The online monitoring system of transmission lines weight based on fiber sensing technology

The online monitoring of ice load of transmission lines, which reflects the dynamic load of line, can alert the early stage ice in advance and guarantee the safety of power supply. However, the fiber sensors, which were used in ice online monitoring of overhead transmission lines, usually had low sensitivity and bad repeatability. And the capacity of sensor network was limited and it was difficult to provide hundreds of FBGs for optical sensing of overhead transmission lines in kilometers. In this paper, we proposed a novel load cell based on Fiber Bragg Grating (FBG) and presented the idea for high-capacity sensing network. Firstly, we adopted shearing structure with additional protection parts to reduce the influence of eccentric force. Then the FBG gauges were welded on the elastic element to avoid glue aging problem. After that, the FBGs were mounted at the front/rear slot with the direction deviation of 90° from the each other to eliminate the temperature effect in strain detection, and the extra FBG which usually used for temperature compensation is not necessary. The results of tension experiment indicate that the tension sensitivity and resolution of the load cell is 0.1285 pm/N and 7.78 N. Moreover, the expanded sensing network proposed can export consecutive modulating pulse as incoming signal for FBG sensors to detect the strain change result transmission line load.