An evaluation method for small-scale conduction cooled SMES cryogenic cooling system based on thermal analysis

The current flowing through a SMES is subjected to variations at a rate ranging from 0.1 A/s to 300 A/s under the influence of the power grid. The duration of power exchange varies from milliseconds to minutes, even to hours. When operating, the impact of AC losses in HTS tapes on the cryogenic cooling system should be considered. If the cryogenic cooling system fails to take away the generated heat effectively, this may lead to the temperature rise of the magnet and its possible damage. Therefore, it is essential to evaluate the technical and economical characteristic of cryogenic cooling system. Thus, a 5 MJ SMES model is built to calculate the temperature characteristic. A new factor δ is defined to assess the technological and economical validity of the chosen cryogenic scheme. The suitable capacity of the cryogenic cooling system is evaluated for different applications. The effect of the operating temperature on the technical and economical factor is also discussed.