A highly parallel method for transient stability analysis

Abstract

A simple but powerful method for solving the transient stability problem with a high degree of parallelism is implemented. The transient stability is seen as a coupled set of nonlinear algebraic and differential equations. By applying a discretization method such as the trapezoidal rule, the overall algebraic-differential set of equations is transformed into a unique algebraic problem at each time step. A solution that considers every time step, not in a sequential way, but concurrently, is suggested. The solution of this set of equations with a relaxation-type indirect method gives rise to a highly parallel algorithm. The parallelism consists of a parallelism in space (that is in the equations at each time step) and a parallelism in time. Another characteristic of the algorithm is that the time step can be changed between iterations using a nested iteration multigrid technique from a coarse time grid to the desired fine time grid to enhance the convergence of the algorithm. The method has been tested on various size power systems, for various solution time periods, and various types of disturbances. It is shown that the method has good convergence properties and can significantly increase computational efficiency in a parallel-processing environment. >