A New Stabilizer and Design Algorithm to Minimize the Excitation of Undesirable Oscillations

A new state-space type stabilizer and its design algorithm to minimize low frequency oscillation is proposed. The proposed power system stabilizer (PSS) design algorithm not only damps the oscillations by moving the eigenvalues to desired left hand plane locations but additionally reduces the excitation of the mode itself through optimization of the left eigenvector of the poorly damped electro-mechanical mode. The stabilizer is implemented as a state-space (SS) type controller which is optimized using a constrained optimization procedure. Two possible inputs, speed and electrical power are considered as candidate inputs to the stabilizers. The state-space design is also compared with one based on traditional lead-lag compensation. The SS type stabilizer with electrical power input is shown to perform better compared to any other type of PSS by minimizing low frequency oscillations.