Research On The Analysis For Low Frequency Oscillation In Power Systems

Research on the analysis method for low frequency oscillation of power system is the basis to study the mechanism for low frequency oscillations.With modern power networks complicated gradually,dynamic non-linear theory grown rapidly,and new equipment and technologies used widespread,the conventional analysis methods have many shortcomings.Therefore,it is necessary to study new methods of vibration analysis in order to more effectively reveal the mechanism of oscillation of the interconnected system.This paper from the perspective of the analysis explored the issue about low frequency oscillations.Firstly,system for low frequency oscillations of the main analytical methods are summarized,and pointed out the advantages and disadvantages of various methods and the scope of application.Secondly,Prony algorithm is Proposed in the analysis of low-frequency oscillations,including the application of its basic principles,common indicators and setting parameters in detail,pointed out that Prony algorithm for low-frequency oscillations in power system analysis have the limitations of non-linear systems research.Thirdly,the Hilbert-Huang (HHT) algorithm for low-frequency oscillations in nonlinear is introduced.The fault transient information from HHT and extract parameters of models were analyzed the dynamics of low-frequency oscillations and the oscillation characteristics,also between the various models with nonlinear interaction.On this basis,then based on empirical mode decomposition (EMD) of the Prony analysis method of low-frequency oscillations is developed.The EMD used as a pre-processing data method,it means that the Prony algorithm could overcome not only difficulty to deal with the shortcomings of non-stationary signals,as well as the problem difficult to select wavelet of small and medium-sized wavelet algorithm,but also to enable them to effectively deal with non-axis symmetric signals,greatly reducing the analysis errors.It provides a new tool for power system stability analysis.Finally,EPRI-36 node simulation is analyzed of the three algorithms,compare the advantages and disadvantages of various analytical methods and analyze the scope of application and the utilization in on-line identification area of each method.