Process Requirements Experience of Offshore Substation Operation and Maintenance
Introduction or Background
It is now over 20 years since the first offshore substation was commissioned and operated. Since then, more than 200 AC and DC offshore facilities have been commissioned worldwide. The industry experience has encountered significant challenges for continued operation. Despite the existence of specific standards for example (Det Norske Veritas) DNV-ST-0145, guidelines for the design and construction of offshore substations. No comprehensive international standard (IEC, ISO, or otherwise) exists that addresses all the specific technical and operational issues needed in the industry. Figure #1 below is a typical representation of an offshore substation supported by jackets (Foundations) and a monopole wind turbine. The offshore wind sector is growing rapidly due to grid transformation and the appetite for renewable generation. Operational experience reports on total asset management and operation are relevant and needed.
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Purpose/Objective/Benefit of this work:
Practices for substation commissioning and inspection while in service vary from company to company without a standard, industry guidance or a defined best practice. The working group will collect best utility practices that would outline new work but also cover topics such as damage from vandalism, environmental impacts (contamination), adverse system conditions (i.e. faults, emergency loading, reactive switching) as part of existing inspections. Contractors and new workers are tasked with inspection and reports that will need guidance and accurate reports to deliver to asset owners.
The WG is to collect, organize and collate the technical knowledge and experience of all stakeholders regarding the life-cycle issues associated with these offshore facilities. The objective is to provide the basis for any future establishment of international standards and provide a road map.
Deliverable Scope:
- International survey to gather feedback, experience and statistics on:
- System Boundaries – Limits of scope under review in a OWF
- Scalability – OWF to Energy islands MW to GW Template 2024-01-08
- Design OSS Design and operational regulations (arising from National regulations)
- Design performance standards and risk-based maintenance.
- Factors influencing the Solution Design Lifetime – (e.g. corrosion, erosion, salt contamination)
- Hazard & risk management practices – e.g. Arc flash & operating in confined spaces
- Equipment selection, optimization and interfacing (special treatments, etc.)
- GIS (impact of environmental legislation for SF6.)
- Main transformers (cooling, winding arrangement/earthing, OLTP, bushings)
- Auxiliary equipment (HVAC, Gensets, etc.),
- Infrastructure design
- Containerized and bespoke layouts o Foundation dynamics
- Maintenance & asset management strategies
- Simplification of Design to lower facilitate maintenance burden,
- O&M strategy (unmanned vs manned, living quarter vs SOV, etc.),
- Maintenance planning and optimization, maintenance activity list,
- OPEX planning in design stage.
- Effectiveness of different regimes and impact on availability, remote monitoring best practices
- Operational experience (review of activities, valuable learning points)
- Resource profiles, access to OSS, requisite skills, training & certification.
- Operational availability statistics (including a focus on corrosion-related faults).
- Equipment intervention and decommissioning experiences.
- Fire Risk Assessment methodologies, incidents, consequences and prevention
- Operational risk, fiscal, environmental, and safety – a review of hazards and safeguards
- Offshore Substation Safety Case, performance standards, and further work
The WG will cover all types of new and existing offshore substations. The idea is to interface with appropriate CIGRE technical committees and provide guidance of existing industry experience as an industry digest of best practices.