Table 23: 1 A channels: input with minimum operating down to 40 mA
Operating
voltage
TripPickup
Stabilizing
resistor R
ohms
Operating
current level
1 A
Stabilizing
resistor R
ohms
Operating
current level
1 A
20 V 500 0.040 A -- --
40 V 1000 0.040 A -- --
60 V 1500 0.040 A 600 0.100 A
80 V 2000 0.040 A 800 0.100 A
100 V 2500 0.040 A 1000 0.100 A
150 V 3750 0.040 A 1500 0.100 A
200 V 5000 0.040 A 2000 0.100 A
Table 24: 5 A channels: input with minimum operating down to 100 mA
Operating
voltage
TripPickup
Stabilizing
resistor R1
ohms
Operating
current level
5 A
Stabilizing
resistor R1
ohms
Operating
current level
5 A
Stabilizing
resistor R1
ohms
Operating
current level
5 A
20 V 200 0.100 A 100 0.200 A -- --
40 V 400 0.100 A 200 0.200 A 100 0.400
60 V 600 0.100 A 300 0.200 A 150 0.400 A
80 V 800 0.100 A 400 0.200 A 200 0.400 A
100 V 1000 0.100 A 500 0.200 A 250 0.400 A
150 V 1500 0.100 A 750 0.200 A 375 0.400 A
200 V 2000 0.100 A 1000 0.200 A 500 0.400 A
The current transformer saturation voltage must be at least 2 ˣ TripPickup to have
suf
ficient operating margin. This must be checked after calculation of TripPickup.
When the R value has been selected and the TripPickup value has been set, the
sensitivity of the scheme IP can be calculated. The IED sensitivity is decided by the
total current in the circuit according to equation
19.
( )IP n IR Ires lmag= × + +
å
EQUATION1747 V1 EN-US (Equation 19)
where:
n is the CT ratio
IP primary current at IED pickup,
Table continues on next page
1MRK 502 071-UUS A Section 7
Differential protection
Generator protection REG670 2.2 ANSI and Injection equipment REX060, REX061, REX062 161
Application manual
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