Quantitative Analysis Method for Subsynchronous Oscillation Power Propagation Characteristics of Wind Power Connected to Grid

The subsynchronous oscillation power caused by large-scale wind power connection to the grid and the large-scale propagation of oscillation energy in the grid leads to system power fluctuations and may result in grid cascading accidents. This paper proposes a quantitative analysis method for the propagation and distribution characteristics of the oscillation power. First, the manifestation and formation mechanism of subsynchronous oscillation power is studied based on instantaneous power theory. Second, two quantitative indicators, namely the oscillating power node propagation intensity and branch transfer coefficient, are proposed to characterize the oscillating power propagation characteristics. Analysis of the oscillating power propagation characteristics and their influencing factors shows that the frequency of the oscillating power is the frequency of the system power frequency minus that of the oscillating current. The two quantitative indicators provide an effective method for locating the critical nodes and identifying the propagation path of the oscillating power propagation. Finally, simulations are conducted to verify the accuracy of the theoretical analysis and demonstrate the validity of the proposed quantitative analysis method.