An aggregated dynamic model of Photovoltaic units for large voltage disturbances

Abstract

Many Photovoltaic (PV) units connected to the low-voltage level greatly impact the distribution network’s dynamic characteristics. However, the dynamic characteristics of PV units under large disturbances are widely different, which leads to the model being unable to effectively describe the dynamic performance of aggregated PV units in the low-voltage transient stability analysis. To overcome this issue, an aggregated dynamic model of PV units is proposed in this paper. First, a general dynamic model of a PV unit is proposed, focusing on the control triggered by voltage disturbances, and multiple PV units is established based on ADPSS. The simulation results show that the major factor which influences the transient characteristics of multiple distributed PV units is its Low Voltage Ride-Through (LVRT) control. Then, an aggregated dynamic model that can describe the multiple transient characteristics is proposed. The simulation verifies that the proposed model can effectively represent aggregated transient characteristics.

Keywords

• Low voltage ride-through
• Dynamic modeling
• Photovoltaic units
• Grey-box model