| Superconducting Magnetic Energy Storage(SMES)systems,with its good qualities like fast response,high energy storage density,small loss,are necessary part in energy storage technology,and is been used for improving power quality and alleviating intermittency.Due to the fact that PCS in SMES system adopts a Pulse-width Modulation(PWM)converter with high carrier frequencies,the output voltage will cause overvoltage at the terminals of the magnet.Moreover,the high-frequency components of the voltage will lead to uneven distribution over the magnet's internal windings.All this can lead damage to the insulation part and even cause failure in the system's normal operation.This paper has completed the following works:(1)Established a high-frequency transient model of high temperature superconducting(HTS)magnet,analyzed the magnet winding parameters algorithms.Established the analytical method,linear time invariant(LTI)system to solve equivalent circuit of the magnet's transient model.And design experiment to test the acuracy of the high frequency transient model and the analytical method of LTI system.(2)Summarized the reflection and refraction transmission characteristics of the connecting cable and the current lead on the condition of PWM voltage output,analyzed the influence of all the factors on the magnet's and the system's voltage distribution,selected and concluded the vital factors and their effect.(3)On the basis of electromagnetic magnet design method,multiple magnet design plans are proposed,aboved transient modeling are established and voltage distribution is analyzed in the respective models to give information on the plan selection.After the optimazed plan is selected,other factors which have influence on the system voltage distribution are also analyzed and preferred parameters are given to minimize the overvoltage problem.Besides,the insulation design and filter design are also proposed for further analysis. |
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