Study On Magnetic Flux Leakage Characteristics Of Transformer And On - Line Monitoring Of Fiber Bragg Grating

With the increase of power transformer capacity, the leakage magnetic field and the loss caused by the structure are increased obviously. The complexity and irregularity of the transformer structure lead to loss in the component distribution is very uneven, This kind of uneven can cause the local overheating of the structural parts, Lead to the transformer can not properly work, At at the same time reduce the operational efficiency and reliability of the transformer.Fiber Grating with the characteristic of anti-electromagnetic interference, corrosion resistance, high temperature resistance and so on other excellent properties. In this paper, the Fiber Bragg Grating (FBG) temperature sensor for 35 kv oil immersed power transformer internal temperature, within the transformer leakage magnetic field and on the structure piece produce magnetic flux leakage were analyzed.The main research contents are as follows:(1)According to the special environment of transformer are developed which can be used in transformer leakage magnetic field analysis of magnetic FBG temperature sensor of the heat loss.The sensor performance parameters such as the nonlinear error is 1.24% FS, sensitivity is 10.76pm/℃.And do the test to adapt to the environment of the sensor, the performance of the sensor is better after aging test.(2)The simulation analysis on leakage magnetic field of oil immersed transformer, analysis of leakage magnetic flux density strongest maximum position, which determine the position of the sensor. Development of sensor is installed inside the transformer leakage magnetic field magnetic flux leakage location of maximum, sensor probe close to the low voltage out of line with the clamping pieces of the lower end and is connected with the coupler, coupler and the joint FC-APC by penetrating device leads connected to the optical Fiber Grating demodulator, the demodulator with computer connection.(3) The temperature rise test of the transformer, the FBG temperature sensor feedback back the value of the wavelength conversion parameters to be measured value, and these data into an intuitive real-time curve. In different states of the transformer transformer top oil temperature and clamps the temperature contrast, the transformer with 1.3 times the load; wind machine; load to 1 times power reduction; measuring high voltage DC resistance and AC; measuring DC resistance of low voltage winding of state under the oil tank upper temperature rise are Ok,49.6K, 39.6K,38K,36.7K,34.2K. The temperature rise of the clamp is 2.7K,58.3K,45.6K, 42.1K,36.8K,40.4K, respectively.