Effects of Feed-Back Signals on Transient Stability - Phase Plane Approach

A great deal of attention is being given to the problem of using feed-back signals in the excitation systems. It has been shown that the transient stability limits improve if signals besides the terminal voltage deviation are fed to the excitation system. A number of different signals based on the rates of change of voltage, current, power and rotor angle have been either tried or suggested. It appears that during the next few years the feed-back signals will play a very important role in the design of excitation systems.