Research on Vibration and Propagation Characteristics of Transformer Winding Based on Multi-Physical Field Coupling

In recent years, domestic power transformer winding mechanical failures have occurred frequently. Using vibration method to monitor the power transformers' mechanical operation can effectively avoid a risk of transformer failure. Firstly, based on the vibration transmission path of transformer and the theory of electromagnetic field, a magnetic-solid-fluid multi-field coupling finite element simulation model of 110 kV oil-immersed power transformer is built. When the transformer is working under rated load, the vibration traits of the transformer winding as well as the box surface are researched. It turns out that the vibration acceleration within the transformer winding's middle section is notably higher than that at its upper and lower extremities. Meanwhile, the vibration at the front side of the transformer box is much stronger compared to vibrations in other orientations. Then, two measuring points of the winding and the box surface are taken respectively to examine the time domain and spectral features of the vibration acceleration curve. It has been discovered that vibration signal's amplitude on the transformer winding surface reduced as it is transmitted from the transformer oil to the box surface. The vibration signal's main frequency, which still stays at 100 Hz, experiences a decrease in its amplitude. The vibration signal on the transformer box surface has a complicated spectral distribution with numerous high - order harmonics emerging. This paper's relevant conclusions are of theoretical reference value when choosing the surface location of the transformer vibration tesexperimental box. Moreover, they play a crucial guiding role in the mechanical fault diagnosis of transformer windings.