A DISCRETE-TIME STATE SPACE MODELLING METHOD APPLYING TO SSO OF RENEWABLE POWER GENERATION

With an increasing integration of renewable power generation (RPG) in the power system, the issue of sub-synchronous oscillation (SSO) is becoming increasingly significant. In this paper, a discrete-time state space modelling and analysis approach with nodal analysis method for SSO investigation is proposed, which solves the disadvantages of traditional eigenvalue analysis method in the face of complex power grids, especially the inconvenience of modelling improper network. This new method modularizes the system components and can directly obtain the discrete transition matrix of any complex network through coefficient matrix expansion. The stability of the system can be discussed by analysing the eigenvalues of discrete-time state matrix in z- and s-domain. The accuracy of the new method is validated by simulation results of a practical wind farm example in northwestern China.