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#129523 - 04/12/05 06:54 AM increasing primary voltage
rmiell Offline
Member

Registered: 11/09/00
Posts: 261
Loc: La Junta, Co. USA
What effect, to the secondary voltage, will increasing the primary voltage produce? Our utility is looking to increase our distribution voltage from 13.8kV to 14.4kV (recommended by an electrical study). As long as the transformers are rated for this voltage, will the secondary voltage be increased enough to warrent looking into? We should be able to lower the taps if necessary, but will it be necessary?

Just wanted to get some basic info, as this will be engineered.

Thanks

Rick Miell

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#129524 - 04/12/05 10:48 AM Re: increasing primary voltage
BPiersel Offline
Member

Registered: 01/06/05
Posts: 18
Loc: Minnesota
The secondary voltage is proportional to the primary voltage. So, for example, if the current output is 480 V, the ratio is 13800/480=28.75. At 14.4kV, the output will be 14400/28.75=500.9 V.

A simple equation you can use:

New output = (Current output/Current Primary) * New Primary

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#129525 - 04/13/05 05:20 AM Re: increasing primary voltage
pauluk Offline
Member

Registered: 08/11/01
Posts: 7693
Loc: Norfolk, England
It's a 4.3% increase in voltage. I would think that you need to allow for possibility of the secondary exceeding the upper tolerance limit under low-load conditions and adjust the taps accordingly.

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