弹性波在高压输电线中的传播特性

采用压电陶瓷设计了一种适用于高压输电线结构健康监测的传感器,分析了该传感器在输电线表面激励弹性波,得到了弹性波在输电线中的传播特性。利用Gabor小波变换计算传感信号到达时间的原理,试验得到了弹性波在输电线中传播的群速度频散曲线。结果表明,在低频段(低于30kHz)时,弹性波在输电线中的传播模态比较简单,适合用于结构健康监测。通过弹性波在输电线中的衰减试验,得到了信号峰值随传播距离的衰减曲线以及激励信号频率与信号峰值之间的关系曲线,得到弹性波在输电线中按照指数规律衰减。

Propagation Characteristics of Elastic Wave in the Overhead Transmission Cable

A new sensor with piezoelectric ceramic is designed for Structural Health Monitoring on high voltage transmission cable used for exciting elastic wave on the surface of transmission cable to obtain the propagation characteristics.Based on an experimental setup with two transducers,a signal generator and a data acquisition system,the dispersive curve of guided wave in the transmission cable is measured through Gabor wavelet transform.The results show that there are at least four modes above 30 kHz,but there are only two modes below 30 kHz,which is suitable for the research of SHM.Another experiment for the damping of elastic wave on the transmission cable is carried out.The curve of the relationship between amplitude attenuation and propagating distance is achieved.The influence of frequency on peak value is researched.Results show that the wave attenuation is exponential function.