The conventional passive and active islanding detection methods have large non-detection zones when employed to detect the islanding of the photovoltaic(PV)power station. The changing situation of voltage amplitude and frequency before and after islanding and failure mechanism of the typical conventional active islanding detection method is analyzed firstly. Then the centralized islanding detection method for PV power station is proposed. According to the structural characteristics of centralized reactive power compensation in the PV power station

when the low output active power of PV power station may match the consumed active power of local loads

regulating the power factor to fluctuate within a narrow range by controlling reactive power output by static var generator(SVG)

leading to the mismatching of reactive power between PV power station system and local loads

and islanding is detected accordingly. Theoretical analysis and simulation result has proven that the proposed method can accurately detect islanding of PV power station without none detection zone.