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Oscillation mode identification of Guizhou-Guangdong II HVDC transmission system

Since Guizhou-Guangdong II high voltage direct current (HVDC) transmission system was put into operation, several activation events of subsynchronous damping control have occurred successively, indicating that there are risks of oscillation instability to some certain extent. This paper studies the oscillation modes of Guizhou-Guangdong II HVDC transmission system based on its detailed parameters and system structure. Firstly, the small signal model of the system is established based on the actual system parameters and system structure. By comparing the calculation results of the small signal model and the simulation characteristics of the detailed electromagnetic transient model, the correctness of the established small signal model is verified. Then eigen-analysis and participation factor methods are used to identify the oscillation modes of the system and explore the mode features and the main participating parts. Finally, these oscillation modes are further classified and analyzed according to the main participating parts. The results can provide guide to find out the causes of oscillation instability of Guizhou-Guangdong II HVDC transmission in the future.