Intelligent monitoring of substation infrastructure based on fiber Bragg grating flexible sensor

To reduce the loss caused by uneven settlement of substation foundation buildings, it is urgent to carry out long-term and real-time monitoring of the engineering structure. The FBG (fiber Bragg grating) flexible sensor was fabricated by using the POM (polyoxymethylene) material with waterproof and moisture-proof properties as the flexible substrate, and encapsulating the sensing points in the substrate by means of grooves. Temperature sensing experiments have shown that flexible sensors have good temperature self-compensation properties. In the displacement sensing experiment, the mean absolute errors of Type 1, 2 and 3 were 2.67 mm, 2.77 mm and 6.76 mm, respectively, after the curvature information obtained by the sensing point was corrected by B-spline interpolation. Compared with before correction, the mean absolute errors were reduced by 38.28 mm, 9.94 mm and 28.54 mm, respectively. The mean absolute displacement error percentages of Type 1, 2, and 3 after correction by B-spline interpolation were 1.87%, 5.28%, and 6.98%, respectively, which were 26.83%, 18.94% and 29.49% lower than those before correction. The above has shown that the interpolation algorithm effectively improves the sensing accuracy of the flexible sensor for displacement. The FBG flexible sensor designed in this paper can realize real-time monitoring of substation settlement and provide early warning, which has important application and promotion value.