Feasibility study of embedded FBG thermal sensing use for monitoring electrical fault-induced thermal excitation in random wound coils

Abstract

This paper reports an experimental feasibility study of the potential for using Fibre Bragg Grating (FBG) thermal sensing technology for electrical fault detection in random wound coils. The study is performed on prototype test coils housed in a purpose built steel core section. The FBG thermal sensors are embedded between copper conductors in multiple positions within the coil structure and in close proximity of the known hot spots of interest. The examined coils are designed to enable emulation of hot spots representative of those that would be expected at the outset of winding fault events. A series of experiments were separately conducted in order to characterise the potential of coil internal thermal stress monitoring to provide recognition of a developing winding fault. To this end, winding fault scenarios with different severity levels of inter-turn fault are experimentally examined. The reported findings demonstrate the potential of the proposed in-situ thermal sensing scheme to enable monitoring and recognition of coil internal thermal stress induced at various stages of emulated electrical fault.

Keywords

• fibre optic sensors
• temperature sensors
• thermal stresses
• windings
• machine testing
• coils
• fault diagnosis
• Bragg gratings
• condition monitoring
• superconducting coils
• emulated electrical fault
• inter-turn fault
• fault scenarios
• developing winding fault
• coil internal thermal stress monitoring
• fault events
• hot spots representative
• examined coils
• coil structure
• purpose built steel core section
• electrical fault detection
• Fibre Bragg Grating
• experimental feasibility study
• random wound coils
• monitoring electrical fault-induced thermal excitation
• embedded FBG