Pad-Mount V.S. Power Transformers

[TCTC1]

Hi All, what are the major differences between padmount and power transformers? I understand power transformers have higher ratings and hence are constructed differently . Why pressure relief valve devices are not used in padmount transformers and protection is achieved by internal fuses ?
Can PRDs be specified for padmount transformers so the use of internal fuses can be eliminated?
Thanks

 

[cranky108]

Larger pad mount transformers may not have internal fuses.
May be that pad mount transformers, in many cases are considered expendable because of there smaller size.

 

[crshears]

Agreed, cranky, as well as the fact that where used in radial only systems and not networks, only a limited number of customers will be interrupted, and as long as a sufficient local inventory of pad-mounts and human resources and work equipment is maintained the duration of the interruption will generally be limited as well.

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]

 

[RRaghunath]

PRD is to prevent tank rupture in case of internal fault.
When the transformer is fused on primary side, the speed of fuse operation removes any possibility of tank rupture. So, there is no need to provide PRD.
Internal fuses are better for quick isolation of faulty transformer and are thus preferred.
In case of power transformers, the current rating of primary windings is high and finding an appropriate size fuse poses a challenge.

R Raghunath