Question 1

What's the difference between a distribution transformer and a power transformer?

Accepted Answer

A power transformer typically operates at the substation level — Seatrust's 110kV and 220kV high-voltage units step transmission voltage down to primary distribution voltage for a substation's outgoing feeders. A distribution transformer operates further downstream, stepping that primary distribution voltage down to the secondary/service voltage used by homes and businesses — mounted on a pole for overhead systems or in a pad-mounted enclosure for underground systems.

Question 2

What voltage is used for a distribution substation?

Accepted Answer

It varies by utility and region, but substation step-down transformers commonly take transmission voltage — Seatrust offers 110kV and 220kV class units — down to a primary distribution voltage that feeds the outgoing feeders. That primary voltage (commonly 25kV or 34.5kV in Seatrust's pole-mounted line) is then stepped down again to the secondary voltage delivered to customers.

Question 3

How long do utility transformers last, and what maintenance do they need?

Accepted Answer

With proper maintenance, Seatrust's high-voltage substation transformers carry a design life of 30–35 years (110kV class) to 30–40 years (220kV class); regular oil analysis and dissolved-gas condition monitoring help predict and prevent failures and can extend service life further. Pole- and pad-mounted distribution units are built to the same durability standard for decades of outdoor service, with actual lifespan depending on loading history, ambient conditions, and maintenance practices.

Question 4

ANSI/IEEE or IEC standards — which applies to my utility project?

Accepted Answer

It depends on your region and your utility's specification. Seatrust's pole-mounted and pad-mounted distribution transformers are built to ANSI/IEEE C57.12 series with UL/CSA listing, matching North American utility practice. Our 110kV and 220kV high-voltage substation transformers are built and factory-tested to IEC 60076 and GB/T 1094 by default, with ANSI/IEEE configurations available on request for projects that require it.

Utility & Substation Transformers | Seatrust Manufacturer