Impact of optical fibre temperature sensors on dielectric withstand of oil channel in paperless winding insulation of power transformers

The paper analyses the impact of optical fibre temperature sensors installation on dielectric withstand of oil-filled paperless transformer winding insulation. A PVA enamel insulated helical winding models with 3 mm oil channel were built according to the technological process of Kolektor Etra and tested at the high-voltage laboratory of the Milan Vidmar Electric Power Research Institute. AC 50Hz breakdown voltage and partial discharge levels of the winding models with and without optical fibre temperature sensor were measured as well as dissolved gas analyses of the oil samples were made. Experimental results were evaluated and analysed through a dielectric study based on the finite elements simulation, and empirical design guidelines based on partial discharge inception models. On the…