Electromagnetic And Thermal Analysis On Conduction-cooled High Temperature Superconducting Energy Storage Magnet

Conduction-cooled High Temperature Superconducting Magnetic Energy Storage System(HTS SMES) have many advantages such as easy maintenance, portable, safe and high efficiency. Now mini-type Cryocooled-HTS SMES is developed and will be developed for practice. With the development of HTS wires, the price of HTS SMES will finally go down and it will be widely used in the future.HTS SMES magnet, in this paper, adopted cryocooler-cooled cooling method. Based on electromagnetic field theory, stress field theory and temperature field theory, the electromagnetic and thermal characteristics are analyzed. The numerical model in various conditions is presented. The paper mainly contains five parts as follows:1. The electromagnetic conceptual design of HTS SMES magnet is completed in this paper. HTS magnet of solenoid and torus is investigated and optimized, and the result is presented and compared. The stress distribution and stray distribution are compared with capacity range between 1MJ and 10MJ. Then, electromagnetic characteristics of the helical and pancake are compared, which is referred as ac loss analysis.2. The ac loss in HTS superconductor part and eddy loss in cooling configuration of HTS SMES magnet are analyzed respectively. The models of ac loss in HTS Superconductor are introduced, and the numerical model of ac loss in the HTS coil is presented. The relationship between the ac loss component of HTS coil and direct current is studied. The eddy loss of cooling configuration is analyzed and a new configuration of cooling plate is present. With the new configuration, the eddy loss will be reduced efficaciously.3. The thermal model of HTS SMES with heat disturbance is present. The thermal responses of magnet with different amplitude of heat disturbance and different time is simulated. The thermal stability of magnet with different number of local disturbance spot is compared. The method to improve the thermal stability of HTS coil is presented. Secondly, the thermal response in different ac condition is simulated, and the thermal stability of HTS magnet is analyzed by different cooling configuration. At last, the thermal analysis and recovery characteristics in over-current state are analyzed with two model as mention above, the results are compared and discussed.4. Based on electromagnetic design, analysis result of ac loss and study on thermal stability, and investigated the optimization by synthesis. The concept about two step optimization on electromagnetic and thermal design of HTS SMES is presented, an optimal example is presented. The optimal result is evident by comparison.5. The electromagnetic characteristics of 35 kJ HTS SMES magnet are analyzed. The ac loss of HTS superconductor and eddy loss of the cooling configuration in exchange power state is computed. The distribution of the temperature field of HTS SMES magnet is presented and compared with experiment result. The simulation is proved correct. At last , the measure is presented to reduce eddy loss and improve the thermal stability.The paper analyzed the electromagnetic, mechanical and thermal characteristics, present the numerical model, workout a series of useful program. The model and method for HTS SMES can be used widely in HTS magnet.