ABB 615 Series - User-Programmable Inverse-Time Characteristics

11.2.1.2 User-programmable inverse-time characteristics
The user can define curves by entering parameters into the following standard formula:
t s
A
I
I
E
B k
c
[ ]
=
>






−
+












⋅
A060641 V3 EN (Equation 174)
t[s] Trip time (in seconds)
A set Curve parameter A
B set Curve parameter B
C set Curve parameter C
E set Curve parameter E
I Measured current
I> set Pickup value
k set Time multiplier
11.2.1.3 RI and RD-type inverse-time characteristics
The RI-type simulates the behavior of electromechanical relays. The RD-type is a ground-
fault specific characteristic.
The RI-type is calculated using the formula
t s
k
I
I
[ ]
. .
=
− ×
>












0 339 0 236
A060642 V2 EN (Equation 175)
The RD-type is calculated using the formula
t s
I
k I
[ ] . .= − ×
× >






5 8 1 35 In
A060643 V2 EN (Equation 176)
1MAC059074-MB A Section 11
General function block features
615 series ANSI 1097
Technical Manual