ABB RELION 620 Series Technical Manual page 625

1MRS757644 F
620 series
Technical Manual
Inv. curve A
The inverse time equation for curve type A is:
k
t s [ ]
=
2
I
 
2
 
I
 r 
GUID-D8A4A304-6C63-4BA4-BAEA-E7891504557A V1 EN
t[s] Operate time in seconds
Machine time Mult
k Set
I Negative-sequence current
2
Rated current
I Set
r
Section 4
Protection functions
(Equation 129)
619