To certainly detect islanding at reactive-power balance.
A method for detecting islanding includes:determining, when additional injection reactive power of a predetermined phase is injected additionally for a fixed period when an immediate injection reactive power is balanced with a load reactive power, the phase of the immediate injection reactive power on the basis of the sign of a system frequency deviation after a period shorter than the fixed period passes after the injection of an additional reactive power;injecting, when the phase of the immediate injection reactive power from the sign of the system frequency deviation at the time of the decision is in antiphase with the predetermined phase of the additional injection reactive power, the additional injection reactive power of the phase corresponding to the sign of the system frequency deviation for the fixed period again;and continuing, when the phase of the immediate injection reactive power from the sign of the system frequency deviation at the time of the deviation is in phase with the predetermined phase of the additional injection reactive power, the injection of the additional injection reactive power by the same phase for the period left until the fixed period elapses after the injection of the additional injection reactive power.
MABUCHI MASAO
TSUBOTA YASUHIRO
| JP2009136096A | 2009-06-18 |