
86 Introduction to Electrical Power and Power Electronics
The excitation control system modeling for analytical studies must be carefully
done as it forms multiple feedback control loops that can become unstable. The IEEE
has developed an industry standard for modeling the excitation systems. The model
must account for any nonlinearity due to magnetic saturation that may be present in
practical designs. The control system stability can be improved by supplementing the
main control signal by auxiliary signals, such as speed and power, as required by the
feedback control system stability.
3.10 SHORT CIRCUIT RATIO
The short circuit ratio (SCR) of ...