Statistical Analysis of VFTO Time Domain Modal Parameters

Abstract

The phenomenon of very fast transient overvoltage (VFTO) is a matter of significant concern in industry. In view of the fact that VFTO lacks the overall identification of time-frequency domain parameters and statistical characteristic analysis. A time-domain identification method combining the singular value decomposition (SVD) and the ESPRIT is proposed. Based on the measured VFTO waveforms obtained from the 220 kV GIS experimental platform, the proposed method is used to obtain the modal parameters of each harmonic component of the VFTO, including subharmonic amplitude, frequency, decay factor and initial phase angle. Further, the mean and variance of each mode parameter with normal distribution are obtained by parameter estimation, and the correlation between subharmonic amplitude and breakdown voltage is analyzed to establish the reconstruction model of VFTO transient waveforms under different breakdown voltages. the effectiveness of the proposed method is verified by comparing the test set.