Pad-mount versus "substation" class transformers

[Kayaker11]

Under what circumstances would I use a "substation" class transformer instead of a pad-mount transformer with all of the key electrical specifications (kVA, primary kV, secondary kV, oil filled, cable connections on primary and secondary) being equal.

Pad-mount are cheaper yet every industrial installation I've been in uses the "gray" (substation type) transformers and the "green" (pad-mount) ones.

 

[VTer]

Three key consideration apply when determining whether a substation style transformer or pad-mounted transformer should be specified: location of transformer, location of incoming and outgoing cables, and loading.

Substation style transformers may be economical choice when:
1. public access to the transformer is not a concern
2. incoming cables are overhead, or transformer is close-coupled to separate switchgear
3. additional flexibility to handle overload conditions is required.

In addition, substation style transformers allow you to view the gauges, purge gas, and take oil samples without having to open the transformer cable termination compartments.

Pad-mounts are typically used where tamper-proof enclosures are required due to public access. All the gauges and accessories are located inside the cable termination compartments. In addition they tend to be smaller than substation style and take up less space. They also tend to be more aesthetically pleasing.

"Throughout space there is energy. Is this energy static or kinetic! If static our hopes are in vain; if kinetic — and this we know it is, for certain — then it is a mere question of time when men will succeed in attaching their machinery to the very wheelwork of nature". – Nikola Tesla

 

[Beardude]

Iis been a long while back, but my experience at the Navy yards in San Diego, CA was that the higher efficiency, higher reliability, overall "robustness" and available options (fan oil cooling, etc) of the industrial transformer made it worth the extra $'s to install in the industrial waterfront areas. We used the pad-mounts at naval housing areas since down times for replacements/repairs were not considered as critical,the inland enviornment was not as harsh and the load profile was more confined and predictible. The pad-mounts are much less conspicuous and can be locked to deter unauthorized entry instead of being behind a fence.