A Dynamic Frequency-and-Voltage Power Flow Simulation Tool for Hybrid AC/DC Power Systems based on Simulink

Abstract

A more renewable energy generation model entails the replacement of synchronous generator-based power plants by converter-interfaced renewable sources, resulting in more susceptible power systems in terms of frequency and voltage oscillations under sudden power perturbations. In addition, dc-based power systems are becoming very popular thanks to the advantages they offer compared to classical ac systems. This has created a need for developing new time-domain simulation tools to represent the dynamic behaviour of converter-dominated, hybrid ac/dc power systems. This paper presents a Simulink® based simulation tool, named DFPF, that can be used to study the dynamic performance of ac, dc and hybrid power system scenarios. The DFPF tool consists of combining the dynamical models of grid-connected elements with the iterative solving of a static power flow algorithm of each part of the power system. The Simulink interface simplifies the implementation of element models and power system test scenarios, and since fast electromagnetic transients are not considered, medium-term simulations can be carried out rapidly for relatively complex scenarios. To test the tool, a hybrid scenario comprised by four ac grids interconnected by a multi-terminal dc grid is implemented and simulated. The results demonstrate that the DFPF tool can be employed to evaluate the transient response of interconnected ac and dc systems under different grid conditions.