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DNVGL-RP-0360 Subsea Power Cables in Shallow Water

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DNVGL-RP-0360 Subsea Power Cables in Shallow Water RECOMMENDED PRACTICE DNVGL-RP-0360 Edition March 2016 Subsea power cables in shallow water The electronic pdf version of this document found through http://www.dnvgl.com is the officially binding version. The documents are available free of charge in PDF format. DNV GL AS FOREWORD DNV GL recommended practices contain sound engineering practice and guidance. © DNV GL AS March 2016 Any comments may be sent by e-mail to [email protected] This service document has been prepared based on available knowledge, technology and/or information at the time of issuance of this document. The use of this document by others than DNV GL is at the user's sole risk. DNV GL does not accept any liability or responsibility for loss or damages resulting from any use of this document. CHANGES – CURRENT General This document supersedes DNV-RP-J301, February 2014. Text affected by the main changes in this edition is highlighted in red colour. However, if the changes involve a whole chapter, section or sub-section, normally only the title will be in red colour. On 12 September 2013, DNV and GL merged to form DNV GL Group. On 25 November 2013 Det Norske Veritas AS became the 100% shareholder of Germanischer Lloyd SE, the parent company of the GL Group, and on 27 November 2013 Det Norske Veritas AS, company registration number 945 748 931, changed its name to DNV GL AS. For further information, see www.dnvgl.com. Any reference in this document to “Det Norske Veritas AS”, “Det Norske Veritas”, “DNV”, “GL”, “Germanischer Lloyd SE”, “GL Group” or any other legal entity name or trading name presently owned by the DNV GL Group shall therefore also be considered a reference to “DNV GL AS”. Changes – current Main changes March 2016 •Sec.1 General — [1.2.3] Addition of the DNVGL-ST-0126 as informative standard. — [1.2.4] Addition of the DNVGL-RP-0005/RP-C203 and CIGRÉ Technical Brochure 610 and 623 as informative guidelines. — [1.2.5] Addition of the guidance of CBRA methodology as informative reference. — [1.3.2] Revision of the definitions “bird caging”, “sealing” and “trenching”. Addition of the definition “departure angle”. • Sec.3 Concept development — [3.2.4.2] Addition of the guidance notes regarding cable design and removing the use of up-rating / de- rating factors for current rating. • Sec.4 Design — [4.6.3.2] Addition of CBRA methodology for determining the burial depth. — [4.7.4.7] Addition of the requirement on corrosion protection. • Sec.6 Installation — [6.1.2] Addition of the guidance note regarding possible change of installation sequencing. [6.2.4.2] Addition of the guidance note regarding minimum clearances between the anchors and the subsea infrastructure. • Sec.7 Operation and maintenance — [7.3.3] Addition of recommendation for recording the as-built positions of cables. — [7.5.3] Addition of recommendation for fault location methods. In addition, the layout of this document has been converted to layout for DNV GL service documentation. Editorial corrections In addition to the above stated main changes, editorial corrections may have been made. Recommended practice, DNVGL-RP-0360 – Edition March 2016 Page 3 DNV GL AS Acknowledgement This recommended practice was developed by a Joint Industry Project (JIP). The work was performed by DNV and discussed in regular project meetings and workshops with individuals from the participating companies. They are hereby acknowledged for their valuable and constructive input. In case consensus has not been achievable, DNV has sought to provide acceptable compromise. Sponsors of the JIP included the following organisations: Bohlen & Doyen Boskalis Offshore DONG Energy Electrabel GDF SUEZ Iberdrola S.A. Inch Cape (Repsol, EDPR) JDR Cable Systems Norddeutsche Seekabelwerke Offshore Marine Management Siem Offshore Contractors Tekmar Energy Tideway Offshore Solutions Van Oord Offshore Wind Projects B.V. Visser & Smit Marine Contracting Changes – current Further organisations have participated in the review process. DNV is grateful for the valuable co-operations and discussions with individuals in these organisations Recommended practice, DNVGL-RP-0360 – Edition March 2016 Page 4 DNV GL AS CONTENTS CHANGES – CURRENT .................................................................................................. 3 Sec.1 General ....................................................................................................... 10 1.1 General ..............................................................................................10 1.1.1 Introduction .............................................................................10 1.1.2 Objectives ...............................................................................10 1.1.3 Scope and application................................................................10 1.1.4 Alternative methods and procedures............................................11 Contents 1.1.5 Structure of recommended practice.............................................11 1.2 References .........................................................................................12 1.2.1 Applicability .............................................................................12 1.2.2 Standards - normative...............................................................12 1.2.3 Standards - informative .............................................................12 1.2.4 Guidelines - informative.............................................................13 1.2.5 Other references - informative....................................................15 1.3 Definitions .........................................................................................15 1.3.1 Verbal forms ............................................................................15 1.3.2 Definitions ...............................................................................15 1.4 Abbreviations and symbols ................................................................27 1.4.1 Abbreviations ...........................................................................27 1.4.2 Symbols ..................................................................................29 Sec.2 Design philosophy ....................................................................................... 30 2.1 General ..............................................................................................30 2.1.1 Objective .................................................................................30 2.1.2 Application...............................................................................30 2.1.3 Stakeholders and interfaces .......................................................30 2.2 Safety philosophy ..............................................................................31 2.2.1 General ...................................................................................31 2.2.2 Safety objective........................................................................32 2.2.3 Systematic review of risks..........................................................32 2.2.4 Dependability and risk based design ............................................33 2.2.5 Quality assurance .....................................................................33 2.3 Design format ....................................................................................34 2.3.1 Approach .................................................................................34 2.3.2 System analysis........................................................................34 Sec.3 Concept development.................................................................................. 39 3.1 General ..............................................................................................39 3.2 Conceptual design..............................................................................39 3.2.1 Systematic approach .................................................................39 3.2.2 Project layout...........................................................................39 3.2.3 Electrical system studies............................................................40 3.2.4 Preliminary cable selection .........................................................41 3.2.5 Preliminary engineering .............................................................42 3.3 Cable route study...............................................................................43 3.3.1 General ...................................................................................43 3.3.2 Route selection and landing........................................................44 3.3.3 Regulatory requirements............................................................44 3.3.4 Commercial operations, restricted areas, obstructions....................45 3.3.5 Geology and seismicity ..............................................................47 3.3.6 Meteorological and marine conditions ..........................................48 Recommended practice, DNVGL-RP-0360 – Edition March 2016 Page 5 DNV GL AS 3.3.7 Natural environment .................................................................50 3.4 Cable route survey .............................................................................52 3.4.1 General ...................................................................................52 3.4.2 Onshore surveys.......................................................................52 3.4.3 Offshore surveys ......................................................................53 3.4.4 Determination
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