Superconducting wires carry very high electrical currents without measurable losses. This makes it possible to design a range of innovative energy-related devices (transformers, electrical engines, current limiters and so forth), which are much more compact and perform much better than conventional devices. Superconducting wires also make it possible to manufacture very strong electromagnets that can serve for a wide variety of applications, such as medical imaging, magnetic separation and more.

One weak point in the new generation of superconducting wires is the difficulty in detecting hot spots following a disturbance. These hot spots may eventually destroy the wire if action isn't taken quickly. The technology developed by Christian Lacroix, Frédéric Sirois and Professor Michel Wertheimer of the Department of Engineering Physics is based on thin-layer architecture optimized using digital simulation. It offers a promising solution to the problem by accelerating the distribution of heat generated at the hot spot so as to make it detectable in a few dozen milliseconds rather than several full seconds. This greatly limits the temperature reached at the hot spot and reduces the likelihood that equipment will be destroyed.

The patent-pending technology has already been proven through lab experiments and must now be tested on large-scale applications. If these tests are conclusive, this may substantially accelerate the pace at which innovative devices such as short-circuit current limiters are brought to market, along with a new generation of strong-field electromagnets.

Above: The illustration on the left shows the transfer of current from the superconductive layer to the metal layer in a commercial wire. The red arrows represent the current in the superconductive layer and the blue arrows represent the current in the metal layer. The illustration on the right shows the current transfer in a wire with the newly proposed architecture. This architecture significantly increases the current transfer length, accelerating the distribution of heat along the wire.

Frédéric Sirois is a Professor in the Department of Electrical Engineering at Polytechnique Montréal. He has published some sixty scientific articles to date. He heads up the Laboratory in Electrical Energy (LEE) and is a member of the Regroupement québécois sur les matériaux de pointe (RQMP).

Christian Lacroix is a Research Associate in the Department of Electrical Engineering at Polytechnique Montréal. He earned his Doctorate in 2010 from Polytechnique Montréal under the supervision of Professors David Ménard and Remo A. Masut. He then performed a Post-Doctoral fellowship at IREQ (Hydro-Québec's research institute) before coming back to work at Polytechnique Montréal. He has authored some fifteen articles in the fields of magnetism and superconductivity.

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See also:
The full article “Concept of a current flow diverter for accelerating the normal zone propagation velocity in 2G HTS coated conductors.”
Expertise fact sheet for Prof. Sirois
Expertise fact sheet for Prof. Wertheimer