Direct Measurement of Transformer Winding Hot Sport Temperature

Fiber optic temperature sensors were embedded diarectly within the windings of a large auto-transformer to measure hot spot temperatures under a variety of loading conditions. Numerous application problems were encountered, but a substantial amount of usable data was acquired. Sensor readings correlated well with the results from other measuring devices in locations where a direct comparison could be made. It was demonstrated that accurate conductor temperature data can be obtained, but that probe insertion methods are critical.