Work

Non-contact structural analysis of transformer housings under dynamic loading conditions using vision-based 3D measurement techniques

Year: 2026

Type: article

Abstract: Prior to deployment, industrial transformers undergo vacuum drying and structural integrity tests to ensure that they are structurally sound and safe to operate. Optical methods offer a promising, non-contact solution for three-dimensional measurements of structural deformation across different sections of a transformer in a factory environment. Preliminary tests were conducted using a stereo optical system and a phase-shifting (PS) terrestrial laser scanner (TLS) to measure surface displacements on EFACEC industrial transformers during a near-vacuum pressure test. The stereo system captured image pairs of speckle patterns affixed to one transformer wall, which were processed using digital image correlation (DIC), while the TLS acquired point clouds of the same surfaces. The measurements were then compared against simulation data. Since painting the transformer’s surface was not possible, alternative speckle patterns were evaluated, such as using magnets and printing on adhesive paper. Both the DIC and TLS produced adequate measurements in a factory setting, with some variation found in the measurements between methods and simulated data. These discrepancies could be attributable to ambient vibrations, necessary personnel access through the area where the optical systems were installed, the alternative speckle implementation, which may yield lower quality results when compared to painted patterns, non optimal speckle sizes due to uncertainty in available space prior to testing, and errors in the simulated data. Despite these challenges, the results show small absolute differences, the highest with an order of magnitude of 10 -3 m, the lowest with 10 -5 m, and the remaining differences with an order of magnitude of 10 -4 m, motivating further research. This work is a result of Agenda “ATE – Aliança para a Transição Energética”, no. C644914747-00000023, investment project no. 56, financed by the Recovery and Resilience Plan (PRR) and by European Union – NextGeneration EU.

Source: Procedia Structural Integrity

DOI: 10.1016/j.prostr.2026.01.073