Monitoring the Winding Hot Spot

When exposed to high temperature, insulating paper found in transformers breaks down and results in a reduction of the useful life of the transformer. Monitoring temperature of the insulating paper via a winding hot spot ensures the insulating paper is not exposed to high temperatures and helps minimize damage.

Conventional methods of monitoring the winding hot spot use calculations to simulate the temperature, but do not measure it. These winding temperature indicators (WTIs) infer the hot spot temperature by measuring the transformer load on a single phase and the surrounding oil temperature and then apply a model. Other issues with the WTIs include a long lag time (up to 5 hours) and actual temperature variance (up to 20 °C).

Diagram of the LumaSMART controller connected to fiber optic probes monitoring the insulating paper in a transformer

Fiber optics, including the LumaSense Luxtron Fluoroptic® probes, enable utilities to measure the winding hot spot directly and accurately in real time. Leveraging 40+ years of Luxtron fiber optic technology, these probes are based on a temperature sensitive phosphorescent sensor attached to the end of an optical fiber. These probes are reliable, stable, and immune to electromagnetic inference. With no thermal lag or temperature variance, controllers can take immediate action when temperatures exceed expected values and prevent transformer asset damage.

Stop by booth #2274 at IEEE PES T & D or #10 at TechCon Australia this week to learn more about LumaSMART and our other solutions for the Energy market.