Study on the Dynamic Performance of AC & DC Hybrid System in China Southern Power Grid

In the AC & DC hybrid system (ADHS) in China Southern Power Grid (CSG), many long-distance, huge-capacity transmission lines operate in parallel. So the reaction and performance of AC & DC system during faults and disturbances have great effect on the stabilization of ADHS. This paper sets up the detail PSCAD/EMTDC models of CSG and analyzes its dynamic performance under different kinds of command or fault, such as step response, control mode transfer, energization of blocked valve group, energization of AC reactive power elements, HVDC system trip, DC line fault, AC system fault, etc.. The study shows that, within the study items in this paper, the control strategy and parameters used in HVDC transmission system in CSG perform well and meet its criterion. The study also shows that, the dynamic characteristic of the ADHS in CSG is favorable.