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 high temperature superconductor wires wrapped around a copper core, and the cryogenic cooling system to maintain proper operating conditions. Superconducting cables offer solutions for utilities facing challenges that include:
Cable Market Applications: Superconducting 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. Superconducting 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 superconducting 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. Superconducting 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.
Another potential use 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. Superconducting cables can tie these existing stations together, avoiding very costly transformer upgrades and construction costs.
Constructing superconducting high-power transmission cable requires a great deal more conductors than one might expect. Independent of the design, each cable type contains hundreds of strands of layered high temperature superconductor wire. Strands of wire are wound around a core in one direction and then the next layer is wound in the opposite direction. This process is repeated many times. Cable manufacturers may use more than 400 kilometers of wire (4mm wide @ 90 A/cm) to construct a single kilometer of superconducting power cable.
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 of each other. A second cable design consists of three separate, single-phase, cables encapsulated in a single cryogenic envelope. The third type of cable uses three individual, single-phase cables, with each encapsulated in an individual cryogenic envelope.