On-site diagnostic method for the degradation of cast resin trasforrmer using optical reflectance.

We propose a new on-site diagnostic method for the degradation of mold transformer using optical reflectance. The mold transformers which use the epoxy resin for coil insulation have excellent characteristics of fire retardancy and environment resistance. From the viewpoint of electric equipment diagnosis, the mold transformers are treated as exceptional for diagnosis test in many cases because of its high lifetime reliability. However, since the mold transformer has been using for 40 years or more, the epoxy resin for coil insulation must be affected by aging degradation. Therefore, degradation diagnosis of the epoxy resin is required to ensure the operational continuity. IEC 60216-2 standard defines the heat life of epoxy resin as three characteristics: bending strength, breakdown…