Mass-Matrix Differential-Algebraic Equation Formulation for Transient Stability Simulation.

This letter proposes a mass-matrix differential-algebraic equation (DAE) formulation for transient stability simulation. This formulation has two prominent advantages: compatible with a multitude of implicit DAE solvers and can be conveniently implemented based on the traditional formulation, for example, by separating the parameters in denominators into the diagonals of the mass matrix. It also allows reducing the dynamics using null time constants. Benchmark studies are presented on the time and accuracy of 17 implicit solvers for the proposed formulation using the Kundur's two-area system and a 2,000 bus system.