| 摘要 |
PROBLEM TO BE SOLVED: To operate an active filter with an optimum detection method, in accordance with a system state and effectively suppress the harmonics of a distribution system according to the purpose. SOLUTION: An active filter 50 is attached to a distribution line 12f of a distribution system which is switched at the time of a ground failure, etc. The active filter 50 receives a system current and a system voltage, which are detected by a system current detecting means 6a and a system voltage detecting means 6b respectively. A power flow monitoring means 80 monitors a power flow direction at the junction of the active filter, and when the system is switched and the power flow direction is changed, switches a sequence switch circuit 53. A control circuit 54 controls a main circuit unit 55 consisting of an inverter, etc., in accordance with the system voltage or the system current which is inputted via the sequence switch circuit 53 to suppress harmonic voltages or harmonic currents of the system. |
