Intrumentação óptica de máquinas industriais de grande porte para medição de temperatura

Abstract

This study demonstrates the development, parameterization and application of optical sensing techniques for temperature measurement in large rotating machines of two industrial segments, high power hydroelectric generator and locomotive diesel engines. A Distributed Temperature Sensor (DTS) technique in an optical fiber was used to monitor the stator surface temperature of a 200MW hydroelectric generator, which resulted in a thermal monitoring system capable of identifying hot spots of possible insulation faults. Another technique using fiber optic Bragg gratings (FBG) was used for temperature measurement of the heat exchangers of the hydroelectric generator, placing fifteen multiplexed FBG in the useful area of the exchanger. Finally, using the same technique with FBG, a transducer was developed with twenty-four multiplexed FBG to monitor the temperature of the diesel engine bearings. The work shows the step-by-step of techniques development, prototype constructions, and field installations. The results demonstrate that the two optical instrumentation techniques used are promising, given their advantages when compared to already existing techniques based on conventional sensors. Because of the intrinsic characteristics of the applied optical sensors, it is possible to obtain more data on the operation of the machine. With the information collected from the optical sensors installed in the machines in question, software analysis and supervisory systems with historical data, machine status indication and alarm generations that improved the planning of preventive and predictive maintenance, reducing machine downtime were developed.