Strain clamp condition monitoring for transmission lines based on acoustic emission signals

Abstract

Abstract To ensure the reliability and safety of the power supply in the electric system, it is significant to realize the strain clamp condition monitoring for transmission lines. A strain clamp vibration test rig was designed and built to collect acoustic emission (AE) signals generated by strain clamps with an excitation frequency of 30, 50, 70, 90, and 110 Hz, respectively. The characteristics of the collected AE signals are then analyzed in the time domain and time-frequency domain. The results of the signal analysis in the time domain show that, the increasing excitation frequency leads to a higher amplitude of the AE signal, and the signal period is consistent with that of the excitation. Meanwhile, both the root-mean-square (RMS) and the average signal level (ASL) of the AE signal increase continuously with the excitation frequency, of which the growth trends are different. Additionally, the results of the signal analysis in the time-frequency domain also show that the signal spectrum is mainly concentrated in the range of 30 kHz to 200 kHz at different excitation frequencies and the increasing excitation frequency significantly leads to more high-frequency components in the AE signal.