ABB PQFA, Instruction Manual

Page: 42 / 98

PQFA Instructions Manual
Asea Brown Boveri Jumet S.A.
42
Condition 3: the tie is closed but only one transformer feeds the loads
(degraded mode).
If only T1 feeds the loads with the tie closed, PQF1 sees (I1-I0) and PQF2
sees I0 (I2 is zero). If only T2 feeds the load, I1 will be zero.
The above described connection must be done for each phase. The CT ratio
to be programmed in the filter is: 2X/5.
6
6
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4
4
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2
2
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5
5
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C
C
a
a
s
s
e
e
5
5
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:
b
b
a
a
c
c
k
k
u
u
p
p
g
g
e
e
n
n
e
e
r
r
a
a
t
t
o
o
r
r
Many installations are fitted with back up generators to ensure the proper
operation of the installation in case of mains power outage.
A typical configuration is given here below.
Figure 6.9. Back-up generator: typical single-line diagram
The CT connection must be such that the active filter works whatever the type
of supply: generators or transformer-MV network.
For each phase, one CT is installed in the transformer feeding and one in the
generator. Those two CT’s must be identical (X / 5 A) and are connected to a
summation CT rated 5+5 / 5 A.
The CT ratio to be programmed in the filter is: 2X/5.
G
LOAD
PQF