Thermal Effects of Artificial Lamination Faults in a Three-Phase Transformer Core Using Infrared Thermography

Abstract

Transformer core lamination faults can significantly affect transformer performance, reliability, and operational lifetime by increasing core losses and localized heating. This paper investigates the thermal effects of edge burr faults and inter-laminar insulation deterioration. An experimental test rig consisting of a 15 kVA three-phase transformer and a FLIR C2 thermal imaging camera was developed to capture temperature distributions under healthy and faulty operating conditions. Faults were introduced by creating controlled short circuits between laminations with varying affected areas and numbers of shorted laminations. Thermal images were acquired at different magnetic flux densities ranging from 0.5 T to 1.8 T under no-load conditions. The results demonstrate that both fault types produce noticeable temperature rises compared with healthy operation, with the severity of heating increasing as the flux density and fault size increase. Edge burr faults resulted in localized hot spots and temperature rises of up to 10% compared with healthy conditions, while insulation deterioration faults produced temperature increases exceeding 18% for severe fault scenarios at 1.8 T. The findings confirm that infrared thermography provides an effective non-invasive technique for detecting and assessing transformer core lamination faults and can support condition monitoring and early fault diagnosis in power transformers.