Mathematical Modeling for Collective Response of Photovoltaic Station Considering Intrinsic Dynamics Under Low Voltage Ride Through

Modern power system features growing complication and vulnerability with largely-penetrating renewable generation. The collective response of renewable power stations plays an important role in the dynamic study. However, the conventional disposal of an entire station as a one-off simultaneous trip-off oversimplifies the local intrinsic dynamics within station, probably resulting in unreliable estimation on system-level dynamics. In this paper, an external formulation describing the aggregation collective response of photovoltaic (PV) power station under grid disturbance is proposed, considering the multi-step -shaped in-station dynamics. Such a formulation is in a closed-form rather than dependent on iteration. It is achieved by decoupling the state variables in the voltage distribution model on the basis of reasonable simplification and correction afterwards. The proposed formulation is straightforward so that it can improve the simulation authenticity if integrated into system-level studies. It explicitly illustrates which variables dominate the local dynamics within PV station. The validation based on MATLAB platform confirms that the proposed model can efficiently and accurately describe the intrinsic multi-step -shaped dynamics of PV station during low voltage ride through.