Dynamic Equivalents of Active Distribution Networks Considering IBDG Transient Characteristics

Abstract

In modern power systems, Inverter-Based Distributed Generators (IBDGs) are rapidly increasing. Their aggregated effects alter the dynamic characteristics of the active distribution network (ADN). However, the typical model of ADNs does not consider the transient characteristics of IBDGs, leading to an inaccurate characterization of the dynamic characteristics of ADNs. This paper proposes an ADN equivalent model that considers the transient characteristics of IBDGs. Firstly, the detailed ADN model with IBDGs and the corresponding typical model are constructed, and the effect of IBDG on the accuracy of the equivalent model under large disturbances is analyzed. To characterize the transient behavior of IBDGs, the Low-Voltage-Ride-Through (LVRT) exit time is introduced. Subsequently, the AGglomerative NESting (AGNES) algorithm is used to cluster IBDGs within ADN based on their LVRT exit times. The determination of several clusters is based on multiple evaluation indexes. Then, a parameterization method is given for an ADN equivalent model structure applicable to IBDG grouping. Finally, the effectiveness of the proposed model is demonstrated by constructing practical engineering. Simulation results illustrate that the proposed model accurately reflects the transient characteristics of ADN and maintains high accuracy under different operating conditions.