Study on vibration characteristics of OPGW cables based on DAS technology

Based on the Distributed Acoustic Sensing (DAS) technology, this paper conducted an indoor simulation experiment on the natural frequency of Optical fiber composite overhead ground wire (OPGW) cables under ice-covered state, aiming to verify the changes in the vibration characteristics of optical cable after ice-covered and the effectiveness of DAS technology in ice-covered monitoring. The experiment was conducted on a 55-meter optical cable, monitoring the vibration frequency of the cable under different simulated ice thicknesses and weight conditions, with the ability to apply fixed-frequency vibrations. By testing the natural frequency of the OPGW optical cable under different working conditions, it was found that the natural frequency showed a downward trend with the increase of ice thickness, and the ice thickness can be calculated using this frequency change. In addition, the high resolution and high sensitivity performance of the DAS equipment were verified by testing the vibration of the optical cable with external excitations of different frequencies. The results show that DAS can effectively detect small vibrations and accurately reflect the vibration state of the optical cable. DAS monitoring technology provides a new method for ice-covered monitoring of OPGW cables, which has the advantages of long-distance sensing and high efficiency and stability, and is expected to provide technical support for the actual ice-covered monitoring of power systems.