Coordinated Restraining of SSO via SSDC and SEDC in hybrid AC-DC System Containing MMC-HVDC

摘要

In this paper, aiming on the sub-synchronous oscillation (SSO) of hybrid AC-DC transmission system which contains modular multilevel converter based High Voltage Direct Current (MMC-HVDC), the coordinated control of sub-synchronous oscillation damping controller (SSDC) and supplementary excitation damping controller (SEDC) is researched. Firstly, aiming on the hybrid system, the structure and parameters of SSDC and SEDC are designed. Then, the practicability of the coordinated control of SSO via SSDC and SEDC is studied in both theory an electrical damping characteristics. Finally, the simulation model with 335 levels is built on PSCAD/EMTDC, and the results validate the correctness of the conclusion and the efficiency of the coordinated control strategy. It is found that SSDC and SEDC can superpose each other on increasing the electrical damping characteristic of whole system, and the coordinated control strategy proposed in this paper is practicabe.