Symbolic Reduction for High-Speed Power System Simulation

High-speed simulations of power transmission systems, which often rely on solving nonlinear systems of equations, are an increasingly important tool for training, testing equipment, on-line control and situational awareness. Such simulations, however, suffer from two major problems: (1) they can be too computationally demanding to simulate large, complex systems within appropriate time constraints; and (2) they are difficult to develop and debug. Prior work has shown how symbolic computation can be used to help reduce both problems. In this paper, we: (1) review common concepts in power system simulations; (2) summarize prior use of symbolic computation in power system simulation; (3) explore the advantages and disadvantages achieved via symbolic techniques; (4) extend the techniques to solve linear systems via a priori symbolic LU decomposition; and (5) demonstrate the advantages of symbolic techniques on a transient event simulation of the IEEE 118-bus test power system, which runs in one-tenth the time of an equivalent traditional (sparse matrix) approach.