Computation comparisons of power system dynamics under random excitation

To compute the dynamic responses of power systems under random excitation, several comparisons are made in this paper. First, the nonlinear and linearized stochastic differential equation (SDE) models for the one machine to infinite bus system are compared. Results indicate that the linearized SDE model is suitable only for small random excitation. Second, two numerical methods, i.e., the Euler-Maruyama method and the Heun method, are compared. The Heun method has higher numerical stability and accuracy. Third, the computational intervals are compared. Results indicate that an appropriate range exists for the calculation time interval. Furthermore, random excitation with different time intervals (i.e., frequencies) may induce the rotor angle oscillation with almost the same natural frequency.