ABB Relion 670 Series Applications Manual page 248

Section 10
Unbalance protection
100
90
80
70
60
50
40
30
20
10
0
IEC19000589 V1 EN-US
Figure 114: Unbalance current with number of elements and units failure for considered
Table 36: Parameter and settings values for ungrounded capacitor bank
Name
SCBConf
IMin
IUnbalWrn>
tDefWrn
IUnbalAlm>
tDefAlm
IUnbal>
BlockTrip
CurveType
tDefTrip
tMin
tReset
k
tPCrv
tACrv
tBCrv
tCCrv
Example 2
Consider a 26.2 kV and 107 MVAr grounded internal fused H-bridge connected filter that is
protected by the current unbalance protection function.
242
92.31
Trip
39.78
18.49
7.16
0
0_1 0_2 0_3 0_4 0_5
ungrounded capacitor bank
In Figure 114, on the X-axis the number of units and elements failure is
represented by units_elements.
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52.19
16.56
4.78
1_1 1_3 2_0
Number of units and elements failure
Default value
1 unbalance curr
10% of IBase1
3% of IBase2
5.00
5% of IBase2
5.00
9% of IBase2
Trip enabled
Programmable
5.00
0.00
0.02
1.00
2.00
28.2
0.1217
1.0
1MRK 511 401-UEN Rev. K
59.05
36.41
4.78
2_2 2_4 2_5
IEC19000589-1-en.vsdx
Bay control REC670
Application manual