Calculating Settings For Step 2 - ABB REQ650 Applications Manual

1MRK 505 291-UEN A
3.1.7.3
Application manual
Z : Low
SC
3
Phase-earth fault
IEC10000152 V1 EN
Figure 18: Fault for step 1 setting
Proposed current setting is therefore 1200 A.
1. Set DirMode1 to Forward.
2. Set Characterist1 to IEC Def. Time.
For the time delay characteristic, definite time is used in this network.
3. Set IN1> to 120% of IBase (1200 A primary current).
4. Set t1 to 0.4 s.

Calculating settings for step 2

The protection shall be able to detect all short circuits in the own busbar. A single
phase-to-earth fault, as shown in figure 19, at the busbar and high source impedance
from the remote line end results in the following fault current to the protection:
= Ð - °
3 I 1.3 87 kA
0
EQUATION2349 V1 EN
REQ650 setting examples
REQ650 (A01)
1
3
Line protection zone 1 reach
Section 3
IEC10000152-1-en.vsd
55