Aeolian vibration‐based structural health monitoring system for transmission line conductors

The transmission line in a power network is similar to a blood vessel. Any disconnection ultimately affects the transmission of electrical energy, and broken strands and detachment of the fittings are early signs of disconnection. Because aeolian vibration occurs on almost all conductors, an aeolian vibration-based structural health-monitoring technology for transmission lines is proposed. First, the influence of strand breakage and detachment of the fittings on the natural frequency of the conductor is described, and the influence of temperature changes on the natural frequency is discussed from the two aspects of the temperature-dependent elastic modulus and temperature-dependent winding angle. Second, we conducted a vibration experiment and found the law of natural frequency variation caused by broken strands, detachment of the fittings, and temperature changes. Finally, we conducted a field test to measure the conductor vibration on a 110-kV transmission line. The results show that the natural frequency can be calculated multiple times by the stochastic subspace identification method, and the calculation results are consistent. After a period of measurement, the natural frequency variation is analyzed. Further, how to determine the structural health of the conductor from the natural frequency measured by the technique under actual operating conditions is explained.