Modelling of magnetostrictive vibration and acoustics in converter transformer

Abstract

The converter transformers are susceptible to more noise and vibration when compared to power transformers due to the presence of DC bias in the DC transmission line. DC bias occurs mostly due to inaccuracies in valve firing resulting in a small residual DC oscillating around zero. Measurement of magnetostriction becomes significant as it influences the vibration and noise from the core. Hence, a magnetostrictive model of a high-voltage DC converter transformer has been developed. This work analyses the vibration and noise acoustics under such an occurrence. First, the core of the transformer model is designed in the stepped configuration for 240 MVA; then, magnetostrictive vibration is analysed by using suitable modules of COMSOL Multiphysics at different magnitudes of DC bias. The physics of noise has been interfaced using the Acoustics Module, and the results are recorded. Finally, artificial neural network model is developed for the prediction of vibration and noise characteristics of the model. The fitting process of neural network was then remodelled using various optimisation techniques, namely teaching-learning-based optimisation, particle swarm optimisation, biogeography-based optimisation, simulated annealing and binary coded genetic algorithm, and their results were compared to obtain the best-suited method using % mean-squared-error evaluation. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Multi-Objective Design Optimization for HVDC-LCC Converter Transformers: Analytical and FEA-Based Comparison

“…These analyzes lead to a better understanding of the problem. A piece of better knowledge can point to the need of improving the model and/or to a more enlightened choice of the final solution [33]. Still respecting the tolerance reduction around Uk, the diamond white solution is the one closest to Pareto's set of solutions.…”

Investigation on magnetostrictive behaviour of a converter transformer influenced by dominant harmonics: AFEMandANNbased approach

“…The electric current through the windings is assumed to be evenly distributed throughout the coil, and a single‐phase supply is fed to the HV windings. It is worth noting that the distribution of flux in the core depends upon the magnetic properties of the chosen material 21 . Magnetic shielding is assumed to be present at the box‐shaped boundary of the transformer.…”

“…Concerning the available literature at the time of the work, the converter transformers are considered to bear higher harmonics content. In an attempt to analyse the behaviour of the converter transformer, authors in Reference 21 successfully modelled the magnetostrictive vibration and acoustics generated in a converter transformer under the influence of DC bias. Despite the significance of harmonics in the behaviour of the converter transformer, there has not been sufficient related research in any of the reported works on converter transformers.…”

“…The physics module present in the COMSOL multiphysics environment namely for electromagnetic, acoustics and thermal fields was coupled to analyse the effects of frequency in the respective behaviour of the transformer. Here, a dual winding, stepped core configuration of a converter transformer rated at 240 MVA, kV is developed similar to that in Reference 21. The simulated results were validated by designing a hybrid Feed Forward Neural Network (FFNN).…”

“…The simulated results were validated by designing a hybrid Feed Forward Neural Network (FFNN). Many works have been reported involving the development of NNs‐based magnetic models 21,24,25 . The work attempts to model the behaviour of the converter transformer characterised in frequency domain.…”