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Views: 0 Author: Site Editor Publish Time: 2025-12-22 Origin: Site
In extremely cold regions such as Russia, natural gas generator sets must confront challenges posed by temperatures as low as -40°C or even lower. Low temperatures not only reduce material toughness and increase the risk of brittle fracture but may also lead to difficulties in equipment startup and unstable operation. Among these challenges, low-temperature-resistant cables and steels, as core materials for energy transmission and structural support, directly determine whether the generator sets can operate reliably in severe cold. This article systematically elaborates on the application strategies of these key materials in extremely cold environments from four aspects: material properties, selection specifications, installation and maintenance, and case validation.
Cables used in extremely cold environments must maintain flexibility and insulation performance below -40°C. Traditional PVC cables are prone to brittle cracking at -20°C, whereas cross-linked polyethylene (XLPE) and ethylene propylene rubber (EPR), through chemical cross-linking or molecular structure design, reduce the brittleness temperature to -70°C. For example, XLPE cables used at a polar research station exhibited no cracks during bending tests at -50°C, while ordinary cables fractured at -20°C. For conductors, high-purity oxygen-free copper (OFC) has a 50% lower resistance temperature coefficient than ordinary copper, with only a 3% increase in resistance at -30°C, significantly reducing energy losses. The sheath materials, such as thermoplastic polyurethane (TPU) or fluoroplastic (FEP), have a low-temperature impact strength five times that of rubber, capable of withstanding hail impacts.
Low-temperature-resistant cables must meet the low-temperature rating requirements of the IEC 60085 standard. For instance, in a -50°C environment, the current-carrying capacity of cables needs to be 20% higher than that at room temperature, necessitating the selection of models with larger cross-sectional areas or higher conductivity. Regarding bending radius, the minimum bending radius of low-temperature-resistant cables can be reduced to 70% of that of conventional cables, accommodating installation in confined spaces. Outdoor cables also require the addition of carbon black as an ultraviolet (UV) inhibitor, with a sheath thickness of no less than 2.5 mm to delay aging. A wind farm project in the Arctic adopted these specifications, resulting in cables retaining 85% of their tensile strength after five years of outdoor exposure, compared to only 40% for unprotected cables.
Steels used in extremely cold environments must possess high toughness (impact energy ≥34 J) and a low ductile-to-brittle transition temperature. 9% nickel steel (e.g., ASTM A353) remains tough at -196°C and is the preferred material for liquefied natural gas (LNG) storage tanks; 3.5% nickel steel (e.g., X7Ni9) is suitable for -40°C environments and offers lower costs; austenitic stainless steels (e.g., 304L) are used in corrosive media scenarios. By controlling the carbon equivalent (CEV ≤ 0.38%) and adding nickel and manganese elements, the risk of welding cracks can be significantly reduced. For example, a drilling platform project in the Arctic reduced the CEV of its steel from 0.45% to 0.35%, resulting in a welding qualification rate of 99%.
Welding of low-temperature-resistant steels requires strict preheating to 100-150°C, followed by immediate post-weld heat treatment at 200-300°C to eliminate stress. The welding consumables must match the base material, such as ERNiCrMo-3 nickel-based welding wire, to ensure that the toughness of the weld metal is not lower than that of the base material. Non-destructive testing (NDT), including ultrasonic testing (UT) and radiographic testing (RT), must cover 100% of the welds, focusing on detecting incomplete fusion and cracks. A pipeline project in the Arctic adopted this process, increasing the impact energy of the welds from 20 J to 50 J at -50°C.
During cable laying, sharp bends must be avoided, and the minimum bending radius must comply with standards (e.g., ≥210 mm for a 30 mm diameter cable). Cable trays should be spaced no more than 1.5 meters apart and secured with low-temperature-resistant plastic clamps to prevent loosening due to thermal expansion and contraction. Connectors must use cold-shrinkable terminals to avoid cracking of heat-shrinkable materials at low temperatures. A substation project in the Arctic adopted cold-shrinkable terminals, reducing the connector failure rate from five times per year to zero.
The steel surface must be coated with low-temperature-resistant anti-corrosion coatings (e.g., epoxy zinc-rich primer + polyurethane topcoat), with a dry film thickness of no less than 200 μm. An oil and gas platform project in the Arctic maintained corrosion-free steel surfaces after five years of sea fog exposure, while unprotected steel exhibited pitting corrosion. Regular ultrasonic thickness measurements should focus on welds and bolt connections. A research station detected and replaced two steel beams with thickness reductions to 80% of the design value through inspections, preventing structural failure.
Arctic NG Project: The use of 9% nickel steel storage tanks and -50°C-resistant cables resulted in no brittle fractures in the steel and no cracking in the cable insulation over three years of operation, with a system availability rate of 99.5%.
Antarctic Research Station: 316L stainless steel pipelines and -60°C-resistant cables provided stable power supply in -80°C extreme environments, with the cable current-carrying capacity meeting 120% of the design requirements.
Extremely cold environments pose stringent challenges to the material performance of natural gas generator sets. By selecting low-temperature-resistant cables and steels and strictly controlling their selection, installation, and maintenance, the reliability and economic efficiency of generator sets in extreme environments can be significantly enhanced. In the future, with continuous advancements in material science and welding technology, the adaptability of energy equipment in extremely cold regions will further improve, providing stronger guarantees for global energy security.
