Power System Simulation Using the Differential Transformation Method

This paper proposes a new semi-analytical approach for online time-domain power system simulation. The approach applies the differential transformation method (DTM) to the power system differential equation model to offline derive a semi-analytical solution (SAS) having symbolic variables about time, the initial state and system conditions. When simulation is online needed for a contingency under the current system condition, the SAS can be evaluated in real time to generate simulation results. Compared to the Adomian decomposition method in obtaining a power system SAS, an SAS derived by the DTM adopts a recursive form to avoid generating and storing its complete symbolic expression, which makes both derivation and evaluation of the SAS more efficient especially for multi-machine power systems. The optimal order of a DTM-based SAS is studied for the best time performance of simulation. The paper also designs a parallel computing strategy for power system simulation using the DTM-based SAS. Tests on the IEEE 10-machine 39-bus system demonstrate significant speedup of simulation using the proposed approach compared with the Runge-Kutta method.