In oil-filled transformer

oil temperature is an important factor in determining speed of insulation aging of electrical equipment. By analyzing the temperature field distribution of oil-filled transformer

layout position of optical fiber temperature sensor which inside the transformer is optimized. Center wavelength of fiber Bragg grating（ FBG） changes with temperature change

and according to this feature

realize oil temperature measurement of oilimmersed transformer. S13—12500 /35 oil-immersed transformers is used as test subject

when transformer is running at double power

oil temperatures of transformer in top

middle

and lower layers are 63

52

40 ℃

and oil temperature gradient difference is about 10 ℃.