Impedance Modeling and Stability Analysis of LCC-HVDC Transmission System

The risk of wideband oscillation in the new energy base system via grid-connected commutated converter-based high voltage direct current (LCC-HVDC) is a serious constraint to the safe operation of the system. Impedance modeling has gradually become an effective method for analyzing and solving large-scale new energy grid-connected oscillation problems. Firstly, based on the impedance analysis method, this paper establishes an impedance model for the LCC-HVDC main circuit and control structure in response to the frequency coupling phenomenon in the LCC-HVDC transmission system. Secondly, establish a simulation model on Matlab/Simulink and verify the accuracy of the LCC-HVDC impedance model through frequency sweep. Finally, the stability analysis of the LCC-HVDC transmission system is carried out using the obtained impedance model. The simulation results show that the established impedance model can correctly represent the stability of the system.