ABB REQ650 - Calculating Settings for Step 3

3
3
1
REQ650 (A01)
Z
SC
: Low
Earth fault
Line protection zone 1 reach
IEC10000154-1-en.vsd
IEC10000154 V1 EN
Figure 20: Fault for step 2 setting
Proposed current setting is therefore 1200 A.
1. Set DirMode2 to Reverse.
2. Set IN2> to 120% of IBase (1200 A primary current).
3. Set t2 to 0.4 s.
3.1.7.4 Calculating settings for step 3
The current setting should be chosen in line with normal setting principles in the
system. To detect high resistive faults, a current setting of about 100 A will detect
earth-faults with a fault resistance up to about 800 Ω. Proposed current setting is
therefore 100 A.
1. Set DirMode3 to Non-directional.
2. Set IN3> to 10% of IBase (100 A primary current).
3. Set t3 to 1.5 s.
1MRK 505 291-UEN A Section 3
REQ650 setting examples
57
Application manual