Parallel-in-Time Power System Simulation Using a Differential Transformation Based Adaptive Parareal Method

For parallel-in-time simulation of large-scale power systems, this paper proposes a differential transformation based adaptive Parareal method for significantly improved convergence and time performance compared to a traditional Parareal method, which iterates a sequential, numerical coarse solution over extended time steps to connect parallel fine solutions within respective time steps. The new method employs the differential transformation to derive a semi-analytical coarse solution of power system differential-algebraic equations, by which the order and time step, as well as the window length with a multi-window solution strategy, can adaptively vary with the response of the system. Thus, the new method can reduce divergences and also speed up the overall simulation. Extensive tests on the IEEE 39-bus system and the Polish 2383-bus system have verified the performance of the proposed method.