Detection Of Small Amplitude Forced Oscillations And Location Of Disturbance Sources

Forced oscillation is a low-frequency oscillation,and its existence will seriously affect the stability and safety of power system operation.When forced oscillation occurs,if the signal can be detected and the source of the disturbance can be located,the continuous process of injecting disturbance to block the oscillation can be cut off in time,which is of great significance for the safe operation and stability of the power system.When the amplitude of forced oscillation is small,it is easily overwhelmed by the environmental noise signal of the system,which makes the oscillation itself more difficult to detect and locate.This paper analyzes the mechanism of forced oscillation and its performance characteristics in frequency domain,time domain and statistics.In terms of detection,the applicability and limitations of detection methods based on power spectrum and coherent spectrum in small amplitude forced oscillations are specifically studied;based on the analysis of the statistical performance characteristics of small amplitude forced oscillations,a method based on The singular spectrum analysis and the detection method of kurtosis use singular spectrum analysis to preprocess the time series data of the response generated by the system after small amplitude forced oscillation,and calculate and analyze the kurtosis coefficient of the preprocessed data Recognized as the characteristic data value of forced oscillation,to realize the detection of small amplitude forced oscillation.Through the simulation experiments on the 4 machine 2 area system and the actual cases in the ISO-NE system,the results verify the feasibility and accuracy of the oscillation detection method.In terms of positioning,the existing DEF method and PMU measurement information are used to analyze the energy flow of small amplitude forced oscillation,and the positioning process of the DEF method is optimized.The singular spectrum analysis is used to replace the filter to process the PMU data,avoiding the original DEF method.The inaccurate disturbance frequency identification will cause errors in the later positioning work.Finally,the processed data is used to calculate the energy flow of each branch according to the energy formula,and the direction of energy flow is determined according to the size of the energy flow to achieve small amplitude forced oscillation disturbance Source positioning.The simulation experiment on the actual case in the ISO-NE system verifies the applicability and accuracy of the oscillation positioning method.