A study on S/N transition type and DC reactor type fault current limfter.

研究了一种直流电抗器型和一种直流S/N过渡型故障限流器，该限流器采用高温超导线圈，通过二极管电桥与Transformer的次级绕组相连，高温超导体较好地应用于直流电抗器或S/N过渡型故障限流器，其中限流元件可以在低电压和DC电流下工作。另外，本发明的特点是在三相电力系统中只需要一个限流元件。此外，它还具有两种方式之一的故障限流中断（FCLI）功能;直流混合三相故障限流断续器作为由HTS电抗器和S/N过渡元件组成的折衷装置也是可行的，S/N过渡元件设置在电抗器内，通过实验和理论分析，比较了这三种装置的故障限流性能，明确了在线圈体积最小的情况下，每线圈体积的中心磁场在线圈纵横比处最大。对于组装的导体，需要建立不均匀电流预防。提出了一种利用相间电抗器使各股电流相等的方法，并通过实验验证了其有效性，明确了实现S/N过渡型和直流电抗器型故障限流器的研发目标。

The purpose of this work is to study a dc reactor type as well as a dc S/N transition type fault current limiter (FCL) using high temperature superconducting(HTS) coil, which is connected with the secondary winding of a transformer through a diode bridge.The high temperature superconductors are preferably applied to the dc reactor or the S/N transition type fault current limiters, where a current limiting element can be operated at both low voltage and dc current. In addition, it features that this device requires only one current limiting element in three-phase power system. Further, it has a function of fault current limiting interruption(FCLI) in one of two ways ; automatic interruption of a fault current with the assistance of a bias current applied to the bridge or gate interruption by blocking thyristor's gate pulses.A dc hybrid three-phase fault current limiting interrupter is also feasible as a compromised device composed of an HTS reactor and an S/N transition element, set up within the reactor, connected in series each other.The performances of a fault current limiting interruption as for above three devices were confirmed both experimentally and analytically and their characteristics were compared.It was made clear that the central magnetic field per coil volume is maximal at the coil aspect ratio providing the minimum coil volume. An establishment of the unequal current prevention is being required for assembled conductors. A method, which makes the current flow equal in each strand, is devised by means of interphase reactors, and its effectiveness was confirmed experimentally.The target of research and development to realize S/N transition type and dc reactor type fault current limiter was made clear by the above researches.