A state-variable-preserving method for the efficient modelling of inverter-based resources in parallel EMT simulation

Abstract

The aggregation models of renewable energy power stations are difficult to apply to the stability research of the fault inside the station or the oscillation analysis between the station and the grid-side system, and the high dimensional characteristics of their detailed model will pose an enormous challenge to the simulation efficiency. To alleviate the contradiction between accuracy and efficiency, this paper proposes a state-variable-preserving method to efficiently model inverter-based resources and a node tearing method to realize parallel simulation of the renewable energy power station consisting of inverter-based resources. The state-variable-preserving model uses discrete state space expression to eliminate the internal nodes on the basis of preserving the original variables of the generation unit and reduces the solving scale of the generation station. The node tearing method reduces the solving complexity of the associated variables, which is more consistent with the topology characteristic that different power generation clusters are interconnected by the same bus. In the case study, the results of numerical accuracy analysis and numerical stability analysis of a photovoltaic power plant verify the reliability of the proposed method, and its simulation efficiency is verified by changing the scale of the photovoltaic power plant.