Parallel Dynamics Simulation Using a Krylov-Schwarz Linear Solution Scheme

Fast dynamics simulation of large-scale power systems is a computational challenge because of the need to solve a large set of stiff, nonlinear differential-algebraic equations at every time step. The main bottleneck in dynamic simulations is the solution of a linear system during each nonlinear iteration of Newton's method. In this paper, we present a parallel Krylov-Schwarz linear solution scheme that uses the Krylov subspace-based iterative linear solver GMRES with an overlapping restricted additive Schwarz preconditioner. Performance tests of the proposed Krylov-Schwarz scheme for several large test cases ranging from 2000 to 20000 buses, including a real utility network, show good scalability on different computing architectures.

I. Introduction

Dynamics simulation, or transient stability analysis, is an important function in the planning, design, and post-disturbance analysis of power systems but its application is restricted to offline studies because of the computational requirements. Providing system operators with the capability to examine the system dynamics in real-time, or faster than real time, creates a new paradigm in power system operation by facilitating real time or predictive control actions. This is particularly important because the power system behavior is becoming increasingly dynamic.