【作者】 周洪梅；

【导师】 陈仁文；

【作者基本信息】 南京航空航天大学 ， 测试计量技术及仪器， 2004， 硕士

【摘要】 长输管道是一种方便经济的运输方法，在工业中有着广泛的应用。但管道运营过程中的泄漏事故不仅造成国民经济的重大损失，也严重污染了环境。因此，研究管道泄漏检测，将带来明显的经济效益和社会效益。 基于应力波检测的管道防盗实时监测报警系统由基站测试单元和主站监控中心两部分构成，基站负责信号采集，主站负责盗油报警定位。本文研究了基站测试部分的硬件设计、调试及功能扩展。首先对应力波检测的原理从物理角度进行了分析。然后从设计的角度，讨论了硬件系统的主要组成。功能扩展方面讨论了超声防盗报警电路以及基站故障的智能检测电路。 此外，本文研究了应用小波分析中的非线性阈值法抑制背景噪声，提高信噪比，从而改善远距离信号检测效果，提高检测距离。应用此方法，对管道防盗检测系统的现场试验表明了系统对盗油破坏的检测距离可以达到1kM。 最后，讨论了管道模型的建立，以分析应力波在管道中的传输特性。借助假设约束条件，考虑土壤的阻尼作用，建立了地下管道的简化数学模型。更多还原

【Abstract】 Long pipeline transportation is a convenient and economical way for oil transportation, and is widely adopted by industries. But the leakage accidents of oils not only bring great economic losses but also seriously pollute our environment. Thus researches on pipelines leakage detection will result in remarkable economic and social benefit.The stealth monitoring system based on stress wave detection technique for oil pipeline on-line monitoring is composed of two parts: the detection net nodes for signal acquisition and the host station for oil stealing alarming and location. In this paper, the hardware design, debugging and expanded function of the nodes is investigated. The principle of stress wave detection is analyzed from physical aspect, and the hardware test system is discussed. For the expanded function part, the ultrasonic testing circuits for anti-stealing and the smart detection circuits for failure diagnosis are discussed.The nonlinear threshold de-noising method of wavelet analysis is adopted for background noise cancellation and SNR (Signal to Noise Ratio) increasing. Thus the signal detection performance at long distance can be improved and the detection distance can be extended. Field experiments employing the above methods indicate that the distance of stress wave detection is more than 1 kilometer.The modeling of the stress wave going through the pipelines is discussed finally. By considering some restriction conditions and the earth damping, a simplified mathematical model of underground pipelines is setup.更多还原