Research On Localization Algorithm For Water-pipeline Leakage Based On The Attenuation Of Pressure Waves

In order to satisfy the demand of water resources in daily life,pipeline is one of the most convenient and economical ways.Caused by numerous problems such as corrosion,aging and third-party interference,pipeline leakage can lead to financial loss and environmental disruption.Thus,there is pressing needs for feasible methods to detect leakage immediately and confirm leakage point accurately.The methods of pipeline leakage detection mainly include acoustic detection method,flow balance method and negative pressure waves method.Among in the all methods,the NPW(negative pressure waves)method stands out for its simplicity to deploy,economy and higher sensitivity.Hence,the NPW method is widely used in pipeline leakage detection and location.The main research content of this paper is the study of pipeline leakage location algorithm.The traditional method of pipeline leakage location based on negative pressure wave is to calculate the leakage location according to the time difference between the start and end station and the wave speed,which is a straight and simply method.In the short distance pipeline leakage localization,pressure sensors installed at start and end of the pipeline can fully monitor the entire pipeline.Due to the rapid propagation speed of negative pressure wave,the time difference between two sensors is almost equal value.Besides,the noise in the pressure signal seriously affects the positioning accuracy even if wavelet transform or Empirical Mode Decomposition(EMD)is used for noise suppression.In addition,in the long distance pipeline leakage localization,only depending on the two pressure sensors cannot completely monitor the whole pipeline.Therefore,the traditional method based on time difference has some limitations whether it is used in short or long distance pipelines,and the positioning accuracy needs to be improved.In this paper,we propose the novel method named the attenuation of negative pressure waves(ANPW)algorithm.Through momentum equation and continuity equation of pipeline,the attenuation formula of pressure wave along pipeline is derived,and then the relationship between pressure variation and leakage position is obtained,and the calculation formula of ANPW algorithm is given.Compared with the time difference between two inflection points of negative pressure wave,it is easier to calculate the pressure change before and after leakage.Because the negative pressure wave curve under the stable state presents a linear relationship,the matching time-frequency peak filtering(TFPF)denoising algorithm is adopted to effectively suppress the noise interference and improve the positioning accuracy.At the same time,the leakagelocalization effect of traditional algorithm and ANPW algorithm are compared.Besides,the leakage localization effect of different denoising algorithms is also researched.Considering the practical projects,pipeline is usually long distance.According to the basic frame of compressive sensing algorithm,this paper proposed a compressive sensing leak location algorithm based on Pressure Variation Decay(PVD).This algorithm can be effectively applied in long distance transmission pipeline.Due to the attenuation characteristics of pressure wave,PVD model can be established as the perception matrix of the compressive sensing algorithm,and the weight vector obtained through reconstruction algorithm can effectively locate the leakage points.Based on the basic principle of compressive sensing algorithm,this paper proposes a novel location algorithm based on PVD model and compressive sensing.The compressive sensing algorithm can use as few sensors as possible to monitor the whole pipeline.Through research and analysis,it determines the minimum number of sensors and the number of pipeline section.This paper selects the most suitable reconstruction algorithm by comparing different reconstruction algorithms.The experimental results show that this algorithm improves the real-time performance of long distance-pipeline leakage location,and is robust to a certain extent.