HV Voltage Transformer - Protection Secondary against Short-Circuits 2

[mikeangel]

Dear friends,

I'm working in a power substation and i've to calculate the protection device of a high voltage VT secondary against short-circuits. Has you certenley know this protection is to prevent the VT lost if a short-circuit occurred.

Could someone please tell me how this protection dimensioning is made (formulas)? What calculations i have to do? Wich device i will apply (fuses or miniature circuit breakers)? what are the main characteristics of the protection device?

Another question. If i have 3 VT (trifasic system) i have to protect each VT secondary individually or only one device protect them all?

best regards
Miguel

 

[scottf]

Mikeangel-

I wasn't trying to say it isn't an important comment. What I was trying to say was that it's not a matter that typically requires coordination with anything up or down stream.

 

[slavag]

Hi Miguel.
I found some document after long time, simple and helpfull
See attached link

http://search.abb.com/library/Downl...tion=Launch&IncludeExternalPublicLimited=True

What good at this document relationship between IEC and ANSI standards.
And very good source, I strongly recommended it to my team too:
reading all Scottf's posts at this forum. Scottf, is not some kind of reverances, I'm very serious.
Best Regards.
Slava

 

[scottf]

slavaq-

I'm not sure I understand your comments. What does " Scottf, is not some kind of reverances, I'm very serious" mean?

 

[slavag]

Scott.
Sorry for my English, that mean:
I read and strongly recommend to my team read all your posts as gold documents, as rules. 99% of our job are protection and metering systems, and CT,VT are very important parts of those systems. I found at your posts
lot of information, what not so explained in books ( or you need read tens sources), and is very, very important for young EE's.
That what I mean, and nothing other.
If you don't understand my comments, forgot and delete it.
Nothing, not good translation from Russian, it's all.
Best Regards.
Slava

 

[scottf]

slavaq...

I understand now, and thank you.

 

[mikeangel]

Thank you scottf and slavag. Thankx to you i'm working in this subject at this moment. I think i've the necessary information to satisfat my client. I've with both of you.

best regards
Miguel