Research On The Method For Improving Accuracy Of Acoustic Pipeline Leak Detection

Pipeline transport is one of the main ways of fluid transportation industry, aging of pipeline is serious in our country. The demand for pipeline leakage detection accuracy is stricter, and the demand for small leakage detection is greatly increased. Existing acoustic leakage detection method based on piezoelectric pressure transducer has high sensitivity and location accuracy. Leakage signal and interference signal has similar time domain and frequency domain characteristic, and the SNR of small leakage is extremely low, false and missing alarm is difficult to avoid. It has important value to explore the method to improve the accuracy of leak detection.In this paper, the method to improve leak detection precision is explored both in signal enhancement and interference signal recognition. Through the analysis of the piezoelectric pressure transmitter, the integration item of output signal is missing, affects the low frequency response of the piezoelectric pressure transmitter. Thus put forward the acoustic leakage signal enhancement method based on time domain integration, the enhancement performance is adjustable through the gain coefficient, the pre-processing method and the gain coefficient selection are analyzed.The problems of interference signal recognition method based on time delay cross-correlation method are found through the theoretical analysis, the interference signal recognition method based on short distance dual-sensor structure is put forward. The interference signals and leaks are classified as abnormal signal, the abnormal signal is found and located through the time-domain statistical features. Abnormal signal hopping edge is extracted and the difference accumulation of two channel signals is calculated. According to the accumulation symbol, the direction of abnormal signal propagation is judged, thus the identification of interference signal is achieved.It has been verified by simulation and field experiment, the leakage signal enhancement method based on time-domain integration has good effect, and has high adaptability and stability, simple calculation without complex parameter optimization. Interference signal identification method based on short distance dual-sensor, has high recognition accuracy, the requirement of installed space and sample rate is low, new idea is put forward to improve the accuracy of leakage detection.