Transformers in Distribution System

Transformers in distribution systems include substation and distribution transformers.

Substation transformers use mineral oil for insulation and cooling, with some featuring inert gas, like nitrogen, to prevent oxidation.

Many substation transformers are equipped with load tap changers, which automatically regulate voltage based on load variations.

Outdoor transformers might have a conservator to manage oil expansion and contraction.

Substation transformers are rated in megavolt-amperes (MVA), reflecting their continuous load capacity.

Distribution transformers, which step down voltage from primary to secondary systems, can be installed outdoors, indoors, or underground.

Distribution transformers are rated in kilovolt-amperes (kVA) and include pole-mounted units, which are liquid-filled and either single or three-phase.

Padmount transformers can be liquid-filled or dry-type and either single or three-phase.

Network transformers are large and liquid-filled three-phase units designed for underground vaults.

Oil-filled distribution transformers can handle loads above their kVA ratings for short periods without significantly affecting lifespan due to their long thermal time constant.