Research And System Implementation Of Pipeline Impact Location Method Based On Piezoceramic Transducer

Pipeline transportation,as one of the important modes of transportation,is often used to transport petroleum,natural gas and other materials.In recent decades,with the rapid development of the national economy,the demand for these important materials is also growing,and the pipeline industry is also developing rapidly.Many pipelines are laid on the ground and span a variety of complex terrain.Because of landslides,rockfalls,man-made damage and other factors,pipeline transportation safety is seriously threatened,and various dangerous accidents will occur.Rapid and accurate detection and location of pipeline collision is an urgent and valuable research topic.Aiming at the problems faced by current pipeline collision positioning system,this paper realizes accurate two-dimensional positioning of pipeline collision by means of designing signal observation system and studying new impact location information extraction algorithm.The specific contents are as follows.The observation system includes two parts: sensor and data acquisition.The Piezoceramic Transducer(PZT)is selected as the sensor to receive signals.It has the advantages of good stability,wide bandwidth and easy distribution.In the data acquisition part,a four-channel synchronous data acquisition system based on FPGA is designed,which has the advantages of low cost compared with the general acquisition card.Collision location information extraction algorithm includes signal arrival extraction and impact location calculation.The time of arrival is commonly used and the envelope calculated by the Hilbert transform is an effective method to determine the time of arrival.However,the envelope used to extract the time of arrival depends on the manual selection of the trigger threshold,incorrect selection of threshold will lead to errors in location calculation.In fact,the instant phase,that changes regularly from-pi to pi as the stress wave travels,is an important characteristic parameter of the signal,and the time of arrival can be determined by the periodicity of the instant phase.In this paper,a new method,time of arrival with instant phase,is developed to calculate the time of arrival without the need of manual selection of the threshold.A two-dimensional collision location method based on geometric approximation and circumferential constraints is proposed in this paper,then the collision positions along the axial and circumferential directions are determined.Finally,pipeline collision location experiment platform is established to verify the above-mentioned signal observation system and the proposed data processing method.The actual measurement and inversion results verify the reliability and accuracy of the signal observation system and data processing method.In summary,this paper studies and implements the collision location system based on PZT,including the design and implementation of the signal observation system,the accurate extraction of signal arrival time and the realization of two-dimensional collision location.The research results have certain reference value for the field of pipeline impact monitoring and positioning.