Vibration Analysis Using Variational Mode Decomposition for Mechanical Fault Diagnosis in The Diverter Switch of On-load Tap Changer

The health condition of On-Load Tap Changer (OLTC) - the only movable part of power transform, is essential for the safety of the whole power system. However, due to frequent use and harsh operating conditions, OLTC has become one of the most fragile parts of the power transform. Therefore, it is desirable to have some indicators that help diagnose the mechanical fault of OLTC. This paper extracted several parameters from time-domain to define the condition of the OLTC based on the vibration signal. Firstly, this signal is divided into several mono-components by Variational Mode Decomposition (VMD) which is utilized to analyze the non-stationary signals with representative results. Then, several characteristic parameters of the vibration signal are extracted. Using the sampled data series from simulated experiments, a statistical analysis about these parameters is generated. When the OLTC get out from the normal state, the values of the above parameters will change correspondingly, and can be successfully utilized for 's on-line monitoring of the OLTC.