The Latest Technologies of Submarine Cable Auxiliary Materials

Abstract

This paper explores the state - of - the - art technologies in submarine cable auxiliary materials. It reviews how these materials are evolving to enhance the performance, durability, and reliability of submarine cables in the challenging marine environment. By examining new materials, manufacturing techniques, and functional enhancements, we can understand how they contribute to the development of more efficient and long - lasting submarine cable systems.

1. Introduction

Submarine cables are the backbone of global communication and power transmission networks, stretching across vast oceans to connect continents. Auxiliary materials play a crucial role in ensuring the smooth operation of these cables. They protect the core cable components from the harsh marine environment, which includes high - pressure water, strong currents, temperature variations, and corrosive seawater. Additionally, they support the installation, maintenance, and monitoring of submarine cables. With the increasing demand for high - speed data transfer and large - scale offshore power generation, the development of advanced submarine cable auxiliary materials has become essential.

2. New Materials for Submarine Cable Auxiliaries

2.1 High - Performance Insulating Materials

- Nanocomposite - Modified XLPE: Cross - Linked Polyethylene (XLPE) has long been a popular choice for submarine cable insulation. Recent research focuses on enhancing its properties through nanocomposite technology. For example, incorporating nanoparticles such as graphene oxide (GO) or montmorillonite nanoclay into XLPE can significantly improve its performance. GO, with its high - aspect - ratio and excellent electrical and mechanical properties, forms a conductive network within the XLPE matrix when properly dispersed. This not only improves the semi - conductive properties for better electric field control but also enhances the mechanical strength of the insulation. In a study, the addition of 1 - 3 wt% of GO to XLPE was found to increase the tensile strength by 20 - 30% and reduce the electrical conductivity under high - voltage stress, thus improving the long - term reliability of the insulation.

- Innovative Polymer Blends: Polymer blends are emerging as promising insulating materials for submarine cables. Blending different polymers can combine their individual advantages. For instance, blending polyimide (PI) with polyethylene (PE) creates a material with the high - temperature resistance of PI and the flexibility and processability of PE. This composite can withstand the extreme temperature variations in the ocean, from the cold deep - sea waters to the warmer surface waters near the shore. It also offers improved chemical resistance against seawater and other corrosive substances, making it suitable for long - term use in submarine cable applications.

2.2 Advanced Armoring Materials

- Corrosion - Resistant Alloys: Traditional steel armoring in submarine cables is prone to corrosion in the marine environment. New alloy materials are being developed to address this issue. For example, nickel - based superalloys with high chromium and molybdenum content show excellent corrosion resistance in seawater. These alloys form a passive film on their surface, which acts as a barrier against chloride ions, the main cause of corrosion in the ocean. In addition to corrosion resistance, these alloys also have high tensile strength and toughness, providing better mechanical protection for the cable. They can withstand the mechanical stress during installation, such as bending, pulling, and the impact of the seabed.

- Fiber - Reinforced Composite Armoring: Fiber - reinforced composites, such as carbon fiber - reinforced polymer (CFRP) and glass fiber - reinforced polymer (GFRP), are becoming popular alternatives for submarine cable armoring. CFRP offers high strength - to - weight ratio, excellent corrosion resistance, and good fatigue resistance. It can reduce the overall weight of the cable, making installation easier, especially in deep - sea areas. GFRP, on the other hand, is more cost - effective and still provides good mechanical protection and corrosion resistance. These composite materials can be customized by adjusting the fiber orientation and resin matrix to meet the specific requirements of different submarine cable applications.

2.3 Superior Water - Blocking and Moisture - Resistant Materials

- Super - Absorbent Polymer (SAP) Composites: Water - blocking is a critical function for submarine cable auxiliary materials. New SAP composites have been developed to improve this performance. These composites can rapidly absorb water and form a gel - like substance that prevents water from penetrating further along the cable. For example, a SAP composite based on polyacrylate and a reinforcing filler can absorb water up to several hundred times its own weight. The reinforcing filler, such as silica nanoparticles, enhances the mechanical strength of the gel, ensuring it remains in place even under high - pressure conditions in the ocean. This effectively protects the cable core from water - induced damage, such as insulation degradation and conductor corrosion.

- Hydrophobic and Barrier Films: Hydrophobic coatings and barrier films are used to prevent moisture ingress. Nanostructured hydrophobic coatings, such as those based on fluoropolymer or silica - based nanocomposites, create a super - hydrophobic surface on the cable sheath or auxiliary components. These coatings have a water contact angle greater than 150°, causing water droplets to roll off easily and preventing water from adhering and penetrating. Barrier films, such as multi - layer polymer films with high - gas - barrier properties, are also used to block the diffusion of water vapor. Materials like polyethylene terephthalate (PET) and ethylene - vinyl alcohol copolymer (EVOH) have low water - vapor permeability. By laminating these films together, a highly effective moisture - resistant barrier can be created.

3. Innovative Manufacturing Technologies

3.1 Precision Extrusion and Coating Processes

- High - Precision Insulating Layer Extrusion: The extrusion process for insulating materials in submarine cable production has seen significant improvements. Modern extrusion machines are equipped with advanced control systems. For example, closed - loop control systems using sensors for temperature, pressure, and flow rate can precisely regulate the extrusion process. This ensures that the XLPE or other insulating materials are extruded uniformly around the cable conductor, resulting in a consistent insulation thickness. The use of advanced extrusion dies, designed with the help of computational fluid dynamics (CFD) simulations, can further optimize the flow of the molten insulating material, reducing the occurrence of defects such as voids and uneven thickness.

- Thin - Film