On - Line Analysis Of Low Frequency Oscillation Based On Oscillation Energy And Cohomology Grouping

With the tightness of network interlinks and enhanced complexity degree of system, there is large probability of system instability in relative region. The low frenquency oscillation of interconnection grid will become more complicated. The gradual development of wide-area measurement system (WAMS) provides an opportunity to analysis low frenquency oscillation for large modern power system.In power system, the existence of weak damp generation units is the main reason of low frequency oscillation. On the local oscillation mode, we focus on negative or weak damp unit caused low frenquency oscillation.On the inter-area oscillation mode, the oscillation frequency of dominant mode, mode shapes, participation factors and other characteristics of the coherent information online identification and access to low-frequency oscillation analysis and reduction are crucial, this paper focus on the low-frequency oscillation characteristics research information acquisition method.Firstly, analysis the limitations of Prony algorithm appling to the analysis of low frequency oscillation, proposed on-line Prony analysis using as the basis of low frequency oscillation mode analysis. For complex grid, the grid is divided into different district and level subnetworks based on Prony identification result, and apply cutest energy theory to achieve rapid and accurate identification of negative damp units. For inter-area oscillation mode involving more units, it is proposed a on-line identification and clustering method of weak damp units based on oscillation energy and coherent.The above theory and method are using PST16machines68nodes system simulation analysis, the simulation results show that the effectiveness of the algorithm, and certain practicality, for the modern power system low-frequency oscillation analysis provides a new train of thought and method.