Development of Oil-immersed Transformers With Built-in Fiber Bragg Grating Sensors

In order to obtain the internal temperature of oil-immersed transformer directly,this paper designed a special electromagnetic wire with fiber Bragg grating(FBG) sensors embedded,and successfully placed 14 optical fibers,that is,218 FBG sensors totally at the windings,iron core,stay and oil-lift of the 35?kV/4?000?kW transformer.The strain of electromagnetic wire during the production has minor influence on the mechanical strength and the temperature sensing performances of FBG sensors.The results of the insulation test performed on the transformer show that,the FBG sensors placed inside the transformer have no impact on the insulating properties of the transformer.Temperature Rise Test and Long-time No-load Test confirm the sensing performance of the FBG sensors,which provide a reliable method for the research on the temperature field of the transformer,and bring a new technique to verify the design of the transformer and predict its service life.