A new PSS parameter design using nonlinear stability analysis

Electrical phenomena in power systems tend to exhibit higher nonlinearity, because more efficient operation accompanies severer power transfer. In such situations, there might exist some limitation to the use of conventional linear control design scheme due to the nonlinearity of power systems. As for consideration of the nonlinearity, we have developed a nonlinear stability analysis method based on normal form theory. In this paper, we propose a new PSS parameter design scheme based on the nonlinear stability analysis method. The proposed design is effective for suppression of oscillatory instability. In the proposed design, parameters of PSS are adjusted so as to enlarge the stability limit with respect to oscillatory instability. We verify its effectiveness in a longitudinal power system model, and we show that it can enhance the transient stability.