Oil-Immersed Transformer Temperature Monitoring

Equipment and thermal risk

Thermal stress develops at current-carrying interfaces, winding regions and cooling-limited structures. A useful monitoring plan identifies failure-sensitive points and distinguishes direct measurements from calculated or bulk temperatures.

Temperature points to monitor

Select points from the equipment thermal design: representative winding hot spots, phase-to-phase comparisons, joints, contacts, or cable terminations. Final probe locations must be approved by the equipment engineer.

Why conventional electrical sensors can be limited

Metallic sensor leads can create insulation, induced-noise and routing concerns near strong electric and magnetic fields. Infrared methods also require optical access and measure surfaces rather than inaccessible embedded points.

Fluorescent sensing approach

A monitor sends excitation light to a fluorescent probe and derives temperature from the decay lifetime of the returned emission. The probe is passive at the measurement point and the optical route is immune to EMI and RFI.

Probe placement and installation

Plan the sensing location, fixation, bend protection, fiber exit, channel labels and service access before assembly. Installation must protect the probe while preserving the intended thermal contact and equipment insulation system.

Monitoring architecture and integration

Probes connect to a multi-channel instrument that calculates temperature, manages local display or alarms, and can expose plant communications when confirmed for the chosen model. Define alarm ownership, register mapping and loss-of-probe behavior during controls engineering.

Monitoring system architecture