Study of interactions between close HVDC links inserted in an AC grid: A mixed nonlinear and modal analysis approach

摘要

This paper focuses on interaction between two closed-connected high-voltage direct current (HVDC) lines. This interaction is studied by employing high-fidelity nonlinear modelling in MATLAB/Simulink software environment. In order to describe the mechanism behind the HVDCs interaction, both nonlinear time-domain simulations and modal analysis of the coupled HVDC links have been performed. System small-signal stability has been assessed, and the path of interactions has been identified by computing the participations of various states in the oscillatory modes; this sets the preliminaries for a global, grid-oriented HVDCs control design approach. After the detailed analysis of newly identified coupling oscillations, the minimal modelling requirements to put them into evidence have also been studied; this significantly facilitates the analysis in a realistic large-scale grid context.