Research on leak acoustic propagation channel identification and leak location for water distribution pipelines

For the conventional method of leak location surveys used in the case of acoustic signals in buried water distribution pipelines,the most widely used technique is the correlation method.The prerequisite of the method is that the leak signal propagation velocity is known.However,in practice,this prerequisite is not always satisfied.The blind identification strategy is applied to estimate the transmission performances of the two acoustic paths associated with the two sensors to the leak source.The absolute propagation times from leak acoustic source to individual monitoring points instead of the time lag between two acquired signals can be extracted from the identified channels,which is one of the channel characteristics.Consequently,for leak location,the known propagation velocity is no longer a prerequisite.For blind system identification,the overlap-save and cross-relation fitting technique are utilized to identify the long impulse response under a built constraint without the prior knowledge of the channel order.In order to avoid converging to the local minima,the genetic algorithm is used to minimize the cost functions.The application results show the validness of the proposed scheme.