Numerically Analysis On Voltage Distribution Of The Superconducting Coil Under Impulse Wave And Quench

Superconducting magnet is potential in electric power, materials, military, biomedical engineering and other industries. However, there are many internal insulation faults in the experimental research in superconducting coils, the main components of the superconducting magnet, in which case the insulation has always been damaged or even burnt. Usually, the fault is attributed to the arc caused by the quench of the conductor and/or various unexpected accidents. Therefore, it is of great significant to understand the voltage distribution in superconducting coils when subjected to external pulse voltage and quench. It can also provide basis for design reference of the superconducting coil insulation.In this thesis, the models of the coils, which may be subjected to the external pulse voltage and quench, are established. The availability of the model is verified. The maximum voltage and voltage distribution in the coil has been numerically analysed.Generally, the superconducting coils consist of a lot of turns. According to the transformer models, a circuit model of suprconducting coils characterized by one turn as a unit has been established. Then the model has been simplified with several turns as a unit, and validated. By analyse the circuit model of the entire system, the transient response can be solved when the coils are subjected to pulse voltage, and both of the maximum voltage and the corresponding voltage distribution can be determined. These results are helpful for designing the internal insulation of superconducting coil.In order to analyse the voltage distribution in the superconduting coils after quenching, a structure model has been established, in which a turn of the coil is divided into a number of small squares. The temperature, resistance and other physical quantities of each cell in each time interval are determined. When the coils quench at different locations, the changes of the temperature, voltage and other parameters are calculated. And then the trends of the voltage distribution in the coils and the voltage between turns and layers are analysed.Learning the over-voltage, to which may be subjected, is helpful for designing the internal insulation of superconducting coil, and is useful for designing the quench protection of the coil.