Experimental Research On Temperature Distribution Characteristics Of Transformer Based On Fiber Bragg Grating Sensor

Power transformers play an important role in the modern power system,keep the normal operation of transformers is the most basic guarantee to the safe,stable and efficient running of the entire electrical power system.Some part of electrical energy will convert into thermal energy in the running process of transformers,which will causes the winding temperature rise.The winding temperature has direct relationship with transformer insulation and aging rate,high temperature will affect the service life of the transformer,low temperature will get transformer load away from fully applying,and reduces the economic benefits.Therefore,by monitoring the internal temperature of the transformer it is of great significance to the safe and efficient operation of the transformer.In this thesis,the temperature sensor network is installed on the transformer to form the temperature sensor network to realize the direct measurement of the multi-point temperature of the transformer winding,the stay and the iron core.The main parts of our research are as follows:(1)According to the internal oil-immersed transformers complex operating environment,we choose the fiber grating temperature sensor that suitable for the internal temperature measurement of the transformer.The sensor can realize the temperature measurement in the range of-30 ~ 150? and a temperature resolution of 0.1?.Through the implementation of fiber Bragg grating sensor` sensing characteristic experiment,good stability and reliability of the optical fiber grating sensor is proved,which inform that it can realize the precise measurement of the transformer internal temperature.(2)According to the special requirements of real-time monitoring of oil-immersed transformer temperature,the reliable installation program of temperature sensor is designed.The optical fiber is installed in 110kV/31.5MVA three-phase three-winding oil-immersed transformer winding,iron core,winding stitch and so on.The grating temperature sensor forms a temperature sensing network,which realizes the effective measurement of the internal temperature distribution of the transformer.(3)Implement temperature rise test of 110 kV / 31.5 MVA three-phase transformer,and calculate winding hot spot temperature by referring to the heat simplified model published in the national standard.Through comparing the experimentally tested winding hot spot temperature data with the theoretically calculated transformer winding hot spot temperature date,proved that the temperature sensor can real-timely and accurately reflects the temperature change where the sensor located as well as effectively monitor the internal temperature distribution of the transformer.