Development and Application of Superconducting Pulsed Power System

本研究制作了超导脉冲功率系统，提出了今后进一步扩大超导脉冲功率系统的研究方向。特别是从放电和高压工程的角度研究了超导线圈中感应高压的特性，指出了机械超导断路开关在能量方面的重要性。主要研究成果如下：1.建立了超导脉冲功率系统，并以系统规模和开关电阻为参数，对系统的能效进行了研究。结果表明，大规模脉冲功率系统需要极高的开通电阻和较小的闭合电阻。2.对超导线圈的浪涌传播特性进行了理论和实验研究，以评估系统中弧光放电产生的浪涌电压的电应力。结果表明，浪涌沿绕组传播时，电压波形的形成取决于导体电阻以及线圈与外部电路结合处的反射和传输。测量了Nb-Ti机械开关在液氦中的接触电阻，考察了表面粗糙度和形状对接触电阻的影响。观察到了超导连接的跃迁现象，实现了超导电流大于200A的机械超导开关。

In this study, superconducting pulsed power system was manufactured and considerable subjects in order to enlarge the system in the future were found out. Especially, characteristics of induced high voltage appeared in the superconducting coil was investigated in regard to electrical discharge and high voltage engineering and then development of mechanical superconducting opening switch was indicated to be very important concerning its energy. Obtained results were summarized as follows.1.Superconducting pulsed power systemSuperconducting pulsed power system was built up and energy efficiency of the system was studied by using a scale of the system and a switching resistances as parameters. It was shown that extremely higher resistance of the switch at the opening and smaller closing resistance of 10^<-7>-10^<-10> W were required as necessary conditions in a large-scale pulsed power system.2.Characteristics of surge propagation in a superconducting coilSurge propagation and transient voltage distribution tests were performed the oretically and experimentally in order to evaluate electric stress of surge voltage generated as a result of arc discharge extinction in the system. It was shown that voltage waveform shaping during surge propagation along the windings depended on conductor resistance as well as reflection and transmission at junction of coil and external circuits.Mechanical superconducting switchContact resistance of Nb Ti mechanical switch in liquid helium was measured and the effects of surface roughness and shape on contact resistance were examined. Transition phenomena which showed a superconducting connection at was observed and the mechanical superconducting switch which supported a superconducting current flow of more than 200A was realized.