footbridge spanning 130 meters. The main objectives of using the health monitoring system are to verify the structural design and the long term behavior of the bridge. The structural health monitoring system consists of GNSS receivers, MEMS accelerometers, laser positioning systems, wireless moisture content sensors, strain gauges and weather stations. The number of timber bridges has increased a lot in Sweden during the past 20 years. In general today the health of the bridges is assessed at regular intervals by visual inspections and if necessary some minor local tests. Continuous measurements could complement the inspections and provide a better basis for planning maintenance activities and evaluating the remaining service life. The overall objective of this project is to develop monitoring tools for timber structures to guide the planning of maintenance and to signal any urgent problems that should be addressed immediately. A timber footbridge will be built over the Skelleftea River in Sweden 2011. It is a cable stayed bridge with span 130 m. The building of this advanced timber structure gives an exclusive opportunity for testing and developing monitoring methods for timber structures. The monitoring of the bridge will contribute to wood research on specific areas such as durability of timber bridges and vibrations of wooden deck plates, but also to research on measurement and data transmitting techniques. This research project takes advantage in that the bridge is being built during the project period and that the measurements are planned in cooperation with manufacturers, builders and the owner. This gives the opportunity to install equipment during the construction of the bridge. In this way, the measurements will deliver

title: Distributed monitoring of deck strains for detection of cable damage in cable stayed bridges

title: Exploratory Topology Modelling of Form active Hybrid Structures
abstract: The development of novel form active hybrid structures (FAHS) is impeded by a lack of modelling tools that allow for exploratory topology modelling of shaped assemblies. We present a flexible and real time computational design modelling pipeline developed for the exploratory modelling of FAHS that enables designers and engineers to iteratively construct and manipulate form active hybrid assembly topology on the fly. The pipeline implements Kangaroo2's projection based methods for modelling hybrid structures consisting of slender beams and cable networks. A selection of design modelling sketches is presented in which the developed modelling pipeline has been integrated to explore the design space delineated by FAHS.