Thermal design and operation performance of the rotating cryostat of a superconducting generator

The most sensitive part of superconducting rotors for power stations is the optimal design of the liquid helium region and long term operation performance of the insulation system. Fundamental publications have highlighted the problems of special parts of this system such as the current leads or torque tubes, which form a conducting connection between the warm ambient region and the cryogenic part of the rotor. This paper reports on the thermal design of the total rotor. The paper starts with a rough estimate of the heat losses using mean values for the material properties. Then some numerical results of calculation codes for the stationary temperature profiles, taking into account the real situation, are reported. Finally transient temperature profiles in individual parts of the rotor are given. The results are compared with experimental measurements of a test rotor