ABB Relion REQ650, Applications Manual

Page: 57 / 340

3
3
1
REQ650 (A01)
Z
SC
: Low
Three phase short circuit
Line protection zone 1 reach
IEC10000150-1-en.vsd
IEC10000150 V1 EN
Figure 16: Fault for step 2 setting
Recommended current setting is therefore 2000 A.
1. Set DirMode2 to Reverse .
2. Set Characterist1 is set to IEC Def. Time .
For the time delay characteristic, definite time is used in this network.
3. Set I2> to 200% of IBase (2000 A primary current).
4. Set t2 to 0.4 s .
3.1.5.4 Calculating settings for step 3
The phase overcurrent protection shall never trip for load current in extreme high load
situations. The maximum load current through the coupler bay is 750 A (the same as
the CT-rated current), corresponding to about 190 MVA. The resetting ratio is 0.95.
The minimum setting can be calculated:
1
3 750 790
0.95
I A
> ³ × × =
EQUATION2344 V1 EN
1. Set DirMode3 to Non-directional .
2. Set Characterist1 is set to IEC Def. Time .
1MRK 505 291-UEN A
Section 3
REQ650 setting examples
51
Application manual