Spatially continuous transformer online temperature monitoring based on distributed optical fibre sensing technology

Abstract

Abstract Transformer internal thermal monitoring exists huge blind areas, and it is difficult for traditional methods to get fully distributed temperature in real time. In this contribution, the distributed optical fibre sensor was creatively applied inside an operating 35 kV oil‐immersed transformer which is also qualified for actual power grid operation through the ex‐factory tests. Furthermore, the full‐region temperature along the windings and iron limbs were firstly monitored in a spatiotemporally continuous manner and the hotspots were also closely traced, fluctuating at 90% of the high‐voltage winding height (80% for low‐voltage winding) during the whole process of the heat‐run test. Corresponding Finite Element Method (FEM) for thermo‐fluid field calculation was then utilized for deeper analysis. On the former basis, the actual detected temperature distributions (both spatial and temporal) were compared with the International Electrotechnical Commission traditional model and some modifications were suggested based on the real time measured data. This novel online monitoring application and the detailed internal thermal information may provide a solid reference for the delicate management of power transformers, which also offers a new horizon for the online monitoring in electrical apparatus industry.