The fundamental frequency models cannot be used in wider
frequency range since they only give the relationship among
fundamental components of variables when at steady-state.
Conventionally, the electromechanical transient programs like
EMTP or PSCAD/EMTDC are used for TCSC transient
stability analysis. These simulation tools are accurate but they
employ trial and error type studies only, implying use of a
large number of repetitive simulation runs for varying
parameters in the case of complex analysis or design tasks. On
the other hand, the application of dynamic systems analysis techniques or modern control design theories would bring
benefits like shorter design time, optimization of resources and
development of new improved designs. In particular, the
eigenvalue and frequency domain analysis are widely
recognized tools and they would prove invaluable for system
designers and operators. These techniques however always
necessitate a suitable and accurate dynamic system model.