| 摘要 |
PURPOSE:To eliminate the erroneous operation of an overcurrent protecting device by altering the set overcurrent value supplied to a discriminator based on a terminal voltage of a synchronous machine. CONSTITUTION:Varying means 30 adds the terminal voltage Vg of a synchronous machine 1 and the set value KIRO from an overcurrent setter 302 and outputs an overcurrent set valueIR. When the field current detected by a field current detector 21 becomes higher than the valueIR, a memory circuit 23B of a discriminator 23 stores the field current to open an analog switch 23C. Thereby, it is applied to a pulse phase shifter 7 which supplies a gate pulse to a thyristor 3 from a voltage deviation detector 6, thereby interrupting a deviation signal. In this manner, the erroneous operation of the overcurrent protecting device can be prevented when a shortcircuit accident occurs at the system side. |
