ABB RER620

Section 10 1MAC309294-MB F
General function block features
466 RER620
Technical Manual
(Equation 57)
t[s] t[s] = Trip time in seconds
I measured current
I> set
Pickup value
kset Time multiplier
Table 421: Curve parameters for ANSI and IEC IDMT curves
Curve name A B C
(1) ANSI Extremely Inverse 28.2 0.1217 2.0
(2) ANSI Very Inverse 19.61 0.491 2.0
(3) ANSI Normal Inverse 0.0086 0.0185 0.02
(4) ANSI Moderately Inverse 0.0515 0.1140 0.02
(6) Long Time Extremely Inverse 64.07 0.250 2.0
(7) Long Time Very Inverse 28.55 0.712 2.0
(8) Long Time Inverse 0.086 0.185 0.02
(9) IEC Normal Inverse 0.14 0.0 0.02
(10) IEC Very Inverse 13.5 0.0 1.0
(11) IEC Inverse 0.14 0.0 0.02
(12) IEC Extremely Inverse 80.0 0.0 2.0
(13) IEC Short Time Inverse 0.05 0.0 0.04
(14) IEC Long Time Inverse 120 0.0 1.0
The maximum guaranteed measured current is 50 x In for the current
protection. When the set Pickup value exceeds 1.00 x In, the turn point
where the theoretical IDMT characteristics are leveling out to the definite
time can be calculated with the formula:
(Equation 58)
ts
A
I
I
Bk
c
[]=
>
⎛
⎝
⎜
⎞
⎠
⎟
−
+
⎛
⎝
⎜
⎜
⎜
⎜
⎜
⎞
⎠
⎟
⎟
⎟
⎟
⎟
⋅
1
Turn point
Pickupvalue
=
50×In