Digital simulation of AC/DC hybrid transmission system

For the 3000 MW Gui-Guang HVDC power transmission project, the NETOMAC (Network Torsion Machine Control) program was used to simulate the complete power system of South China, which includes AC/DC hybrid transmission systems. The simulation results of the NETOMAC program are compared with the results from the BPA (Bonneville Power Administration) program used by the owner of the Gui-Guang HVDC system. The fundamental differences of generator models between the two simulation programs are analyzed by comparing the results of a new simulation composed of a two-generator model. For the complete power system, the simulation results between the two programs show good agreement for both the load flow an dynamic cases. Finally, the studies of system stability and power oscillation damping for South China´s power system including the Gui-Guang HVDC system is briefly discussed. The possibility of the HVDC system providing an overall enhancement of system stability is shown.