The application of terahertz technology in ultra high voltage large tonnage insulator detection

Abstract

Among major nondestructive testing technologies (NDT), such as X-ray and ultra-sound, Terahertz (THz) waves present significant transmission rate through most of nonconductive materials without the need of applying couplant while posing zero ionized radiation hazard. In comparison to microwave NDT, terahertz technology boasts a superior spatial resolution and measurement precision due to its shorter wavelength. As such, it is considered to be the most promising technology for industrial NDT applications. To analyze of THz wave transmission characteristics within porcelain insulator and obtain large quantity of testing data with repeatable measurement condition, this paper reports an experimental approach using Kaolin, in powdery form, to emulate the aging behavior of porcelain, and a THz sensor to detect such imperceptible aging process where micrometer-scale cracks slowly develop inside of porcelain insulators. To support the data acquisition from distance, a LORA communication module was integrated in the sensor for using under high-voltage environment. In addition, a dedicated user-interface software has been developed to receive the wireless data as well as conducting data analysis, crack recognition and graphic display. The experiment successfully demonstrated a very feasible solution for online monitoring of the aging process of porcelain insulators by using compact THz sensor buried in the insulator.

Keywords

• Terahertz wave
• Insulator
• Kaolin
• Electromagnetic interference