AC Network Response Behaviors to Time-Varying Amplitude-Frequency Internal Voltage of Voltage Source Converters

During an AC fault, voltage source converter (VSC) has a different excitation-response characteristic compared with the synchronous generator (SG). As a result, for power systems with a high penetration of VSC-based equipment, the network response behaviors are mainly determined by the VSCs' internal voltage whose amplitude and frequency are time-varying. However, the lumped parameter π-equivalent circuit model is established based on a sine steady-state signal. Thus, in order to analyze the network response behavior, an excitation-response relation model of AC network is proposed. Then, the response behaviors of node-voltage vectors are compared when using two different types line model in electromagnetic transient program (EMTP). Finally, the determinants of network response behaviors are analyzed. The conclusions of this paper indicate that the π-equivalent circuit model is improper and the distributed parameter line model is suggested to simulate the transient behaviors of a power system with high penetration of VSCs.