Over fluxing protection on Network Transformers

[dfdt]

I invite your response to usefullness of providing over fluxing ( V/F) protection on network power transformers. I am aware that this form of protection on generator stepup transformer is essential.

 

[zub]

i am not sure but agree with you. i think it is not neccessary to protect the network trf.'s against overf luxing. For the networks if it happens there are tons of protections on the generation plants for V/Hz. But maybe the experts can show us the right way.

regards,

zub.

 

[johnspark]

Dear bholaS and zub,
the network I am involved in had a large fire in a critical power station of our network. It resulted in our 275/132kV system breaking up, load being tripped off by underfrequency load shedding, isolated network volts running very very high and some of our new transformers bubbling hydrogen gas. As a consequence of this, the risk managers decided to have overfluxing retrofitted to network trannies. So in answering your question, the network I am involved in does use specific overfluxing settings. As a side benefit, we get voltage in our disturbance recorder in the multifunction tranny relay as well.

Why not help someone today, eg carry groceries at the supermarket for someone...

 

[jbartos]

Suggestion: Visit

http://www.gsp.co.nz/library/gsc_feb2002

with a MS Word document
transformer_fsg_final-1.doc
describing the Transformer Overfluxing on page 19

http://www.cea.nic.in/opt3_best practise.htm

(Over flux protection is considered as part of best protection practices.)
etc. for more info.

 

[Bung]

Do your worst-case loading and voltage profiles justify it? The only reason you would protect against a particular scenario (in this case, over-fluxing) is if analysis of your network shows it to be a significant risk. Just what constitutes a "significant" risk is whole new argument!

So before spending lotsa money, first work do the load flow and voltage calcs, see what taps the transformers are at, and then decide if they are in need of help.


Bung
Life is non-linear...