Research And Realization On M-SPRT In Pipeline Leak Detection And Location

The leakage accidents in long pipelines transportation cause not only economic losses and environmental pollution, but also serious casualty. The frequency of these accidents becomes more and higher in recent years. In order to duly detect the leaks and reduce losses which leakage accidents cause, the methods of pipeline leak detection and location have been studied deeply under the background of engineering application based on the detection methods which have been used and some new technologies issued recently, and a software of leakage detection and location in long pipelines is developed. The main efforts accomplished can be summed up as the following aspects:1. A method is presented based on Multi-Sequential Probability Ratio Test in pipeline leak detection. On account of the problems which are how to make sure the alternative hypothesis and how to resolve detection delay-time, first of all, alternative hypothesis have been optimized through the objective function which is about the detection time expectation. Secondly, the decision function has been improved for eliminate detection delay-time.2. Some methods to calculate the average quantity of leakage, average time of leakage, the total quantity of leakage, are presented based on Multi-Sequential Probability Ratio Test.3. In order to find out the location of leakage in pipeline, the localization expression in gas pipeline has been derivated using for reference of the expression in petroleum pipeline based on grads of pressure through single pressure sensor. In methods based on grads of pressure nowadays, the nonlinear factor about grads of pressure in pipeline is not considered absolutely. So the localization method based on nonlinearity pressure grdas has been presented attemptly. The testing result with practical pressure datas and simulate pressure datas indicated that the localization method based on nonlinearity pressure grads has higher positioning accuracys and less calculated amounts.4. The software of leakage detection and location of pipeline is developed by using the VC++.NET 2003. The software can been set freely according to the changing of the pipes at real occasions. And it has several characteristics such as easily-doing user interface, real time datas displaying, and dynamic detection image showing online, and including several kinds of detection methods. At last, the testing result with real datas in pipeline indicated that the software can detect and locate the leakage of pipeline and estimate the quantity of leakage.