PCCP断丝的电磁无损检测技术研究

Research on Electromagnetic NDE Inspection Method for Broken Wire of PCCP

摘要: 预应力钢筒混凝土管(Pre-stressed Concrete Cylinder Pipe, PCCP)作为一种新型的输水管材，被广泛应用于水利工程。在PCCP运行过程中，环境腐蚀或操作不当会导致管内高强钢丝的腐蚀或断裂，进而导致泄漏、爆管等事故。目前国内外普遍采用电磁涡流检测技术，对PCCP的断丝与金属管壁健康状态进行无损检测，检测系统在管内运行并配合计程轮等工具实现断丝位置的定位。本文针对国内外两种常用的PCCP断丝电磁检测技术，即远场涡流检测方法和正交电磁检测方法，建立了简化分析模型，并给出了等效交流电路，通过仿真分析验证了模型的正确性。分析了电磁检测频率的选取原则，建议选取23 Hz作为检测频率。给出了电磁检测系统的设计与实现，并经过了管道断丝试验验证，有效提取了故障特征。

Abstract: Pre-stressed Concrete Cylinder Pipe (PCCP), as a new type of pipeline for water delivery, has been widely used in water conservancy projects. During the operation of PCCP, environmental corrosion or improper operation will lead to corrosion or fracture of high-strength steel wire in the pipe, resulting in leakage, explosion and other accidents. Currently some nondestructive methods, such as electromagnetic eddy current inspection method, are widely used to test the broken wire and assess the health PCCP, and equipped with a counting-wheel or other tools to achieve the localization of broken wires. This paper presents a simple model of two famous electromagnetic detection technologies for PCCP broken wire, i.e. the remote field eddy current testing method and orthogonal electromagnetic detection method. Also the equivalent AC circuit is given. By simulation analysis the simple model is verified. The selection principle of electromagnetic detection frequency is analyzed, and 23 Hz is selected as the detection frequency. The design and implementation of the electromagnetic detection system are given, and the fault characteristics are effectively extracted through the broken wire tests.