Coupling Characteristics of Subsynchronous Oscillation Frequencies in Multi-Renewable Power Plants Integrated to Power System

The subsynchronous oscillation (SSO) frequently occurs in the renewable power plants, which is harmful to the stability of power system and the development of the renewable power. This paper studies the coupling characteristics of subsynchronous oscillation frequencies in multi-renewable power plants integrated to power system. Combined with the characteristics of PLL and Park’s transformer, the analysis of the mechanism on the oscillation frequencies coupling is carried out. Then, based on eigenvalue analysis and simulation analysis, a case that multi-wind farms integrated to power system is considered to verify the mechanism analysis. A conclusion can be made that the characteristics of PLL and Park’s transformer cause the oscillation frequencies coupling in the multi-renewable power plants integrated to power system. At the same time, the influence of the oscillation components derived by natural modes on the system should be considered.