Feasibility of non destructive testing for aluminium sheaths of HV cables using ultrasonic guided waves
                       CAO Jun ping1, HU Wen tang1, LIU Hao jun1, WANG Shao hua1, WU Jian jun2, LV Fu zai2, TANG Zhi feng3
(1.State Grid Zhejiang Electric Power Research Institute, Hangzhou 310014, China;2.State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou 310027, China；3.Institute of Advanced Digital Technologies and Instrumentation, Zhejiang University, Hangzhou 310027, China)

Abstract: Aiming at the problem that aluminium sheaths of HV cables can easily be injured mechanically and corroded to fail during the service, the dispersion curve was calculated by solving the dispersion equation from the simplified model of aluminium sheaths of HV cables. Thus, the propagation characteristic of guided waves in aluminium sheaths of HV cables like multiple modes、frequency disperision and attenuation were studied. The method of fast non destructive testing for aluminium sheaths of HV cables using ultrasonic guided waves was proposed. Based on the theoretical analysis and finite element simulation, the experiments were carried out for aluminium sheaths of HV cables using the ultrasonic guided wave detector. The results indicated that: cracks with loss ratio of sectional area over 4.25% can be detected by theT(0,1) mode whose frequency is 32 kHz, the amplitude of the flaw echo increases along with the loss ratio of the crack. Theoretical analysis, finite element simulation and experiments prove the feasibility of aluminium sheaths testing using ultrasonic guided waves.

Key words: aluminium sheaths of HV cables; ultrasonic guided waves; the dispersion curve; T(0,1) mode;defect testing