A contribution to modelling and experimental studies of flow electrification in transformers

摘要

As part of the research program of Electricite de France on static electrification in power transformers, on one hand an experiment has been carried out at the University of Poitiers to simulate the oil path in a transformer and on the other hand the 3D Computational Fluid Dynamics software ESTET developed at the R&D centre of Electricite de France has been extended to the modelling of the phenomena. The experimental devices has enabled us to study in a pressboard duct the wall current response to a heat transfer step produced from the outer side of the duct and to calibrate the interfacial charge transfer laws used in our simulation. So we can characterise the influence of parameters such as velocity, temperature, moisture, transient and steady states on the phenomena. This paper shows that some parameters sets lead to important dielectric stresses in the pressboard which might be the cause of the hazardous discharges observed in power transformers.