Abstract: A device for limiting current with variable coil impedance includes a choke coil and a cooling device. An additional coil is made of a high-temperature superconducting material and is disposed in the choke coil such that the current is limited by the device without using an iron core.

Abstract: A high-temperature superconducting ribbon conductor composite device includes a high-temperature superconducting ribbon conducing composite including a substrate ribbon, at least one buffer layer disposed above the substrate ribbon, an HTSL layer disposed above the at least one buffer layer, and a cover. A cooling layer is disposed on the high-temperature superconducting ribbon conductor composite and includes at least one of a metal and a partly conductive or non-conductive oxide layer of at least one of an alkali, an alkaline earth and a rare earth element. The cooling layer has a thickness of 20 ?m to 200 ?m.