PowerSAS.m is a robust, efficient and scalable power grid analysis framework based on semi-analytical solutions (SAS) technology. The PowerSAS.m is the version for MATLAB/Octave users. It currently provides the following functionalities (more coming soon!):

Steady-state analysis, including power flow (PF), continuation power flow (CPF), contingency analysis.
Dynamic security analysis, including voltage stability analysis, transient stability analysis, and flexible user-defined simulation.
Hybrid extended-term simulation provides adaptive QSS-dynamic hybrid simulation in extended term with high accuracy and efficiency.

Key features

High numerical robustness. Backed by the SAS approach, the PowerSAS tool provides much better convergence than the tools using traditional Newton-type algebraic equation solvers when solving algebraic equations (AE)/ordinary differential equations (ODE)/differential-algebraic equations(DAE).
Enhanced computational performance. Due to the analytical nature, PowerSAS provides model-adaptive high-accuracy approximation, which brings significantly extended effective range and much larger steps for steady-state/dynamic analysis. PowerSAS has been used to solve large-scale system cases with 200,000+ buses.
Customizable and extensible. PowerSAS supports flexible customization of grid analysis scenarios, including complex event sequences in extended simulation term.