Considering the safety margins mentioned previously, the minimum setting (Is) is:
EQUATION288 V3 EN-US (Equation 36)
The IED setting value IN>> is given in percent of the primary base current value,
IBase. The value for IN>> is given by the formula:
( ) 100
s
IN I IBase 
IECEQUATION17003 V1 EN-US (Equation 37)
Transformer inrush current shall be considered.
The setting of the protection is set as a percentage of the base current (IBase).
Operation: set the protection to Enabled or Disabled.
Pickup: Set operate current in % of IB.
IN>>Max and IN>>Min should only be changed if remote setting of operation current
level, IN>>, is used. The limits are used for decreasing the used range of the IN>>
setting. If IN>> is set outside IN>>Max and IN>>Min, the closest of the limits to
IN>> is used by the function. If IN>>Max is smaller than IN>>Min, the limits are
swapped.
MultPU: The set operate current can be changed by activation of the binary input
MUL
TPU to the set factor MultPU.
8.4 Directional residual overcurrent protection, four steps
EF4PTOC (51N/67N)
IP14509-1 v8
8.4.1 Identification
M14881-1 v6
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Directional residual overcurrent
protection, four steps
EF4PTOC
TEF-REVA V2 EN-US
51N_67N
Section 8 1MRK 511 401-UUS A
Current protection
168 Bay control REC670 2.2 ANSI
Application manual