The use of Laplace transforms in the simulation of power system frequency transients

The differential equations describing a frequency transient are solved in the Laplace domain: a numerical inverse transformation method is used in conjunction with an iterative technique to account for system nonlinearities. This method has the advantage of "filtering out" synchronizing oscillations between individual machines, thus speeding up the solution process. If a complete numerical integration time-domain solution is needed the S-domain method can be used to 1) assess directly the sensitivity of the solution to changes in the model, thus enabling model reduction. 2) determine regions with common average frequency.