72kVA四巻線構造超電導変圧器の試作 (II) クエンチ特性
1988 年 23 巻 6 号 p. 362-368
詳細
1988 年 23 巻 6 号 p. 362-368
We have studied experimentally quench processes in a 72kVA superconducting four-winding power transformer. Quenches in main windings were initiated by excess current due to sudden short-circuit or a local heating. An instantaneous decrease in the transport current originated from appearing extensive normal regions just after the short-circuit was observed in both of the primary and the secondary main windings. Similar phenomena were generated by a local heating in the secondary main winding. The equivalent propagation velocity of normal zones along the winding during the first half cycle after the initiation of the quench was about two orders larger than the existing theoretical predictions. Two dimensional propagations of the normal region were observed after the instantaneous transitions to the normal state in the main windings. We discussed the mechanism of these abnormal transition to the normal state in relation with possibility of quench protection in AC superconducting windings.
