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Plotting Overcurrent TCC on High/Low Side of Xfmr

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111R

Electrical
Joined
May 4, 2012
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114
Location
US
When plotting multiple time-current curves showing coordination between various protection devices, what is typically done to show the coordination between the high and low side of the transformer? If the X-axis shows the multiple of pick-up or current, the low voltage side will be graphed as picking up much quicker than the high side due to the transformer turns ratio. Do I need to reflect the primary fault current to the secondary so the curves reflect the correct coordination?

Thank you
 
Yes, you transpose curves using the transformer turns ratio.
 
Any good coordination program will do that for you.
 
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