There are increasing environmental concerns such that governments are pressured to cooperate with international concurrences. One of the most harmful contaminants is mineral oil when it infiltrates the soil. Although it is a good material in the act of insulating in distribution/power transformers, it presents some environmental hazards and safety disadvantages. For this reason, gas-insulated transformers are considered particularly for hazardous locations. An oil-insulated distribution transformer of 50 kVA, 34.5/0.4 kV, and 50 Hz is investigated and converted to SF6 gas-insulated transformer in this study. The suggested distribution transformer model with SF6 insulated has many benefits, such as being explosion-proof and light, with a compact design. Therefore, the new design provides a safer transformation for security risk environments such as nuclear power plants, mines, and submarines. The prototype is more compact and proposes lighter designs between 25{\%} and 55{\%} as compared to conventional oil-insulated transformers. COMSOL is used for modeling and breakdown optimization studies.