Table of Contents
Advertisement
It is also seen that terminal X5.1 and X5.2 are related to the CT located in
phase L1, terminal X5.3 and X5.4 are related to the CT located in phase L2
and terminal X5.5 and X5.6 are related to the CT located in phase L3.
9.3.2. Material needed & hypotheses for correct measurements
A two channel scopemeter with one voltage input and one current input is
needed. Adequate sensors are also needed. A power analyser like the Fluke
41B can also be used.
Some minor knowledge of the load is also required. For instance, the method
explained below is based on the fact that the load is inductive and not
regenerative (i.e. the load current lags by less than 90° the phase voltage). If
a capacitor bank is present, it is better to disconnect it before making
measurements in order to ensure an inductive behaviour of the load. It is also
assumed that the load is approximately balanced.
9.3.3. Checking the correct connection of the CTs with a two channel
scopemeter.
The first channel of the scopemeter must be connected to the phase voltage
referenced to the neutral or to the ground if the neutral is not accessible.
The second channel must measure the associated current flowing from the
network to the load as seen by the CT input of the PQF.
9
.
3
.
3
.
1
.
M
e
a
s
u
r
e
m
9
.
3
.
3
.
1
.
M
e
a
s
u
r
e
For the voltage measurement (channel 1), the positive (red) clamp must be
connected to the phase L1 and the negative clamp (black) must be connected
to the neutral (ground).
For the current measurement (channel 2), the clamp should be inserted into
the wire connected on terminal X5.1 and the arrow indicating positive direction
of the current should point towards the PQF. Do not forget to remove the short
on the CT secondary before making the measurement.
L1
K
L2
Supply side
L3
k
Figure 9.2. Connection of the scopemeter for checking CT in phase L1.
e
n
t
o
f
C
T
i
n
p
h
a
s
m
e
n
t
o
f
C
T
i
n
p
h
a
s
L
K
L
K
L
l
k
l
k
l
Positive direction
Ch1
Asea Brown Boveri Jumet S.A.
PQFA Instructions Manual
e
L
1
e
L
1
Load side
L1
L2
L3
X5.6
X5.5
X5.4
PQF
X5.3
X5.2
X5.1
Ch2
53
Advertisement
Table of Contents
Troubleshooting
