基于弹性波的碳纤维复合芯导线 结构健康监测系统

碳纤维复合芯(ACCC)导线的结构不同于钢芯铝绞线(ACSR),传统的导线检测方法难以在ACCC导线上得到有效应用。为了保证电力系统运行的稳定性与可靠性,有必要对ACCC导线的结构健康进行快速、全面的检测。根据ACCC导线的结构与弹性波的传播特性,分析了弹性波的相速度、群速度及频散特性,采用虚拟仪器技术,提出了一种基于弹性波检测技术的ACCC导线结构健康监测系统。基于小波变换理论,分析了峰值到达时间的计算方法,研究了激励信号的波形、频率、幅值及波峰数的选择策略。根据弹性波的信号特征,进行了幅值衰减特性实验,研究了信号幅值随距离变化的规律与不同中心频率下的幅值变化特征,结果表明,激励信号的幅值在传播过程中随距离呈指数衰减。以ACCC/TW导线为实验对象,搭建实验平台,进行了损伤定位与损伤辨识,实验中定位的最大误差不超过4. 28 cm。通过比较损伤的实际位置与结构健康监测系统的输出结果,表明所研究的系统能够有效地对ACCC导线损伤进行定位并具有良好的精度。基于功率谱密度的分析方法,实验研究了不同频率和不同损伤条件下的信号特征。结果表明,通过分析功率谱密度曲线的特征,实现了对ACCC导线不同损伤状态的辨识。

Energy Monitoring System of ACCC Conductor Based on Elastic Wave

Due to the different structure of ACCC and ACSR, most of traditional detecting methods for ACSR is no longer effective for ACCC conductor. To guarantee the stable and reliable power supply, it is necessary to develop a rapid and comprehensive detection for the structural health of ACCC conductor. The phase velocity, group velocity and dispersion characteristic of elastic wave were analyzed with the damage mechanism of ACCC conductor, and a structural health monitoring system was designed with virtual instrument. The waveform, frequency, amplitude, peak number and peak arrival time of excitation signal were studied with the wavelet transform theory. An experiment of amplitude attenuation was carried out to analyze the relationship between distance and the amplitude variation under different center frequencies. The results indicate that the amplitude of the excitation signal exhibits exponential decay characteristics with the distance. An experimental platform was setup with ACCC / TW conductor to test the proposed structure health monitoring system, and the maximum positioning error is 4.28 cm in the experiments of damage localization. Comparing the actual location and output of proposed structural health monitoring system, it indicates the proposed system can effectively precisely locate the ACCC conductor damage. With power spectral density method, the signal characteristics under different frequencies and different damage states were analyzed by experiments. The results manifest that the damage states of ACCC conductor can be identified by the proposed power spectral density method.