The Improvement Of Acoustic Positioning Technology In Boiler ’Four Tube’ Leakage Detection

In recent years, the safe and economic operation of thermal power units, whichis seriously affected by the boiler "four tube" leak accidents that frequently happenedin power plant boiler. These accidents have caused a great loss to the plant, and alsoaffected the economic benefits of the plant. The acoustic leakage detectiontechnology is not only the main method for the early leakage detection of the boilertubes, but also the main development direction. It has great development space andpromise prospect.However, at present, the tube leak positioning based on the acousticdetection technology is limited to the reginal positioning.The key step of acoustic positioning is the time delay estimation, in order to getmore accurate time delay estimation, least mean square time-delay estimationt andgeneralized correlation time delay estimation based on wavelet threshold denoisingare used to estimate two-way signal delay time, and then the support vector regressionis adopted to deal with the results comprehensively. Three leakage data from powerplant are used to process and analyze. The simulation results show that the fused timedelay estimation is more accurate than the single method. The experiments show thatthe support vector regression method is adopted to deal with the result that comesfrom these two kinds of the time delay estimation method, which can get moreaccurate delay estimation and improve the positioning precision of boiler "four tube"leakage detection.On the one hand, as the monitoring configuration software, the "KingView"industrial control software has the great advantage in collecting the field data andsupervising the system; on the other hand, MATLAB is widely applied in the controlsystem calculation because it provides the user abundant of toolbox. This thesisadopts the DDE data communication technology which can change the EXCEL intointermediate variable, then realize the data communication between the "KingView" and MATLAB. This method makes full use of the "KingView" to collect the data anddesign the control system interface; at the same time, it can make use of theMATLAB to realize the complex control algorithm. By this way, we can construct theboiler "four tube" leakage monitor software flexibly that can satisfy the demand ofthe users.