稳定性论文高温超导体稳定性分析与交流损耗.doc

稳定性论文：高温超导体稳定性分析与交流损耗的研究 【中文摘要】超导电力技术的实际应用要求超导电力设备中的超导体具有很高的稳定性,而超导体的失超传播特性和交流损耗是直接影响超导电力设备的运行成本和稳定性的关键因素。本文首先对高温超导带材及线圈的失超传播特性进行了理论研究,分析传热方程,得出失超传播速度的计算表达式,并建立模型求解温度分布。然后分别对YBCO高温超导带材和线圈进行了失超传播实验,测得了不同传输电流和不同触发能量下的电压、温度变化曲线,得出纵向和径向的失超传播速度,并对实验结果进行了讨论。得出如下结论：触发能量的大小不影响失超传播速度,但是较大的触发能量使失超变得提前,超导体存在一个最小失超能,即触发失超需加的最小能量；失超传播速度与传输电流的大小成正比,但是当传输电流小于某一值时,即使加很大的触发能量失超也不会传播,说明超导体还存在一个最小传输电流。然后本文针对两种不同结构的高温超导电流引线的交流损耗建立了新的计算模型。在无限长堆叠带材模型的基础上,考虑外磁场的影响,在电流引线横截面上建立合适的坐标系,利用坐标的平移和旋转求出磁场之和,进而得到穿透区域的曲线,并在穿透区域内积分得到交流损耗的值,本文使用MATLAB编程计算并生成一系列可视化图表。最后,我们搭建了实验平台,对交流损耗的电测法加以改进,设计并实现了三种电测法的实验方案,分别对两种不同结构的电流引线的交流损耗进行了多次实验测量,测得了不同频率下,不同电流下的交流损耗。将三种电测法的实验结果进行了对比,将实验结果与理论值进行了对比,均显示了良好的一致性。 【英文摘要】High stability of the superconductor is needed for the practical application ofsuperconducting power technology. The quench propagation characteristic and AC loss are the key factors for the stability and operating cost of the superconducting power device. In this paper, we first make theoretical research of the quench propagation characteristics for YBCO tapes and coil. The mathematical model is established in order to determine the temperature profile by analysing theheat transfer equation, and a velocity calculation formula is developed. Then quench propagation experiments of YBCO tapes and coils are done, we get the voltage and temperature curves at different currents and input energies. And we get the experimental value of the normal zone propagation velocities (NZPV) both in the longitudinal and radical direction. Then we analyse the experimental results.Draw the following conclusion: the input energy of the superconductor tapes and coils hardly affects NZPV. With larger input energy, quench occurs earlier, however NZPV keeps constant. Quench can抰 propagate when the transfer current is too small, even if the input energy is large.Then, AC loss calculation models for two different structures of current leads are built. Based on the Clem model, the effects of external magnetic field are taken i