电缆及其附件局部放电超声波检测技术研究进展

Research progress of partial discharge ultrasonic detection technology for cable and its accessories

近年来电缆及其附件的各类局部放电检测技术快速发展,其中,超声波检测技术以绝缘性能好、受电磁干扰小等优点受到重视,本文将重点阐述该技术的最新研究进展。首先介绍了电缆及其附件局放超声波的产生和传播机理。然后,综述了不同类型超声波检测技术的系统组成,研究进展以及优缺点。分析发现,AE超声检测传感器结构简单、安装方便,但因无法彻底排除电磁干扰导致灵敏度低,加之不能进行分布式测量,其发展遇到瓶颈;光纤Sagnac传感器具有抗电磁干扰能力强、灵敏度高、长距离监测、定位方便等优势,但其不能进行分布式测量;光纤COTDR传感系统可实现分布式测量,并可检测到nC级放电量,但因只能测量光信号的振幅,需要对检测位置进行增敏处理;光纤φ-OTDR传感系统可同时测量光信号的振幅和相位,灵敏度大幅提升,无需增敏处理,满足电力电缆及附件的长距离分布式测量,应用前景好。

In recent years, various types of partial discharge detection technologies for cables and their accessories have developed rapidly. Among them, ultrasonic detection technology has attracted attention for its good insulation performance and low electromagnetic interference. This article will focus on the latest research progress of this technology. Firstly, the generation and propagation mechanism of local ultrasonic wave in cable and its accessories are introduced. Then, the system composition, research progress and advantages and disadvantages of different types of ultrasonic detection technology are summarized. Research finds that AE ultrasonic detection sensor has a simple structure and easy installation, but the sensitivity is low due to the inability to completely eliminate electromagnetic interference, and the distributed measurement cannot be performed. Its development has encountered a bottleneck. The optical fiber Sagnac sensor has the advantages of strong anti-electromagnetic interference ability, high sensitivity, long-distance monitoring, convenient positioning, etc. but it cannot perform distributed measurement;the optical fiber COTDR sensing system can realize distributed measurement and can detect nC-level discharge. However, since only the amplitude of the optical signal can be measured, the detection position needs to be sensitized. The optical fiber φ-OTDR sensing system can measure the phase amplitude and phase amplitude of the optical signal at the same time. The sensitivity is higher and is greatly improved. It has low requirements for optical fiber layout and does not require sensitization processing. It can meet the long-distance distributed measurement of power cables and accessories in the future, and the application prospects are good.