JDR Unveils Next-Generation 132 kV Subsea Cables, Powering Offshore Wind's Future

JDR Cable Systems, a UK-based manufacturer specializing in subsea and power cables and a part of the TFKable Group, has successfully completed the type test qualifications for its next-generation subsea cables. These advanced cables are specifically engineered for offshore energy applications, with a particular focus on both fixed and floating offshore wind projects. A key innovation lies in their ability to double the electricity voltage capacity from the industry-standard 66 kV to 132 kV, thereby enabling the deployment of larger, more powerful turbines.

The development and rigorous testing of JDR's static cables received vital support from a development grant provided by the Offshore Wind Growth Partnership. This initiative also involved a collaborative effort with an unnamed materials supplier, with extensive testing protocols meticulously executed at the Offshore Renewable Energy Catapult. As a result of this comprehensive process, JDR has officially confirmed the completion of two new type test qualifications at 132 kV for both static and dynamic array cables.

This technological leap is poised to significantly bolster the next generation of fixed and floating offshore wind projects. It represents a critical step in providing UK-manufactured high-voltage cables capable of supporting larger turbines, facilitating power transmission over greater distances, and ultimately contributing to more efficient and cost-effective offshore wind energy generation.

Understanding the Backbone of Offshore Energy: Subsea Cables

At the heart of offshore wind farms are subsea cables, often referred to as the "arteries" that transport the generated electricity to shore. These sophisticated power conduits are crucial for connecting individual turbines to an offshore substation, and then the entire wind farm to the national grid. The design and construction of subsea cables are highly specialized to withstand the harsh marine environment, including constant immersion in saltwater, varying temperatures, and the dynamic forces of currents and waves.

Cable Construction: A Deep Dive

A typical high-voltage subsea power cable, such as the 132 kV cables developed by JDR, consists of several layers, each serving a specific function:

• Conductor: This is the core of the cable, typically made of copper or aluminum, responsible for carrying the electrical current. For high-voltage applications, multiple strands are often used to reduce resistance and heat generation.

• Insulation: Surrounding the conductor is a robust insulating layer, often made of cross-linked polyethylene (XLPE), which prevents electrical leakage and ensures the safe transmission of high voltages. The thickness and quality of this insulation are paramount for cable performance and longevity.

• Semiconducting Layers: Thin semiconducting layers are often placed on either side of the insulation to smooth out the electric field and prevent partial discharges, which can degrade the insulation over time.

• Metallic Screen/Sheath: A metallic layer, typically copper or lead, surrounds the insulation. This serves as an electromagnetic shield, containing the electric field and preventing interference, and also provides a return path for fault currents.

• Bedding: A protective layer, often made of polypropylene yarn or similar material, cushions the internal components.

• Armouring: This is a crucial protective layer, usually made of steel wires, designed to withstand mechanical stresses, abrasion, and impacts during installation and operation. It provides tensile strength and protects against external damage.

• Outer Sheath: The outermost layer, typically made of a tough polymer like polyethylene, provides final protection against the marine environment, including seawater ingress and chemical degradation.

The integrity of each layer is vital for the cable's overall performance and its ability to transmit significant amounts of power reliably over long distances, often in challenging deep-water conditions. The transition from 66 kV to 132 kV, as achieved by JDR, requires meticulous engineering across all these layers to manage the increased voltage and associated electrical stresses.

Joe Cole, Technology Manager – Power Cables at JDR, expressed the company's forward-thinking approach, stating, "We pride ourselves on providing solutions to the energy sector ahead of time, and with our 132 kV technology, we will do exactly that." He further elaborated on the significance of this breakthrough: "Dynamic cables for floating wind and advanced 132 kV cable technologies are critical for the progressive deployment of both fixed and floating offshore wind, enabling developers to not only deploy larger turbines but also to site floating offshore wind in deeper waters, further offshore."

Production of these innovative 132 kV cables will take place at JDR's upgraded Hartlepool facility and their new high-voltage cable manufacturing plant in Cambois, near Blyth, Northumberland. By doubling the voltage capacity from 66 kV to 132 kV, these new cables are anticipated to facilitate the deployment of turbines rated at 20 MW and above, allowing offshore wind farms to be strategically located further from shore and in significantly deeper waters.

JDR's latest high-voltage cable development, conducted under the Department of Energy Security and Net-Zero’s Floating Offshore Wind Demonstration Programme, is also seen as a crucial step in supporting the type test qualification of fixed foundation 132 kV static cable technology.

The company highlighted the success of its Advanced High-Voltage Export and Array Dynamic (AHEAD) cable project. This initiative, supported by a £1.6 million (almost $2.2 million) grant, definitively demonstrated the viability of 132 kV dynamic cables for floating wind applications. The extensive testing program for these cables, which included over 1.5 million tension-bending cycles, unequivocally validated the reliability of their advanced design even when subjected to the continuous dynamic motion inherent in offshore floating applications.

"It’s an exciting time for the industry, and we are right at the forefront by developing, validating, and delivering new solutions for the benefit of the offshore energy industry and electricity consumers," added Cole, underscoring JDR's commitment to innovation.

Furthermore, JDR is actively contributing its technical findings to the international standards body CIGRE. This engagement forms part of their broader strategy to drive innovation in high-voltage subsea technology and helps inform the evolution of safety standards for higher voltage applications globally. The British firm is also a proactive participant in the Carbon Trust’s Offshore Wind Accelerator High Voltage Array Systems project, which specifically champions the development and qualification of 132 kV cable technology within the UK.

JDR emphasized that "These efforts align closely with the UK Government’s commitment to advancing floating offshore wind, as reflected in the £31.6 million in grant funding awarded by the Department for Energy Security and Net Zero through the Net Zero Innovation Portfolio, aimed at accelerating the demonstration of innovative technologies in this sector."

A Note from Feichun Cable:

As a company dedicated to excellence in cable manufacturing, Feichun Cable recognizes the groundbreaking work being done by industry leaders like JDR. The advancements in high-voltage subsea cable technology, particularly the shift to 132 kV, are truly inspiring and highlight the continuous innovation required to support the global energy transition. We are committed to learning from such pioneering efforts, understanding the intricate technical demands, and applying these insights to our own product development and manufacturing processes. Our goal is to contribute to a sustainable future by consistently improving our cable solutions, drawing inspiration from the cutting edge of the industry. We believe in collaborative progress and are eager to explore how we can contribute to and further understand the evolving needs of the renewable energy sector.

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