Experimental Investigation of Vapour Phase Drying System

Electrical equipment such as power transformer is required to withstand high voltages during the process of power transfer from primary to secondary. So it is always required to have adequate insulation. Types of insulation material used in transformer are insulation oil, insulation paper (Craft paper), pressboard, wood and insulation tape. A major factor that affects performance and life of transformer is, “moisture in the transformer”. The term, moisture in the transformer, either refers to the water absorbed by the paper in the transformer, or the water that gets dissolved in the oil of the transformer. In the transformer industry the process of heat extraction is done regularly as part of the production process Drying of transformers must be done because such moisture is injurious to the health of the transformers. Moisture inside transformer reduces the electric strength, resistivity and accelerates deterioration of solid insulation. By removing moisture from transformer insulation, one can maintain its insulation properties. Conventional method used for removing such moisture content from transformer is Simple Vacuum Drying (SVD) Method. Over the period the process has not remained efficient in terms of energy and efficiency. Use of vacuum has improved the process largely but a lot needs to be done on the thermal engineering aspects of the moisture removal process. So advanced and more efficient method used for drying for transformer is Vapour Phase Drying (VPD) Method. Experimental analysis for both methods is done and results with conclusion are discussed in this research paper. From results it observed that increase in drying percentage by use of VPD Method is around 70% as compared to SVD Method.