| 摘要 |
PROBLEM TO BE SOLVED: To release a condensive capacitor at an overload state or an overvoltage state, by monitoring whether the phase advance capacitor is in a thermal overload or overvoltage state when the phase advance capacitor is put in a power system. SOLUTION: When an electromagnetic contactor 6 is closed and a current at a phase advance capacitor 4 is detected by a CT 7, and a harmonic current factor for each order is detected through an A/D converter 23 and a fast Fourier transform circuit (FFT) by using a harmonic factor measuring unit 21. A monitoring alarm unit 25 detects a thermal overload or overvoltage state of the capacitor 4 on the basis of the measured data and judges whether the overload or overvoltage state is caused or not. When the result detected is an overload or overvoltage state, the signal is entered through a signal inversion circuit 27 and the phase advance capacitor 4 is released by a capacitor actuating control unit 8. |
