The World’s Highest Voltage Cable Project: The Pinnacle of ±1100kV UHVDC Technology

As the global energy landscape shifts toward long-distance and high-capacity power transmission, ultra-high voltage direct current (UHVDC) technology has become a key driver in national and regional grid development. Among all UHVDC projects, China’s ±1100kV transmission system currently holds the record as the highest voltage cable system in the world, representing the ultimate achievement in modern power cable engineering.

What is a UHVDC Cable?

UHVDC (Ultra High Voltage Direct Current) transmission refers to systems operating at ±800kV and above. Compared to traditional AC transmission, HVDC systems offer:

  • Lower power loss over long distances
  • Higher efficiency
  • Better suitability for renewable energy integration
ultra-high voltage cable project
ultra-high voltage cable projects

The UHVDC cable, which connects converter stations, passes through cities or rivers, and integrates with underground systems, plays a critical role in these projects. These cables must withstand high electrical, thermal, and mechanical stress, demanding the most advanced insulation and manufacturing technology.

World’s Highest Voltage Cable: China’s Changji–Guquan ±1100kV Project

Project Overview

  • Project Name: Changji–Guquan ±1100kV UHVDC Transmission Line
  • Location: From Changji, Xinjiang to Guquan, Anhui (China)
  • Transmission Distance: ~3300 km
  • Voltage Level: ±1100kV — world’s highest voltage rating
  • Power Capacity: 12 GW (12,000 MW)
  • Commissioned: 2019
  • Developer: State Grid Corporation of China
China’s Changji–Guquan ±1100kV Project

Technical Highlights

  • Advanced Insulation Materials: Innovative high-strength composite insulation system ensures safe operation under ultra-high voltage.
  • World Record Transmission Distance: Over 3,000 km of continuous high-voltage transmission.
  • Green Energy Channel: Transmits renewable power (wind and solar) from remote western regions to the eastern industrial hubs.

Cable Usage

While most of the ±1100kV line is overhead, specialized high-voltage cables are used at converter station exits, urban underground sections, and river crossings. These UHV cables are critical for safe and stable system integration.

Highest Voltage Submarine Cable: North Sea Link ±525kV HVDC

In submarine cable applications, the North Sea Link project between Norway and the UK is one of the most advanced:

  • Voltage Rating: ±525kV HVDC
  • Cable Length: ~720 km
  • Power Transmission Capacity: 1400 MW
  • Commissioned: 2021
  • Technology: XLPE-insulated HVDC submarine cable
  • Purpose: Enables clean hydropower exchange between the Nordic and British grids
North Sea Link ±525kV HVDC

Cable Industry Trends: Pushing Voltage and Distance Limits

Countries like China, India, and Brazil are investing in next-generation ±800kV to ±1100kV cable projects.

Emerging innovations such as:

  • Nano-modified XLPE insulation
  • Dry-type DC cable terminations
  • Smart joint monitoring systems
  • They are making ultra-high voltage cable systems more efficient and reliable.

From transmission capacity to voltage rating, the Changji–Guquan ±1100kV UHVDC cable remains the world’s most powerful cable project. It is a testament to China’s leadership in power grid technology and offers a blueprint for global energy infrastructure development.

Looking for more details about HVDC cable standards, insulation structure, or export certifications?
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