| Along with the change of management system of electricity enterprise, hydropower enterprise has gotten higher requests of maintenance quality, maintenance cost, maintenance period and equipments' safe and stable operation. The progress and development of electromechanical equipments' design and manufacture, on one hand, improve the reliability of the equipment, on the other hand, it also increase the technical difficulty of fault diagnosis and the maintenance cost of equipment. Therefore, in order to reduce down time and maintenance cost, we make offer the transition request from original planned maintenance to optical maintenance which is based on equipment condition monitoring and diagnostic analysis. Hydropower units' fault diagnosis operation and condition base maintenance are experienced work, which is very suitable to be realized by expert system technology. The expert system can accumulate all sorts of knowledge and recur specialist's knowledge. It can digitize expert knowledge, realize equipment's state monitoring and fault diagnosis analysis, offer decision support for state monitoring and fault diagnosis of hydropower plant.This chapter summarizes the general development of the equipment maintenance and fault diagnosis technology of hydropower plant in our country. It also introduces the importance of specialist system in fault diagnosis and maintenance of hydropower plant.This chapter introduces the basic knowledge of the expert system. Considering main task of maintaining expert system, the model of system structure and its behavior in production process was set up. The digitization of information was proposed. By simulating realistic expert to capture abnormal phenomenon, read technical document, diagnose abnormal reasons of positioning, the technology to analyse and diagnose the system of expert intellectual state was set up. By applying the method of model reference fault diagnosis and "signature analysis" based on experience in equipment analysis, the digitization of maintenance-oriented specialist system was realized, which has important significance of methodology. There is practical value of implementation approach and application of digitization information in equipment state analysis, fault analysis, deductive analysis, fault forecast, equipment maintenance decision. The expert consulation mechanism was talked about.From the need of digitization, it apply the method of adopting tree form classification structure to sort process equipment knowledge in the technical date complication of equipment, it also solve the contradictoriness between the decentralized editor process and central management inquire of equipment technical document. Proceed from the request of equipment maintenance, by abstracting, classifying and processing, we build up the technical document date and realize technical document digitization revolving the encoding rules of equipment structure layer, which support the important guarantee for sharing date and information of specialist system. Adopting the strong function of modern multimedia in digital information processing, the multimedia technical document management system was built.Digitization of experts' knowledge and experience is the core of expert system. From different point of view of model base of equipment kinetic characteristic, model base of unit working condition conversion, FMECA model base and FTA base, it describes fault type, inspect method, fault representation characteristic and fault diagnose reasoning method of hydropower units. It sets up expert analytical knowledge base and realizes digitization of expert knowledge and experience, which offers key technology to implement the automatic fault diagnosis. It has important theory significance.This chapter also introduces the application achievement of digital expert knowledge in GeZhouba Hydropower Plant, which proves the feasibility and practicability of the system. It also point out the shortage of the system and questions which need to be further studied and solved.
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