1MRS757454 D
9.2.1.2
9.2.1.3
611 series
Technical Manual
User-programmable inverse-time characteristics
The user can define curves by entering parameters into the following standard
formula:
A
t s
B k
[ ]
=
+
⋅
c
I
E
−
I
>
A060641 V3 EN
t[s] Operate time (in seconds)
Curve parameter A
A
set
Curve parameter B
B
set
Curve parameter C
C
set
Curve parameter E
E
set
I
Measured current
Start value
I>
set
Time multiplier
k
set
RI and RD-type inverse-time characteristics
The RI-type simulates the behavior of electromechanical relays. The RD-type is an
earth-fault specific characteristic.
The RI-type is calculated using the formula
k
[ ]
t s
=
I
>
0 339 0 236
.
.
−
×
I
A060642 V2 EN
The RD-type is calculated using the formula
I
t s
[ ]
5 8 1 35 In
.
.
=
−
×
k I
× >
A060643 V2 EN
General function block features
Section 9
(Equation 41)
(Equation 42)
(Equation 43)
461