Procedures of oil sampling, oil-gas separation and gas detection are generally adopted to measure dissolved gases in power transformer oil. However, there are several disadvantages in the conventional methods, such as the complicated operation, large measurement error, long test cycle and so on. To solve these problems, fiber Bragg grating (FBG) dissolved hydrogen sensor and the related detection scheme in transformer oil are proposed. In order to improve the sensitivity of FBG hydrogen sensor, side polishing technique is utilized due to its sensitivity to bending deformation. Then, based on the wheel grinding method and magnetron sputtering on fiber surface with palladium membrane, side polishing FBG sensors with the polishing depth of 20μm were prepared and fabricated. Furthermore, a hydrogen sensing and testing platform was built in the laboratory. Hydrogen sensing experiments were carried out to examine the sensitivity and repeatability. The results show that the sensitivity reaches up to 0.477μL/L, and high repeatability is also verified. Direct measurement of dissolved gas in transformer oil is achieved based on side polishing FBG hydrogen sensor, providing a novel sensing technique for on-line monitoring of hydrogen dissolved in transformer oil.%针对变压器油中溶解气体在线监测装置,常规取油样-油气分离-气体检测的模式存在操作繁琐、检测环节多、检测误差大、试验周期长等缺点.为此提出基于光纤布喇格光栅的油中溶解氢气传感器和检测方案.为了提高光纤光栅氢气传感的灵敏度,通过侧边抛磨增敏设计,采用轮式抛磨法对布喇格栅区的光纤进行抛磨,使用磁控溅射的方法在光纤表面溅射氢敏钯膜材料,制备侧边抛磨深度为20μm的光纤光栅氢气传感器.在实验室搭建油中氢气传感测试平台,开展多次溶解氢气传感灵敏度和重复性试验,测试灵敏度达到0.477μL/L,具有较高的重复性,可以满足实际变压器油中溶解氢气的传感需求.基于侧边抛磨的光纤布喇格光栅油中氢气传感器实现了变压器油中溶解气体的直接测量,为油中溶解氢气在线监测提供了一种传感思路和技术手段.
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