Treatment of insulation in EHV-transformers and reactors

Over the past decade, there has been a rapid increase in both the power and service voltages of transformers and reactors. The use of greatly reduced insulation levels has become wide-spread. This trend gave rise to more demanding requirements for transformer and reactor insulation. Drying and impregnation procedures both in the factory and on site, determine the final quality of the insulation. Since EHV equipment is now in wide use, the authors felt the necessity to stress the fact that careful attention to quality and processing leads to definite improvement in insulation.