The Experiment Investigation Of Ultrasonic Nondestructive Characterization For High Voltage Aluminous Insulator

High voltage insulator are important component of the transmission line and substation,and the reliability about operation of insulator is always the one of the key factors which decide whether power transmission and transformation project can run safely or not.As the main part of insulator,the porcelain insulator's characteristics and quality immediately determine the operation of insulator's reliability.However,the break accidents of insulator have happened frequently in recent years,which brought huge losses to production of national economy.So how to characterize and evaluate the property of insulator in order to improve the quality of productions which has become important problem that people are concerned.Manufacturing technology,microstructure and performance of porcelain insulator are introduced in this paper,the influences of microstructure to the insulator's property are also introduced.And often used at present characterization methods about structure characteristic are reviewed.Ultrasonic nondestructive characterization and evaluation is introduced especially,and summarize its application in characterizing material density,elastic modulus and the porosity.Because of material property and material structure are closely related to each other,and acoustic parameters(sound velocity,acoustic attenuation and so on) are determined by material structure.Contrasts to destructive testing,people take more and more attention in the advantages and practicability of ultrasonic characterization. However,Ceramic Materials are inhomogeneous and multiphase mixture,at the same time. ultrasonic wave attenuates strongly when it propagates in structure,the factors influence ultrasonic signs are complex;the extraction accuracy about acoustic parameters are poor,all these problems bring big difficulties to characterize material property and material structure by ultrasonic.In this paper,research objects are aluminum high pressure base electric ceramic slab samples,ultrasonic pulse water immersion line focus echo detection techniques and direct contact methods are applied in test analysis in respectively.Three electric ceramic slab samples' structure information are obtained Whose longitudinal wave and transverse wave echo sign are 2.5MHz,2MHz,respectively and firing temperature are 1230℃,1260℃,1290℃.The relationship among sound velocity,acoustic attenuation and three samples' structure also researched.Regularity are studied in porosity,sound velocity,acoustic attenuation and firing temperature.The results showed that high voltage insulator's structure characteristics can be characterized effectively by Ultrasonic nondestructive characterization and evaluation technology.