Application Of Improved Hilbert-Huang Transform In Traveling Wave Signal

With the rapid development of society, the scale of power system is in expanding,users are increasingly high requirements for power supply stability. Therefore, how toimprove the reliability of power supply has become a hot research. On one hand, thesystem should avoid the occurrence of the fault when the system is working properly.On the other hand, after the fault occurred, it should be found out as soon as possible tominimize the loss.This paper first introduces the basic theory and transmission characteristics of thetraveling-wave. According to the characteristics of the traveling wave signal, this paperputs forward the Hilbert-Huang Transform to detection and analysis fault transientsignal. Use Empirical Mode Decomposition to process the original traveling wavesignal, and get some Intrinsic Mode Function. At last, each instantaneous frequency isgot by Hilbert transform. According to the instantaneous frequency of the correspondingtime point, the timing of the detection point can be determined.For the modal aliasing problem of Hilbert-Huang Transform, this paper applies theImproved Hilbert-Huang Transform to the traveling wave signal processing, and appliesit to fault line selection for hybrid lines. This method is using the characteristics that thewhite Gaussian noise frequency can distribute in the entire time-frequency space evenly,and the signal has continuity in different scales. In this way, EMD decomposition can beavoid modal aliasing problem.This paper uses the Improved Hilbert-Huang Transform to extract the featureinformation in the zero-sequence current. The improved Hilbert-Huang Transform canprocess it effectively, and then the improved HHT is used to select fault lines to extractthe feature information of zero sequence current. Theories and MATLAB simulationhave proved that the improved HHT can select the fault phase of distribution networkwhich neutral is grounded by the coil of arc suppression.