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

The paper analyses the impact of optical fibre temperature sensors installation on the dielectric withstand properties of paperless oil-filled transformer winding insulation. Two groups of PVA enamel insulated helical winding models with and without optical fibre temperature sensors installed inside the oil channel were built and tested according to regular transformer manufacturer procedures. To quantify the dielectric withstand impact of sensors installation, AC 50Hz breakdown voltage and partial discharge magnitude of the test winding models were measured and analyses of dissolved gas in oil samples were carried out. The experiment results were correlated to the results of finite elements electric field simulations of the winding models as well as compared to the existing empirical…