ABB Relion 670 Series Applications Manual page 253

1MRK 511 401-UEN Rev. K
If the failure of the elements or the units results in the unbalance current of at least 1% of
IBase2, the SCUCPTOC function detects the fault.
Figure 117
failure for considered grounded H-bridge capacitor bank.
45
40
35
30
25
20
15
10
5
0
IEC19000592 V1 EN-US
Figure 117: Unbalance current with the number of elements failure in the faulty unit for
Table 39: Parameter and settings values for grounded H-bridge connected capacitor bank
Name
SCBConf
IMin
IUnbalWrn>
tDefWrn
IUnbalAlm>
tDefAlm
IUnbal>
BlockTrip
CurveType
tDefTrip
tMin
tReset
k
tPCrv
tACrv
tBCrv
tCCrv
Bay control REC670
Application manual
shows the calculated unbalance current variation with the number of elements
5.36
2.5
1.25
1 2 3 5
considered grounded H-bridge capacitor bank
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Trip
20.15
15.08
10.74
12.73
8.77
7 10 12
8 9
Number of elements failed
Default value
3 unbalance curr
10% of IBase1
10% of IBase2
5.00
15% of IBase2
5.00
25% IBase2
Trip enabled
Programmable
5.0
0.00
0.02
1.0
2.00
28.2
0.1217
1.0
Unbalance protection
44.52
34.28
26.51
IEC19000592-1-en.vsdx
Section 10
247