Quasi-Periodic Mode
In some ferroresonance cases, the waveform includes a repetition of a pattern, as shown in
Figure 6(a). However, the peak magnitudes of the pattern change as the pattern is continuously repeated in the waveform. This oscillatory mode is not a periodic one and due to its similarity to a periodic waveform, it is referred to as the quasiperiodic mode.
The frequency spectrum of this mode indicates two base frequency components fA and fB, Figure
6(b), and the other frequency components are the linear combinations of these two base frequency components. The Poincare map of the quasi-periodic mode represents a closed loop of the voltage and current samples, Figure 6(c).