| 摘要 |
PURPOSE: To obtain a harmonic monitor capable of adequately protecting series reactor. CONSTITUTION: In a harmonic monitor 10, a current input in an auxiliary CT54 is input to a processing controller 44 by passing an LPF56 and an A/D converter 52. At the processing control unit 44, the harmonic content of each order and a loss at series reactor are calculated by considering contact α processed by series reactor to be protected, and a loss accumulated in the series reactor in a predetermined time (integral time) is calculated. The loss accumulated in the series reactor increases as the harmonic increase; and if a loss accumulated in the series reactor exceeds a preset protection level, an output relay 58 is operated through a driver 60, the series reactor is tripped from the power source and, in this way, the series reactor can be protected from the harmonics. |
