Table of Contents
Advertisement
5.5. Step 5: Automatic and manual CT detection procedure
Three CTs of 15VA, class 1.0 X/5A rating is needed. This is valid for a cable length of 35m, 2.5 sqmm only. For more
details, refer to the detailed PQF Manual for CT selection guide.
WARNING: Before programming or detecting the CTs, make sure that all shorting links in the CT path have
been removed (i.e. on the CTs, on the filter CT terminal X21 ...).
CT shorting links are provided with the filter for servicing purposes, but they are not installed by default on the X21
terminal.
The CT settings can be detected with the automatic CT detection feature or in a conventional way. The automatic CT
detection approach allows compensating for physical connection errors in software. For multi-unit filters, the automatic
CT detection feature will automatically try and detect the CT-connections for the different units.
5.5.1.
PQF connection diagram
Figure 22
shows the standard connection diagram for the PQF. It must be noted that:
– L1, L2 and L3 rotation must be clockwise.
– The CTs must be on the supply (line) side of the PQF.
– The CT monitoring a phase must be connected to the filter CT terminal dedicated to the same phase.
– One secondary terminal of the CT must be earthed.
It is also seen that terminal X21.1 and X21.2 are related to the CT located in phase L1, terminal X21.4 and X21.5 are
related to the CT located in phase L2 and terminal X21.7 and X21.8 are related to the CT located in phase L3.
For multi-unit filters, the following diagram is applicable:
STATUS
Approved
L1
K
L2
Supply side
L3
k
l
N
To X21.1/X21.2
K = P1, L = P2, k = S1, l = S2
Figure 22: Basic CT connection diagram
SECURITY LEVEL
Public
L
K
L
K
L
k
l
k
l
To X21.7/X21.8
To X21.4/X21.5
DOCUMENT ID
9AKK107045A4703
Q UICK STA RT-UP G UI DE
Load side
L1
L2
L3
N
X21.1
X21.2
X21.3
X21.4
PQF
X21.5
X21.6
X21.7
X21.8
X21.9
REV.
LANG.
D
en
© 2022 Hitachi Energy. All rights reserved.
PAGE
28/41
Advertisement
Table of Contents
