Offshore power cable assurance

Offshore wind and subsea transmission rely on power cables that must perform electrically and mechanically under harsh conditions. DNV supports electrotechnical design/specification and mechanical integrity (loads, stress, fatigue) and provides independent verification through QA/QC, witnessing and commissioning support.

Offshore wind and interconnectivity are driving demand for high-voltage subsea transmission systems, where cable performance depends on both electrical engineering (design/specification) and mechanical integrity under dynamic water conditions. Cables are difficult to repair once installed, so failure consequences and downtime can be severe; reducing failure risk requires strong specifications and disciplined quality verification throughout design, manufacturing, installation, and commissioning. 

About DNV’s power cable services

DNV provides (1) advisory to define technically sound cable concepts and specifications and (2) independent verification/QA to confirm quality throughout delivery-covering design verification, ITP review, audits and witnessing across manufacturing, installation and commissioning:

• Electrotechnical advisory: Providing end-to-end advisory for offshore electrical infrastructure, including drafting robust technical specifications for power cables and cable laying, supporting bid evaluation and contractor selection, and delivering cable connection advisory across underground to submarine AC/DC systems-from feasibility and conceptual design through design basis and tender preparation-complemented by independent QA/QC reviews (specification, tendering, bid evaluation, detailed design) and verification support to ensure clear requirements, reduce downstream risks, and secure high-quality project delivery.
• Mechanical & structural advisory: Providing advanced engineering support for offshore cables and umbilicals through dynamic analysis of combined environmental and operational loads (including wind, waves and motion effects), complemented by detailed mechanical testing and cross-section analysis of key properties such as stiffness, tension, curvature and fatigue behaviour; combined with installation planning and risk analysis (e.g. weather limits and control parameters), geotechnical input for burial and protection optimization, and structural strength and fatigue assessments (ULS/FLS) using recognized tools and methodologies to ensure robust, reliable performance throughout design and operation.
• Independent verification: Delivering comprehensive independent verification across offshore and subsea cable projects, including technical design verification, review of Inspection & Test Plans (ITPs), and thorough document review across design, manufacturing, testing, and installation phases, complemented by factory audits, manufacturing witnessing, and non-conformity review with root-cause analysis; extended through installation witnessing (laying, burial, protection, jointing) and commissioning/acceptance test witnessing, within a broader QA/QC framework spanning conceptual design to commissioning-acting as an independent guardian of delivery quality and ensuring compliance, reliability, and performance across T&D systems.

Higher confidence early: technical assurance in early phases to ensure design/engineering is sound and identify critical issues early, minimizing cost and limiting changes.

Clear, decision-grade specifications for offshore electrical infrastructure and cable laying, supporting tendering and contractor selection.

Independent verification evidence: audits, ITP review, witnessing and reporting across manufacturing, installation and commissioning, supporting transparent quality assurance decisions.

Mechanical integrity confidence through dynamic analysis, mechanical testing and fatigue capacity assessment to support structural strength and lifetime performance.

Why DNV

DNV uniquely bridges offshore engineering and power systems, combining subsea, structural and electrical expertise to de-risk complex cable projects end-to-end. Its role as a global standards-setter, backed by decades of research, ensures solutions are grounded in widely accepted industry practices, while proprietary tools translate these standards into robust engineering and lifetime integrity assessments.