Identification method for tiny leakage signal of oil transportation pipeline

Abstract

The invention discloses an identification method for a tiny leakage signal of an oil transportation pipeline, relating to the field of pipeline signal processing. The identification method comprises the following steps: selecting a db4-10 series wavelet function as a wavelet base for wavelet conversion and determining that the quantity of layers of wavelet decomposition is four; carrying out four-layer discrete wavelet decomposition on an original sound signal by adopting a MALLAT pyramid algorithm; selecting detail signals of a third scale and a fourth scale and carrying out wavelet reconstruction to obtain de-noised signals; uniformly dividing the de-noised signals according to time to obtain divided sound signal segments; carrying out short-time Fourier transform on each divided sound signal segment to obtain a conversion matrix; manufacturing a normalized energy pattern of the sound signals by utilizing the conversion matrix; and judging whether the oil transportation pipeline has tiny leakage or not according to the normalized energy pattern. According to the identification method disclosed by the invention, effective identification of the leakage signal is realized and various requirements in actual application are met.

Description

technical field [0001] The invention relates to the field of pipeline signal processing, in particular to a method for identifying tiny leakage signals of oil pipelines. Background technique [0002] Pipeline workers at home and abroad have been committed to the research of pipeline leakage detection technology. At present, the commonly used pipeline detection methods in China are divided into external detection method and internal detection method according to the location of the detection device. [0003] The most widely used external detection method is the negative pressure wave method. When a pipeline leaks, a transient pressure drop occurs at this point, and a negative pressure wave is generated, which propagates along the pipe wall to both ends of the pipe at a specific speed, and is determined by the pressure. The negative pressure wave is collected by the sensor, and can be located according to the transmission speed of the negative pressure wave and the time differ...

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Problems solved by technology

[0004] In the internal detection method, an internal detector equipped with a sound sensor is placed in the pipeline, and it advances along the pipeline under the push of the oil, and can collect leakage sound signals near the leakage point, so it can detect small leakage signals with a leakage volume of less than 1L / min. The background noise in the pipeline is complex, including: the friction and collision sound between the inner detector and the pipe wall, the noise of the surrounding environment (vehicles, rivers), etc. It is necessary to use appropriate signal processing methods to effectively identify the leakage signal

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