Development of AC network dynamic equivalents for large scale power system

Network equivalent by vector fitting‐based rational approximation in wind power integrated power systems

“…Vector fitting (VF) has attracted wide attention to the frequency‐dependent network equivalent (FDNE) problem due to its robustness and stability [4–9] in which the external system is considered as a black‐box. Current studies about VF‐based network equivalent mostly focus on the detailed process about identifying the element parameters of a linear RLC circuit whose admittance‐frequency characteristic is similar to the given external network [3, 10–12]. However, it is worthy to be noticed that there may exist some complex non‐linear elements such as WTGs which may cause error in the sampling of the frequency response in the external system.…”