ABB Relion 670 Series Applications Manual page 301

1MRK 511 401-UEN Rev. K
Furthermore the other build-in protection elements can be used for other protection and
alarming purposes.
0.8
0.6
0.4
0.2
-0.2
-0.4
-0.6
-0.8
IEC05000535 V2 EN-US
Figure 134: Loss of excitation
12.1.3.7 Undercurrent protection for capacitor bank
Following example explains how an undercurrent protection within CVGAPC function can be
used for the disconnection of shunt capacitor bank (SCB) in case of very low voltages at the
busbar.
This functionality can be achieved by using one CVGAPC function and following shall be done
to ensure proper operation of the function:
1. Connect three-phase terminal currents to CVGAPC function and no need of voltage input,
that is, connect GRP_OFF from FXDSIGN to U3P of CVGAPC.
2. Set
3. Set
4. Set
5. Set
6. Set
7. Set
8. Set
9. Set
Bay control REC670
Application manual
Q [pu]
A
B
0
0.2 0.4 0.6 0.8
-rca
C
ILowSet
D
Operating Region
operation = On , select CurrentInput = MaxPh and set VoltageInput to default value
Operation_UC1 = On
EnBlkLowl_UC1 = On
BlkLowCurr_UC1 = 10.0 %IB
StartCurr_UC1 = 70.0 %IB
tDef_UC1 = 5.00 s
tResetDef_UC1 = 0.0 s
HarmRestr_UC1 = Off
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Operating region
ILowSet
P
1 1.2 1.4
[pu]
Multipurpose protection
I
PS
rca
U
PS
en05000535.vsd
GUID-1AAD3844-6FEE-4050-8260-27E7A30F6352 v1
Section 12
295