Finding Semi-Analytic Solutions of Power System Differential-Algebraic Equations for Fast Transient Stability Simulation
For power system operators, this provides a faster transient stability simulation method that maintains accuracy, though it is incremental over existing decomposition-based approaches.
The paper proposes a semi-analytic solution (SAS) approach for fast transient stability simulation of power systems, using Adomian Decomposition Method offline and online evaluation for sequential time windows. On the IEEE 39-bus system, the method achieves accurate trajectories with adaptive time windows, reducing computational burden compared to numerical integration.
This paper studies the semi-analytic solution (SAS) of a power system's differential-algebraic equation. A SAS is a closed-form function of symbolic variables including time, the initial state and the parameters on system operating conditions, and hence able to directly give trajectories on system state variables, which are accurate for at least a certain time window. A two-stage SAS-based approach for fast transient stability simulation is proposed, which offline derives the SAS by the Adomian Decomposition Method and online evaluates the SAS for each of sequential time windows until making up a desired simulation period. When applied to fault simulation, the new approach employs numerical integration only for the fault-on period to determine the post-disturbance initial state of the SAS. The paper further analyzes the maximum length of a time window for a SAS to keep its accuracy, and accordingly, introduces a divergence indicator for adaptive time windows. The proposed SAS-based new approach is validated on the IEEE 10-machine, 39-bus system.