Natural modes in SR-compensated transmission networks

The authors´ study of the subharmonic modes of oscillatory response to which the combination of saturated reactors (SRs) and their slope-correcting capacitor circuits give rise in networks for which SRs provide voltage-control functions. The authors identify the range of modes, and the distinguishable forms of mode responses, that can be encountered. For these purposes, a procedure is adopted in which the contribution of SR bypass filters in very effectively suppressing or damping out subharmonic oscillations is initially discounted. Several different forms of modal response then emerge. The authors conclude with an example which indicates the very effective suppression or damping of subharmonic modes which SR bypass filters decisively achieve. The view is expressed that subharmonic mode identification provides a comprehensive basis for optimal by-pass filter design