Stator Winding Internal Thermal Monitoring and Analysis Using In Situ FBG Sensing Technology

Abstract

This paper reports a novel thermal monitoring scheme for on-line internal temperature measurement in lowvoltage random wound machine stator windings. The scheme is based on utilizing electrically nonconductive and electromagnetic interference immune fiber optic sensing technology embedded in close proximity of hot spots of interest to create a robust distributed thermal monitoring network within the machine windings. The key design and implementation features of the proposed system are presented and applied on a prototype mains-fed induction motor. The on-line thermal monitoring performance is examined in a number of typical continuous and periodic running duty tests, as defined by the relevant IEC standards for rating and performance of rotating electrical machines. It is shown that the presented scheme has the potential to provide competent on-line measurement of critical machine thermal hot spots that are largely beyond the effective reach of conventional thermal monitoring solutions. Furthermore, the proposed scheme underpins a higher fidelity understanding of the distribution and propagation of winding thermal stress, demonstrated by the experimental analysis reported in the paper.

Teste para Prognósticos de Falhas em Motores de Indução: Discussão Teórica e Estudo de Caso

“…O estresse térmico que ocorre durante um sobreaquecimento ao qual o motor está sujeito provoca uma rápida deterioração do sistema de isolação que, eventualmente, pode ocasionar a falha da máquina (Mohammed and Djurovic, 2018). Nesta conjuntura, o monitoramento térmico configura um mecanismo eficaz para realizar a proteção do equipamento, uma vez que permite verificar se a temperatura dos pontos mais quentes da máquina está em consonância com os valores estabelecidos para a classe de isolação térmica do motor em questão, conforme ilustrado pela Fig.…”

“…Fig. 3 Limites térmicos para motores Classes A, B, F e H (adaptado de (Mohammed and Djurovic, 2018)).…”

Development of a Starter with Protective Systems for a Three-Phase Induction Motor

“…In addition to the burning out of the windings, an increase in temperature could result in increased power consumption and decreased speed and efficiency. ermal stress resulting from excessive temperature greatly contributes to the reduction of the performance and lifetime of induction motors [8]. us, there is a need to protect the motor against excessive temperatures.…”

Design, Instrumentation and Usage Protocols for Distributed In Situ Thermal Hot Spots Monitoring in Electric Coils using FBG Sensor Multiplexing

“…Thermal overloads are particularly pertinent in this regard as these can cause insulation coil insulation system breakdown and ultimately its total failure 1 ; this can arise due to excessive coil current levels, or other causes such as a coil electrical fault or a cooling system malfunction, where localized hot spots are induced in the coil structure leading to insulation breakdown. Enabling operative in situ distributed thermal monitoring of an in-service coil's internal structure allows for development of improved utilization and condition based maintenance routines; it would allow for advanced understanding and identification of the coils' operating status and any degradation process, and thus condition based corrective action to maintain the operating status and prevent or slow down further damage 2,3 .…”