Impact of Mechanical Deformations of Transformer Corners on Core Losses

The clamping of the power transformer magnetic circuit allows maintaining the sheet stack and provides an additional mechanical rigidity. It has consequences on the acoustic noise of transformers as the magnetic cores of power transformers vibrate because of the magnetostriction and, if the corners are considered, Maxwell's forces. The indirect impact of a lack of clamping on the core losses is studied, especially on the interlaminar air gaps in the corners. In this paper, it is shown numerically with finite element modeling and experimentally with a specific testbench that induced vibrations can change the flux distribution and thus the losses.