ABB RELION REX640 Technical Manual page 953

1MRS759142 C
REX640
Technical Manual
GUID-1335EC74-159F-4D76-AF24-5AA155FD4A3C V1 EN
Figure 512: Short circuit current waveform, fault occurs at time 0 seconds
(Current setting limit is multiplied by the square root of 2)
The phase voltage in a three-phase short circuit when a fault occurs at time = 0 s is
shown in Figure 513. The voltage drop caused by a three-phase fault provides more
time for determining the fault by means of an underimpedance protection.
Section 4
Protection functions
947