ABB RELION REX640 Technical Manual page 606

Protection functions
Figure 345: Operation timer characteristic of IFPTOC function when Operation
principle = "EF-current based" and Operating curve type = "Inverse time EN50522".
Setting UTp multiplier is 4.0, Maximum earthing Ris = 10 ohms, EF current Str Val =
0.06*In (6 A), IDMT stage Min Op Tm = 100 ms and IDMT stage Max Op Tm = 5000
ms. Reduction factor = 1.0. Characteristics are according to standard EN50522.
When Operating curve type = "Inverse time IEEE80" is selected, then
• Operate time is inverse time according to standard IEEE80:
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1MRS759142 F
REX640
Technical Manual