STANDARD DNVGL-ST-0359 Edition June 2016 Subsea power cables for wind power plants 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 standards contain requirements, principles and acceptance criteria for objects, personnel, organisations and/or operations. © DNV GL AS June 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 is a new document. Changes – current Standard, DNVGL-ST-0359 – Edition June 2016 Page 3 DNV GL AS Contents CHANGES – CURRENT .................................................................................................. 3 Sec.1 General ......................................................................................................... 6 1.1 Introduction ...........................................................................................6 1.1.1 Scope and application.....................................................................6 1.1.2 Alternative methods and procedures.................................................7 1.2 References and definitions .....................................................................7 Contents 1.2.1 General ........................................................................................7 1.2.2 Standards ....................................................................................7 1.2.3 Guidelines ....................................................................................8 1.2.4 Terminology and definitions.............................................................8 1.2.5 Abbreviations and symbols............................................................15 Sec.2 Project life cycle.......................................................................................... 16 2.1 General.................................................................................................16 2.1.1 Objective ....................................................................................16 2.1.2 Application..................................................................................16 2.1.3 Dependability and risk based design ...............................................16 2.2 Preliminary design ..............................................................................16 2.2.1 Approach ....................................................................................16 2.2.2 System analysis...........................................................................17 2.2.3 Conceptual design........................................................................17 2.3 Detailed design ....................................................................................18 2.3.1 General ......................................................................................18 2.3.2 Cable system design.....................................................................18 2.3.3 Subsea power cables ....................................................................19 2.3.4 Cable protection design ................................................................21 2.3.5 Cable interface at fixed offshore units .............................................22 2.3.6 Landfall ......................................................................................24 Sec.3 Manufacturing and testing .......................................................................... 25 3.1 General.................................................................................................25 3.2 Quality assurance and testing ..............................................................25 Sec.4 Transport and installation .......................................................................... 26 4.1 General.................................................................................................26 4.2 Cable storage .......................................................................................27 4.3 Cable load-out ......................................................................................27 4.4 Cable transport ....................................................................................28 4.5 Cable installation..................................................................................28 4.5.1 Jointing ......................................................................................29 4.5.2 Cable pull–in to offshore unit .........................................................29 4.5.3 Landfall ......................................................................................29 4.5.4 Cable protection ..........................................................................30 4.6 Infrastructure crossings.......................................................................31 4.7 As-built survey .....................................................................................31 4.7.1 General ......................................................................................31 4.7.2 Survey requirements ....................................................................31 4.8 Termination..........................................................................................31 Sec.5 Commissioning ........................................................................................... 32 5.1 General.................................................................................................32 Standard, DNVGL-ST-0359 – Edition June 2016 Page 4 DNV GL AS 5.2 Testing after installation ......................................................................32 Sec.6 In-service.................................................................................................... 33 6.1 General.................................................................................................33 6.2 Operation planning...............................................................................33 6.3 Maintenance and monitoring requirements ..........................................33 6.4 Repair work..........................................................................................34 6.4.1 General ......................................................................................34 6.4.2 Repair planning and execution .......................................................34 Contents Sec.7 Decommissioning ........................................................................................ 36 7.1 General.................................................................................................36 7.2 Removal process ..................................................................................36 App. A Documentation ........................................................................................... 37 A.1 General................................................................................................ 37 A.2 Preliminary design .............................................................................. 37 A.3 Detailed design ................................................................................... 37 A.4 Manufacturing and testing................................................................... 38 A.5 Transport and installation ................................................................... 38 A.6 Commissioning .................................................................................... 39 A.7 In-service............................................................................................ 39 A.8 Decommissioning ................................................................................ 39 Standard, DNVGL-ST-0359 – Edition June 2016 Page 5 DNV GL AS SECTION 1 GENERAL 1.1 Introduction Subsea power cables account for just a small portion of the total amount of investments in offshore wind farms. However, when these power cables fail, the impact typically is very significant. In order to reduce the failure risk this standard specifies the requirements to subsea power cable installations during all phases of a subsea power cable project with a focus on evaluation of renewable energy applications in shallow water and landfall. The objectives of this standard are to: — support developers of wind power plants and their contractors for the application of certification. It helps to clarify requirements related to certification of subsea power cables and their accessories for offshore wind power plants — define minimum requirements and scope for third-party evaluation of the design, manufacturing, transport, installation and operation of power cable components and projects — provide a common platform for communicating the scope and extent of key activities during subsea power cable certification projects in renewable energy applications, e.g., with regard to approval by authorities. Guidance note: Locally applicable regulations should be consulted to ensure that all requirements, which can be in excess of those provided in this standard, are met. ---e-n-d---of---g-u-i-d-a-n-c-e---n-o-t-e--- 1.1.1 Scope and application The scope and applicability of this standard are detailed in Table 1-1. Table 1-1 Scope and application summary