ABB Relion 670 Series Applications Manual page 264

Section 10
Unbalance protection
Example 2
Consider a 22.9 kV, 5 MVAr externally fused ungrounded single WYE connected filter that is
protected by the phase voltage differential protection function.
Table 43: Parameters of the ungrounded capacitor bank
Parameters of SCB
Connection type of SCB
Rated filter voltage
Filter rated MVAr
System frequency
Number of capacitor units per phase
Number of capacitor elements in a
unit
Number of parallel group of elements
in a unit (P
Number of series groups of elements
in a unit (S
Number of parallel units in a group
(P )
u
Number of unit groups in series in a
phase (S
Capacitive element value (C
VT ratio
Figure 124
5 MVAR
22.9 kV
IEC19000702 V1 EN-US
Figure 124: Single line diagram for the ungrounded single WYE capacitor bank
The configuration of capacitor unit (Cu) and capacitor element (Ce) in the filter are shown in
Figure 125.
258
)
e
)
e
)
u
)
e
shows the single-line diagram for the ungrounded single WYE capacitor bank.
22.9 kV Bus
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Value
Externally fused ungrounded single WYE
22.9 kV
5 MVAr
60 Hz
18×2=36
4×8=32
8
4
18
2
1.405 µF
110 kV/100 V
Preprocessing Function Block
SMAI1
GRP1Lx G1AI3P
SMAI2
GRP2Lx G2AI3P
SMAI3
GRPIN G3AI3P
Lx = Phase L1, L2 and L3
1MRK 511 401-UEN Rev. K
SCPDPTOV
U3P
U3PTAP
U3NEUT
IED
IEC19000702-1-en.vsdx
Bay control REC670
Application manual