Application of Nonlinear Stability Indices of Power Swing Oscillation to Analysis of Autoparametric Resonance in Longitudinal Power Systems

We have proposed nonlinear stability indices of power swing oscillation using normal form theory. The proposed indices are effective when there are several modes to be focused on. For each oscillation mode, the proposed indices indicate the characteristics of damping factor with regard to its amplitude change, and the stability region. In this paper, we apply the indices to autoparametric resonances between oscillation modes in longitudinal power systems. It is shown that we can evaluate stability of the power systems appropriately by modifying the proposed indices taking the autoparametric resonances into consideration.