Diagnosis of Transformer Winding Looseness Based on Vibration Sensor Array

Abstract

The vibration of the oil-tank can reflect the mechanical condition of transformer internal windings and cores. Although there were several studies about the vibration of the transformer, most of them do not take into account the inherent connection between different measuring points, which results in insufficient utilization of vibration information. To conquer this shortcoming, a fault diagnosis method for transformer winding looseness based on vibration sensor array is proposed. An array measurement system was set up, and a suitable measurement method was put forward. Because the voltage fluctuation of the transformer in actual operation is very small while the load current fluctuates greatly and the winding vibration is mainly influenced by the current. Load tests were conducted on a single-phase transformer. The influence of the current on the vibration characteristics was studied. Different levels of winding looseness were set up and their vibration characteristics were studied. The matrix distance was used to judge the deviation of the array signal. The results show that the array signal does not change with the current change. When the windings are loosened, the array distance of the array signal increases significantly. It provides a new idea for the diagnosis of the mechanical fault of transformer windings based on vibration signals.