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Superconducting materials lose their ohmic resistance, if they are cooled down to their operating temperature of approx. -200°C. Cables, manufactured out of these materials, can provide power transmission with almost no losses.
The design of a superconducting cable is similar to conventional cables. Instead or in addition to the conductive material, superconducting wires or tapes were used. This cable is arranged inside a cable cryostat, which insulates the cold cable core from the environment. A coolant is pumped through the cable cryostat to keep the cable on its operating temperature. Main coolants are liquid nitrogen (LN2) or He-gas.
A cooling system compensates the thermal and electrical losses.
Advantages of superconducting cables:
• High current densities. Up to1000 times higher than in copper. Less weight and reduced space.
• Thermal independency. Superconducting cables are active cooled and thermal insulated against the environment.
• Energy transmission on lower voltage levels. Due to the high current densities it is possible to supply city centers with energy on medium voltage level. Saving of high voltage power lines and transformer substations.
• No external magnetic field. Superconducting cables do not generate magnetic fields, due to their coaxial design. There is no interference between the three phases among each other or cables in the surrounding area.
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