| 摘要 |
PURPOSE:To quickly cut off a synchronous phase modifier from a power system and prevent the malfunction during operation with low excitation by detecting the excessiveness of the rate of change of the current of a main circuit and the drop of a field current thereby detecting the abnormality of the synchronous phase modifier. CONSTITUTION:A current converter 12 detects the current of the main circuit of a synchronous phase modifier 1. A rate-of-current detector 13 operates the rate of change of the current detected by the current converter 12, and outputs a detection signal b when this operation value is above the specified value. A field current drop detector 14 outputs a detection signal c when the field current from a field current detector 1a is below the specified minimum current. A control circuit 15 detects the abnormality of the synchronous phase modifier 1 by the materialization of AND conditions of the close signal a of a breaker 4 for parallel, the detection signal b of a rate-of-change detector 13, and the detection signal c of the field current drop detector 14, and outputs the open signal d of the breaker 4, and isolates the synchronous phase modifier from the power system quickly. Moreover, hereby it never wrongly judges that it is field loss during rather weak exciting operation and stops the synchronous phase modifier needlessly. |
