The Influence of Multi-terminal MMC-HVDC on the Subsynchronous Oscillation Characteristics of the Unit

The five-terminal MMC-HVDC in Zhoushan can bring the risk of SSO to the units in the neighbouring Zhoushan power plant. This paper illustrates the five-terminal MMC-HVDC on the topology structure and the working principle of the three-layer control system (the system level, the convert level and the valve level, etc.); the shaft multi-mass model of steam turbine generator in the Zhoushan power plant is established, too. Finally, the simulation model based on the actual power grid in Zhoushan area is established in the RTDS, and the influence of different control methods and operation modes on SSO characteristics of Zhoushan power plant unit is analyzed. This paper reveals the influence of different control methods on SSO characteristics of the units, and the influence of different operation modes on the initial values of the SSO modal