Qualification of Dynamic Deep Water Power Cable

2010 ◽  
Author(s):  
Bjorn Roger Slora ◽  
Stian Karlsen ◽  
Sjur Lund ◽  
Per-Arne Osborg ◽  
Kristian Heide
Keyword(s):  
Deep Water ◽  
Power Cable ◽  
Water Power

Mechanical Qualification of Dynamic Deep Water Power Cable

2011 ◽  
Author(s):  
Roger Slora ◽  
Stian Karlsen ◽  
Per Arne Osborg
Keyword(s):  
Water Depth ◽  
Deep Water ◽  
Failure Modes ◽  
Electrical Power ◽  
Oil And Gas Industry ◽  
Electrical Heating ◽  
Power Cable ◽  
Water Power ◽  
System Integrity ◽  
Water Depths

There is an increasing demand for subsea electrical power transmission in the oil- and gas industry. Electrical power is mainly required for subsea pumps, compressors and for direct electrical heating of pipelines. The majority of subsea processing equipment is installed at water depths less than 1000 meters. However, projects located offshore Africa, Brazil and in the Gulf of Mexico are reported to be in water depths down to 3000 meters. Hence, Nexans initiated a development programme to qualify a dynamic deep water power cable. The qualification programme was based on DNV-RP-A203. An overall project plan, consisting of feasibility study, concept selection and pre-engineering was outlined as defined in DNV-OSS-401. An armoured three-phase power cable concept assumed suspended from a semi-submersible vessel at 3000 m water depth was selected as qualification basis. As proven cable technology was selected, the overall qualification scope is classified as class 2 according to DNV-RP-A203. Presumed high conductor stress at 3000 m water depth made basis for the identified failure modes. An optimised prototype cable, with the aim of reducing the failure mode risks, was designed based on extensive testing and analyses of various test cables. Analyses confirmed that the prototype cable will withstand the extreme loads and fatigue damage during a service life of 30 years with good margins. The system integrity, consisting of prototype cable and end terminations, was verified by means of tension tests. The electrical integrity was intact after tensioning to 2040 kN, which corresponds to 13 000 m static water depth. A full scale flex test of the prototype cable verified the extreme and fatigue analyses. Hence, the prototype cable is qualified for 3000 m water depth.

Long-term abrasion and corrosion damage to the Hawaii deep water power cable

2003 ◽  
Author(s):  
J. Larsen-Basse ◽  
B.E. Liebert ◽  
K.M. Htun ◽  
A. Tadjvar
Keyword(s):  
Deep Water ◽  
Corrosion Damage ◽  
Power Cable ◽  
Water Power

Risk Mitigation Through the Application of New Power Umbilical Technology

2012 ◽  
Author(s):  
Alan Dobson ◽  
Steven Frazer
Keyword(s):  
Aluminum Alloy ◽  
Deep Water ◽  
Risk Mitigation ◽  
Electrical Power ◽  
Structural Response ◽  
Power Cable ◽  
Enabling Technology ◽  
Effect Analysis ◽  
Design Case Study

This paper describes the substantial service life improvements that can be achieved through a new, high technology solution developed for deep water electrical power umbilical and cable applications. The new design represents an enabling technology for power cable projects in the deepest and most dynamic waters, provides a lower risk solution for risers in highly stressed conditions and can give a technically improved solution for the range of electrical power umbilical application. The significant advantages of aluminum alloy cable bundles over traditional copper cable bundles under static and dynamic loading associated with a typical deep water floating installation are presented. A design case study is used to illustrate improvements in structural response and fatigue life associated with the aluminum alloy cable cores against conventional technologies. The paper concludes with an overview of the associated risk reduction through the implementation of the aluminum alloy cables in the form of a failure mode and effect analysis.

A Novel Fatigue Stress Model of Power Phases and Coated Tubes in Deep-Water Power Cables, Umbilicals, and Power Umbilicals

2016 ◽  
Author(s):  
Magnus Komperød
Keyword(s):  
Real Life ◽  
Power Cable ◽  
The Novel ◽  
Power Cables ◽  
Insulation System ◽  
Fatigue Stress ◽  
Water Power ◽  
Significant Challenge ◽  
Deep Waters ◽  
Novel Model

Short fatigue life is a significant challenge for power cables, umbilicals, and power umbilicals to be installed in ultra-deep and hyper-deep waters. This paper presents a novel model for calculating fatigue stresses in conductors of power phases and in tubes with coating. The novelty is that the axial displacement of the conductor within the electric insulation system, or the tube within the sheath, is taken into consideration. For a real-life power cable designed for 2 300 m water depth, the novel model gives a reduction in fatigue stress of 69% compared to the traditional resultant-based approach for oscillations smaller than the slip curvature. This corresponds to a reduction in fatigue damage of more than 99%.

