Distribution Transformers: Essential Components in Power Distribution Systems

Distribution transformers are static electrical devices designed to convert high-voltage electricity from transmission lines to lower, usable voltages for end-users. Typically, these transformers operate within voltage levels of 10–35 kV and capacities up to 6,300 kVA, directly supplying power to residential, commercial, and industrial consumers.​

Key Components:

Core: Made from high-quality cold-rolled grain-oriented silicon steel sheets, often with 45° slanted joints to minimize magnetic losses.​

Windings: Comprising primary and secondary coils, these are insulated and arranged to handle the required voltage levels.​

Tank and Cooling System: The transformer is housed in a tank filled with insulating oil or resin, with radiators or fans to dissipate heat.​

Tap Changer: Allows for voltage adjustment to maintain stable output.​


Cooling Methods:

ONAN (Oil Natural Air Natural): Utilizes natural convection of oil and air for cooling.​

ONAF (Oil Natural Air Forced): Enhances cooling by using fans to force air over the transformer surface.​

OFWF (Oil Forced Water Forced): Employs forced oil circulation combined with water cooling for large-capacity transformers.​


Advantages:

Safety: Eliminates fire hazards associated with oil-immersed transformers.​

Low Maintenance: Reduced need for regular servicing due to the absence of oil.​

Compact Design: Smaller and lighter, saving installation space and reducing costs.​

Noise Reduction: Designed to operate quietly, suitable for noise-sensitive environments.​


Applications:

Distribution transformers are widely used in urban and industrial power distribution networks, as well as in prefabricated substations, due to their reliability and efficiency.​


Conclusion:

Dry-type transformers offer a safe, efficient, and low-maintenance solution for electrical distribution needs. Their design and construction make them suitable for a wide range of applications, particularly where space, safety, and environmental concerns are important.

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