Power Transformer Noise Analysis based on All-phase FFT and Filtering Technique

Analyses of frequency domain characteristics of transformer noises are beneficial for the research of active noise control technology in substations. In this paper, all-phase FFT spectrum analysis is used to study the collected transformer noise signals. As shown in the frequency spectrograms, the fundamental frequency of the noise signals is 100Hz; the noise signals reach their peaks in 100Hz and 200Hz. A comparison of all-phase filtering and traditional segment filtering techniques is also conducted in this paper to extract the fundamental frequency components of the noise signals. It has shown that all-phase filtering can ensure phase linearity. Frequency leakages and latency can also be improved due to its continuous nature. Finally It is concluded that frequency domain characteristics can be better analyzed and extracted by applying all-phase FFT spectrum analysis and all-phase filtering techniques to the active noise control of transformers.