Transient Stability Analysis of Line Commutated Converter Under Grid Faults

LCC-HVDC inverter is widely used in power transmission, which lacks transient stability analysis when the fault occurs on the grid side. In this paper, the nonlinear differential equations about the advanced trigger are obtained from the control structure of the system, and the dynamic process of the advanced trigger and the transient stability of the inverter side are analyzed in combination with the phase portraits analysis method when the voltage of the grid sags. At the same time, the method of analyzing transient stability under various degrees of voltage drops is improved by combining with the restrictions on the occurrence of the CF. Simulation results in PSCAD/EMTDC prove the validity of the analysis.