Research on Bifurcation and High-Frequency Stability of the Secondary System in the Measurement Link of Flexible DC Power Transmission

During operation of the Chongqing-Hubei & Zhangbei flexible DC projects, high-freq resonances emerged. This article analyzes the dynamics of electromagnetic CTs, constructs a state space model for an isolated flexible DC new energy system with no-load current measurement. Using avg iteration, a current bifurcation diagram under cable param changes is obtained, verifying bifurcation during resonance via simulations. Nonlinear theory explains modulation wave changes & control saturation's effect on resonance. Model accuracy & resonance mechanism are validated through simulations & condition comparisons, offering tech guidance for flexible DC projects.