Impact of Photovoltaic Grid-connected on Distribution of Power System Disturbed Oscillation Center

With the continuous development of photovoltaic (PV) grid-connected technology, the PV grid-connected capacity has increased sustainably. Due to the stochastic volatility and indirectness of PV power, the PV grid-connected technology has greatly influenced system instability mode and oscillation center distribution. The simulation is carried out under two conditions: the location of PV grid-connected; the relative position between fault point and PV power, which is based on the out-of-step oscillation criterion of the bus voltage frequency, the PV power supply model and its control strategy. The results show that the change of PV grid-connected location will change the system's equivalent external characteristics and cause the oscillation center to migrate between different lines. The frequency of oscillation center migration increases when the fault location is closer to the PV grid-connected location.