Online transmission line impedance parameter identification for distributed generation

An online transmission line impedance parameter identification method is proposed for distributed generation (DG) in this paper. The droop control is adopted for local controller of DG units, which aims to realize accurate power sharing. The impedance parameter model is established by producing a small perturbation on load power after transforming voltage and current to dq coordinate, thus the line resistance and inductive reactance can be identified. The accuracy of this method has been validated in Matlab simulation and experiment based on the direct-drive permanent magnet synchronous generator (PMSG) system.