What Is a Superconducting Wire?
A superconducting wire is a cable that transmits electric power using a conductor that exhibits no electrical resistance.
While technically feasible, its commercialization faces challenges, including the development of cooling system technologies and the establishment of reliable cable-to-cable connections.
Despite having no electrical resistance theoretically and thus no power transmission loss, practical use reveals minimal losses during high-current AC power transmission, albeit significantly lower than those of conventional cables.
Uses of Superconducting Wires
Utilizing superconducting technology, superconducting wires are employed in electric power transmission. They allow for the transmission of large power loads without heat generation or voltage drop, thanks to their lack of electrical resistance. However, AC loss, a minor yet present loss, does occur.
In AC power transmission, superconducting wires can reduce transmission losses by approximately 95% compared to traditional copper cables.
Principle of Superconducting Wires
With zero resistance, superconducting wires enable significantly smaller power transmission cables, potentially downsizing the extensive infrastructure of power transmission. They facilitate long-distance power transmission without voltage drops, allowing for lower voltage use. Direct current (DC) power transmission, though still experimental, is being explored globally.
Types of Superconducting Wires
Yttrium-based superconducting wires, operable with liquid nitrogen, are known for their high critical currents and favorable magnetic field properties. They promise reduced power transmission losses to about a quarter of those with conventional cables and are suitable for compact, lightweight, and high-capacity applications.
How to Select a Superconducting Wire
Superconducting wires offer low-loss power transmission but face challenges, particularly in AC power transmission where cable losses vary with the power amount. The critical temperature for superconductivity, now at -196°C, necessitates advanced cooling system technologies. For natural energy sources that generate DC power, using superconducting wires can halve the transmission loss compared to AC transmission.
Structure of Superconducting Wires
High-temperature superconducting wire cables comprise a superconducting conductor layer of spirally wound wire tapes around a central former, which adds mechanical strength and acts as a bypass in accidents. An electrical insulating material encases this layer, topped by a superconducting shield layer that blocks magnetic fields from the conductor layer without external leakage. A protective copper wire layer and an insulating double-tube structure, maintaining a vacuum to prevent external heat ingress, enclose the assembly.