Designing stable and high-current density rotor windings of superconducting generator

A method to statistically predict quench training characteristics of a rotor windings of a superconducting generator is presented. In the method, energy of a disturbance due to a conductor motion and a quench current is statistically estimated. The authors apply this method to a rotor of the 70 MW class superconducting generator being developed in the Super-GM project and study the dependence of the stability on parameters of the rotor conductors, such as amount of copper stabilizer, accuracy of conductor dimensions and operating current density. To predict the stability, compliance of the rotor winding pack is a key parameter and estimated by a finite clement method. In the study, it is shown that there is an optimum value of ratio of copper to superconductor to maximize the current density of the winding pack keeping necessary stability. Based on the study, a designing method for stable and high current density rotor winding is discussed.