| 摘要 |
PURPOSE:To restrict an effect of the transient overvoltage, by making the second group transformer to a minimum voltage for operating a parallel running of the second group, which is in no operational condition, when AC-DC changeover tapped transformer of the first group is in an operational condition. CONSTITUTION:In a case that, the first group of the transformers, with AC-DC changeover tap provided, is in an operational condition and the second group is in no operational condition, the parallel closing method of operating the second group transformer in parallel with the first group transformer will be made as follows. With the second group transformer 4 made to a minimum voltage tap, a discrepancy of the tap between the first and second group transformer 3, 4 is detected, and on condition that, AC breaker CB-21, linked to the second group transformer, be made closing, agreement of the taps is made between the first and the second group transformer. In this way, an effect of the transient overvoltage, generated when closing the AC breaker, affecting AC-DC changeover switch is made small, with the tap automatically made agreed, and an operating work can be simplified. |
