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In any subsea cable project, 80% of procurement attention goes to the submarine cable itself. But within the actual cable procurement budget, the supporting cable demand inside the converter stations is a real and consistently underestimated market.
The global HVDC transmission system market is expected to grow from $10.34 billion in 2026 to $21.87 billion by 2036, at a CAGR of 7.8%. Every new converter station built — and every existing one maintained — means substantial procurement of high-voltage power cables, control cables, instrumentation cables, and fiber optic communication cables.
Converter stations are not a "once-in-a-while" project type. They are becoming a routine component of global power infrastructure.
In June 2026, Italy's Terna and Tunisia's STEG awarded Hitachi Energy a contract worth approximately €770 million to build two converter stations for the ELMED project. The project has a transmission capacity of 600MW, a total length of approximately 220km, and a maximum water depth of 800 meters. This is the first DC subsea interconnection between Europe and Africa, with the two converter stations located in Partanna, Italy, and Mlaabi, Tunisia. Each converter station represents a complete cable system in itself.
The UK National Grid has launched a £59 billion HVDC supply chain framework agreement. Four converter station suppliers have been shortlisted: GE Vernova, Hitachi Energy, Mitsubishi Electric, and Siemens Energy. The converter station portion of the framework is valued at approximately £24.6 billion, with a 5-year term extendable by 3 years. First-wave projects include Eastern Green Link 4, Sealink, Lionlink, and others. This signals at least 5 to 8 years of sustained converter station cable procurement.
Globally, the HVDC converter station market is projected to grow from $13.32 billion in 2025 to $20.17 billion by 2031, at a CAGR of 7.16%. This is not about isolated projects — this is a sustained market expansion.
Cable Type | Function | Key Requirements |
High-Voltage Power Cables | Connect converter transformers to the AC grid and converter valves to the DC yard | XLPE insulation, single-core construction, voltage rating varies by project (commonly 320kV or ±500kV) |
Medium-Voltage Power Cables | Station auxiliary power supply, cooling systems | Typically 33kV and below |
Control Cables | Valve control, protection system signal transmission | High-density shielding (EMI immunity is critical) |
Instrumentation Cables | Monitoring signals — temperature, pressure, current, voltage | Stable signal transmission, interference-resistant |
Fiber Optic Cables | Station communication, remote dispatch, data acquisition | Some projects require fiber bundled with power cables |
The procurement logic differs across the five cable types required for converter stations:
This is the largest-volume and highest-technical-barrier category in converter station procurement. High-voltage cables for converter stations typically require suppliers to provide complete type test reports and pre-qualification test reports. ENTSO-E published a draft framework for pre-qualification and type testing of 525kV HVDC land and submarine cable systems in May 2026.
What buyers should verify: Request supply records from similar HVDC projects and complete type test reports, including space charge effect and polarity reversal voltage test results. Confirm that the product has undergone a full pre-qualification test cycle.
Valve switching operations generate strong electromagnetic fields, imposing strict EMI immunity requirements on control signals. Standard industrial control cables are not necessarily suitable for converter station environments.
What buyers should verify: Confirm shield material and braid density. Request EMC test reports and verify that they meet the specific EMI immunity requirements for HVDC converter stations.
Converter stations have extensive monitoring points for temperature, pressure, current, voltage, and other parameters. Signal stability from instrumentation directly affects system operation and diagnostic accuracy.
What buyers should verify: Request signal transmission stability test data. Confirm that moisture resistance and temperature ratings match the converter station's operating environment.
While the technical barrier is lower than high-voltage cables, procurement volumes are substantial. Station auxiliary power systems, including lighting, HVAC, pumps, and cooling fans, all rely on medium-voltage cable supply.
What buyers should verify: Confirm that the supplier holds manufacturing qualifications for 33kV and below cables and that products have passed routine testing per IEC 60502-2.
Some HVDC projects require fiber optic cables to be bundled with power cables for real-time monitoring of cable operating conditions, including temperature and strain. This imposes special mechanical strength and tensile requirements.
What buyers should verify: Confirm whether the supplier has experience manufacturing fiber cables for bundled deployment with power cables. Request tensile strength and bend performance test reports. Verify that the fiber's mechanical design is compatible with the power cable bundling arrangement.
Converter station cable procurement has several distinct characteristics. For buyers without relevant project experience, these differences can significantly impact supplier selection and procurement outcomes:
HVDC projects typically require suppliers to provide complete type test reports and pre-qualification test reports. ENTSO-E published a draft framework for pre-qualification and type testing of 525kV HVDC land and submarine cable systems in May 2026. For suppliers without prior HVDC project supply records, this represents a significant additional preparation requirement.
In the UK National Grid's HVDC supply chain framework, only 6 cable suppliers were shortlisted: Hellenic Cables (with Jan De Nul), LS Cable, NKT, Prysmian, Sumitomo Electric, and Taihan Cable. This is not a list that "has production capacity" can get you onto. Suppliers need comparable project supply records and complete testing and certification systems.
HVDC converter station construction typically takes 2 to 3 years. Cable procurement often begins early in the project timeline. Suppliers need the capability to engage early and coordinate with design teams, participating from the technical specification discussion phase.
A single converter station requires multiple cable categories. Suppliers capable of providing multi-category, one-stop supply offer clear advantages in procurement efficiency and coordination cost. Buyers should verify whether potential suppliers have full product line coverage to avoid interface compatibility issues from multi-supplier coordination.
HVDC converter station construction typically takes 2 to 3 years, with cable procurement often commencing early in the project timeline. Suppliers need the capability to engage early and coordinate with design teams, participating from the technical specification discussion phase. For suppliers without prior HVDC project experience, this means building technical liaison capabilities in advance.
There are three main differences: technical documentation requirements are more stringent, requiring complete type test reports and pre-qualification test reports; supplier qualification standards are stricter, typically requiring comparable project supply records; and procurement cycles are longer, requiring early design coordination capability. Additionally, converter station projects often require multi-category one-stop supply, placing higher demands on supplier product line coverage.
Cable procurement for converter station projects is typically handled by the EPC contractor or project owner. In the ELMED project, converter station procurement was jointly tendered by Terna and STEG via the EU Official Journal. In the UK National Grid's HVDC supply chain framework, cable and converter station procurement are conducted separately through framework agreements. Different cable types may be procured by different entities: high-voltage power cables are typically procured alongside main converter station equipment, while control cables, instrumentation cables, and fiber optic cables may be procured separately by different subcontractors.
The unique environment of HVDC converter stations imposes several critical requirements. Control cables require high-density shielding to withstand strong EMI from valve switching operations. Power cables must meet special insulation requirements for DC transmission systems, including space charge effects and polarity reversal voltage withstand capability. Some projects require fiber optic cables bundled with power cables for real-time monitoring.
If your company is currently involved in or planning to participate in cable procurement for HVDC converter station projects, please contact us for product specifications and certification documentation.
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