34.5 kV/ 13.8 kV transformer nameplate? 1

[ralleuc23]

Please help me find the nameplate ratings of a 34.5kV/13.8kV tranformer or at least its percent impedance for our substation design. tnx

 

[davidbeach]

Some place on the nameplate of the transformer is where you will find that information.

 

[ralleuc23]

I'm still looking for an available transformer with that rating, but I only need its nameplate ratings for my computations on overcurrent protection.tnx

 

[alehman]

You will have to find the transformer first and get the information from its nameplate.

 

[Zogzog]

I have 2 oil filled 34.5/13.8kV units. 12/20/22.4 MVA
Nameplate %Z=6.3

 

[Kiribanda]

ralleuc23,

It looks like an ANSI transformer. Then ANSI C57.12.10 is the reference for manufacturing.

Per C57.12.10 the BIL for 34.5 kV is 200 kV. That means based on 200 kV BIL, then

Z=7.5% with a LTC

Z=7.0% without LTC.

This is the guranteed impedance. The nameplate impedance cannot change very much from this value unless it is a custom built one to satisfy any high impedance requirements. Anyhow, in your SC calculations you have to use (-)7.5% tolerence for the impedance per ANSI.

 

[Marmite]

I need a piece of string to wrap my wife's Christmas present, but I don't know what length as I haven't bought the present yet. Any ideas?
Please note I'm in the UK so I need IEC string in cm, not ANSI string in inches.


Regards
Marmite