engleski

Characterisation of the dynamical behaviour of a power transformer’s tank

The characterisation of the dynamical behaviour of power transformers is essential in complying with ever increasing regulative limitations on their noise levels. In fact, noise generation is a complex multiphysics phenomenon induced by the interaction of the excitations in the core and windings, the transmission via the insulating fluid and the resulting vibroacoustic performances of transformers’ tank, that are all subject matter of thorough recent modelling and experimental studies. The aim of this work is, thus, to experimentally assess, via structured laser-Doppler vibration measurements, the dynamics of a transformer’s tank. The obtained results allow attaining a deeper insight of the dynamics of the tank of a 90 MVA - 33 kV power transformer. It is, thus, established that the dominant vibrating frequency is 100 Hz, with the highest amplitudes localized around a single point whose dynamical response is highly correlated across all operating conditions. Tank stiffeners show, in turn, a significant positive effect on the reduction of the vibration amplitudes. The obtained results and considerations create the preconditions to iteratively tune the modelling of the behaviour of the transformer along the core – windings – insulating fluid – tank interaction chain, and to systematically work on affecting the resulting vibroacoustic response of the transformer. In the ongoing work, the study of these relationships will hence be deepened.

power transformer ; dynamics ; noise ; laser vibrometer ; DoE

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