Transient Stability Boundary of a Droop-Controlled Voltage Source Converter with Different Control Parameters

Abstract

Voltage source converters (VSCs) equipped with P-f and Q-U droop control can provide voltage and frequency support for power grid. The safe and stable operation of the VSC is of great significance to the power system. However, under fault conditions, a VSC may lose transient stability, similar to synchronous generators (SGs). The transient stability boundary of VSCs can provide guidance for the transient control, but there are few researches about the quantitative description of VSC transient stability boundary. Based on these, the critical clearing angle (CCA) and critical clearing time (CCT) are analyzed quantitatively to describe the transient stability boundary of a VSC under different control parameters and fault conditions. Finally, simulation tests are performed to validate the correctness of the theoretical analysis.