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| Author: | RJohnson [ Wed Jul 28, 2010 8:08 pm ] |
| Post subject: | 3-Phase Transformer Model |
If I have a 300 kVA utility transformer bank made up of 3 single phase 100 kVA transformers each with an impedance of 1.9%, is the equivalent impedance of the 300 kVA transformer simply 3 x 1.9, or is it the square root of 3 times 1.9? |
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| Author: | jghrist [ Thu Jul 29, 2010 9:51 am ] |
| Post subject: | |
RJohnson wrote: If I have a 300 kVA utility transformer bank made up of 3 single phase 100 kVA transformers each with an impedance of 1.9%, is the equivalent impedance of the 300 kVA transformer simply 3 x 1.9, or is it the square root of 3 times 1.9?
1.9%. The impedance is a per phase value. |
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| Author: | stevenal [ Fri Jul 30, 2010 8:04 am ] |
| Post subject: | |
How are the transformers connected? Wye or delta? |
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| Author: | RJohnson [ Sat Jul 31, 2010 10:42 am ] |
| Post subject: | |
Connected delta-wye. |
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| Author: | stevenal [ Mon Aug 02, 2010 8:52 am ] |
| Post subject: | |
Edited: Sorry I misremembered. Connections make no difference. 1.9% using 100 kVA and line to neutral voltage to get ohms secondary equates to 1.9% using 300 kVA and line to line voltage. |
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| Author: | J.T [ Tue Aug 03, 2010 6:38 am ] |
| Post subject: | |
RJohnson wrote: Connected delta-wye.
No matter how the 3 single phase transformer connected, the impedance should be the same as the single phase tested value |
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| Author: | LarryJo [ Tue Jun 07, 2011 12:32 pm ] |
| Post subject: | |
What is one of the transformers has a different nameplate impedance? |
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| Author: | stevenal [ Fri Jun 10, 2011 8:35 am ] |
| Post subject: | |
Then there is no equivalent three phase impedance. |
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| Author: | J.T [ Sun Jun 12, 2011 6:08 pm ] |
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Can 3 single phase transformers with different IZ% be connected to a transformer bank? |
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| Author: | glen1971 [ Sun Jun 12, 2011 10:33 pm ] |
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J.T wrote: Can 3 single phase transformers with different IZ% be connected to a transformer bank?
It is my understanding that they can be, but they still have to be within a very tight range.. |
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