Forced Low Frequency Oscillation of Wind-Integrated Power Systems

The integration of a large amount of wind generators to the power system may pose new issues to its control and operation. One of important issues is that low frequency oscillation may be induced by the variation of the wind power, which is also referred as forced low frequency oscillation. To analyze the mechanism of the forced low frequency oscillation of the wind-integrated power system, a 7-order-model of the typical wind generator, DFIG, is established. Based on this model, linearized mathematical model for small signal stability analysis is obtained. According to the linearized model, the mechanism of the low frequency oscillation is analyzed, and the characteristics regarding the oscillation such as oscillation mode, oscillation frequency, participation factors are also discussed. Two possible forced low oscillation modes that are related to the shaft system and pitch angle control system of the DFIG are identified through the analysis. The simulation validates this conclusion and proves the effectiveness of the established models for the forced low frequency oscillation of the wind-integrated power systems.