Stability analysis of AC/DC power transmission system based on bifurcation theories

Bifurcation theories are widely applied in the analysis of both static and dynamic characteristics of power systems for they can be of tremendous value for our understanding of the instability issues of a power system. In this paper, the dynamic characteristics of a power system with HVDC transmission system has been studied with nonlinear bifurcation theory, in addition, eigenvalues analysis and time-domain simulation are also used to study this problem. First, the dynamic stability of the control modes of HVDC system are studied with bifurcation analysis and the relationships between dynamic analysis and static analysis of HVDC are revealed, factors that affect HVDC stability has been pointed out. Second, bifurcation theory is applied to the analysis of an AC/DC interacting power system. With the single-parameter and multi-parameter bifurcation analysis, it´s been showed that increasing the magnitude of power ratio in a DC transportation system can greatly improve the system stability; while too much HVDC controlling amplification is detrimental to the system stability.