Oil-immersed transformer online hot spot temperature monitoring and accurate life lose calculation based on liber Bragg grating sensor technology

The insulation capacity of electric power transformer will be affected by running in overheated conditions, and the winding hot spot temperature is the main limiting factor of transformer load, so the winding hot spot temperature should be measured accurately. Online temperature monitoring method using Fiber Bragg grating is presented in this paper. By the application of optical fiber grating temperature sensor in oil-immersed transformer, electromagnetic interference is avoided and direct temperature measurement of internal transformer can be realized. The system is built in an 110kV oil-immersed transformer and the transformer is put in operation for 10 months, it works safely and the measurement temperature data is stable and accurate. Based on the data, an accurate estimate of transformer life loss is work out through continuous integration of hot spot temperature and measurement time.