Study on Vibration Characteristics of Three-Dimensional Coil Core Transformer Under Interturn Short Circuit Fault

In this study, the vibration characteristics of the core and winding of an SG-RL-50 / 0.38 / 0.22 open three-dimensional wound core transformer were studied. Firstly, the magnetostrictive characteristics and stress-strain characteristics of oriented electrical steel and copper wire are measured, and the B- $\lambda $ curve and stress-strain $\sigma $ - $\varepsilon $ curve are given. Secondly, the theory and calculation method of the short-circuit current, leakage magnetic field and axial spring mass model of the transformer were analyzed. On this basis, electromagnetic-vibration research of a three-dimensional wound core transformer under different interturn short circuit was carried out. The magnetic induction intensity, vibration acceleration and vibration displacement characteristic curves of normal operation conditions, short-circuit 1 turn, 3 turns, 9 turns, and 19 turns are given, and their amplitude-frequency characteristics are analyzed. Finally, a prototype of three-dimensional wound core transformer was manufactured. An experimental platform was built to measure the vibration of the core and winding under an interturn short circuit fault, and the results were compared with the simulation results. The results show that the interturn short-circuit fault significantly change the vibration characteristics of the transformer, and the characteristic frequency and amplitude of the winding vibration are much higher than those of the core. This finding provides a key basis for monitoring transformer interturn short-circuit faults.