超電導コイルの一保護方式の検討

抄録

With increasing of the magnetic stored energy in superconducting coils, the risk of their transition into normal conduction may be getting abnormally higher.
In the past the protection methods to prevent superconducting coils from their transition faults were developed, and some of them have been practically used in actual superconducting coils. In this paper, new types of protection methods are proposed: 1) constant DC voltage power line energy sink, 2) precharged capacitor energy sink, 3) prerotating DC motor energy sink, and their performances and how to select parameters of protection systems are also presented.
In an analysis, as an example of protection criterion we consider the current-decrement time constant of coil circuit made of NbZr of 0.01 inches in diameter, as stated in the Smith's paper.
The precharged capacitor and prerotating DC motor energy sink systems would be thought to be practicable for small and medium scale superconducting coils, and on the other hand the constant DC power line energy sink system constructed of a thyristor converter-inverter would be practically suitable for large scale superconducting coils.