ABB REF615 E - 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:
A060641 V2 EN (Equation 100)
t[s] Operate 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 Start 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 an
earth-fault specific characteristic.
The RI-type is calculated using the formula
t s
k
I
I
[ ]
. .
=
− ×
>












0 339 0 236
A060642 V2 EN (Equation 101)
The RD-type is calculated using the formula
t s
I
k I
[ ] . .= − ×
× >






5 8 1 35 In
A060643 V2 EN (Equation 102)
1YHT530004D05 D Section 11
General function block features
615 series 813
Technical Manual