ABB Relion 670 Series Applications Manual page 198

Section 11
Multipurpose protection
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
ANSI05000535 V1 EN-US
Figure 77:
11.1.3.7 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
192
Q [pu]
A
B
0.8 1
0.2 0.4 0.6
-rca
C
ILowSet
D
Operating Region
Loss of excitation
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 [pu]
1.2 1.4
1MRK 511 407-UUS Rev. J
I
PS
rca
V
PS
en05000535_ansi.vsd
GUID-1AAD3844-6FEE-4050-8260-27E7A30F6352 v1
Phasor measurement unit RES670
Application manual