Design of Hawaii deep water +/- 250 KVDC power cable

1982 ◽  
Author(s):  
R. Traut ◽  
J. Soden ◽  
J. Kurt ◽  
G. Chapman ◽  
G. Okura
Keyword(s):  
Deep Water ◽  
Power Cable

Informing Components Development Innovations for Floating Offshore Wind Through Applied FMEA Framework

2020 ◽  
Author(s):  
Giovanni Rinaldi ◽  
Philipp Thies ◽  
Lars Johanning ◽  
Paul McEvoy ◽  
Georgios Georgallis ◽  
...  
Keyword(s):  
Deep Water ◽  
Failure Modes ◽  
Low Cost ◽  
Cost Savings ◽  
Offshore Wind ◽  
Mitigation Measures ◽  
Power Cable ◽  
Floating Platform ◽  
Potential Cost ◽  
Mooring Lines

Abstract Future offshore wind technology solutions will be floating to facilitate deep water locations. The EUH2020 funded project FLOTANT (Innovative, low cost, low weight and safe floating wind technology optimized for deep water wind sites) aims to address the arising technical and economic challenges linked to this progress. In particular, innovative solutions in terms of mooring lines, power cable and floating platform, specifically designed for floating offshore wind devices, will be developed and tested, and the benefits provided by these components assessed. In this paper a purpose-built Failure Modes and Effect Analysis (FMEA) technique is presented, and applied to the novel floating offshore wind components. The aim is to determine the technology qualification, identify the key failure modes and assess the criticality of these components and their relative contributions to the reliability, availability and maintainability of the device. This will allow for the identification of suitable mitigation measures in the development lifecycle, as well as an assessment of potential cost savings and impacts of the specific innovations. The methodology takes into account inputs from the components developers and other project partners, as well as information extracted from existing literature and databases. Findings in terms of components innovations, their main criticalities and related mitigation measures, and impacts on preventive and corrective maintenance, will be presented in order to inform current and future developments for floating offshore wind devices.

Benthic foraminiferal zonation in deep-water carbonate platform margin environments, northern Little Bahama Bank

1988 ◽  
Vol 62 (01) ◽  
pp. 1-8 ◽  
Author(s):  
Ronald E. Martin
Keyword(s):  
Deep Water ◽  
Benthic Foraminifera ◽  
Carbonate Platform ◽  
Sedimentary Facies ◽  
Depositional Environments ◽  
Near Surface ◽  
Sediment Gravity Flows ◽  
Gravity Flows ◽  
Platform Margin ◽  
Water Carbonate

The utility of benthic foraminifera in bathymetric interpretation of clastic depositional environments is well established. In contrast, bathymetric distribution of benthic foraminifera in deep-water carbonate environments has been largely neglected. Approximately 260 species and morphotypes of benthic foraminifera were identified from 12 piston core tops and grab samples collected along two traverses 25 km apart across the northern windward margin of Little Bahama Bank at depths of 275-1,135 m. Certain species and operational taxonomic groups of benthic foraminifera correspond to major near-surface sedimentary facies of the windward margin of Little Bahama Bank and serve as reliable depth indicators. Globocassidulina subglobosa, Cibicides rugosus, and Cibicides wuellerstorfi are all reliable depth indicators, being most abundant at depths >1,000 m, and are found in lower slope periplatform aprons, which are primarily comprised of sediment gravity flows. Reef-dwelling peneroplids and soritids (suborder Miliolina) and rotaliines (suborder Rotaliina) are most abundant at depths <300 m, reflecting downslope bottom transport in proximity to bank-margin reefs. Small miliolines, rosalinids, and discorbids are abundant in periplatform ooze at depths <300 m and are winnowed from the carbonate platform. Increased variation in assemblage diversity below 900 m reflects mixing of shallow- and deep-water species by sediment gravity flows.

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