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High Power Superconducting Transmission and Distribution Cables

Superconducting High Power Transmission Cable transmits 5 to 10 times the electrical current of traditional copper or aluminum cables with significantly improved efficiency. HTS power cable systems consist of the cable, which is comprised of 100s of strands of HTS wire wrapped around a copper core, and the cryogenic cooling system to maintain proper operating conditions.

HTS superconducting cables offer solutions for utilities facing challenges that include:
  • Substation footprint availability
  • Lack of available rights of way
  • Capacity load relief
  • Retire/avoid substation
  • High load connections between substations
  • Retire/replace transmission cable
HTS Cable Market Applications:

HTS power cables act as a bridge between electric energy transmission and distribution. Transmission High Voltages (HV) range from 60 kV to 765 kV and distribution medium voltages (MV) range from 5 kV to 46 kV. HTS power cables are particularly suited to high load areas such as the dense urban business districts of large cities, where purchases of easements and construction costs for traditional low capacity cables may be cost prohibitive. The primary application for HTS cables is medium voltage feeds to load pockets in dense urban areas. In these high demand zones the grid is often saturated with aging infrastructure. HTS technology brings a considerable amount of power to new locations where the construction of additional transmission to distribution substations, with major transformer assets, is simply not feasible.
Holly Power Plant - Austin, Texas

Another potential use of HTS power cable is to improve grid power transmission by connecting two existing substations. In dense urban environments many substations often reach capacity limits and require redundant transformer capacity to improve reliability. HTS cables can tie these existing stations together, avoiding very costly transformer upgrades and construction costs.

What is an HTS Power Cable?

Constructing superconducting high power transmission cable requires a great deal more HTS wire than one might expect. Independent of the design, each cable type contains hundreds of strands of layered HTS wire. Strands of HTS wire are wound around a core in a one direction and then the next layer is wound in the opposite direction. This process is repeated many times. Cable manufacturers use more than 400 kilometers of HTS wire (4mm wide @ 90 A/cm) to construct a single kilometer of superconducting power cable.

Typical HTS cable structure
There are several unique configurations utilized to construct an HTS power cable. One superconducting cable design is the Triax. This proprietary configuration winds three phases concentrically on a single inner copper core. This superconducting cable design integrates each AC phase into a single cable stacked on top each other. A second cable design consists of three separate, single-phase, cables encapsulated in a single cryogenic envelope. A third type of HTS cable uses three individual, single-phase cables, with each encapsulated in an individual cryogenic envelope.

HTS cable configurations

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Quick Fact - HTS cables can transmit 5 to 10 times the electrical power of similar sized copper or aluminum transmission cables with improved efficiency.