ABB ESI-S, Installation, Operation And Maintanance Manual

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58 Electrical design and installation  Manual Energy Storage Inverter ESI-S
• The k (S1) terminal of the line 2 CT (L2, Yellow, V) must be connected to
terminal X21-4 of the inverter
• The l (S2) terminal of the line 2 CT (L2, Yellow, V) must be connected to
terminal X21-5 of the inverter
• The k (S1) terminal of the line 3 CT (L3, Blue, W) must be connected to
terminal X21-7 of the inverter
• The l (S2) terminal of the line 3 CT (L3, Blue, W) must be connected to
terminal X21-8 of the inverter
− The CT connection terminal X21 is located in the middle of the top plate of the
inverter (Cf.
Figure 43 ).
L1
L2
L3
Load side
Supply side
K L
k l
K L
k l
K L
k l
ESI
X21.1
X21.2
X21.3
X21.4
X21.5
X21.6
X21.7
X21.8
X21.9
L1 L2 L3
To X21.1/X21.2
To X21.4/X21.5
To X21.7/X21.8
K = P1, L = P2, k = S1, l = S2
N
N
Figure 42: Basic CT connection example for a single unit.
Figure 43: Location of the CT connection terminal X21 in the ESI-S
The terminal block X21 can handle control cable wiring with sections from 2.5 mm² to 10
mm².
In addition to the 6-wire CT cabling approach shown in Figure 42 above, a 4-wire
approach may also be used. This approach is illustrated in Figure 44 . In this case the CT
secondary terminal to which the guard circuit is connected is interconnected between
the CTs and also on the inverter terminal X21. One common cable is used for this
terminal. Note that this cable must be able to withstand three times the secondary
current rating of the CTs.