12470 Buck/Boost Arrangement

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Otis2011

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Has anyone ever seen this? Strange to see distribution line connected to transformer secondaries. Anyone have an idea why it is being done? 12KV to 12.47 KV..... Upstate New York, NYSEG.

Thanks
 

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Otis2011 said:
Has anyone ever seen this? Strange to see distribution line connected to transformer secondaries. Anyone have an idea why it is being done? 12KV to 12.47 KV..... Upstate New York, NYSEG.

Thanks
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There is no way the secondary is 12kv. The secondary bushing are typical for 5kv and under. Id say this is a "jumbo" step down bank that takes 12kv and steps it down to either 4160Y/2400 or 8300Y/4800 to feed an older hold over segment or a customer that runs at that voltage.


Most older distribution systems ran in the 5kv and under range before they started to be upgraded to higher voltages such as 12 and 25kv over the years. Older reaming segments that were still in good shape were just fed from step down banks like this from the newer upgraded segment. This setup is actually very, very common for utilities that have a lot of obsolete hold over lines, or are running different voltages with a need to tie them together.


FWIW, those appear to be a 2 winding isolation transformers connected in Y grounded-Y grounded. When voltage transformation isn't as great such as 13.8kv to 12.47 auto transformers are generally chosen being cheaper in those cases.
 
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Thanks mbrooke. I missed the secondary 5KV bushings and the fact they are two wire single voltage. I also see now the strain insulators on the lower voltage side have 1/2 the number of bells (creep distance). I believe you are correct....2400/4160Y.

I learned something. Thanks!!
 
Otis2011 said:
Thanks mbrooke. I missed the secondary 5KV bushings and the fact they are two wire single voltage. I also see now the strain insulators on the lower voltage side have 1/2 the number of bells (creep distance). I believe you are correct....2400/4160Y.

I learned something. Thanks!!
Click to expand...


Welcome! Glad I could be of help:)
 
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