变压器铁芯表面温度的光纤Bragg光栅监测与热特征研究

Fiber Bragg grating monitoring for the surface temperature of transformer core and study of thermal characteristics

通过ANSYS有限元分析,仿真出铁芯的热点位置和温升范围。设计了一种FBG传感器安装于变压器铁芯的上下轭表面,通过Bragg光栅波长随温度变化的数学模型计算,实现了对变压器铁芯的温度实时在线监测。SFZ11-10000/35型35kV变压器的温升试验表明,铁芯上下轭最高温度达到65.3℃和52.9℃,上轭高于下轭12.4℃。铁芯作为变压器内部的储热部件,在开动风机降温初始阶段,温度仍然表现出少许上升,随后温度趋于平稳,铁芯的温度变化呈现出趋势平稳,降温缓慢的特点。实现了对于油浸式变压器铁芯表面温度的光纤光栅监测,并分析其原因,为变压器正常工作时铁芯的热特征分析提供了数据支持。

The hot spot and temperature range of iron core are simulated by ANSYS finite element analysis. A FBG sensor is designed for the upper and lower yoke surfaces of the transformer core. The temperature of the transformer core is monitored on-line by the model of the Bragg wavelength. Temperature rise test of 35kV SFZ1l-10000/35 transformer indicates that the maximum temperature of the upper and lower yoke of the iron core reaches 65. 3℃and 52. 9℃. The up- per yoke is higher than the lower yoke 12. 4℃. The iron core temperature is still showing a little rise at the initial stage of cooling because it is stored as heat storage unit in the transformer, and the temperature tends to be stable. The temperature change of the iron core presents two features of stable trend and slow cooling. The FBG monitoring of iron core surface temperature of oil immersed transformer is realized. And the cause of heat generation is analyzed. Data support is provided for the thermal feature analysis of the iron core when the transformer is working properly.