Interferometric measurement: Phase is measured between returned laser light and an internal reference.

• Velocity extraction: A phase-locked-loop algorithm computes vibration velocity per channel and scan position.
• Spectral analysis: Fourier analysis identifies dominant lines and synthesizes vibration maps at selected frequencies. Outcome: Utilities can evaluate both frequency content and the precise physical location of abnormal activity in a single workflow. Typical inspection geometry: Stand-off approximately 9–10 m, angular step around 2°, and about 175–225 scan lines depending on asset size. For each line, the system records around 1 s of data on 65 parallel points. Field campaigns showed low background noise and stable spectra; peak amplitudes were on the order of 10^-2 mm/s, confirming sensitivity for low-level diagnostics in substations.

A transformer is a coupled electro-mechanical system in which core, windings, clamps, insulation, leads, oil, and tank shape how vibration is generated and transmitted. Exterior tank response is spatially non-uniform; panels, corners, stiffeners, and radiators exhibit different amplitudes, harmonics, and local resonances. Single or few-point accelerometers risk missing localized hotspots or asymmetries. LDV scans many positions to reconstruct full-field maps, improving sensitivity to localized defects, enabling side-to-side comparisons, and supporting screening, trending, and targeted follow-up.

Transformers and shunt reactors generate vibration from electromagnetic forces, magnetostriction, structural coupling, and local resonances. Changes in amplitude, harmonic balance, or spatial distribution can indicate looseness, altered clamping, degraded supports, or other evolving mechanical issues. Unlike sparse contact instrumentation, LDV is non-contact, operates from a safe distance, and delivers spatially resolved vibration maps across visible tank surfaces. Ommatidia Q2 advantage: The Q2 Laser RADAR combines coherent vibrometry with an RGB camera for alignment and documentation, an elevation microscanner for dense vertical sampling, autofocus for optimal return, and 65 simultaneous parallel channels. This enables rapid, full-field screening of large grid assets up to 50 m.

Dominant signature on 50 Hz grids: a strong 100 Hz peak with 200 Hz, 300 Hz, and higher harmonics as electromagnetic forces and magnetostriction scale with flux squared.

• Condition indicators: increase in 100 Hz amplitude, unusually strong higher harmonics, localized hotspots, left–right asymmetries, and deviations from fleet norms.
• Example: One asset exhibited a notably stronger 300 Hz component in specific regions, an outlier flagged for engineering review.

Baseline characterization: establish vibration fingerprints for new or known-good units.

• Periodic condition assessment: repeat surveys for drift, asymmetry, or harmonic growth.
• Screening of noisy or suspect assets: separate global electromagnetic vibration from localized structural issues.
• Post-intervention verification: confirm effects of tightening, support changes, or rework.
• Fleet comparison: identify outliers among nominally similar units under comparable load.

Discuss how this measurement approach could support applications workflows with the Ommatidia LiDAR team.