Analogized Synchronous-Generator Model of PLL-Based VSC and Transient Synchronizing Stability of Converter Dominated Power System
Qi Hu, Lijun Fu, Fan Ma, Feng Ji, Yan Zhang
Abstract
In this article, the synchronizing dynamic issue of VSC dominated power system is focused on. First, based on the discovered analogous synchronizing dynamical process of VSC (voltage source converter) and SG (synchronous generator), the dynamics of VSC's PLL (phase locked loop) is modeled in the similar form of SG's rotor motion. The influence of control interaction on PLL is modeled in the same way as that of control dynamics on rotor motion. Then the analogized SG model of PLL-based VSC is developed. Based on the proposed model, the analysis idea jointing accelerating-decelerating area method and numerical simulation is employed to study the transient synchronizing stability of single VSC infinite bus system. It is identified that the influence of ACC (alternating current control) on PLL is to accelerate PLL's equivalent motion in first swing, which aggravates the mismatch of accelerating-decelerating area and thus deteriorates the transient stability. Furtherly, the influence factors including ACC's bandwidth, PLL's bandwidth and current references on the transient stability are studied. This article provides a useful analysis idea for transient synchronizing stability analysis of VSC with influence of control interaction considered.