Impedance-Decoupled Modeling Method of Multiport Transmission Network in Inverter-Fed Power Plant

This article presents an impedance-decoupled modeling method of multiport transmission network in an inverter-fed power plant, which is able to simplify modeling and stability analysis procedure for power plant with complicated transmission network. Impedance-decoupled models of three-port and four-port transmission networks are first established. On the basis of them, impedance-decoupled model of multiport transmission network is derived, where transmission node with multiple branches is modeled by means of Norton equivalent circuit. Furthermore, based on the proposed impedance-decoupled network modeling method, the whole power plant is divided into multiple subsystems, and Nyquist stability criterion is performed for all subsystems, where oscillation source can be identified in an explicit way. Simulation and experimental results are given to validate effectiveness of the proposed impedance-decoupled modeling and stability analysis method. The proposed modeling method is able to simplify modeling procedure of large-scale power plant with complicated transmission network, which is also applicable in power plant with various transmission network topologies.