Offshore Cable Burial: How deep is deep enough?

海上电缆埋设：多深才算足够深？

• 批准号: EP/W000970/1
• 负责人: William Coombs
• 金额: $ 59.16万
• 依托单位: Durham University
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FW000970%2F1
• 关键词: Offshore; Cable; Burial; How; deep

Offshore Wind (OSW) is critical for the UK's economy and energy security. It is also an area of huge investment, for example £14bn has been committed up to the end of 2021 for new OSW sites - the 4th largest construction programme in the UK. Beyond this, the UK's current 2030 OSW installed capacity targets will require £48bn of investment and provide direct employment for 27,000 people.Despite the growing maturity of the OSW sector, certain elements of the installed infrastructure remain problematic. Principally, problems associated with subsea power cables that transport and distribute the electricity generated offshore in wind turbine generators to the onshore transmission system currently account for 75% of the cost of all insurance claims and faults typically take 100+ days to rectify. This leads to breaks in supply and loss of revenue for the wind farm operator which in the long term can lead to longer payback periods and reduced investment elsewhere in their renewables portfolio. In shallow waters these cables must be protected from anchors and fishing gear and the primary protection method is to bury the cable below the seabed. The cable burial depth is a compromise between economic cost of burial (going deeper takes longer, requires larger ships and may require more complex operations) and risk to the cable being damaged by anchors/fishing gear penetrating the seabed. Within this context, anchor-cable interactions currently account for 85% of power cable failures. The planned rapid expansion of offshore wind around the UK - installed capacity increasing 7.5 times over the next 30 years - will require new cable installations within some of the busiest shipping/fishing waters in the world and it is essential that these new cables are installed at the appropriate depth. However, the industry currently lacks appropriate scientific tools to determine anchor penetration depths in different soil conditions. Instead they use simple look-up tables based on very broad descriptive classifications of the soils on the seabed that basically split the huge spectrum of real soil conditions into two categories - soft or hard. This approach has been shown to be highly conservative in some soils leading to unnecessarily deep (and costly) burial. However, it is clearly non-conservative in other conditions as anchor-cable interactions dominate cable failures. This proposal will tackle the lack of sound anchor penetration models head on and, through physical testing and computational modelling, develop a toolkit to assess anchor penetration in different soil conditions. This anchor penetration prediction tool will be based on the site investigation data typically available along cabling routes and avoid the use of oversimplistic look-up tables. Its development will be guided by an industrial project steering group made up of key parties from the OSW sector. Crucially, this innovative anchor penetration model will be calibrated and validated using a geodatabase comprising actual site investigation data. Model performance will be assessed against proven, demonstrable ground conditions and therefore will not rely on hypothetical ground conditions which can be oversimplified using current cable burial assessment techniques (e.g. descriptive single-type soils that do not change with burial depths, as opposed to more complex, multi-layered soil types). In addition to the anchor penetration predictive tool, a number of spatial mapping layers (specific to the UK Continental Shelf) will be created, derived from the tool application to known ground conditions across the UK seafloor. These mapping layers will be made openly available, and are anticipated to feed into high-level spatial planning decisions at project concept stage.In summary, this project will provide an industry usable anchor penetration model allowing the OSW sector to answer the key cable burial question - how deep is deep enough?

海上风电（OSW）对英国的经济和能源安全至关重要。这也是一个巨大的投资领域，例如，到2021年底，新的OSW站点已承诺投入140亿英镑-这是英国第四大建设计划。除此之外，英国目前的2030年OSW装机容量目标将需要480亿英镑的投资，并为27，000人提供直接就业机会。尽管OSW行业日益成熟，但已安装基础设施的某些要素仍然存在问题。主要地，与将海上风力涡轮机发电机产生的电力输送和分配到陆上传输系统的海底电力电缆相关的问题目前占所有保险索赔成本的75%，并且故障通常需要100多天才能纠正。这导致风电场运营商的供应中断和收入损失，从长远来看，这可能导致更长的投资回收期，并减少其可再生能源投资组合中其他地方的投资。在浅水沃茨，必须保护这些电缆免受锚和渔具的影响，主要保护方法是将电缆埋在海床以下。电缆埋设深度是埋设的经济成本（更深需要更长的时间，需要更大的船只，可能需要更复杂的操作）和电缆被穿透海底的锚/渔具损坏的风险之间的折衷。在这种情况下，锚电缆相互作用目前占电力电缆故障的85%。英国海上风电的计划快速扩张-在未来30年内装机容量增加7.5倍-将需要在世界上一些最繁忙的航运/捕鱼沃茨内安装新的电缆，这些新电缆必须安装在适当的深度。然而，该行业目前缺乏适当的科学工具来确定不同土壤条件下的锚穿透深度。相反，他们使用简单的查找表，该表基于对海底土壤的非常广泛的描述性分类，基本上将真实的土壤条件的巨大范围分为两类-软或硬。这种方法在某些土壤中被证明是高度保守的，导致不必要的深埋（和昂贵的）。然而，它显然是不保守的，在其他条件下，锚-索相互作用主导电缆故障。该提案将解决缺乏健全的锚穿透模型的问题，并通过物理测试和计算建模，开发一个工具包，以评估不同土壤条件下的锚穿透力。该锚穿透预测工具将基于通常沿沿着电缆线路可用的现场调查数据，并避免使用过于简单的查找表。它的发展将由一个工业项目指导小组指导，该小组由来自OSW部门的主要各方组成。至关重要的是，这一创新的锚穿透模型将使用包含实际现场调查数据的地理数据库进行校准和验证。模型性能将根据已证实的、可论证的地面条件进行评估，因此将不依赖于假设的地面条件，而假设的地面条件可能会使用当前的电缆埋设评估技术（例如，描述性的单一类型土壤，不随埋设深度而变化，而不是更复杂的多层土壤类型）进行过度简化。除了锚穿透预测工具外，还将创建一些空间测绘层（特定于英国大陆架），这些测绘层来自于工具应用于英国海底的已知地面条件。这些测绘图层将公开提供，预计将在项目概念阶段提供给高层空间规划决策。总之，该项目将提供一个行业可用的锚穿透模型，使OSW部门能够回答关键的电缆埋设问题--多深才算足够深？