Abstract：Abstract：Employing the adaptive Hilbert-Huang Transform (HHT) technique, a novel vibration based method for monitoring core clamping pressure of power transformers was proposed. Core vibration signals were decomposed into a set of intrinsic mode functions (IMFs) by means of ensemble empirical mode decomposition (EEMD). The IMFs representing the changes of core clamping pressure were identified according to the core vibration behavior，and their instantaneous frequencies and time-frequency-energy distribution were obtained by using HHT. With the instantaneous frequencies and time-frequency-energy distribution, a feature vector was constructed and its value obtained by a distance algorithm was used to quantify the clamping pressure. The experimental results show that the derived energy-frequency-time distribution of the core vibration has clear physical meaning and the proposed feature vector and distance algorithm can characterize the core vibration under different clamping pressure condition. The method is effective for vibration condition monitoring and diagnosis of power transformers.
2010, Vol. 29 
