Quench/Thermal Runaway Detection and Protection Technique for Conduction-cooled HTS Conductors

点击翻译按钮获取中文摘要

Superconducting Magnetic Energy Storage (SMES) is expected to play a significant role in a highly reliable electric power supply system. For size and cost reduction, conduction-cooled SMES system with Bi2212 HTS wire has been investigated. For the reliable operation of conduction-cooled HTS SMES, thermal runaway characteristics of Bi2212 coil should be evaluated and understood.From the viewpoint mentioned above, this research project investigated thermal runaway characteristics of conduction-cooled Bi2212 HTS coil with 4K-GM cryocooler system. We measured temperature and voltage distribution of the HTS solenoidal coil for typical current patterns of load fluctuation compensation and so on at different ambient temperatures from 5K to 20K. The voltage in the innermost layer of solenoidal coil increased rapidly under the current pattern and the HTS coil reached thermal runaway. Then, we carried out thermal analysis including heat generation, conduction and transfer under conduction-cooling condition. We reproduced the experimental results by thermal analysis, and evaluated the thermal runaway characteristics. The critical current for thermal runaway increased with the temperature decrease and saturated at the temperature lower than 10K. Furthermore, we found key parameters for evaluation of thermal runaway characteristics of conduction-cooled HTS coils, and suggested a criterion for the diagnosis of HTS SMES system.