| 摘要 |
PURPOSE:To prevent the secondary trouble due to a circulating overcurrent by operating a control rectifier set in the direction opposite to a faulty system in an adverse converting area and operating a nondefective unit control rectifier set in the same direction as the faulty system in a forward area after a fixed period of time. CONSTITUTION:When a unit control rectifier has a fault, this rectifier has an instant gate blocking. At the same time, a unit control rectifier connected in adversely parallel has an instant gate shift to be operated in an adverse converting area. While a unit rectifier connected in parallel to a faulty rectifier has a gate advance after a period of time set by a delay circuit 16-2 and is operated in a forward area. Then this rectifier has a gate shift after a period of time set by a delay circuit 12-2 and is shifted to an operation in an adverse converting area. As a result, the circulating current between unit control rectifiers is suppressed or cut off. Then the nondefective unit control rectifier set in the same direction as a faulty unit control rectifier is operated in a forward converting area. Thus a faulty current of a faulty unit control rectifier is cut off, and then the nondefective control rectifier has a gate shift. As a result, a direct current is produced at the AC side. |
