Methodology for the Building of a Fuzzy Expert System for Predictive Maintenance of Hydroelectric Power Plants

The aim of this study is giving continuity to the evolution of the SIMPREBAL methodology and computer system based on the specification OSA-CBM (Open System Architecture for Condition Based Maintenance). The operation of the SIMPREBAL (Predictive Maintenance System of Balbina) system mainly is based on the collection and analysis of the monitored physics variables in hydroelectric power plants, those variables are obtained from intelligent sensors to be usually installed on the generator units of hydroelectric power plants and on the implementation of a computer system based on diagnosis of the running states of the devices with the objective to help the establishment of decision making and maintenance operational actions of the machines thus, increasing their availability. It will therefore develop a new intelligent system to improve the performance of the SIMPREBAL system. This approach involves the development of a production rules based fuzzy expert system; this model and reasoning mechanisms are implemented using Java, JESS (Java Expert System Shell) and the NRC FuzzyJ Toolkit for the Java Platform Version 1.8. Basically the development of the methodology will be divided in 3 main parts; In summary, first the dates to be obtained from sensors, will be fuzzificated with their fuzzy sets, then those fuzzificated inputs will be matched against the production rules of the system applying the main fuzzy inference techniques such as MandaniStyle, Sugeno-Style, etc. to evaluate the performance of the system and finally the outputs of the system will be defuzzificated applying some appropriates methods of defuzzification (Decoding) such as the Center of Gravity (COG) technique, the Center of Area (COA) technique, etc. and then apply those defuzzificated outputs to the new system with the final objective of establishing one or several maintenance procedures so that the process operator can make the best decisions. Finally, to be able to establish final conclusions, it will analyze a case study to validate the performance of the new system in the hydroelectric power plant of Balbina to be approximately to 220 km of the Manaus city.