Performance enhancement of coated conductor magnet with double-layer metal insulation

Abstract

The double-layer metal-insulation method using the brass sheets as the double-layer insulators was proposed in this paper. It can enhance the contact resistivity while reserving greater thermal conductivity merit. The underlying mechanism of the contact resistivity enhancement is to increase the number of contact surfaces and to degrade the contact quality between the insulators. Then, we wound a single-layer brass-insulation coil and a double-layer brass-insulation coil to compare their contact resistivities and confirmed the effectiveness of the double-layer metal-insulation method. Besides, since the capacity withstanding the overcurrent is weakened with the increscent contact resistance of the metal-insulation coil, we further investigated the influence of the contact surface resistivity distribution on the coil performance under different scenarios to optimize the double-layer metal-insulation coil for receiving a superior thermal stability. Simulation results indicated that the coil possessed the dominated 2nd contact surface resistivity and minimum 1st and 3rd contact resistivity is the optimal design for the double-layer metal-insulation coil to receive the best thermal stability, irrespective of the cooling environment, contact resistivity magnitude, operating current and coil dimension. In addition, in regard to the thermal performance differences caused by the contact surface resistivity distribution, we found that the increment of contact surface resistivity and the overcurrent would enlarge the distinctions at different levels.