Figure. 5.2.1 - 61. Scalings display (based on the CT nominal).
Figure. 5.2.1 - 62. Scalings display (based on the protected object's nominal current).
As the images above show, the scaling selection does not affect how primary and secondary currents
are displayed (as actual values). The only effect is that the per-unit system in the relay is scaled either
to the CT nominal or to the object nominal, making the settings input straightforward.
Example of zero sequence CT scaling
Zero sequence CT scaling (ZCT scaling) is done when a zero sequence CT instead of a ring core CT is
part of the measurement connection. In such a case the zero sequence CT should be connected to the
I02 channel which has lower CT scaling ranges (see the image below).
A
AQ
Q-C215
-C215
Instruction manual
Version: 2.07
© Arcteq Relays Ltd
IM00040
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