SSAT™ is a software tool designed for power system analysis with linearized system models. It includes a number of analysis functions, in both frequency- and time-domain. Study tools are provided for addressing specific problems, making it ideal for investigating oscillatory behavior in power systems and for designing and tuning controls to improve system damping. Like VSAT and TSAT, SSAT can be used to calculate small signal security limits under specified criteria, contingencies, and transfer conditions.


  • Studies of low-frequency oscillations
  • Transmission system design and operation studies, including small signal security limit assessment
  • IPP and renewable integration studies
  • Investigation of sensitivity of system parameters on modes of oscillations
  • Development and validation of system models
  • Performance of power system stabilizer design and tuning using CDT add-on module
  • Performance of subsynchronous resonance analysis using SSR add-on module
  • On-line small signal security assessment


  • Eigenvalue analysis based on analytical linearization of the system equations
  • Various eigenvalue solvers for specific types of modes, such as inter-area modes, local modes, etc.
  • Frequency response and time-domain step response calculations
  • Comprehensive model library, including user-defined models, renewable generation models, special protection system models, and FACTS/HVDC models
  • No limitation on system model size
  • Easy-to-use graphical interface for data setup, program operation, and output analysis
  • Compatibility with major third-party input data formats