ABB rec670 - Page 138

Table 17: 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 18: 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
14.
( )IP n IR Ires lmag= × + +
å
EQUATION1747 V1 EN-US (Equation 14)
where:
n is the CT ratio
IP primary current at IED pickup,
Table continues on next page
Section 7 1MRK 511 401-UUS A
Differential protection
132 Bay control REC670 2.2 ANSI
Application manual