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

Abstract

Considering the electromagnetic transient (EMT) simulation for a large power system is complicated and impractical, a feasible solution is to model the area not of interest (external system) as a frequency-dependent network equivalent circuit by vector fitting (VF)-based rational approximation methods. However, when the external system is wind power integrated, errors may be generated from the equivalent network by traditional approximation methods. A proposed algorithm in which the wind turbines or dynamic loads in the external system are reduced at its working points of steady-state firstly and the results from VF method are passivity enforced can improve the accuracy of network equivalent both in frequency and time domain. A case study is considered to evaluate the performance of the proposed algorithm and the simulation results prove the validity of the algorithm for the good accuracy and less time consuming in simulation.