ABB RELION REX640 Technical Manual page 1700

Section 11
General function block features
1694
k A
t s ⋅
 
=
   
U U
− >

B C
⋅ −

U
>

GUID-E6AA2249-97B9-410A-A2CC-BE990F393A58 V1 EN
t [s] Operate time in seconds
U Measured voltage
Start value
U> Set value of
Time multiplier
k Set value of
Table 1476: Curve coefficients for the standard overvoltage IDMT curves
Curve name A
(17) Inverse Curve A 1
(18) Inverse Curve B 480
(19) Inverse Curve C 480
D
+
E



B C
1 0
32 0.5
32 0.5
1MRS759142 C
(Equation 361)
D E
0 1
0.035 2
0.035 3
REX640
Technical Manual