Transients of Synchronous Generator with PIDD2 Excitation Controller at Stability Boundary

Stabilization of the nonlinear generator model was carried out by PIDD
₂
excitation controller. We've found system stability boundary on proportional control parameter axis and limits of stabilizable voltage surges or slumps on buses. Transients in the neighborhood of the boundary point exhibit five main types of stability and unstable dynamics. Nonlinear closed loop system is unstable to sufficiently small perturbations and turns out to be stable to not too small ones in the instability domain of its linearization. In a certain area the steady-state oscillations amplitude increases while the initial perturbation decreases; it can be regarded as cumulative hunting.