Subsynchronous oscillation mechanism and analysis for wind farm integration through HVDC system

Subsynchronous oscillation of wind farm integration through HVDC system includes both AC series compensation lines and DC transmission lines, which is difficult for the analysis. In this paper, a simplified model of the actual wind farm is established and time-domain waveforms are gotten by the simulation. Transient waveforms in the system are closely related to the operating status and reveal some possible failures. Chaos and fractal theory are used to analyze the transient waveform in the system. By extracting characteristics values, a new fractal dimension and mean density method is proposed. Different frequencies transient waveforms can be identified to analyze the operating status. The analysis of the characteristics can be further extended as a detection technique for the subsynchronous oscillations identification and suppression.