Transient Stability of Multiple Phase-Locked-Loop-Type Voltage Source Converters System Based on Amplitude Mapping Model

Abstract

Compared to the traditional power grids, the multiple converters integration system are more vulnerable to the disturbances from transient events. However, the high-order characteristics of the system model is still a barrier not ignored. Inspired by averaging method of nonlinear vibration, the amplitude mapping model (AMM) is firstly proposed to evaluate the transient stability for multiple phase-locked-loop-type (PLL-type) voltage source converters (VSCs) system in this paper. Specifically, the origin and meaning of amplitude mapping model is introduced. Next, the mathematical model of the PLL-type VSCs system is derived. Based on AMM, the stability evaluation strategy of the PLL-type VSCs system is obtained. After that, the influence of key parameters, including the system gSCR, d-axis current reference, and PLL control parameters, on the system stability and the coupling effect between the VSCs are analyzed. Finally, a 6-VSCs 14-nodes system is applied to verify the correctness of the method proposed in this paper.