In recent years, my country’s offshore wind power industry has made significant progress. By 2024, my country’s newly connected offshore wind power capacity reached 4.04 GW, bringing the cumulative grid-connected capacity to 41.27 GW, ranking first globally for four consecutive years. Global offshore wind power installations are expected to reach 19 GW in 2025, with total installed capacity rebounding to a historic high.

Amid the global energy transition, offshore wind power, as a core clean energy source, is experiencing accelerated growth. However, the technical challenges presented by its unique operating environment cannot be ignored. The industry has long faced multiple challenges, including high salt spray corrosion, severe mechanical vibration and shock, extreme temperature fluctuations, complex electromagnetic interference (EMC), and potential explosion risks. Cable penetrations, as key electrical connections in turbines, have a sealing reliability that is directly related to equipment safety. A seal failure can lead to seawater infiltration, causing short circuits, localized overheating and fire, or even catastrophic accidents in explosive gas environments. Therefore, developing high-performance penetration sealing solutions that adapt to harsh marine environments and ensure the safety and stability of power transmission systems is a crucial issue.

The TST SEALMCT sealing system, centered around the core goals of “full-scenario adaptability, comprehensive risk mitigation, and end-of-life convenience,” provides comprehensive protection for offshore wind power cable sealing, from installation to operation and maintenance, through modular design, specialized materials, and customized services.

Core Advantages

Targetedly addressing the key pain points of offshore wind power

01 Multi-specification compatibility, adapting to complex cable and pipeline scenarios

Flexible cable size adaptation: Utilizing adjustable sealing modules and reducer components, the system covers common cable sizes from φ3.8mm to φ1023mm. Whether single-core power cables, multi-core control cables, or high-voltage cables, this significantly reduces spare parts inventory and construction adaptation costs.

Dedicated protection for armored cables: For submarine armored cables (such as steel wire armor and steel tape armor), a sealing structure with armor fixing grooves is designed. This not only prevents the armor layer from scratching the sealing material, but also strengthens the cable’s resistance to vibration and displacement through rigid fixation, preventing seal failure caused by long-term wave impact and ensuring the reliability of the submarine cable connection to the platform.

02 Full-condition resistance: Withstands extreme offshore environments

Corrosion and salt spray resistance: The core sealing material is made of ethylene propylene diene monomer (EPDM), and the metal components are made of 316L stainless steel. They have passed 1000 hours of C5-M salt spray testing (simulating high salt spray conditions at sea) with no rust or degradation. This solves the problem of traditional plugging and sealing materials failing after 3-5 years, extending their service life to 30 years or more. Vibration and shock resistance: The modular structure utilizes an elastic buffer design with a vibration amplitude of 1-5mm in the 10-500Hz frequency range, maintaining IP68 sealing while ensuring dynamic sealing reliability. It effectively absorbs vibration and shock from waves and turbine operation, preventing gap leakage caused by loosening of the sealing module.

Stable operation over a wide temperature range: To address special operating conditions, TST SEAL’s proprietary sealing material ensures it maintains elasticity, resists brittle cracking, and softening, from -52°C (the low temperature in winter in northern waters) to 90°C (the high temperature inside the nacelle). Even under extreme temperature fluctuations, it maintains stable sealing performance, eliminating seal failure caused by temperature fluctuations.

Aging and UV resistance: The seal has passed 2000 hours of UV and ozone aging tests, demonstrating long-term exposure to strong UV and high ozone environments at sea without cracking, hardening, or other aging issues, making it suitable for the 20-plus year lifecycle requirements of offshore wind power.

03 Safety Upgrades: Strengthening Explosion-Proof and Electromagnetic Protection

Explosion-Proof Design for Hazardous Areas: Designed for potentially explosive environments such as the engine room and pitch control cabinet, the sealing system meets Ex d IIC Gb and Ex d IIC Gc explosion-proof standards. Flame-retardant sealing materials and a flameproof enclosure block the propagation of flames and explosion shock waves, preventing cable penetrations from becoming explosion paths.

EMC Protection: With an electromagnetic shielding effectiveness of 42-63dB (14kHz-18GHz frequency band), it effectively blocks strong electromagnetic interference generated by the unit’s inverter and transformer, preventing interference signals from affecting the control system through cable penetrations, ensuring stable transmission of critical signals such as wind turbine pitch control and grid connection.

Full-Life Convenience: Cost-Efficient Installation and Operation Design

Simple Installation, Suitable for Confined Offshore Workspaces

Utilizing a high-strength modular assembly structure, the system eliminates the need for complex on-site casting processes. Equipped with dedicated positioning tools and sealing components, the system allows for simple and convenient assembly of individual modules, significantly reducing construction time in high-altitude and confined spaces on offshore platforms.

Supporting both “cable-on” and “install first, cable later” installation modes, it adapts to both the simultaneous construction of new wind power projects and the retrofit and upgrade needs of older turbines, minimizing turbine downtime.

Reserving spare capacity reduces future upgrade costs.

The sealing module has built-in spare capacity. When adding or replacing cables later, the upgrade can be completed by directly using the spare channel without dismantling the existing sealing structure. This avoids secondary damage to the sealing system caused by the retrofit, reducing O&M costs and safety risks.

Application Scenarios

Sealing Protection in Three Major Offshore Wind Power Scenarios

Cabinets and Racks:

The cabinets and racks of offshore wind power platforms house a large number of electrical equipment and control systems. The TST SEAL transit sealing system can be used to seal cable penetrations in these cabinets and racks. It effectively prevents water, air, and dust from entering the cabinets and racks, protecting electrical equipment from damage caused by moisture, corrosion, and dust accumulation. Furthermore, its electromagnetic shielding function protects the electrical equipment within the cabinets and racks from external electromagnetic interference and prevents internal electromagnetic signal leakage, ensuring normal equipment operation and stable signal transmission.

Offshore substations:

Offshore substations face harsh environments such as high salt spray, intense vibration, and extreme temperature fluctuations. The TST SEAL transit seal system can be used to seal cable holes and pipe penetrations within substations. Its fire-resistant sealing modules meet the A-0 and A-60 fire resistance ratings of the 2010 International Fire Test Procedures (FTP) standards. In addition to meeting the GB23864 standards, some models now offer a 3-hour fire resistance rating, effectively preventing the spread of flames and buying valuable time for evacuation and firefighting. Furthermore, the system’s watertightness and airtightness meet 0.5 MPa pressure sealing requirements, and its IP68 protection rating prevents the permeation of water and gas. It also offers noise reduction, corrosion resistance, and vibration and shock resistance. Explosion-proof modules can be used in explosion-proof spaces of corresponding levels, comprehensively ensuring the safe and stable operation of offshore substations.

Offshore wind turbine tower foundations:

Offshore wind turbine tower foundations are constantly exposed to wave impact, salt spray corrosion, and strong wind vibration. The TST SEAL transit seal system utilizes high-quality materials such as EPDM and 316 stainless steel, providing a robust structural support for the seal system and enhancing its impact and fatigue resistance. This ensures the stability of the seal even under long-term dynamic loads. Its standardized, variable-diameter sealing modules and flexible modular structure adapt to the actual layout of cables and pipes, accommodating tower foundation displacements caused by waves and strong winds. This effectively prevents the intrusion of seawater, moisture, and dust into the tower interior, protecting the cables and equipment within.

TST SEAL Sealing module construction case diagram: