The invention discloses an OLTC mechanical fault diagnosis method based on 
sample entropy and SVM. The method comprises the steps that step 1, an acceleration 
vibration sensor is placed on an OLTC topcover to collect vibration signals in various states; step 2, performing EEMD 
decomposition on the original vibration 
signal to obtain components IMF, and further 
processing the first four IMF components; step 3, calculating and selecting a 
sample entropy of the IMF component; step 4, for the training 
data set, using the 
sample entropy obtained through calculation as a 
feature vector, inputting the 
feature vector into an SVM for training to obtain an 
SVM classifier, inputting the SampEn value of the IMF component of the 
test sample into the 
SVM classifier, and outputting the SampEn value of the IMF component of the 
test sample through the 
SVM classifier to obtain the operation state of the 
test sample. The working state of the 
transformer on-load tap-changer can be monitored in real time,the real-time fault diagnosis requirement of the 
transformer on-load tap-changer is met, data support and theoretical basis are provided for targeted maintenance, and waste of manpower, 
material resources and time is avoided.