Modeling of LCC-HVDC Stations Based on Concept of Motion Equation

Line Commutated Converter based High Voltage Direct Current (LCC-HVDC) Transmissions are widely applied in transmitting large-capacity electricity in China. The stability of power system may be threatened due to dynamic interactions between multiple large-capacity converter stations in AC and DC power grids. Several studies have reported some stability problems caused by the dynamic interactions in AC and DC power grids, but mechanism of the dynamic interactions has not been totally understood. To analyze the dynamic interactions between multiple converter stations in AC and DC power grids, this paper presents a small-signal model to understand the external characteristic of LCC-HVDC stations based on motion equation concept. Comparison of time-domain simulation response with detailed switching model shows that the proposed model can hold the main behaviors of concern. Dynamic interactions between multiple converter stations in AC and DC power grids will be studied based on the proposed model in the future.