High moisture (water) content in oil used in transformer will:

e correct answer is option 3):(Reduce dielectric strength of oil and lead to flashover)

Concept:

• High moisture (water) content in oil used in the transformer will reduce the dielectric strength of oil and lead to flashover
• Moisture is one of the Transformer's enemies that affects the life cycle of the transformer and leads the material of the transformer to deteriorate with time very quickly.
• The presence of moisture reduces the dielectric strength of the insulating oil because the moisture will break down the molecular chains of the insulating oil, making the oil more conductive
• The better method to reduce the moisture is spraying hot oil into the transformer under a vacuum. The combination of the heat from the hot oil and the vacuum will cause the moisture in the insulation to ''flash off'' and dry the transform