Research Of Cavitation Monitoring And Fault Diagnosis System For Turbine

With the vigorous development of China’s hydropower industry, the percentage of thegenerating capacity in the power system is increasing, and more and more large capacityunits appeared. The security and stability of the hydropower units are becomingincreasingly important for the entire power grid. There are many reasons which haveinfluence on the long-term normal operation of hydro turbine, especially the cavitationerosion. Due to fluid mechanical vane design, installation, operation, water quality andother factors, the phenomenon of cavitation is widespread in the long-term operation offluid machinery. Cavitation will cause the turbine flow components structure damage,deteriorate the operating condition, reduce the output of generating unit and water powerutilization rate. However, cavitation test is a recognized the problem of academia andengineering. So far, it does not exist a unified standard system for detection of cavitation,which is accepted in engineering. Do a real-time online monitoring on cavitation withinthe normal operation of the turbine; processing and analysis the cavitation signals; get areal-time forecasting of cavitation condition, which have a positive influence over the unitoperation, help to determine the unit maintenance cycle and provide important referenceindex to the economic operation of hydropower station.This paper focuses on the monitoring of turbine cavitation and cavitation noisecharacteristics which are monitored from the range of cavitation noise frequency bandwhen the cavitation occurred. Completed the design and development of the turbinecavitation monitoring system, and provide a solid foundation for the status maintenance ofthe hydropower equipment.This paper firstly introduced the phenomenon of cavitation, the types, characteristicsof cavitation noise, and the influence caused by cavitation. It discussed the importantmeaning of cavitation monitoring system for hydropower unit. Then it introduced theprinciple and method of monitoring system, and the structure of hardware platforms andsoftware system, made research and analysis of sensor node data acquisition,preprocessing, feature extraction and data transmission. And it developed the applicationprocedures for monitoring and diagnosis of cavitation which include the real-timecavitation monitoring, parameter trend analysis, parameter analysis, comprehensivemulti-dimensional evaluation, and automatic report generation module etc. Finally thearticle summarizes the research results, explores the problems which need to be improvedand points out some aspects to be further studied.