Large step size electromagnetic transient simulations by matrix transformation-based shifted-frequency phasor models

摘要

To evaluate and improve the performances of control and protection strategies for large-scale AC grids, simulation models that can adopt a much larger time-step, provide instantaneous and wide frequency-band phasor values simultaneously are desirable. However, the traditional electromagnetic transient (EMT) model is numerically expensive and the transient stability (TS) model only preserves low-frequency dynamics. To resolve these issues, the shifted frequency phasor (SFP) modelling is generalised based on specific matrix transformations and SFP models of typical components in large-scale AC grids are derived hereafter. Unlike traditional models, the SFP models can produce instantaneous and wide frequency-band phasor waveforms simultaneously, while the latter matches the envelopes of the former exactly. Moreover, the simulation efficiency is dramatically improved by adopting a much larger time-step. The performance concerning the accuracy and efficiency is compared with the traditional EMT and TS models by simulating a practical large-scale AC grid under different scenarios.