Sensoriamento ótico pontual e distribuído para monitoramento de temperatura e vibração de motores elétrico de indução trifásicos

Abstract

This study presents the combination of two temperature monitoring methods in three-phase induction motors using fiber optic sensors: 1) Fiber Bragg Gratings (FBG); 2) Distributed Temperature Sensing (DTS). It also introduces an approach to analyzing the vibration of three-phase induction motors using FBGs. This study is motivated by the need to ensure the proper functioning of Submersible Centrifugal Pumps (SCP) used in offshore oil extraction while maintaining the temperature limits established by the machine manufacturer. Two machines were instrumented: the first is a 11,04 kW three-phase induction motor, equipped with DTS in all stator slots, in the end-windings region, in the junction box, and on the external part of the housing; the second is a 3 HP SCP, instrumented with DTS on the copper coils of the stator, in the coil head region, on the inner face of the housing, in the oil expansion chamber, and on the external face of the housing. Both machines have dimensions smaller than the spatial resolution of DTS, which required the development of a fiber optic installation strategy to accurately measure the real temperature of the target regions without resorting to signal reconstruction algorithms to improve spatial resolution. The results of the study demonstrate that the combination of the optical sensors used can efficiently monitor the temperature of the machines, complementing each other satisfactorily. Moreover, the cross-sensitivity of FBGs enables vibration monitoring without the need for additional sensors.