Use of sacrificial metal to protect 55 MVA transformer 3

[SA07]

Hi
We have corrosion on our 2 x 55 MVA outdoor transformers. We are located a few km from the sea. We can only maintain the transfo. during 1-2 week during annual shutdown. Has someone used sacrificial metal to protect power transformers?

 

[cranky108]

Other than fuses, I don't know of any. Maybe an active corrosion system.

 

[FacEngrPE]

The closest you van get to cathodic protection on a transformer is galvanized, or zinc rich paint as the primer coat. Using anodes for protection of equipment not immersed in water is not going to be beneficial.
For installed transformers, repair corroded areas with a high performance coating system, prep and apply per the coating systems data sheet. There are really good coating systems for salt spray zones. Get a recommendation from your local coating supplier.

 

[Parchie]

@SA07,
The power plant I was working with in my other life was located right at the seaside. The jetty was just a kilometer from the power plant. The jetty has cathodic protection.
The only barrier from seawater spray to our units was the storage silo for coal and the 100-ft diameter X 40-ft high IFO/ diesel storage tanks (4 tanks). We specified anti-corrosion coating on all our transformers at our switchyard. Maybe, you could arrange for re-coating of transformers next shutdown.

 

[SA07]

Thank you for your feedback. Our local paint company has recommended zinc rich primer

 

[cranky108]

May have nothing to do with your issue, but, we had a problem with an aluminum street light base corroding. Turned out to be it was making contact with a copper neutral.

 

[prc]

An ISO standard ISO12944 series covers various corrosive environmental conditions and recommends a paint system for each category.
Your system will come under CX class (ISO 12944-2), and the paint usually used is two coats of two-pack epoxy primer + two coats of two-component epoxy intermediate coating + two coats of two-component polyurethane coating—Total dry film thickness of 200-280 microns.

 

[SA07]

Thank you PRC