The STUDY on vibration detection and diagnosis FOR distribution transformer in operation

This paper makes in-depth research on the vibration of distribution transformer in the operation. It points out the vibration of the distribution transformer mainly from the iron core and winding, and sets up the mechanical model of the iron core and winding. The ANSYS software is used to conduct the finite element simulation for the enclosure vibration affected by the vibration of internal transformer. The results show that the most serious vibration occurs in the central of the distribution transformer tank's top part, so this part should be considered as the most important for the vibration test of distribution transformer. This experimental study on the physical model of distribution transformer, and arranges several acceleration sensors in the distribution transformer tank according to the results of the simulation calculation is completed. Meanwhile, the acceleration sensors are arranged in the iron core after swing the core of distribution transformer, in order to analyse the spread characteristic of the distribution transformer's internal vibration. The real-time data from sens or are collected by NI PXIe - 4499 data acquisition card, which are effectively controlled by NI PXIe - 8133 controller, and NI Labview is used to develop background software for operation analysis and diagnosis. Through constructing test loop, it simulates the different operation conditions of the distribution transformer, such as no-loading, part-loading and full-loading. It analyses the influencing factors of distribution transformer operation vibration from the perspectives of core and winding, e specially the fastening degree of the core and winding and the dc bias in the operation process. The variation test of distribution transformer in operation brings about several conclusions. If the vibration amplitude of tank top center increases sharply, and the vibration frequency is mostly odd times to power frequency, then it may be the problem of loose core. If vibration amplitude of tank top center increases considerably, and most of the vibration frequency is even times to the power frequency, it may be the problem of loose winding. Moreover, in the fastening condition, the dc bias is easier to intensify the vibration of distribution transformers than the load current.