Rethinking Offshore Power Smart EHV Solutions for a Greener Future

Abstract EHV networks at offshore fields require long Submarine Cables, Gas Insulated Switchgears, EHV Power Transformers, Shunt Reactors and associated Control & Protection Systems. Due to the dielectric properties of SF6 gas, EHV Busducts are traditionally used for interconnection of EHV Power Equipment. This paper highlights methodology followed to minimize the use of EHV Busducts and associated carbon footprint, during recent offshore projects and strategies adopted to mitigate the design concerns. A methodical approach covering all the aspects of the design and installation is discussed to avoid the constraints during the execution stage. This paper explores the replacement of GIBs with EHV cables on offshore platforms, targeting reduced carbon emissions and improved system efficiency. Subsea Cable routing on the topside of an offshore project is a multi-disciplinary activity that requires close coordination of Electrical, Structural, Piping and Offshore Installation teams. In addition to the permanent items, there are a lot of temporary equipment required to facilitate safe cable pulling offshore. To avoid clashes, cable pulling exclusion volumes need to be considered in 3D Model. Multiple design reviews are undertaken to reach a design acceptable to all the stakeholders. This is extremely challenging without the use of technologies such as Digital Twin with Smart Modeling Techniques. The study assesses the feasibility of adopting SF6-free EHV solution through Technology-enabled 3D modeling and digital twin simulations. These tools optimize space utilization and predict constructability challenges under offshore constraints, especially during cable pulling through the J Tubes and further routing to GIS in an offshore environment where clashes with equipment and structure are major concerns. Detailed evaluations were conducted to ensure compatibility among GIS, transformers, and reactors, while incorporating smart design principles for operability and maintainability. Stakeholder collaboration was vital in resolving termination complexity and defining robust cable support systems. AI-assisted clash detection and smart configuration mapping improved decision-making, supporting compliance with layout, structural, and safety standards. Integrating EHV cables impacts engineering and installation phases, especially under deck height constraints due to Minimum Bending Radius requirements and space required for cable pulling equipment / volumes. Smart design simulations identified a 12-meter deck to deck height, optimal for accommodating terminations. A hybrid solution with L-Shape GIB with horizontal EHV cable interface, proved effective, reducing offshore scope and enhancing layout flexibility. Terminations at transformers/reactors required cable boxes and standard alignment per IEC 62271-209/EN 50299-2, emphasizing the role of precision design and cross-discipline coordination. AI-aided predictive clash analysis helped structural and piping teams adjust their design early in the design phase. High-strength, MBR-compliant supports and trefoil clamp specifications were selected based on data-based installation modeling. Testing posed challenges due to IEC 62067 voltage protocols. This paper introduces a smart approach to replace GIBs with EHV cables, achieving measurable reductions in carbon footprint and lifecycle costs (CAPEX/OPEX). It highlights the importance of intelligent design tools in ensuring code compliance, optimizing layout, and minimizing operational disruptions. With smart tools, stakeholder collaboration, the design enables easier maintenance and better integration across disciplines. The resulting system supports long-term reliability, efficiency, and environmental goals in offshore electrical infrastructure.